Muscles of the pelvis

Question 1

Iliacus

Answer 1

Attachments: from iliac fossa to lesser trochanter of the femur

Actions: flexes thigh and stabilizes hip joint

Innervation: femoral n. & lumbar plexus branches

Blood supply: iliolumbar, deep circumflex iliac, femoral & obturator aa.

Question 2

Psoas

Answer 2

Attachments: from anterior lumbar transverse processes, vertebral bodies, & discs to the lesser trochanter of the femur

Actions: Flexes thight and stabilizes hip joint

Innervation: ventral rami L1-3

Blood supply: lumbar, iliolumbar, obturator, external iliac, & femoral aa.

Question 3

Piriformis

Answer 3

Attachments: from the anterolateral sacrum to the upper border of the greater trochanter

Actions: abducts & laterally rotates thigh

Innervation: branches of the lumbosacral plexus

Blood supply: lateral sacral, superior gluteal & internal pudenal aa.

Question 4

Obturator internus

Answer 4

Attachments: from the anterolateral wall of the pelvis, obturator foramen & obturator membrane to the medial surface of the greater trochanter

Actions: laterally rotates thigh

Innervation: sacral plexus (nerve to obturator internus)

Blood supply: obturator & internal pudendal aa.

Question 5

Pelvic diaphragm-Coccygeus

Answer 5

Attachments: from ischial spine & sacrospinous ligament to coccyx

Actions: supports & compresses posterior pelvic floor

Innervation: ventral rami S4-5

Blood supply: inferior gluteal, internal pudendal, & inferior rectal aa.

Question 6

Pelvic diaphragm-Levator ani

Answer 6

Attachments: from pubic symphysis, obturator fascia & ischial spine to midline raphe & anococcygeal ligament

Actions: supports pelvic viscera & compresses rectum & vagina

Innervation: pudendal n. (inferior rectal branches) & S4

Blood supply: inferior gluteal, internal pudendal, inferior rectal & inferior vesical aa.