2-6 Osteology of the Pelvis Flashcards
Review the following coxal bones & structures in an atlas.
- Os Coxa (coxal bones)
a. Pubis: - Body
- Superior ramus
- Inferior ramus
- Crest
- Pubic Tubercle
- Pectineal line
b. Ischium
1. Body
2. Ramus (ischiopubic ramus)
3. Lesser sciatic notch
4. Spine
5. Tuberosity
c. Ilium
1. Ala
2. Body
3. Ant. sup. iliac spine (ASIS)
4. Ant. inf. iliac spine (AIIS)
5. Post. sup. iliac spine (PSIS)
6. Post. inf. iliac spine (PIIS)
7. Greater sciatic notch
8. Arcuate line
9. Auricular surface (for articulation with sacrum)
Review the following sacral and coccyx structures in an atlas.
Sacral: base sacral promontory ala pelvic sacral foramina median, intermediate and lateral sacral crests dorsal sacral foramina sacral hiatus, horns and canal auricular articular surfaces superior articular processes
Coccyx:
itself
What is the orientation of the ASIS and pubic symphysis in anatomical position?
ASIS and the pubic symphysis lie in the same coronal plane.
What is the angle of the pelvis in anatomical position?
The pelvis tips forward 50-60o from the horizontal.
Where is the position of the sacral promontory in relation to perineal body?
Sacral promontory directly superior to perineal body.
What are the 4 types of pelvic inlet shapes?
a. Android
1. Heart-shaped pelvic inlet.
2. Most common male pelvis; 30% of female pelves.
3. May present problems for vaginal delivery.
b. Gynecoid
1. Oval-shaped pelvic inlet.
2. Most common female pelvis (47%).
c. Anthropoid
1. Exaggerated anterior/posterior inlet.
2. 2nd most common male pelvis; 20% of female pelves.
d. Platypelloid
1. Exaggerated transverse inlet diameter.
2. Least common in both sexes.
How does the pubic arch and subpubic angle differ between genders?
males: 80 degrees
What is the articulation between pubic bones? What kind of cartilage?
Pubic symphysis
Symphysis joint – bones united by fibrocartilaginous disc (interpubic disc).
Interpubic disc is thicker in females than males.
What are the supporting ligaments of the pubic arch?
c. Supporting ligaments
1. Superior pubic ligament
2. Inferior public ligament (arcuate ligament)
What is the articulation between the sacrum and ilium? What kind of joint is it?
- Sacroiliac joint
a. Articulation between sacrum and ilium.
b. Anterior portion of joint is synovial between auricular surface of sacrum and ilium.
c. Posterior portion of joint is a syndesmosis between the tuberosities of sacrum and ilium.
What kind of motion is allowed at the sacroiliac joint? What limits it?
limited gliding and rotary movements
movement is limited due to irregular surfaces of bony surfaces and strong supporting ligaments.
What are the 5 supporting ligaments of the sacroiliac joints?
- Anterior sacroiliac ligament
- Posterior sacroiliac ligament
- Interosseous sacroiliac ligament
- Sacrotuberous ligament
- Sacrospinous ligament
What forms the syndesmosis portion of the sacroiliac joint? Why is it important?
- Interosseous sacroiliac ligament (syndesmosis portion of joint)
a. These are thick, strong ligaments that span from tuberosity of the ilium to tuberosity of the sacrum.
b. Main structures involved in transmitting the weight of the axial skeleton to the pelvis and ultimately to the lower limb.
What is the extent of the sacrotuberous ligament? What does it limit?
a. Extends from sacrum, coccyx, and ilium to ischial tuberosity.
b. Limits posterosuperior rotation of sacrum and coccyx.
What makes the sciatic notches into foramina?
The sacrospinous and sacrotuberous ligaments transform the sciatic notches into greater and lesser sciatic foramina.
