Pelvic Walls and Floor Flashcards
What forms the greater sciatic foramen and the lesser sciatic foramen?
Sacrotuberous and sacrospinous ligaments
What are the wall muscles of the pelvis?
Iliacus, psoas, obturator externus, obturator internus and piriformis,
The iliac fossa joins psoas as what?
iliopsoas
Where does the iliopsoas insert into?
Lesser trochanter of femur
What is the function of the iliacus?
Hip flexion
What innervates the iliacus?
Femoral nerve
Fibers of the psoas pass from?
T12 - L4
What is the function of psoas?
Hip flexion, bend trunk lateral, raise trunk from supine position
What innervates the psoas?
Lumbar plexus direct branches L2-4 anterior rami
What are the gluteal muscles?
Gluteus maximus, medius and minimus
What do the gluteal muscles attach to?
Pelvic bones but to within pelvic cavity
Function of gluteal muscles?
Act on the hip joint
Fibers of obturator externus pass?
From the outer surface of obturator membrane to trochanteric fossa of femur
Fibers of obturator internus pass?
From the inner surface of obturator membrane to medial surface of greater trochanter of femur
What is the function of obturator internus?
Lateral rotation of the hip
What innervates the obturator internus?
Nerve to obturator internus direct from sacral plexus (L5, S1)
Fibers of the piriformis pass?
From the anterior surface of the sacrum to greater trochanter of the femur
What is the function of piriformis?
Lateral rotation of the hip joint
What innervates piriformis?
Nerve to piriformis direct branch of sacral plexus (S1 and S2)
What is the pelvic diaphragm?
A muscular floor composed of elevator ani and coccyges to prevent prolapse
What is the muscular roof of the anal triangle?
Levator ani
Fibers pass in the coccyges from?
Ischial spine and sacrospinous ligament to the coccyx and inferior sacrum
What is the function of the coccygeus?
Support pelvic viscera, flexion of coccyx
What innervates the Coccygeus?
Direct branches from sacral plexus (S4-S5)
What are the two muscles involved in the levator ani?
Pubococcygeus and iliococcygeus
Describe the fibres in the Pubococcygeus?
Most medial fibres, attach to and support vagina/prostat gland and rectum
Describe the fibres in the Iliococcygeus?
More lateral fibres of elevator ani, anterior to coccygeus
What is pubococcygeus divided into?
Puborectalis, puboprostaticus and pubovaginalis
What must relax to allow urination and defecation?
Levator ani
What innervates the pubococcygeus?
Pudendal and nerve to levator ani
In males what is the muscle that has medial fibres that pass around prostate and insert into perineal body?
Puboprostaticus
In females, what is the muscle that has medial fibres that pass around the vagina and insert into perineal body?
Pubovaginalis
What muscle is in both sexes?
Puborectalis
Describe the fibres in Puborectalis?
Mix with those from external anal sphincter
Why are the fibres modified as a sling around the rectum in puborectalis?
To help maintain faecal continence
What innervates the Puborectalis?
Pudendal nerve and nerve to levator ani
What does the iliococcygeus muscle attach to?
Fascia of obturator internus and the anococcygeal body/ligament/levator plate
Iliococcygeus is more fibrous than?
Pubococcygeus
What is described as the tendinous arch of levator ani?
Area of attachment to the fascia of obturator internus
What innervates the iliococcygeus?
Pudendal nerve and nerve to levator ani
What is the perineal body composed of?
Fibrous connective tissue
What attaches to the perineal body?
Levator prostatae, pubovaginalis, external anal sphincter and perineal muscles
