Pelvic Cavity and Sacrum Flashcards
functions of the pelvic cavity
support urinary bladder, rectum, anal canal, reproductive tracts
contain reproductive tract in women and part of male reproductive tract
What happens when structures in the pelvic cavity expand?
The pelvic cavity is continuous with the abdominal cavity so they expand upwards into there
What is contained in the female pelvic cavity?
uterus, uterine tubes, vagina, bladder, terminal ureters, internal/external iliac, rectum, anal canal, anal sphincter
urethra, ovaries
What is contained in the male pelvic cavity?
ductus deferens, seminal vesicles, prostate, ejaculatory duct, rectum, anal canal, anal aperture, bladder, urethra
sacrum base vs apex
base is the widest part at the top, apex is the pointy end at the bottom
What part of the sacrum does the cauda equina pass through?
sacral canal
Does the coccyx have a vertebral arch?
No, cauda equina/nerves do not pass through the coccyx so no arch
What is the lumbosacral joint?
L5 and S1, consisting of 2 facet joints and an intervertebral disc
What ligaments stabilize the lumbosacral joint?
iliolumbar ligament, lumbosacral ligament, secondarily anterior longitudinal ligament
all function to reduce movement at this joint
Why does the lumbosacral joint need to be stable?
It accepts weight/force transmission from the LE into the spine
sacro iliac joint function
transmit force from lower limbs to vertebral column
what ligaments stabilize sacroiliac joints
anterior sacroiliac ligament (thickening of joint capsule), interosseous sacroiliac ligament (largest, strongest), posterior sacroiliac ligament (covers interosseous)
ligaments stabilizing pubic symphysis? Function?
superior pubic ligament, inferior pubic ligament
above and below symphysis
don’t function normally but serve as a back up to keep pubic bones together if symphysis starts to fail like in child birth
obturator internus
origin: anterolateral wall of true pelvis
insertion: medial surface greater trochanter femur
innervation: nerve to obturator internus
action: ER of extended hip, abduct flexed hip
piriformis
origin: anterior sacrum, btwn anterior sacral foramina
insertion: greater troch
innervation: L5-S2
action: ER extended hip, abduct flexed hip
what forms sacral plexus?
L4-L5 contributions, S1-C0
dorsal and ventral
Where do sacral plexus nerves exit?
out of anterior sacral foramina
sciatic nerve
L4-S3
Tibial
motor: all posterior thigh except short biceps, all posterior leg, all sole of foot muscles
sensory: posterolateral/medial skin of foot/sole
Common fibular
motor: short biceps, anterior and lateral leg, ext digitorum brevis, 1st dorsal interossei
sensory: anterolateral leg skin, dorsal foot skin
pudendal nerve
S2-S4
motor: skeletal m. perineum, urethral and anal sphincters, levator ani
sensory: perineum, penis, clitoris
superior gluteal nerve
L4-S1
motor: glut min, med, TFL
inferior gluteal
L5-S2
motor: glut max
nerve to obturator internus and superior gemellus
roots
L5-S2
motor: obturator internus and superior gemellus
nerve to quadratus femoris and inferior gemellus
L4-S1
motor: quadratus femoris and inferior gemellus
posterior femoral cutaneous nerve
S1, S3
sensory: posterior thigh skin
nerve to piriformis
S2-3
sensory: gluteal fold skin
motor: piriformis
nerves to levator ani, coccygeous, external anal sphincter
S4
motor: evator ani, coccygeous, external anal sphincter
sensory: skin btwn anus and coccyx
coccygeal plexus formed by
S4 small contribution, mainly formed by anterior rami of S5 and C0
anococcygeal nerves
S4-C0
senosry: perianal skin
