Pelvic Wall Flashcards
What are the functions of the pelvis?
1) Attachment for lower limb muscles
2) protect pelvic viscera
3) support abdominopelvic viscera
4) attachment of erectile bodies and external genitalia on perineal membrane
5) attachment of muscles on pelvic floor
6) bear weight
What makes up the boney pelvis?
The pelvic = ilium, ischium, and pubic; sacrum; coccyx.
What is the thickest portion of the ilium and what is its significance?
The arcuate line bears the weight dispersing function of the pelvis.
What runs through the anterior and posterior formina of the sacrum? Be specific.
The rami of spinal nerves. Ventral rami leave anterior foramina. Dorsal rami leave posterior famina.
Which ligament divides the lesser and greater sciatic notches into lesser and greater sciatic foramina?
The sacrospinous ligament.
Which ligament helps to close off the lesser sciatic notch to complete the lesser sciatic foramen?
The sacrotuberous ligament.
What is the pelvic inlet or superior pelvic aperture?
It is an area of the pelvis from the promontory of sacrum to ala of sacrum to arcuate line to pectineal line (pecten pubis) to pubic creast to pubic symphysis. It also divides the pelvis into 2 regions, the greater and lesser, or false and true, pelvis.
What is the linea terminalis?
The combined structure made of the arcuate lines, pectineal lines, pubic crests
Where is the greater (false) pelvis?
Superior to pelvic inlet and contains ala of ilium and iliac crest - and abdominal muscles
Which part of the pelvis is inferior to the pelvic inlet and contains visceral structures?
The lesser (true) pelvis.
What is the pelvic outlet?
Area of the pelvis including pubic arch, ischiopubic rami, ischial tuberosities, tip of coccyx, sacrotuberous ligaments
What is superficial and inferior to the pelvic outlet?
The perineum.
Which gender has a rounder pelvic inlet and a subpubic angle of 90 degrees?
Female.
Which gender has a heart-shaped pelvic inlet and a subpubic angle of 50-60 degrees?
Male.
What is the interspinous distance?
The variable, most narrow part of the pelvic canal between the ischial spines.
What are the 3 categories of conjugates that describe the anterior-posterior distance of the pelvic inlet?
1) True conjugate - distance between superior aspect of pubic symphysis and sacral promontory
2) Obstetrical conjugate - distance between thickest/middle part of pubic symphysis and sacral promontory
3) Diagonal conjugate - distance between inferior aspect of pubic symphysis and sacral promontory.
Why would the interspinous distance increase? How much can it increase?
Pregnancy/delivery; 10-15% with hormones
What are the muscles of the pelvic wall?
1) Obturator internus
2) Piriformis
Obturator internus
Obturator forament; greater trochanter of femur
Inn: nerve to obturator internus
F: lateral rotation of hip and abduction of hip
Piriformis
Anterior surface of sacrum; grater trochanter
Inn: nerve to piriformis
F: later rotation of hip and abduction of hip
What are the muscles of the pelvic diaphragm?
1,2) Levator ani = pubococcygeus + iliococcygeus
3) Coccygeus or ischococcygeus
Pubococcygeus
Pubis bone to coccyx’ supports pelvic viscera, attaches to perineal body, medial part forms puborectalis muscle
Iliococcygeus
tendinous arch off inferior boarder of obturator internus tendon to ischial spine; support viscera
Coccygeus or Ischococcygeus
Attaches superior to ischial spine and anterior surface of sacrum
Which nerve innervates the muscles of the pelvic diaphragm?
The pudendal nerve.
