Gluteal Region Muscles PDF

Gluteal Region Boundaries of the Gluteal Region  superior: iliac crest  inferior: gluteal fold (skin fold that separates gluteal region from posterior thigh)  medial: natal (intergluteal) cleft and cleft between right and left buttocks  lateral: line connecting ASIS to...

Gluteal Region Boundaries of the Gluteal Region  superior: iliac crest  inferior: gluteal fold (skin fold that separates gluteal region from posterior thigh)  medial: natal (intergluteal) cleft and cleft between right and left buttocks  lateral: line connecting ASIS to greater trochanter Muscles of Gluteal Region  Gluteus Maximus o partly responsible for prominence of buttock o Origin: outer (gluteal) surface of ilium (behind posterior gluteal line), posterior surfaces of sacrum and coccyx, sacrotuberous ligament o Insertion: fibers run inferiorly and laterally and most fibers insert into iliotibial tract - deeper and lower fibers insert into gluteal tuberosity of femur o iliotibial tract: thickening of deep fascia of thigh (fascia lata) along its lateral aspect and extends from tubercle of iliac crest to anterolateral aspect of lateral condyle of tibia (Gerdy’s or iliotibial tract tubercle) o Nerve supply: inferior gluteal nerve o Action: extension of thigh at hip joint (important in rising from sitting position and in climbing stairs), lateral rotation of thigh at hip joint, provides stability to extended knee (via iliotibial tract)  Gluteus Medius o fan-shaped muscle o inferior part covered by gluteus maximus o superior part covered by gluteal aponeurosis o Origin: outer (gluteal) surface of ilium (between anterior and posterior gluteal lines) o Insertion: fibers pass inferiorly and laterally to attach to lateral surface of greater trochanter of femur  Gluteus Minimus o fan-shaped muscle o lies deep to gluteus medius o Origin: outer (gluteal) surface of ilium (between anterior and inferior gluteal lines) o Insertion: fibers pass inferiorly and laterally to attach to anterior surface of greater trochanter of femur  Gluteus Medius and Minimus o Nerve supply: superior gluteal nerve o Action:  abduction and medial rotation of thigh at hip joint  during walking, when foot of opposite side is taken o the ground and thrust forward, gluteus medius and minimus steady pelvis on supporting lower limb (prevent pelvis from tilting downward on unsupported side) o paralysis of gluteus medius and minimus - when patient stands on lower limb on the side of paralysis, pelvis sinks on opposite, unsupported side (positive Trendelenburg’s sign)  Tensor Fasciae Latae o fascia lata splits to enclose this muscle o Origin: outer edge of iliac crest between ASIS and tubercle of iliac crest o Insertion: fibers run inferiorly and slightly posteriorly and insert into iliotibial tract o Nerve supply: superior gluteal nerve o Action:  helps with flexion, abduction and medial rotation of thigh at hip joint  provides stability to extended knee (via iliotibial tract)  Piriformis o important landmark in gluteal region o all vessels and nerves that pass from pelvic cavity to gluteal region, via greater sciatic foramen, are related to superior or inferior borders of piriformis o Origin: within pelvis, from anterior surface of sacrum, lateral to anterior sacral foramina (S2-S4 sacral segments)  o Insertion: it passes laterally and inferiorly and exits pelvis via greater sciatic foramen and inserts into upper border of greater trochanter o Nerve supply: nerve to piriformis (supplies piriformis inside pelvis, does not enter gluteal region) o Action: lateral rotation of thigh at hip joint, steadies femoral head in acetabulum  Obturator Internus o lies within pelvis at its origin o Origin: pelvic (internal) surface of obturator membrane and bony margins of obturator foramen o Insertion: muscle tapers posteriorly to a narrow belly and tendon and enters gluteal region via lesser sciatic foramen and is joined by superior and inferior gemelli in gluteal region and together they insert into medial surface of greater trochanter o Nerve supply: nerve to obturator internus o Action: lateral rotation of thigh at hip joint, steadies femoral head in acetabulum  Superior Gemellus o Origin: posterior surface of ischial spine o Insertion: with tendon of obturator internus into medial aspect of greater trochanter o Nerve supply: nerve to obturator internus o Action: lateral rotation of thigh at hip joint, steadies femoral head in acetabulum  Inferior Gemellus o Origin: upper part of ischial tuberosity o Insertion: with tendon of obturator internus into medial aspect of greater trochanter o Nerve supply: nerve to quadratus femoris o Action: lateral rotation of thigh at hip joint, steadies femoral head in acetabulum  Quadratus Femoris o Origin: upper part of lateral border of ischial tuberosity o Insertion: fibers pass laterally and insert into quadrate tubercle (on intertrochanteric crest of femur) and area inferior to it o Nerve supply: nerve to quadratus femoris o Action: lateral rotation of thigh at hip joint, steadies femoral head in acetabulum Structures Passing Through the Greater Sciatic Foramen  piriformis muscle  sciatic nerve  posterior cutaneous nerve of thigh  superior and inferior gluteal nerves  nerve to obturator internus  nerve to quadratus femoris  pudendal nerve  superior and inferior gluteal vessels  internal pudendal vessels Structures Passing Through the Lesser Sciatic Foramen  obturator internus muscle  nerve to obturator internus  pudendal nerve  internal pudendal vessels