Lower Extremity Anatomy Overview

Supports body weight, providing a stable base for standing, walking, and running.

Lower extremities (LE) are similar in structure to upper extremities (UE) but have less movement freedom and are attached to the trunk.

Lower extremities are divided into gluteal, thigh, knee, leg, and ankle/foot regions.

The thigh and leg regions have several different muscle groups.

The gluteal region is bounded superiorly by the iliac crest and inferiorly by the fold of the buttocks.

A layer of tissue, primarily fatty, over the thigh, extending from the abdominal wall and attaching to deep fascia.

A tough membrane that encloses the thigh muscles.

A gap in the deep thigh fascia.

A thickened band of fascia on the lateral thigh.

Another name for the Iliotibial Tract.

The fused Ilium, Ischium, and Pubis.

Lower boundary of the opening, anterior to the femoral vessels.

An artery in the thigh.

A major vein in the thigh.

Fills the opening of the femoral canal.

The foot's function in bearing body weight.

The Anterior Cruciate Ligament (ACL) prevents the tibia from being pulled forward, stopping excessive forward movement of the tibia relative to the femur.

The ACL is commonly injured during activities that involve sudden stops, changes in direction, or twisting motions, particularly those involving forces applied to the knee.

The Posterior Cruciate Ligament (PCL) prevents the tibia from being pulled backward, stopping excessive backward movement of the tibia relative to the femur.

The PCL is less commonly injured than the ACL, often occurring in situations where the knee receives a direct blow with the leg bent.

The prepatellar bursa is a fluid-filled sac located between the skin and the patellar ligament.

The superficial infrapatellar bursa lies between the skin and the lower part of the patellar ligament.

The deep infrapatellar bursa exists between the patellar ligament and the tibia.

The popliteal bursa is a sac situated in association with the tendon of the popliteus muscle, located behind the knee.

The gluteus medius, along with the gluteus minimus, abducts the thigh, which helps with walking and running.

The gluteus medius is a thick, fan-shaped muscle located beneath the gluteus maximus.

The pectineus muscle flexes and adducts the hip.

The quadriceps femoris, composed of four muscles, extends the knee powerfully.

A lateral lurching motion of the hip can be a sign of weak gluteus medius, which aids in hip abduction.

Located between the lower ends of the tibia and fibula, the two malleoli, and the body of the talus.

Synovial hinge joint.

Deltoid, Lateral, and Transverse Tibiofibular ligaments.

Gliding and Rotatory motions.

Located between the head of the talus, the upper surface of the Sustentaculum tali, and the posterior concave surface of the navicular.

Synovial Joint.

Plantar Calcaneonavicular Ligament.

Gliding and Rotatory motions.

Located between the anterior calcaneum and the posterior surface of the cuboid.

Synovial Plane joint.

Bifurcate Ligament, Long Plantar Ligament, and Short Plantar Ligament.

Located between the inferior surface of the talus body and the facet on the middle of the upper surface of the calcaneus.

Synovial Plane Joint.

Medial and Lateral Talocalcaneal Ligaments, and Interosseous Ligament.

A crucial stone that holds the arch structure together, forming the apex of the arch and ensuring its stability.

A movement that rotates the anatomical structure inward, towards the midline of the body.

Assists the gluteus maximus in extending the knee and maintaining stability; keeps the knee straight.

Muscles that straighten the knee joint.

A muscle in the buttock that rotates the hip laterally; important for hip movement and stability.

A large nerve that runs down the back of the thigh; it can be compressed by the piriformis muscle.

A condition where the piriformis muscle compresses the sciatic nerve, causing pain in the lower back, buttock, and leg.

The four muscles at the front of the thigh: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

The lower, horizontal fibers of the vastus medialis muscle; they help stabilize the kneecap.

A small muscle that helps to pull the knee joint capsule during knee extension.

A fascial sleeve that surrounds the femoral artery, vein, and nerve as they pass into the thigh.

A small space in the medial compartment of the thigh, containing fatty connective tissue and lymph vessels.

The opening at the top of the femoral canal, which can sometimes be the site of a hernia.

A protrusion of abdominal contents through the femoral ring, into the femoral canal.

A group of muscles on the inner side of the thigh that help to move the leg toward the midline of the body.

Three muscles at the back of the thigh: biceps femoris, semitendinosus, and semimembranosus.