Wet Lab 3 - The Bony Pelvis Flashcards
Are the abdominal and pelvis cavities separated by anything/membrane ?
No - they are continuous through the pelvic inlet
Where is the true pelvis located ?
Below the pelvic brim/inlet
Where is the false pelvis located?
Above the pelvic brim/inlet
What is the pelvic brim composed of
- sacral promontory
- sacral ala
- arcuate line
- pectineal line
- pubic symphysis
How is the pubic outlet viewed?
It is on the underside, viewed upwards from below on a ligamentous pelvis where it has a diamond-shaped border
What is the pelvic outlet composed of ?
- pubic symphysis
- ischiopubic ramus
- ischial tuberosity
- sacrotuberous ligament
- coccyx
What is the pubic arch referred to as?
The subpubic arch and the ischiopubic ramus
What is the pelvic outlet closed by ?
Pelvic diaphragm
What are other names for the hip bone
- innominate
- os coxa
What is the hip bone composed of ?
3 ossification elements s
- ilium
- ischium
- the pubis
What is the process of these ossification elements ?
In childhood, these ossification elements are true seperate bones which are separated bones with a cartilage the joins between them. They fuse together in the early 20s
What it the cartilage that is joint between the ossification elements ?
Triradiate cartilage
What happens in the fused adult pelvis ?
The bone is thicker wherever the ossification elements meet
What is the sacrum
It is a triangular bone just below the lumbar vertebrae
What is nutation of the sacrum
It means “nodding” which is a tiny movement within the pelvis of the sacrum relative to the hip bone
Why is nutation a tiny movement ?
Because the sacrum is tightly held in place by strong thick ligaments - sacrotuberous, sacrospinous and the sacroiliac joint capsule
What causes nutation of the sacrum
The tendency of gravitational body weight - it tightens the ligaments which prevents further movement
What is are the movements during nutation of the sacrum ?
- the promontory moves forward-down
- coccyx moves backward-up
Where is the axis of rotation during nutation of the sacrum ?
Somewhere within the SIJ and it does not move
What is counternutation of the sacrum ?
It is the opposite-direction movement of nutation
What planes do these movements take place ?
The sacrum can move at the SIJ in all 3 cardinal planes (Sagittarius, coronal and transverse), making it a true multiaxial joint.
Most move to occur in the Sagittarius plane: nutation-counternutation
