Pelvis & Perineurium Flashcards
What are the 3 parts of the pelvic bone(os coxa)?
- Ilium
- ischium
- pubis
What do pelvic bones do in puberty?
Fuses together at the acetubulum during adolescence
-articulation site for the femoral head
Describe the pelvic girdle
- two pelvic bones and sacrum
- left and right ilia articulate with sacrum posteriorly
- left and right pubis articulates anteriorly with pubic symphysis
What are the pelvic openings?
Sublinguinal canal- Abdomen/ abdominopelvis and anterior thigh
Obturator canal- pelvis and medial thigh
Greater sciatic foramen- pelvis and gluteal region
Lesser sciatic foramen- gluteal region and perineum
Contrast the true and false pelvis
The iliac blades contribute to the abdominal cavity = false pelvis
Below the pelvic inlet is the pelvic cavity= true pelvis
Contrast the pelvic inlet and pelvic outlet
Pelvic inlet- sacral promontory, sacral ala, arcuate line, pectineal line, pubic crest
Pelvic outlet- Anterior: pubic symphysis, ischiopubic ramus; posterior is hail tuberosities, sacrotuberous ligaments and sacrum
What are the sacroiliac joints?
Iliac and sacral ala
Two components:
-synovial- mobile
-syndesmosis- immobile
Sacrotuberous and sacrospinous…
Ligaments oppose posterior sacral rotation
Sacraspinous ligaament- from sacrum to ischial spine
Sacrotuberous ligament- from sacrum to ischial tuberosity
Describe pelvic measurements
A variety of obstetric measurements can be done
- conjugate (AP)
- conjugate diagonal
- transverse
- oblique
- interspinous diameter(narrowest)
- anterior posterior (AP) diameter of pelvic inlet
These measurements are used to determine the fixed size of the birth canal and the likelihood of a safe vaginal delivery
Contrast the male and female pelvis
Female:
- flared ala
- oval pelvic inlet(brim)
- wide pelvic outlet
- wide subpubic angle
- J-shaped sacrum
Male:
- upright ala
- heart shaped pelvic inlet(brim)
- narrow pelvic outlet
- narrow subpubic angle
- C-shaped sacrum
What are the muscles of the pelvic walls?
Wall
- piriformis
- obturator internus
What are the muscles of the pelvic floor?
Floor (pelvic diaphragm)
- Coccygeus
- levator ani-(assists in maintaining fecal and urinary continence)
- iliococcygeus
- pubococcygeus
- puborectalis-forms a “U” shaped sling around the anorectal junction that helps maintain fecal continence
What is the function of obturator internus?
- Lateral rotation
- abduction
What is the innervation and blood supply of the obturator canal?
Obturator nerve
Obturator artery
What is the function of the piriformis?
- Lateral rotation
- abduction