TBL 21 Flashcards
What separates the abdominal cavity from the bony pelvis?
iliac crest
What is the bony pelvis subdivided into?
It is subdivided by the pelvic brim into the greater pelvis (which is occupied by the inferior abdominal viscera) and lesser pelvis
What is the pelvic brim?
It is the bony edge surrounding the pelvic inlet that opens into the lesser pelvic cavity
What distinguishes the pelvic cavity?
It is continuous with the greater pelvis and abdominal cavity but is angulated posteriorly from them.
It is bound by the hip bones, sacrum and coccyx.
What does the pelvic diaphragm form?
It forms the bowl-like floor of the cavity.
What does the piriformis muscle do?
It traverses the greater sciatic foramen to its distal attachment on the femur. It attaches proximally to the pelvic surface of vertebrae S2-S4.
What does the obturator internus muscle do?
It pads the lateral wall of the pelvic cavity
What is the tendinous arch formed by the obturator internus fascia used for?
It provides lateral attachment site for the levator ani, the broad muscular sheet forming most of the pelvic diaphragm
What is the pubococcygeus muscle?
It is the intermediate part of the levator ani. It attaches anteriorly to the body of the pubis and the tendinous arch.
What is the puborectalis muscle?
It is the medial part of the levator ani and it forms the puborectal sling.
What is the urogenital hiatus?
It is an anterior gap between the medial borders of the puborectalis for passage of the urethra and in females the vagina.
What is the iliococcygeus?
It forms the posterolateral part of the levator ani.
What happens to the levator ani muscles before they attach to the coccyx?
the merge posteriorly.
What is the levator ani controlled by?
voluntarily controlled by the spinal nerve S4
Why is the levator ani tonically contracted and when must it relax?
Its tonic contraction bends the anorectum anteriorly. The levator ani must relax to allow urination and defecation.
Which levator ani muscles are most commonly torn during childbirth and what are the consequences?
The pubococcygeus and puborectalis, the main and most medial parts of the levator ani are the most commonly torn muscles during childbirth. Weakening of the levator ani from tearing during childbirth may decrease support for the vagina, bladder, uterus or rectum. It can also alter the position of the neck of the bladder and the urethra.
This may cause urinary stress incontinence which is characterized by dribbling of urine when intra-abdominal pressure is raised during coughing or lifting.
What does the coccygeus msucle do?
It attaches to the deep surface of sacrospinous ligament and provides minor assistance to the levator ani in supporting the pelvic viscera.
What covers the obturator internus and levator ani muscles?
fibrous parietal pelvic fascia
What does adventitia of the pelvic organs do?
It constitutes the visceral pelvic fascia.
What happens to the space between the parietal and visceral pelvic fasciae?
Loose connective tissue fills the space but eventually they become continuous where organs penetrate the levator ani.
What suspends organs from the lateral walls of the pelvic cavity?
parietal fascia derived lateral ligaments of the bladder and rectum
What does the cardinal ligament do?
It suspends the uterine cervix and vagina from the lateral walls of the cavity.
It provides passage to vessels and periarterial nerve plexuses from the lateral walls of the pelvic cavity to the pelvic viscera
What are some branches of the internal iliac artery? What does the internal iliac artery generate?
superior and inferior gluteal arteries are branches
provides branches that supply the pelvic viscera
generates the umbilical arteries
What are vesicle arteries?
They arise from patent parts of the umbilical arteries
They supply the bladder
What forms medial umbilical ligaments?
obliterated parts of the umbilical arteries form the medial umbilical ligaments which are covered by medial umbilical folds
What forms the superior hypogastric plexus?
postsynaptic sympathetic fibers with accompanying visceral afferent fibers exit the prevertebral ganglia to form the intermesenteric plexus that descends along the abdominal aorta and at its terminal bifurcation forms the superior hypogastric plexus