Thigh

The Thigh

• The thigh is the region of the lower limb between the hip and knee joints.

Fascia of the Gluteal Region and Thigh

• Gluteal fascia covers the gluteus maximus and medius muscles, attaching proximally to the iliac crest and distally continuing as the fascia lata.

• Fascia lata is a strong deep fascia that envelops the thigh and attaches to the iliac crest, inguinal ligament, epicondyles of the femur, base of the patella, and head of the fibula.

• The iliotibial tract is a thickened lateral band of fascia lata that attaches to the tuberosity for the iliotibial tract (tubercle of Gerdy).

• Lateral, medial, and anteromedial femoral intermuscular septa divide the thigh into anterior, posterior, and medial compartments.

Muscles of the Thigh

• Thigh muscles are organized into anterior, medial, and posterior groups.

• The quadriceps femoris forms the anterior group and is the only extensor of the leg.

Anterior Group

• The sartorius muscle, also known as the tailor's muscle, is responsible for flexion, abduction, and external rotation of the hip, and flexion of the knee.

• The quadriceps femoris muscle is comprised of four heads: rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis.

• The rectus femoris is the only head that acts on both the hip and knee joint.

• The quadriceps femoris muscle is responsible for extending the leg, controlling flexion of the leg, and flexing the thigh (rectus femoris only).

Medial Group

• The medial group of thigh muscles includes the pectineus, adductor longus, gracilis, adductor brevis, adductor magnus, and obturator externus muscles.

• These muscles are responsible for adduction, flexion, and external rotation of the hip.

Posterior Group

• The posterior group of thigh muscles, also known as the hamstring muscles, includes the biceps femoris, semitendinosus, and semimembranosus muscles.

• These muscles are responsible for extending the hip and flexing the knee.

• The biceps femoris has a long and short head, and if the sciatic nerve divides proximally, the biceps femoris is innervated by both the tibial and fibular nerves.

Femoral Artery

• The femoral artery is a continuation of the external iliac artery and enters the femoral triangle where it supplies muscles of the thigh.

• It passes between the two insertions of the adductor magnus and continues to the popliteal fossa as the popliteal artery.

Femoral Triangle

• The femoral triangle is a triangular depression on the front of the thigh below the inguinal ligament.

• Its boundaries are laterally: medial border of Sartorius, medially: medial border of adductor longus, and base: inguinal ligament.

• The apex is formed by the meeting point of the medial borders of adductor longus and sartorius.

• The floor is gutter-shaped and muscular, formed by the iliacus, psoas major (tendon), pectineus, and adductor longus muscles.

• The roof is formed by the fascia lata with the saphenous opening.

• The femoral triangle contains the femoral artery and its branches, the femoral vein and its tributaries, the femoral nerve, deep inguinal lymph nodes, and the lateral cutaneous nerve of the thigh.

Femoral Sheath

• The femoral sheath is a funnel-shaped fascial sheath that encloses the upper 3-4 cm of the femoral vessels.

• It is divided into three compartments by two septa: lateral compartment contains the femoral artery and genitofemoral nerve, intermediate compartment contains the femoral vein, and the medial compartment, known as the femoral canal, is small and can be a site for femoral hernias.

Clinical correlation – Femoral Hernias

• A femoral hernia is an uncommon type of inguinal hernia where abdominal contents protrude through the femoral canal.

• Risk factors for femoral hernias include old age, female sex, obesity, and previous hernia repair.

• Femoral hernias occur predominantly in women due to the wider female pelvis and larger vascular lacuna.

Adductor Canal (Canalis Adductorius)

• The adductor canal is a continuation of the femoral triangle that leads to the popliteal fossa.

• Its boundaries are medially: adductor longus, laterally: vastus medialis, ventrally: vasto-adductor membrane, and dorsally: adductor magnus.

• It contains the femoral artery and vein, and the saphenous nerve.

Popliteal Fossa

• The popliteal fossa is a diamond-shaped depression behind the knee.

• Its boundaries are medioproximally: semimembranosus and semitendinosus, lateroproximally: biceps femoris, mediodistally: medial head of gastrocnemius, laterodistally: lateral head of gastrocnemius, and bottom (ventrally): popliteus.

• It contains the sciatic nerve (tibial and common fibular nerves), popliteal artery and its branches, popliteal vein and tributary veins, and popliteal lymph nodes.

This quiz explores the anatomy of the thigh, focusing on the regions and fascia of the gluteal region and thigh. Additionally, it covers the organization and functions of thigh muscles, emphasizing the quadriceps femoris and related structures. Test your knowledge of these crucial components of human anatomy.