Acute Shoulder Pain

Overview: Anatomy

• Focused anatomy of the shoulder joint Shoulder joint The articulation between the head of the humerus and the glenoid cavity of the scapula. Examination of the Upper Limbs
• The shoulder complex Shoulder complex The shoulder complex comprises the glenohumeral joint, sternoclavicular joint, acromioclavicular joint, and the scapulothoracic articulation, and connects the upper limb to the trunk. This group of joints consists of the clavicle, scapula, and humerus bones, multiple muscles and supporting ligaments, cartilage, and bursae. Shoulder Joint: Anatomy is made up of multiple joints, bones, ligaments, and tendons.
• The glenohumeral joint has the most mobility of any joint in the body.
• Glenohumeral joint:
  • Passive restraints:
    • Joint capsule Capsule An envelope of loose gel surrounding a bacterial cell which is associated with the virulence of pathogenic bacteria. Some capsules have a well-defined border, whereas others form a slime layer that trails off into the medium. Most capsules consist of relatively simple polysaccharides but there are some bacteria whose capsules are made of polypeptides. Bacteroides
    • Glenohumeral ligaments
    • Glenoid labrum
  • Active stabilizers:
    • Rotator cuff muscles
    • Periscapular muscles
• Rotator cuff muscles (active stabilizers):
  • Supraspinatus, infraspinatus, teres minor, subscapularis
  • Forms a cuff around the head of the humerus Head of The Humerus The upper rounded extremity of the humerus fitting into the glenoid cavity of the scapula. Arm: Anatomy
  • Stabilizes the joint while allowing motion
  • Supraspinatus is the most commonly torn rotator cuff tendon.
• The shoulder complex Shoulder complex The shoulder complex comprises the glenohumeral joint, sternoclavicular joint, acromioclavicular joint, and the scapulothoracic articulation, and connects the upper limb to the trunk. This group of joints consists of the clavicle, scapula, and humerus bones, multiple muscles and supporting ligaments, cartilage, and bursae. Shoulder Joint: Anatomy also includes:
  • Acromioclavicular joint Acromioclavicular joint The gliding joint formed by the outer extremity of the clavicle and the inner margin of the acromion process of the scapula. Examination of the Upper Limbs
  • Sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs
  • Scapulothoracic articulation
  • Long head of the bicep tendon
• Cervical 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 evaluation is part of the assessment of shoulder pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways.
• Thorough neurovascular examination is essential after trauma to the upper extremity.

Mnemonic

Remember the rotator cuff muscles with SITS:

• Supraspinatus
• Infraspinatus
• Teres minor
• Subscapularis

Clinical Presentation

History

• Mechanism of trauma:
  • Type of trauma
  • Other associated injuries
• Previous injuries:
  • History of 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(s)
  • History of dislocation(s)
• Age of individual

Physical examination

• Exposure of shoulder
• Compare to unaffected side.
• Inspection Inspection Dermatologic Examination/observation:
  • Swelling Swelling Inflammation, gross deformity Deformity Examination of the Upper Limbs
  • Asymmetry Asymmetry Examination of the Upper Limbs
• Cervical 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 exam: Always consider associated injury.
• Range of motion Range of motion The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate muscle strength exercises. Examination of the Upper Limbs: limited because of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, injury
• Palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination:
  • Palpate:
    • Cervical 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
    • Sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs
    • Acromioclavicular joint Acromioclavicular joint The gliding joint formed by the outer extremity of the clavicle and the inner margin of the acromion process of the scapula. Examination of the Upper Limbs
    • Glenohumeral joint
    • Proximal humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy
  • Assess for warmth and swelling Swelling Inflammation.
• Neurovascular exam:
  • Evaluation of muscle groups of the upper extremity
  • Evaluation of 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
  • Vascular status

Imaging

• Imaging studies helpful to support or confirm diagnosis
• Plain radiographs:
  • Anteroposterior (AP) shoulder
  • AP glenoid
  • Scapular Y view
  • Axillary view
• MRI, CT, or ultrasonography for more difficult cases

Common Causes and Management of Acute Shoulder Pain

Clavicular 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

• Common in adults, secondary to trauma to the lateral shoulder
• Most common location (80%): middle ⅓ of the clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture (group I)
• Presents with pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, tenderness, and swelling Swelling Inflammation over the clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture
• Often obvious deformity Deformity Examination of the Upper Limbs:
  • Lateral fragment is displaced downward and medially because of unopposed action of pectoralis major muscle.
  • Proximal fragment is displaced upward because of unopposed action of the sternocleidomastoid Sternocleidomastoid Muscles of the Neck: Anatomy muscle.
• Diagnosis is based on clinical examination and is confirmed by 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.
• Careful neurovascular exam should be done because of proximity to the:
  • Great vessels
  • Lung
  • 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
• Management:
  • Based on type of injury, age of individual, and location
  • Majority of clavicular fractures are treated nonoperatively
• Allman classification Allman Classification Clavicle Fracture of clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture fractures:
  • Group I fractures (midshaft fractures):
    • Overlap of > 2 cm or grossly displaced
    • Often undergo surgical intervention
  • Group II fractures (distal ⅓ of fractures): orthopedic referral
  • Group III fractures (medial ⅓ of fractures): generally treated nonoperatively

Acromioclavicular joint Acromioclavicular joint The gliding joint formed by the outer extremity of the clavicle and the inner margin of the acromion process of the scapula. Examination of the Upper Limbs injuries

• Common injury in adults, caused by a fall on the lateral shoulder with 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 adducted
• Diagnosis is clinical, with pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways on palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination of the AC joint and associated deformity Deformity Examination of the Upper Limbs.
• 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 may be useful in classifying degree of injury and associated fractures.
• Rockwood classifications:
  • Type I: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture not elevated with respect to the acromion
  • Type II: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture elevated but not above the superior border of the acromion
  • Type III: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture elevated above the superior border of the acromion but < 2× normal
  • Type IV: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture displaced posterior into the trapezius
  • Type V: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture markedly elevated, > 2× normal
  • Type VI: clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture inferiorly displaced behind coracobrachialis Coracobrachialis Arm: Anatomy and biceps Biceps Arm: Anatomy tendons (rare)
• Types I–III injuries: nonoperative
• Type IV–VI injuries: orthopedic consult for surgical evaluation

Sternoclavicular sprains and dislocations

• Injured secondary to trauma to lateral shoulder
• Medial clavicular epiphysis Epiphysis The head of a long bone that is separated from the shaft by the epiphyseal plate until bone growth stops. At that time, the plate disappears and the head and shaft are united. Bones: Structure and Types is last to develop:
  • May not close until age 25
  • Apparent sternoclavicular joint Sternoclavicular Joint Examination of the Upper Limbs injury in young adults may be a Salter-Harris I/II injury rather than sprain.
• Majority are anterior dislocations with prominent medial clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture.
• Posterior dislocation can result from direct blow or fall:
  • May cause impingement of superior mediastinal contents
  • Injury to trachea Trachea The trachea is a tubular structure that forms part of the lower respiratory tract. The trachea is continuous superiorly with the larynx and inferiorly becomes the bronchial tree within the lungs. The trachea consists of a support frame of semicircular, or C-shaped, rings made out of hyaline cartilage and reinforced by collagenous connective tissue. Trachea: Anatomy and great vessels is potentially life-threatening.
  • CT scan is imaging modality of choice.

Glenohumeral dislocation

• Most commonly dislocated joint
• Over 90% of shoulder dislocations are in the anterior direction.
• Caused by a direct blow, fall, sports injury, or other high-impact trauma
• May be associated with axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy injury:
  • Function of axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy should be assessed both before and after reduction, along with a complete neurovascular examination.
  • Test: sensation over the deltoid
• Diagnosis is based on clinical examination and is confirmed by 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.
• Plain x-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays:
  • AP glenoid
  • Scapular Y view
  • Axillary view
• Management:
  • Multiple maneuvers have been described.
  • After reduction, repeat radiographs and sling placement
  • Length of immobilization Immobilization Delirium is controversial.
  • Risk of recurrent dislocation varies according to age and activity level.
  • Surgical intervention may be required for:
    • Repeated dislocations
    • 1st-time dislocation in an athlete participating in a high-impact sport

Posterior dislocation

• Uncommon injury (2%–4%); can be missed
• Classically described in individuals with seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures and electrocution injury; also seen with trauma 
• May be related to underlying multidirectional instability
• Individual keeps shoulder adducted and internally rotated; limited external rotation External Rotation Examination of the Upper Limbs
• 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:
  • May be missed on AP view of shoulder
  • Requires axillary or Y view for definite diagnosis
  • Classic: “light bulb” sign (internally rotated proximal humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy with circular appearance)

Proximal humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy 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

• More common in older individuals (70% > 60 years); occurs secondary to low-energy fall
• Related to high-energy trauma when seen in younger individuals
• Presents with pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways/ swelling Swelling Inflammation of proximal humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy after fall/trauma
• Assess neurovascular status, including axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy.
• Plain x-rays X-rays X-rays are high-energy particles of electromagnetic radiation used in the medical field for the generation of anatomical images. X-rays are projected through the body of a patient and onto a film, and this technique is called conventional or projectional radiography. X-rays:
  • AP shoulder
  • AP glenoid
  • Scapular Y view
  • Consider axillary view
• Management varies according to age and activity level.
• Most treated nonoperatively
• Nonoperative treatment:
  • Sling for comfort followed by pendulum exercises
  • Then a graduated physical therapy Physical Therapy Becker Muscular Dystrophy program

Scapular fractures

• Fractures to scapula related to high-impact trauma
• Most commonly involve fractures of the body of the scapula and/or neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess of glenoid
• The nature of this 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 raises a high suspicion for associated lung injury, rib fractures Rib fractures Fractures of any of the ribs. Flail Chest, and other injuries.
• Majority nondisplaced and treated nonsurgically

Acute rotator cuff tendon tear Rotator Cuff Tendon Tear Chronic Shoulder Pain

• Rotator cuff tears may result from acute trauma, falls, or tendon degeneration.
• Generally, age is helpful in classifying the tear:
  • Younger individuals more commonly have acute tears.
  • Older individuals often have degenerative-type tears.
  • Important: A significant number of individuals > 60 have asymptomatic degenerative rotator cuff tears on MRI.
• Supraspinatus is the most commonly torn rotator cuff tendon:
  • Shoulder weakness and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways when reaching overhead or behind
  • Often bothersome at night
• Physical examination/muscle-strength testing specific to location of rotator cuff tendon tear Rotator Cuff Tendon Tear Chronic Shoulder Pain
• Initial diagnosis based on clinical examination
• MRI used to confirm diagnosis
• Management:
  • Based on multiple factors:
    • Age
    • Duration of symptoms
    • Partial versus full tear
    • Comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus
  • Generally conservative for elderly individuals or chronic tears
  • Full-thickness tears typically require surgical repair.

Clinical Relevance

• Axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy injury: Axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy (C5–C6) may be injured in individuals with shoulder dislocation or proximal humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy 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. The axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy innervates the deltoid and teres minor. Axillary nerve Axillary nerve Axilla and Brachial Plexus: Anatomy injury results in weakness of the deltoid muscle and numbness on the side of the shoulder. May require surgery if associated with a 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 injury.
• Recurrent instability: Individuals with a history of shoulder dislocation have an increased risk of recurrent dislocation. Risk factors include younger age, playing contact sports, presence of Hill-Sachs or Bankart lesions, and underlying ligamentous laxity. Management is often with surgery.
• 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 malunion Malunion Hip Fractures: Nonunion Nonunion Hip Fractures or malunion Malunion Hip Fractures occurs with a relatively small number of clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture fractures. Whereas the operative management of clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture fractures has become more common, the surgical indications are uncertain.