Introduction to the Thigh Anatomy

The superficial fascia of the thigh has two layers: a superficial fatty layer and a deep membranous layer.

The deep membranous layer of the superficial fascia is loosely attached to the fascia lata except just below the inguinal ligament where it shows a linear fusion extending laterally from the pubic tubercle.

The deep fascia of the thigh is strong and inelastic, forming a stockinglike structure surrounding the entire thigh. It extends from the root of the limb (above) to the bony prominences around the knee (below).

The fascia lata is thickened laterally to form the iliotibial tract, a strong band of connective tissue that runs down the lateral side of the thigh.

The superomedial part of the fascia lata has a perforation called the saphenous opening, which allows the greater saphenous vein to pass through.

The thigh is divided into three compartments: the anterior compartment, the medial compartment, and the posterior compartment.

The anterior compartment of the thigh contains muscles that extend the knee and flex the hip. The medial compartment contains muscles that adduct the thigh. The posterior compartment contains muscles that extend the hip and flex the knee.

The femoral triangle is a triangular region in the upper thigh, bounded by the inguinal ligament, sartorius muscle, and adductor longus muscle. Its contents include the femoral nerve, artery, vein, and lymph nodes.

The intermuscular septa divide the thigh into three compartments: anterior, medial, and posterior. Each compartment houses specific muscle groups responsible for knee movements. The anterior compartment contains the extensors, the medial compartment contains the adductors, and the posterior compartment contains the flexors.

The anterior compartment of the thigh contains the extensor muscles responsible for extending the knee joint. It is supplied by the femoral nerve.

The medial compartment of the thigh contains the adductor muscles responsible for bringing the thigh towards the midline of the body. It is supplied by the obturator nerve.

The posterior compartment of the thigh contains the flexor muscles responsible for bending the knee joint. It is supplied by the sciatic nerve.

The ilio-tibial tract serves as an anchor for the gluteus maximus and tensor fasciae latae muscles, extending their insertion points to the knee joint. It also acts as a stabilizer for the knee joint.

The psoas major muscle originates from the sides of the last thoracic and all lumbar vertebrae, their intervertebral discs, lumbar transverse processes, and tendineous arches bridging over the lumbar arteries.

The psoas major muscle inserts into the lesser trochanter of the femur, along with the iliacus muscle, as part of the iliopsoas tendon.

The iliacus muscle originates from the iliac fossa and the adjoining part of the ala of the sacrum.

The iliacus muscle inserts into the lesser trochanter of the femur, along with the psoas major muscle, as part of the iliopsoas tendon.

The iliopsoas muscle flexes and medially rotates the thigh powerfully, and passively rotates it medially when the thigh is extended.

The psoas major and iliacus muscles together form the iliopsoas muscle.

The iliopsoas muscle is supplied by lumbar nerves (L1, 2, 3) within the abdomen.

The iliacus is supplied by the femoral nerve (branches arising within the abdomen).

The psoas major muscle originates from the sides of the last thoracic and the first three lumbar vertebrae, their intervertebral discs, lumbar transverse processes, and tendineous arches bridging over the lumbar arteries.

The psoas major muscle inserts into the lesser trochanter of the femur, along with the iliacus muscle, as part of the iliopsoas tendon.

The most medial muscle of the thigh, originating from the lower pubis and pubic arch, inserting into the medial tibia, and responsible for adducting the thigh, flexing and medially rotating the leg, and stabilizing the pelvis.

The first layer of adductor muscles, consisting of the pectineus and adductor longus muscles, both involved in thigh adduction.

The second layer of adductor muscles, containing the adductor brevis muscle, which acts as a key player in thigh adduction.

The third and deepest layer of adductor muscles, with the adductor magnus muscle taking center stage, responsible for strong thigh adduction.

The pectineus muscle originates from the pectineal line and surface of the superior pubic ramus, inserting onto the upper part of the line extending from the lesser trochanter to the linea aspera of the femur.

The obturator nerve, specifically its anterior division, innervates the pectineus muscle, providing the nerve signals for its actions.

The main action of the pectineus muscle is to adduct the thigh, bringing it towards the midline of the body. It also assists in flexing and medially rotating the leg, and helps stabilize the pelvis on the femur.

The longest muscle in the body, with parallel fibers. It originates from the lower part of the anterior superior iliac spine.

A group of four muscles that extends the knee joint. It includes the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

One of the four heads of the quadriceps femoris. It originates from the anterior inferior iliac spine and a depression just above the acetabulum.

One of the four heads of the quadriceps femoris. It originates from the upper part of the intertrochanteric line, the root of the greater trochanter, the lateral lip of the gluteal tuberosity, and the lateral lip of the linea aspera.

The action of bending a joint, as in bringing the forearm towards the shoulder or the thigh towards the abdomen.

The action of moving a limb away from the midline of the body. For example, raising your arm to the side.

The action of rotating a limb outward, away from the midline of the body. For example, rotating your forearm so your palm faces up.

The action of moving a limb towards the midline of the body. For example, lowering your arm to your side.

The action of turning a limb inward, towards the midline of the body. For example, rotating your forearm so your palm faces down.

The action of straightening a joint, as in extending the arm or leg.