AN16.1-6 | Gluteal region & back of thigh — Glossary

The largest muscle in the body, a powerful hip extensor and lateral rotator supplied by the inferior gluteal nerve

The primary hip abductor supplied by the superior gluteal nerve; weakness causes positive Trendelenburg sign

When standing on the affected leg, the pelvis drops on the opposite side due to weakness of gluteus medius and minimus

A waddling gait where the patient compensates for abductor weakness by swinging the trunk to the affected side with each step

A key landmark muscle in the gluteal region; the sciatic nerve usually exits below it through the greater sciatic foramen

The largest nerve in the body (L4-S3), exiting below piriformis and supplying the posterior thigh and entire leg and foot

The opening through which the sciatic nerve, superior and inferior gluteal vessels, and pudendal nerve pass from pelvis to gluteal region

The upper outer quadrant of the gluteal region, avoiding the sciatic nerve which lies in the lower and inner quadrants

The nerve (L4, L5, S1) supplying gluteus medius and minimus; injury causes Trendelenburg sign and abductor weakness

The nerve (L5, S1, S2) supplying gluteus maximus; injury weakens hip extension especially in climbing stairs

Three posterior thigh muscles (biceps femoris, semitendinosus, semimembranosus) that extend the hip and flex the knee

A two-headed hamstring muscle; the long head (tibial nerve) and short head (common peroneal nerve) insert on the fibular head

A diamond-shaped space at the back of the knee containing the popliteal artery and vein, tibial and common peroneal nerves

The deepest structure in the popliteal fossa, vulnerable to injury in posterior knee dislocations; absence of popliteal pulse suggests PAD

A posterior knee swelling from synovial fluid herniation between the medial head of gastrocnemius and semimembranosus

A cross-shaped arterial anastomosis at the back of the upper thigh providing collateral circulation around the hip

Compression of the sciatic nerve by a tight or spasmed piriformis muscle causing buttock pain radiating down the leg

A branch of the sciatic nerve that winds around the neck of the fibula; the most commonly injured nerve in the lower limb

Six small muscles deep to gluteus maximus (piriformis, obturator internus, gemelli, quadratus femoris) that laterally rotate the hip

The bony prominence you sit on; the common origin of all three hamstring muscles

A thickened band of fascia lata on the lateral thigh receiving insertion of gluteus maximus and tensor fasciae latae

A nerve from S2-S4 that exits through the greater sciatic foramen, hooks around the ischial spine, and re-enters through the lesser sciatic foramen

A network of arterial branches around the knee from the popliteal artery that provides collateral circulation