Pelvic Wall Flashcards
function of pelvic girdle (pelvis)
1) . weight bearing linkage between legs and axial skeleton
2) . muscle attachment point
3) .protects organs in pelvic cavity
Hip bones
Ilium, ischium, pubis
landmarks on the ilium
1) . ala & body
2) . iliac crest
3) . iliac fossa
4) . ASIS and AIIS
5) . PSIS and PIIS
6) . auricular surface
7) . tuberosities
8) . arcuate line
function of auricular surface of ilium
synovial articulation with sacrum
landmarks on the ischium
1) . body
2) . ramus of ischium
3) . ischial tuberosity
4) . ischial spine
5) . lesser sciatic notch
landmarks on the pubis
1) . S/I ramus
2) . body
3) . pubic crest
4) . pubic tubercle
5) . pectin pubis (pectineal line)
what are the composite structures in the pelvis?
1) . acetabulum
2) . obturator foramen
3) . greater sciatic notch
4) . pelvic brim (pelvic inlet)
what forms the acetabulum?
ilium, ischium, and pubis
what forms the obturator foramen?
ischium and pubis
what forms the greater sciatic notch?
ilium and ischium
T/F: the pelvic brim is different between males and females?
TRUE, reflective functional difference due to childbirth
what forms the pelvic brim?
1) . sacral promontory
2) . arcuate line of ilium
3) . pectineal line of pubis
4) . crest of pubis
what forms the pelvic outlet?
1) . ischial tuberosities
2) . inferior pubic symphysis
3) . coccyx
what are the divisions of the pelvis?
1) . greater (false) pelvis
2) . lesser (true) pelvis
3) . perineum
what is the greater (false) pelvis?
lies above pelvic brim, contains inferior abdominal organs (ileum, sigmoid colon)
what is the lesser (true) pelvis?
lies between the pelvic brim and pelvic diaphragm and contains pelvic organs (urinary bladder/distal ureters; rectum, genital organs)
what is the perineum?
not part of the pelvic cavity but consists of soft tissue below the pelvic diaphragm between the base of the thighs
what articulates at the sacroiliac joint?
sacrum and ilium
what type of joint is the sacroiliac joint?
complex joint, both a syndesmosis and synovial joint
which portion of the sacroiliac joint is synovial?
Anterior - modified planar with interlocking irregular articular surface
which portion of the sacroiliac joint is syndesmosis?
Posterior - formed by interosseus sacroiliac ligaments
what do the interosseus sacroiliac ligaments do?
limit the tilt of the pelvis
name the sacroiliac ligaments
1) . anterior sacroiliac ligament
2) . posterior sacroiliac ligament
3) . sacrotuberous ligament
4) . sacrospinous ligament
5) . iliolumbar ligament
anterior sacroiliac ligament function
capsule thickening
posterior sacroiliac ligament function
limits depression of the sacrum (or elevation of the hips) - continuation of interosseus sacroiliac ligaments
sacrotuberous and sacrospinous ligament function
limit upward rotation of inf sacrum (post tilt of coccyx)
what forms the greater sciatic foramen?
1) . greater sciatic notch (superior, anterior)
2) . sacrotuberous ligament (posterior)
3) . sacrospinous ligament (inferior)
what passes thru the greater sciatic foramen?
1) . sciatic nerve
2) . S/I gluteal nerves, arteries, and veins
3) . piriformis muscle
what forms the lesser sciatic foramen?
1) . lesser sciatic notch (ant, inf)
2) . sacrotuberous ligament (post)
3) . sacrospinous ligament (sup)
what movements occur at the sacroiliac joint?
limited gliding and rotation act as shock absorber
what articulates at the pubic symphysis?
pubic bones of R/L hip
pubic symphysis joint type
cartilaginous disk = symphysis
pubic symphysis ligaments
S/I pubic ligments
what does the inferior pubic ligament form?
apex of pubic arch
functional joint type of pubic symphysis
syn- or amphiarthrosis depending on age
what forms the anterior wall of the true pelvis?
pubic bones (body and rami) and pubic symphysis
what forms the lateral wall of the pelvis?
1) . obturator foramen
2) . obturator membrane
3) . obturator internus muscle
4) . tendinous arch of the levator ani muscle
what forms the posterior wall of the pelvis?
1) . sacrum
2) . ilium
3) . posterior sacroiliac joint ligaments
4) . piriformis muscle
what forms the floor of the pelvis?
pelvic diaphragm
pelvic diaphragm role
1) . regulate abdominal pressure
2) . supports abdominopelvic organs
3) . functions in micturition, defecation, and respiration
what structures pass through the pelvic diaphragm?
1) . urethra
2) . rectum
3) . vagina
4) . nerves of lumbosacral plexus
5) . branches of internal iliac artery & vein
pelvic floor muscles
1) . coccygeus muscle
2) . levator ani
Coccygeus muscle
also called ischeococcgeus - attached sacrum/coccyx to ischial spine
Coccygeus muscle prox attachment
sacrum/coccyx
Coccygeus muscle distal attachment
ischial spine
Coccygeus muscle action
supports pelvic organs; regulate abdominal pressure
Coccygeus innervation
ventral rami
Levator ani
composite of 3 muscles:
1) . puborectalis
2) . pubococcygeus
3) . iliococcygeus
puborectalis prox attachment
anococcygeal body (ligament)
puborectalis distal attachment
pubis
puborectalis action
supports pelvic organs; forms external anal sphincter
puborectalis innervation
ventral rami
pubococcygeus prox attachment
coccyx
pubococcygeus distal attachment
pubis
pubococcygeus action
supports pelvic organs’ regulate abdominal pressure
pubococcygeus innervation
ventral rami
iliococcygeus prox attachment
coccyx
iliococcygeus distal attachment
tendinous arch between ischial spine and pubic body
iliococcygeus action
supports pelvic organs’ regulate abdominal pressure
iliococcygeus innervation
ventral rami
what is the urogenital hiatus?
“V” shaped opening in pelvic diaphragm between puborectalis muscle - from pubis symphysis to perineal body of rectum
urogenital hiatus contents
peroneal structures including:
1) . deep transverse perineal muscle
2) . external urethral sphincter/compressor urethra
3) . perineal body
what is the perineal body?
CT running down center of perineum
connects the rectum to prostate/urethra
Pelvic vasculature: arteries
1) . paired internal iliac
2) . S/I rectal
3) . median sacral
4) . paired ovarian
paired internal iliac arteries are branches off of what?
common iliac
S rectal artery is a branch from what?
inferior mesenteric artery
median sacral artery is from what?
abdominal aorta
Venous route in pelvic vasculature
organs -> venous plexi -> internal iliac veins -> common iliac veins -> inferior vena cava
what is the Lumbosacral plexus?
ventral rami L1-S4
Sympathetic innervation of pelvic region
sympathetic chain ganglia; hypogastric plexus; sacral splanchnic nerves
Parasympathetic innervation of pelvic region
pelvic splanchnic nerves = ventral rami S2-4
what is the role of the ilolumbar ligament?
stabilize L5 and holds it to the posterior ilium bone,
what is found in the soft tissue of the perineum?
external genitalia
what shape is the pelvic floor/diaphragm?
diamond,
can be further divided into 2 triangles
what 2 triangles can the pelvic floor/diaphragm be divided into?
- urogential (anterior)
- anal (posterior)
what provides parasympathetic innervation to the pelvic region?
Pelvic splanchnic nerve (ventral rami S2-4)
what is the central point of the perinum called?
perineal body
connects rectum to prostate/urethra
Where is the perinal body?
Between the urogenital hiatus and the external anal spinchter
what are the muscles of the perineum?
- external anal sphincter
- bulbospongiosus
- ischocavernosus
- superficial transverse perineal muscle
- perineal membrane
- deep transverse perineal muscle
- external urethral sphincter/compressor urethrae
What is the origin of the external anal sphincter?
coccyx via the anococcyceal ligament
insertion of the external anal sphincter?
perineal body
External anal sphincter action?
- resists/regulates defecation
- supports and fixes perineal body and pelvic floor
External anal sphincter innervation
inferior anal (rectal) nerve
Bulbospongiosus origin to insertion
median raphe on ventral surface wraps around the bulb of the penis (in males) and perineal body (in females)
Bulbospongiosus main action
- males = ejaculation
- females = maintain erection
Ischiocavernosus origin
internal surface of ishiopubic ramus and ischial tuberosity
Ischiocavernosus insertion
surrounds the crus
Ischiocavernosus main action
responsible for erection in both males and females
Ischiocavernosus innervation
Muscular branch of perineal nerve
superficial transverse perineal muscle origin
internal surface of ischiopubic ramus and ischial tuberosity
Superficial transverse perineal muscle insertion
perineal body
Superficial transverse perineal muscle action
supports and fixes perineal body/pelvic floor to support abdominopelvic viscera and regulate abdominal pressure
Superficial transverse perineal muscle innervation
muscular branch of perineal nerve
deep transverse perineal muscle origin
internal surface of ischiopubic ramus and ischial tuberosity
deep transverse perineal muscle insertion
perineal body and external anal sphincter
deep transverse perineal muscle action
supports and fixes perineal body/pelvic floor to support abdominopelvic viscera and help regulate abdominal pressure
deep transverse perineal muscle innervation
muscular branch of perineal nerve
T/F: the external urethral sphincter/compressor urethrae is skeletal muscle and thus under voluntary control?
TRUE, main action is voluntary control of urine flow
what is the external urtheral sphincter/compressor urethrae formed by?
- thickening of the wall – called the external urethral sphincter
- sling around the urethrae associated with the thickening called the compressor urethrae – acts like the puborectalis – squeezes the tube
