Lecture 18: gluteal muscles and thigh external rotators (OINA)

Gluteal muscles

gluteus maximus, gluteus medius, gluteus minimus

Gluteus maximus Origin

Posterior gluteal line, iliac crest, posterior surface of sacrum and sacrotuberous ligament

Gluteus maximus Insertion

Iliotibial band (75%) and gluteal tuberosity of femur (25%)

Gluteus maximus Innervation

Inferior gluteal nerve

Gluteus maximus Action

Extension and external rotation of thigh

Gluteus medius Origin

Area between anterior and posterior gluteal lines

Gluteus medius Insertion

lateral surface of greater trochanter

Gluteus medius Innervation

Superior gluteal nerve

Gluteus medius Action

Abduction of thigh

Anterior fibers: flex and internally rotate thigh

Posterior fibers: extend and externally rotate thigh

Gluteus minimus Origin

Area between anterior and inferior gluteal lines

Gluteus minimus Insertion

Anterior surface of greater trochanter

Gluteus minimus Innervation

Superior gluteal nerve

Gluteus minimus Action

Abduction and internal rotation of thigh

Thigh External Rotators

pirifirmis
obturator internus
Superior gemellus
Inferior gemellus
Quadratus femoris

Piriformis origin

anterior surface of sacrum

piriformis insertion

upper border of greater trochanter

piriformis innervation

S1-2

piriformis action

external rotation of thigh

abduction when thigh is flexed

Obturator Internus Origin

Internal surface of obturator membrane and surrounding margin

Obturator Internus Insertion

Trochanteric fossa of femur

Obturator Internus Innervation

Nerve to obturator internus

Obturator Internus Action

External rotation of thigh

Superior gemellus Origin

Spine of ischium

Superior gemellus Insertion

tendon of obturator internus

Superior gemellus Innervation

Nerve to obturator internus

Superior gemellus Action

External rotation of thigh

Inferior gemellus Origin

Superior part of ischial tuberosity

Inferior gemellus Insertion

Tendon of obturator internus

Inferior gemellus Innervation

Nerve to quadratus femoris

Inferior gemellus Action

External rotation of thigh

Quadratus femoris Origin

Lateral border of ischial tuberosity

Quadratus femoris Insertion

Quadrate tubercle

Quadratus femoris Innervation

Nerve to quadratus femoris

Quadratus femoris Action

External rotation of thigh