Mononeuropathy and Plexopathy

Overview

Definitions

Neuropathy Neuropathy Leprosy is a term used to describe nerve pathology presenting with sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology, motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology, or autonomic impairment secondary to dysfunction of the affected nerve.

• Mononeuropathy describes a condition in which a single nerve is affected.
• Peripheral mononeuropathy is damage to a peripheral nerve (outside the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy).
• Polyneuropathies affect multiple nerves, and diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus is the most common cause. 
• Distinct from both mononeuropathy and polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy, mononeuropathy multiplex Mononeuropathy Multiplex Polyneuropathy is a condition:
  • Involving ≥ 2 single nerves (often in different parts of the body)
  • Associated with chronic disease (e.g., leprosy Leprosy Leprosy, also known as Hansen’s disease, is a chronic bacterial infection caused by Mycobacterium leprae complex bacteria. Symptoms primarily affect the skin and peripheral nerves, resulting in cutaneous manifestations (e.g., hypopigmented macules) and neurologic manifestations (e.g., loss of sensation). Leprosy) due to multiple nerves being affected at the same time
• Plexopathy is a disorder affecting the network of nerves or a plexus, of which the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region and the lumbosacral plexus are commonly affected.

Etiology

There are numerous etiologies for mononeuropathy, which can be acute or chronic. 

• Acute etiologies are most often due to trauma, and chronic etiologies are frequently due to a trapped nerve.
• Causes include:
  • Lesions to individual peripheral nerves Peripheral Nerves The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium. Nervous System: Histology (e.g., ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage/ infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage, tumors)
  • Hereditary
  • Trauma (e.g., nerve transection Nerve Transection Brachial Plexus Injuries or neurotmesis, compression Compression Blunt Chest Trauma)
  • Inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation (e.g., infectious process such as herpes zoster Herpes Zoster Varicella-zoster virus (VZV) is a linear, double-stranded DNA virus in the Herpesviridae family. Shingles (also known as herpes zoster) is more common in adults and occurs due to the reactivation of VZV. Varicella-Zoster Virus/Chickenpox)
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma injury
  • Toxins
  • Nutritional deficiency
  • Medications
  • Diseases or conditions such as:
    • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus
    • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care 
    • Guillain-Barré syndrome Guillain-Barré syndrome Guillain-Barré syndrome (GBS), once thought to be a single disease process, is a family of immune-mediated polyneuropathies that occur after infections (e.g., with Campylobacter jejuni). Guillain-Barré Syndrome
    • Inflammatory diseases
    • Alcoholism Alcoholism A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. Wernicke Encephalopathy and Korsakoff Syndrome

Epidemiology

• Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency of neuropathy Neuropathy Leprosy in older populations: approximately 8%
• Carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome: most common mononeuropathy
• Charcot-Marie-Tooth disease Charcot-Marie-Tooth Disease A hereditary motor and sensory neuropathy transmitted most often as an autosomal dominant trait and characterized by progressive distal wasting and loss of reflexes in the muscles of the legs (and occasionally involving the arms). Onset is usually in the second to fourth decade of life. This condition has been divided into two subtypes, hereditary motor and sensory neuropathy (hmsn) types I and II. Hmsn I is associated with abnormal nerve conduction velocities and nerve hypertrophy, features not seen in hmsn II. Polyneuropathy: most common genetic sensorimotor polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy

Upper-Limb Neuropathies

Neuropathies Neuropathies Chédiak-Higashi Syndrome in the upper extremities can affect the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region (causing brachial plexopathy) or the individual nerves that branch off to supply different areas.

Brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region

• A network of nerves serving as a conduit for signals between the spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy and the shoulder, arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy, and hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
• Formed from the anterior rami of the spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy segments C5–T1, which are the roots of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region
• Causes of brachial plexopathy:
  • Acute: trauma (e.g., fall, shoulder injury) or obstetric injury (e.g., stretching of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region occurs in shoulder dystocia Shoulder Dystocia Obstetric complication during obstetric delivery in which exit of the fetus is delayed due to physical obstruction involving fetal shoulder(s). Complications during Childbirth)
  • Chronic: inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation or tumor Tumor Inflammation
• Presentation:
  • In general, the condition causes arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy paralysis or loss of sensation in the C5 and C6 dermatomes Dermatomes Spinal Cord: Anatomy.
  • Erb palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies:
    • Commonly, C5 and C6 (occasionally C7) affected
    • Forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy extended and pronated, arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy rotated medially, wrist flexed (waiter’s tip posture)
  • Klumpke’s palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies:
    • Affects C8/T1 (more rare than Erb palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies)
    • Caused by hyperabduction of the arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy
    • Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy paralysis with flexed wrist and interphalangeal joints Interphalangeal joints Hand: Anatomy (claw hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy)
    • Severe injury → flail arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy and Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome
  • Brachial plexitis:
    • Other names: neuralgic amyotrophy, Parsonage-Turner syndrome
    • Increasing deep burning pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the deltoid area
    • Followed by muscular weakness, often within 2 weeks of the pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Weakness commonly affects serratus anterior, deltoid, biceps Biceps Arm: Anatomy, or triceps.
    • Recovery from 2 months to 1 year

Median neuropathy Neuropathy Leprosy

• Median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy: formed from the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region, with contributions from C5–T1, supplying:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology:
    • Flexor muscles of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy and hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
    • Muscles for flexion Flexion Examination of the Upper Limbs, abduction Abduction Examination of the Upper Limbs, opposition, and extension Extension Examination of the Upper Limbs of the thumb
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology:
    • Dorsal aspect of the distal 1st 2 digits of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
    • Volar aspect of the thumb, the index and middle fingers, ½ of the ring finger, and the palm
    • Medial forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
• Carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome (distal nerve injured at the wrist):
  • Paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome in the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy territory, 1st 3 digits and the radial ½ of the 4th digit
  • Dropping objects from hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy (thumb, index, and/or middle fingers)
  • Atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation of thenar eminence
  • Chronic injury: inability to abduct and oppose thumb, termed the ape-hand deformity Deformity Examination of the Upper Limbs
• Pronator teres Pronator teres Forearm: Anatomy or pronator syndrome ( forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy injured):
  • Seen in cyclists
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy 
  • Loss of sensation in the lateral palm and thenar eminence
  • Elbow extension Extension Examination of the Upper Limbs and repeated pronation Pronation Applies to movements of the forearm in turning the palm backward or downward. When referring to the foot, a combination of eversion and abduction movements in the tarsal and metatarsal joints (turning the foot up and in toward the midline of the body). Examination of the Upper Limbs produce symptoms.
• Anterior interosseous neuropathy Neuropathy Leprosy ( forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy injured):
  • Muscle weakness ( flexor pollicis longus Flexor pollicis longus Forearm: Anatomy, deep flexors of 2nd and 3rd fingers, and pronator quadratus Pronator quadratus Forearm: Anatomy)
  • ↓ Thumb and index finger pincer movement (cannot make an O sign)
  • Forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Sensation not affected
• Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy of benediction or preacher’s hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy (wrist or elbow injury):
  • Extended 2nd and 3rd fingers when asked to make a fist 
  • Cannot flex 2nd and 3rd fingers

Ulnar neuropathy Neuropathy Leprosy

• Ulnar nerve Ulnar Nerve A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm. Axilla and Brachial Plexus: Anatomy:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology:
    • Flexor carpi ulnaris Flexor carpi ulnaris Forearm: Anatomy and medial ½ of the flexor digitorum profundus Flexor digitorum profundus Forearm: Anatomy (FDP) in the anterior or flexor compartment
    • 3rd and 4th lumbricals Lumbricals Hand: Anatomy, dorsal interossei Dorsal interossei Hand: Anatomy, palmar interossei Palmar interossei Hand: Anatomy, adductor pollicis Adductor pollicis Hand: Anatomy, flexor pollicis brevis Flexor pollicis brevis Hand: Anatomy and palmaris brevis Palmaris brevis Hand: Anatomy in the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology:
    • Medial forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
    • Medial wrist
    • Medial 1½ digits
• Presentation:
  • Ulnar nerve injury Ulnar Nerve Injury Peripheral Nerve Injuries in the Upper Extremity at the elbow (distal nerve injury Nerve Injury Surgical Complications):
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology > motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology symptoms, with sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology changes often from sustained flexed elbow
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology changes in volar aspect (4th and 5th digits) and ulnar aspect of the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy
    • Tingling Tingling Posterior Cord Syndrome or numbness of the 4th and 5th digits
    • ↓ Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy grip
    • Medial elbow pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Ulnar injury at the wrist:
    • Hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy weakness and atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
    • Loss of dexterity
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology changes vary.
    • Ulnar claw: clawing of 4th and 5th digits when asked to extend fingers (unable to extend interphalangeal joints Interphalangeal joints Hand: Anatomy)

Radial neuropathy Neuropathy Leprosy

• Radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: all muscles of the posterior or extensor compartment of the forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: inferior or posterior lateral cutaneous nerve Inferior or posterior lateral cutaneous nerve Forearm: Anatomy (from the radial nerve Radial Nerve A major nerve of the upper extremity. In humans the fibers of the radial nerve originate in the lower cervical and upper thoracic spinal cord (usually C5 to T1), travel via the posterior cord of the brachial plexus, and supply motor innervation to extensor muscles of the arm and cutaneous sensory fibers to extensor regions of the arm and hand. Axilla and Brachial Plexus: Anatomy), which innervates the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions over the posterior arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy
• Presentation:
  • Weak wrist extensors: unable to extend the wrist (wrist drop) 
  • Weak finger extensors and brachioradialis Brachioradialis Forearm: Anatomy
  • Weak thumb abduction Abduction Examination of the Upper Limbs ( abductor pollicis longus Abductor pollicis longus Forearm: Anatomy affected)
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology changes to the posterior forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy, lateral 3 digits, and dorsolateral palm

Suprascapular neuropathy Neuropathy Leprosy

• Suprascapular nerve Suprascapular nerve Axilla and Brachial Plexus: Anatomy comes from the upper trunk of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region, supplying:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: supraspinatus and infraspinatus muscles
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: glenohumeral and acromioclavicular joints
• Causes of suprascapular neuropathy Neuropathy Leprosy:
  • Trauma (e.g., fall, motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology vehicle accident, football tackle)
  • Compression Compression Blunt Chest Trauma (e.g., from tumor Tumor Inflammation, cyst)
• Presentation:
  • Shoulder pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Weak shoulder abduction Abduction Examination of the Upper Limbs (due to affected supraspinatus)
  • Weak external shoulder rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays (due to affected infraspinatus)

Axillary neuropathy Neuropathy Leprosy

• Axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy comes from the posterior cord of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region, supplying:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: deltoid and teres minor muscles
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: lateral shoulder
• Injury:
  • Trauma (e.g., shoulder dislocation, humeral fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures)
  • Sleeping in prone position (arms above the head)
• Presentation:
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss in the lateral shoulder
  • Varying degrees of weakness in shoulder abduction Abduction Examination of the Upper Limbs and external rotation External Rotation Examination of the Upper Limbs (as other muscles aid in similar functions)

Long thoracic neuropathy Neuropathy Leprosy

• Long thoracic nerve Long thoracic nerve Axilla and Brachial Plexus: Anatomy arises from the 5th, 6th, and 7th cervical roots, supplying the serratus anterior muscle Serratus anterior muscle Chest Wall: Anatomy (fixes the lateral scapula to the chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy).
• Causes of long thoracic neuropathy Neuropathy Leprosy:
  • Trauma or compression Compression Blunt Chest Trauma:
    • Chest wall Chest wall The chest wall consists of skin, fat, muscles, bones, and cartilage. The bony structure of the chest wall is composed of the ribs, sternum, and thoracic vertebrae. The chest wall serves as armor for the vital intrathoracic organs and provides the stability necessary for the movement of the shoulders and arms. Chest Wall: Anatomy or shoulder injuries
    • Surgeries such as mastectomy Mastectomy Surgical procedure to remove one or both breasts. Fat Necrosis of the Breast with axillary node dissection, chest tube insertion, cardiothoracic surgeries
  • Neuralgic amyotrophy
  • Traction from repetitive movements
• Presentation:
  • Winging of the scapula (upon pressing outstretched arms against a wall)
  • Finding can be seen with other neuropathies Neuropathies Chédiak-Higashi Syndrome (e.g., spinal accessory, dorsal scapular).

Spinal accessory neuropathy Neuropathy Leprosy

• Spinal accessory nerve Spinal accessory nerve The 11th cranial nerve which originates from neurons in the medulla and in the cervical spinal cord. It has a cranial root, which joins the vagus nerve (10th cranial) and sends motor fibers to the muscles of the larynx, and a spinal root, which sends motor fibers to the trapezius and the sternocleidomastoid muscles. The 12 Cranial Nerves: Overview and Functions, a motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology nerve from upper cervical nerve roots, supplies the:
  • Sternocleidomastoid Sternocleidomastoid Muscles of the Neck: Anatomy 
  • Trapezius
• Causes of neuropathy Neuropathy Leprosy:
  • Most commonly from procedures
    • Biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma of cervical lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy in the posterior triangle Posterior triangle Triangles of the Neck: Anatomy
    • Radical neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess dissection
  • Trauma (e.g., sports)
• Presentation:
  • Drooped shoulder 
  • Weak abduction Abduction Examination of the Upper Limbs (cannot abduct beyond 90 degrees)
  • Weak and atrophied sternocleidomastoid Sternocleidomastoid Muscles of the Neck: Anatomy muscle (proximal nerve injury Nerve Injury Surgical Complications)
  • Weak and atrophied trapezius (distal nerve injury Nerve Injury Surgical Complications)
  • Winging of scapula

Musculocutaneous neuropathy Neuropathy Leprosy

• Musculocutaneous nerve Musculocutaneous Nerve A major nerve of the upper extremity. The fibers of the musculocutaneous nerve originate in the lower cervical spinal cord (usually C5 to C7), travel via the lateral cord of the brachial plexus, and supply sensory and motor innervation to the upper arm, elbow, and forearm. Axilla and Brachial Plexus: Anatomy arises from the lateral cord of the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region (C5–C7) and supplies the following:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: coracobrachialis Coracobrachialis Arm: Anatomy, biceps Biceps Arm: Anatomy, and brachialis Brachialis Arm: Anatomy muscles
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: lateral forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy
• Causes of neuropathy Neuropathy Leprosy:
  • Strenuous exercise Strenuous exercise Physical activity which is usually regular and done with the intention of improving or maintaining physical fitness or health. Contrast with physical exertion which is concerned largely with the physiologic and metabolic response to energy expenditure. Cardiovascular Response to Exercise
  • Trauma
  • Malpositioned arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy (during anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts)
• Presentation:
  • Weak elbow flexion Flexion Examination of the Upper Limbs
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss in lateral forearm Forearm The forearm is the region of the upper limb between the elbow and the wrist. The term “forearm” is used in anatomy to distinguish this area from the arm, a term that is commonly used to describe the entire upper limb. The forearm consists of 2 long bones (the radius and the ulna), the interosseous membrane, and multiple arteries, nerves, and muscles. Forearm: Anatomy

Phrenic Neuropathy

Phrenic nerve Phrenic nerve The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm. Diaphragm: Anatomy

• Nerve supplies:
  • The primary motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology control of the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: right and left phrenic nerves (originate from cervical spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy: C3–C5)
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: central part of diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
• Causes of phrenic neuropathy Neuropathy Leprosy:
  • Malignancies or masses (e.g., lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer)
  • Thoracic or cardiac surgery Cardiac surgery Cardiac surgery is the surgical management of cardiac abnormalities and of the great vessels of the thorax. In general terms, surgical intervention of the heart is performed to directly restore adequate pump function, correct inherent structural issues, and reestablish proper blood supply via the coronary circulation. Cardiac Surgery ( iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome is often unilateral)
  • Infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease such as HIV HIV Anti-HIV Drugs, Lyme disease Lyme disease Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Lyme Disease, herpes zoster Herpes Zoster Varicella-zoster virus (VZV) is a linear, double-stranded DNA virus in the Herpesviridae family. Shingles (also known as herpes zoster) is more common in adults and occurs due to the reactivation of VZV. Varicella-Zoster Virus/Chickenpox, and TB TB Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis 
  • Diseases such as diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus and multiple sclerosis Sclerosis A pathological process consisting of hardening or fibrosis of an anatomical structure, often a vessel or a nerve. Wilms Tumor

Presentation

• Overall, can present with shortness of breath Shortness of breath Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea due to diaphragmatic dysfunction or unilateral or bilateral diaphragmatic paralysis
• If one side is damaged, the contralateral side functions normally, allowing inspiration Inspiration Ventilation: Mechanics of Breathing.
• Associated with exertional dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
• Irritation to the phrenic nerve Phrenic nerve The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm. Diaphragm: Anatomy can cause hiccups.
• Exam and other findings:
  • ↓ Breath sounds and dullness (to percussion Percussion Act of striking a part with short, sharp blows as an aid in diagnosing the condition beneath the sound obtained. Pulmonary Examination) on the affected side
  • Epigastrium Epigastrium Surgical Anatomy of the Abdomen moves inward during inspiration Inspiration Ventilation: Mechanics of Breathing.
  • Elevated hemidiaphragm (in unilateral injury)

Lower-Limb Neuropathies

Lumbosacral plexus

• Network of nerves formed from the 12th thoracic (T12), 1st–5th lumbar (L1–L5), and 1st–3rd sacral ( S1 S1 Heart Sounds– S3 S3 Heart Sounds) spinal nerve roots 
• Lumbar plexus:
  • From the anterior rami of the L1–L4 nerve roots
  • Unites with the sacral plexus Sacral plexus Pelvis: Anatomy via the lumbosacral trunk (which consists of a portion of L4 nerve root anterior rami and all L5 anterior rami)
• Sacral plexus Sacral plexus Pelvis: Anatomy: the lumbosacral trunk and the anterior rami of the S1 S1 Heart Sounds– S4 S4 Heart Sounds nerve roots 
• Innervate the muscles of the lower extremities
• Causes of plexopathy:
  • Malignancy Malignancy Hemothorax
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma
  • Idiopathic Idiopathic Dermatomyositis
  • Occasionally trauma
• Lumbosacral plexopathy:
  • Lumbar plexus lesions:
    • Weak hip flexion Flexion Examination of the Upper Limbs
    • Weak adduction Adduction Examination of the Upper Limbs
    • Knee extension Extension Examination of the Upper Limbs
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the anterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy and leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy
  • Lumbosacral trunk and sacral plexus Sacral plexus Pelvis: Anatomy lesions:
    • Weak posterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy, and foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy muscles
    • Loss of sensation over the 1st and 2nd sacral segments
  • Entire plexus (rare):
    • Weak and atrophied lower extremity muscles
    • Areflexia Areflexia Duchenne Muscular Dystrophy
    • Anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts (perianal region to the toes)

Sciatic neuropathy Neuropathy Leprosy

• Sciatic nerve Sciatic Nerve A nerve which originates in the lumbar and sacral spinal cord (l4 to s3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the tibial nerve and the peroneal nerve. Gluteal Region: Anatomy:
  • Biggest and longest nerve from the lumbosacral plexus, gives off many branches and divides into the:
    • Common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy
    • Tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy
  • Comes from the 4th and 5th lumbar and the 1st and 2nd sacral roots
  • Supplies:
    •   Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: hamstring muscles and all the muscles below the knee through the tibial and peroneal nerves
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: posterior aspect of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, the posterolateral leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy, and the entire sole
• Common site of injury: sciatic notch ( gluteal region Gluteal region The gluteal region is located posterior to the pelvic girdle and extends distally into the upper leg as the posterior thigh. The gluteal region consists of the gluteal muscles and several clinically important arteries, veins, and nerves. The muscles of the gluteal region help to move the hip joint during walking, running, standing, and sitting. Gluteal Region: Anatomy)
• Causes of neuropathy Neuropathy Leprosy:
  • Trauma (e.g., hip dislocation, fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures, or surgeries)
  • Compression Compression Blunt Chest Trauma (e.g., prolonged bed rest because of coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma)
  • Buttock injections
  • Deep-seated mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast in the pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy (e.g., hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception)
• Presentation:
  • Leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy weakness
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss in peroneal, tibial and sural territories (medial calf and foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy arch spared)
  • Normal knee jerk 
  • Absent ankle jerk

Common peroneal neuropathy Neuropathy Leprosy

• The common peroneal nerve Peroneal nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy, also called the common fibular nerve Common Fibular Nerve The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot. Popliteal Fossa: Anatomy, supplies:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function to the short head of the biceps femoris Biceps femoris Thigh: Anatomy
  • Sensation in the posterolateral leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy
• Site of injury: commonly injured at the head of the fibula Fibula The bone of the lower leg lateral to and smaller than the tibia. In proportion to its length, it is the most slender of the long bones. Leg: Anatomy (below the knee)
• Causes of neuropathy Neuropathy Leprosy:
  • Frequent leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy crossing
  • Prolonged lying down
  • Squatting
  • Leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy cast
• Presentation:
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the dorsum of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy and lateral shin Shin Erythema Nodosum
  • Weak foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy eversion Eversion Chronic Apophyseal Injury and dorsiflexion
  • Foot drop Foot Drop Leprosy (affected foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy drags on ground while walking)
  • Normal reflexes

Tibial neuropathy Neuropathy Leprosy

• Tibial nerve Tibial Nerve The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot. Popliteal Fossa: Anatomy:
  • Along with the other of the 2 divisions of the sciatic nerve Sciatic Nerve A nerve which originates in the lumbar and sacral spinal cord (l4 to s3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the tibial nerve and the peroneal nerve. Gluteal Region: Anatomy, supplies:
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy or calf muscles (posterior compartment) and intrinsic foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy muscles
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: posterolateral leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy, heel, lateral foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy, plantar surface of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • Descends down to the ankle (inferior and posterior to the medial malleolus Medial malleolus Ankle Joint: Anatomy in the ankle) passing beneath the flexor retinaculum Flexor Retinaculum Ankle Joint: Anatomy through the tarsal tunnel
• Common site of injury: tarsal tunnel of the ankle
• Causes of neuropathy Neuropathy Leprosy:
  • Fractures or dislocation:
    • Talus Talus The second largest of the tarsal bones. It articulates with the tibia and fibula to form the ankle joint. Ankle Joint: Anatomy
    • Calcaneus Calcaneus The largest of the tarsal bones which is situated at the lower and back part of the foot, forming the heel. Foot: Anatomy
    • Medial malleolus Medial malleolus Ankle Joint: Anatomy
  • Rheumatoid arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis
  • Tumor Tumor Inflammation
• Presentation:
  • Tingling Tingling Posterior Cord Syndrome, numbness, aching on the sole of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy and toes (occasionally, the heel)
  • Symptoms worse on standing
  • + Tinel’s sign (posterior to the medial malleolus Medial malleolus Ankle Joint: Anatomy)
  • Severe: atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation of foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy muscles

Femoral neuropathy Neuropathy Leprosy

• Femoral nerve Femoral Nerve A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints. Femoral Region and Hernias: Anatomy:
  • Derived from the 2nd, 3rd, and 4th lumbar roots
  • Supplies:
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: muscles of anterior compartment, iliacus, pectineus Pectineus Thigh: Anatomy
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions of anterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy and lower ⅔ of medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
• Site of injury: pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy and anterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
• Causes of neuropathy Neuropathy Leprosy:
  • Hip or pelvic fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
  • Hip replacement
  • Lithotomy position
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus
• Presentation:
  • Weak quadriceps
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss in the anterior and medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, medial shin Shin Erythema Nodosum, arch of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy
  • ↓ Knee jerk

Lateral femoral cutaneous neuropathy Neuropathy Leprosy

• Meralgia paresthetica
• Lateral femoral cutaneous nerve:
  • Derived from L2–L3
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions of the anterolateral thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy 
• Site of injury: inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy
• Causes of neuropathy Neuropathy Leprosy:
  • Tight-fitting belts
  • Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
  • Idiopathic Idiopathic Dermatomyositis
• Presentation:
  • Paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways radiating down the lateral aspect of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy 
  • No weakness of the quadriceps

Obturator neuropathy Neuropathy Leprosy

• Obturator nerve Obturator Nerve A nerve originating in the lumbar spinal cord (L2 to L4) and traveling through the lumbar plexus to the lower extremity. The obturator nerve provides motor innervation to the adductor muscles of the thigh and cutaneous sensory innervation of the inner thigh. Thigh: Anatomy:
  •  From the branches of L2–L4 ventral rami
  • Supplies:
    • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology: muscles of the medial compartment (adductors) and contributes to internal and external rotators
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology: skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions of upper ⅓ of the medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
• Causes of neuropathy Neuropathy Leprosy:
  • Pelvic trauma
  • Pelvic surgery
• Presentation:
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and weakness with leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy adduction Adduction Examination of the Upper Limbs
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss over the medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy

Diagnosis

History and physical

• Complete history (include past medical history Past Medical History Adult Health Maintenance, exposure to toxins, substance use, and family history Family History Adult Health Maintenance)
• Detailed physical examination:
  • Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology deficits:
    • Weakness
    • Cramps Cramps Ion Channel Myopathy
    • Fasciculations Fasciculations Involuntary contraction of the muscle fibers innervated by a motor unit. Fasciculations may be visualized as a muscle twitch or dimpling under the skin, but usually do not generate sufficient force to move a limb. They may represent a benign condition or occur as a manifestation of motor neuron disease or peripheral nervous system diseases. Polyneuropathy
    • Muscle atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology deficits:
    • Touch changes
    • Vibration Vibration A continuing periodic change in displacement with respect to a fixed reference. Neurological Examination changes
    • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways sensation changes
    • Changes in temperature perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment
  • Autonomic deficiency:
    • Sweating
    • Heat Heat Inflammation intolerance
    • Blood pressure changes

Workup

• Laboratory studies, depending on clinical picture, include (but not limited to):
  • Fasting glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance, HbA_1c to screen for diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus
  • CMP
  • CBC and inflammatory markers
  • Serologies such as HIV HIV Anti-HIV Drugs, hepatitis C Hepatitis C Hepatitis C is an infection of the liver caused by the hepatitis C virus (HCV). The infection can be transmitted through infectious blood or body fluids and may be transmitted during childbirth or through IV drug use or sexual intercourse. Hepatitis C virus can cause both acute and chronic hepatitis, ranging from a mild to a serious, lifelong illness including liver cirrhosis and hepatocellular carcinoma (HCC). Hepatitis C Virus, Lyme disease Lyme disease Lyme disease is a tick-borne infection caused by the gram-negative spirochete Borrelia burgdorferi. Lyme disease is transmitted by the black-legged Ixodes tick (known as a deer tick), which is only found in specific geographic regions. Patient presentation can vary depending on the stage of the disease and may include a characteristic erythema migrans rash. Lyme Disease
  • Toxicology 
• Nerve conduction studies and electromyography Electromyography Recording of the changes in electric potential of muscle by means of surface or needle electrodes. Becker Muscular Dystrophy (EMG):
  • Nerve conduction studies and EMG are often considered definitive diagnostic tests Diagnostic tests Diagnostic tests are important aspects in making a diagnosis. Some of the most important epidemiological values of diagnostic tests include sensitivity and specificity, false positives and false negatives, positive and negative predictive values, likelihood ratios, and pre-test and post-test probabilities. Epidemiological Values of Diagnostic Tests for mononeuropathies.
  • Demyelination Demyelination Multiple Sclerosis is quantified via slowing of conduction velocity across affected nerve segments.
• Imaging based on presentation, such as:
  • Lumbosacral MRI for lumbosacral spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy disease with nerve-root compression Compression Blunt Chest Trauma
  • Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests for respiratory symptoms from phrenic nerve injury Nerve Injury Surgical Complications
• Lumbar puncture Lumbar Puncture Febrile Infant: for unusual presentation or suspected inflammatory conditions

Management

Principles

• General management for mononeuropathy is modification of lifestyle and adequate control of any underlying illness. 
• Treatment varies with the nerve involved, degree of impairment, and mechanism of injury.
• More severe conditions may require surgical intervention. 

Treatment options

• Splinting or immobilization Immobilization Delirium (e.g., wrist splinting Wrist Splinting Carpal Tunnel Syndrome for carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome)
• Physical therapy Physical Therapy Becker Muscular Dystrophy and exercise
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control:
  • NSAIDs NSAIDS Primary vs Secondary Headaches
  • Corticosteroid injection
• Surgery (if conservative management fails) such as:
  • Surgical release (e.g., release of flexor retinaculum Flexor Retinaculum Ankle Joint: Anatomy in carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome)
  • Nerve grafting

Clinical Relevance

• Polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy: disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system Peripheral nervous system The nervous system outside of the brain and spinal cord. The peripheral nervous system has autonomic and somatic divisions. The autonomic nervous system includes the enteric, parasympathetic, and sympathetic subdivisions. The somatic nervous system includes the cranial and spinal nerves and their ganglia and the peripheral sensory receptors. Nervous System: Anatomy, Structure, and Classification. There are numerous etiologies of polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy, and most are systemic; the most common is diabetic neuropathy Neuropathy Leprosy. The presentation varies, but generally manifests as sensorimotor disturbances ( pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, paresthesia, numbness, weakness, loss of coordination Coordination Cerebellar Disorders and balance), which have a gradual onset and progressive course. Diagnosis is made clinically, but laboratory studies, electrodiagnostic testing, and/or nerve biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma may be required in some cases. Management varies depending on the etiology of the polyneuropathy Polyneuropathy Polyneuropathy is any disease process affecting the function of or causing damage to multiple nerves of the peripheral nervous system. There are numerous etiologies of polyneuropathy, most of which are systemic and the most common of which is diabetic neuropathy. Polyneuropathy.  
• Carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome syndrome: caused by compression Compression Blunt Chest Trauma of the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy as it crosses the carpal tunnel Carpal Tunnel The carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly. Carpal Tunnel Syndrome. Features of this syndrome include pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and paresthesia of the dermatomal Dermatomal Dermatologic Examination target tissues innervated by the median nerve Median Nerve A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand. Cubital Fossa: Anatomy as well as weakness and atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation of its myotomal targets. A clinical diagnosis may be made on the basis of history and physical examination and confirmed with electrodiagnostic testing. Splinting and physical therapy Physical Therapy Becker Muscular Dystrophy are recommended, whereas more severe cases may require surgical correction. 
• Brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region injuries: conditions that impair the brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region. Causes of brachial plexopathies include traumatic injuries, birth-related injuries, iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome procedures, neoplastic processes, or previous treatment with radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma. Presentation is with sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology and motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology deficits related to the site of the lesion and the nerves involved. Diagnosis is made based on clinical findings, imaging, and electrodiagnostic studies. Treatment is related to the underlying cause and may be medical or surgical. 
• Peripheral nerve injuries in the cervicothoracic region: commonly involve the nerves arising from the cervical plexus Cervical Plexus A network of nerve fibers originating in the upper four cervical spinal cord segments. The cervical plexus distributes cutaneous nerves to parts of the neck, shoulders, and back of the head. It also distributes motor fibers to muscles of the cervical spinal column, infrahyoid muscles, and the diaphragm. Peripheral Nerve Injuries in the Cervicothoracic Region and brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region. Causes of injury vary and may include surgical injury, trauma, compression Compression Blunt Chest Trauma, nerve entrapment, stretch or traction from repetitive movement, infection, and metabolic causes. Clinical presentation depends on motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology and sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation of the affected nerves. Diagnosis is mostly clinical but can also be confirmed through imaging and electrodiagnostic studies. Management can be conservative ( physical therapy Physical Therapy Becker Muscular Dystrophy and avoiding precipitating movements) or surgical, depending on the specific injury.