Thigh: Anatomy

Bone of the Thigh: Femur

• The longest and strongest bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types in the human body
• The only bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types located in the thigh
• Articulations of the femur:
  • With the acetabulum of the hip bone Acetabulum of the hip bone The part of the pelvis that comprises the pelvic socket where the head of femur joins to form hip joint (acetabulofemoral joint). Hip Joint: Anatomy proximally: to form the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy
  • With the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy distally: to form medial and lateral tibiofemoral articulations
  • With the patella Patella The flat, triangular bone situated at the anterior part of the knee. Knee Joint: Anatomy distally: to form the patellofemoral articulation

Fascial Compartments of the Thigh

The iliotibial tract or iliotibial band is a thickening of the fascia lata Fascia lata Femoral Region and Hernias: Anatomy located on the lateral surface of the thigh. The iliotibial tract is a stabilizer of the hip and knee.

• Proximally:
  • Splits into a superficial and deep layer, enclosing the tensor fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis latae muscle
  • Attaches proximally to the iliac crest of 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
• Distally:
  • Merges with the aponeurosis of the vastus lateralis muscle
  • Attaches to Gerdy’s tubercle on the lateral tibial condyle

The 3 intermuscular septa arise from the fascia lata Fascia lata Femoral Region and Hernias: Anatomy and attach to the linea aspera of the femur. The lateral, medial, and posterior intermuscular septums divide the thigh into the following:

1. The anterior or extensor compartment:
   • Quadriceps (rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis)
   • Sartorius
2. The posterior or flexor compartment:
   • Biceps Biceps Arm: Anatomy femoris
   • Semitendinosus
   • Semimembranosus
3. The medial or adductor compartment:
   • Adductor magnus
   • Adductor longus
   • Adductor brevis
   • Gracilis
   • Pectineus

Anterior Compartment of the Thigh

• The anterior compartment of the thigh contains the following muscles:
  • Quadriceps femoris: comprises the rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis
  • Sartorius
  • Sometimes, the iliopsoas is considered part of the anterior compartment; otherwise, it is considered a muscle of the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy/ 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.
• The primary function of the muscles of the anterior compartment of the thigh is knee extension Extension Examination of the Upper Limbs.
• All these muscles all innervated by the 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.

Posterior Compartment of the Thigh

• The posterior compartment of the thigh contains the hamstring muscles:
  • Biceps Biceps Arm: Anatomy femoris
  • Semitendinosus
  • Semimembranosus
• The muscles of the posterior compartment have the primary function of knee flexion Flexion Examination of the Upper Limbs and hip extension Extension Examination of the Upper Limbs.
• These muscles are innervated by branches 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.

Medial Compartment of the Thigh

• The medial compartment of the thigh contains the following muscles:
  • Adductor magnus, longus, and brevis
  • Gracilis
  • Pectineus
  • The obturator externus is sometimes included, although it is primarily an external rotator and secondarily an adductor.
• The primary function of the muscles of the medial compartment is hip adduction Adduction Examination of the Upper Limbs.
• These muscles are primarily innervated by the obturator nerve, except for the pectineus ( 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).

Pes PES Removal of plasma and replacement with various fluids, e.g., fresh frozen plasma, plasma protein fractions (ppf), albumin preparations, dextran solutions, saline. Used in treatment of autoimmune diseases, immune complex diseases, diseases of excess plasma factors, and other conditions. Thrombotic Thrombocytopenic Purpura anserinus

The distal end of the medial region of the thigh is the location of the pes anserinus or “goose foot,” which comprises the conjoined tendons of the sartorius, gracilis, and semitendinosus muscles inserting into the tibia Tibia The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the fibula laterally, the talus distally, and the femur proximally. Knee Joint: Anatomy.

Blood Supply

Arterial blood supply

Three arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology exit 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: the femoral, obturator, and inferior gluteal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology. However, the femoral and obturator arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology continue toward the thigh, while the inferior gluteal supplies and ends in the 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.

• Femoral artery Femoral Artery The main artery of the thigh, a continuation of the external iliac artery. Femoral Region and Hernias: Anatomy:
  • Supplies the majority of the lower limb
  • A direct continuation of the external iliac artery
  • Originates and enters the thigh upon passing under the inguinal canal Inguinal canal The tunnel in the lower anterior abdominal wall through which the spermatic cord, in the male; round ligament, in the female; nerves; and vessels pass. Its internal end is at the deep inguinal ring and its external end is at the superficial inguinal ring. Inguinal Canal: Anatomy and Hernias 
  • Passes through the femoral triangle Femoral triangle Femoral Region and Hernias: Anatomy, where it can be palpated
  • Enters the adductor canal distally in the thigh, terminates at the adductor hiatus, and becomes the popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy
  • Has several branches:
    • Profunda femoris artery (deep artery of the thigh): the main branch of the femoral; supplies most of the structures in the thigh and gives off perforating branches and the medial and lateral circumflex femoral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology ( MCFAs MCFAs Digestion and Absorption and LCFAs LCFAs Digestion and Absorption) to the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy
    • Superficial epigastric artery
    • Superficial circumflex iliac artery
    • Superficial external pudendal artery
    • Deep external pudendal artery

• Obturator artery:
  • Branch of the internal iliac artery
  • Passes through the obturator foramen to the muscles of the medial compartment
  • Gives off important extra-pelvic branches:
    • Anterior branch: supplies the obturator externus muscle, adductor muscles, and 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 medial thigh
    • Posterior branch: supplies the muscles attached to the ischial tuberosity Ischial Tuberosity Chronic Apophyseal Injury
    • Artery of the ligamentum teres Ligamentum teres A cord-like remnant structure formed from the closed left fetal umbilical vein. It is located along the lower edge of the falciform ligament. Liver: Anatomy: supplies the head of the femur Head of the femur The hemispheric articular surface at the upper extremity of the thigh bone. Hip Joint: Anatomy

Venous drainage

• Deep venous system:
  • The popliteal vein Popliteal Vein The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein. Popliteal Fossa: Anatomy becomes the femoral vein as it ascends into the thigh.
  • The femoral vein accompanies the femoral artery Femoral Artery The main artery of the thigh, a continuation of the external iliac artery. Femoral Region and Hernias: Anatomy in its trajectory and receives the deep vein of the thigh (profunda femoris vein) in the proximal thigh.
  • The femoral vein becomes the external iliac vein once it passes underneath the inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy.
• Superficial venous system: 
  • The great saphenous vein originates from the dorsal venous arch Dorsal venous arch Foot: Anatomy 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.
  • Ascends the medial side of the 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 passing posterior to the medial condyle at the knee
  • Drains into the femoral vein in the femoral triangle Femoral triangle Femoral Region and Hernias: Anatomy

Innervation

The thigh is innervated by branches of the lumbar and sacral plexus Sacral plexus Pelvis: Anatomy.

Clinical Relevance

The following conditions are clinically relevant to the thigh:

• Femoral shaft 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: 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 anywhere along the shaft or diaphysis Diaphysis The shaft of long bones. Bones: Structure and Types of the femur. Femoral shaft fractures generally occur in young adults due to high-impact injuries. In the elderly, these fractures are usually due to low-impact falls, even a fall from standing, and are related to osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis. Typically present as a painfully swollen, tense thigh with restricted 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. Vascular compromise secondary to blood loss and fat embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding are possible complications.
• Proximal femur fractures: most commonly seen in the elderly and related to osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis. Generally classified into intracapsular and extracapsular fractures; intracapsular fractures may lead to avascular necrosis Avascular Necrosis Hip Fractures of the femoral head.
• Femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: an uncommon type of groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias, in which intraabdominal contents herniate under the inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy and through the femoral ring Femoral ring Femoral Region and Hernias: Anatomy into the femoral canal Femoral canal Femoral Region and Hernias: Anatomy. More common in adults than in children, femoral hernias usually present with swelling Swelling Inflammation that worsens with coughing or straining and that protrudes into the femoral triangle Femoral triangle Femoral Region and Hernias: Anatomy (inferiorly to the inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy and medial to the femoral vein).