Topic 10

Question 1

what are the functions of the pelvis

Answer 1

support and protects pelvis viscera and lower abdominal viscera.

provides bone support for the birth canal and therefore an exit for the foetus.

provides extensive muscle attachment sites

supports the weight of the head, trunk and upper limbs.

allows for weight transfer when sitting.

Question 2

what does the pelvic inlet house

what is its function

Answer 2

pubic crest
pectineal line
arcuate line
sacral alar and promontary

communicates with abdominal cavities.

Question 3

what is the pelvic outlet

function

Answer 3

cocyx
ischial tuberosities
pubic symphysis

provides a passageway for child birth.

Question 4

where is the true and false pelvis

Answer 4

true pelvis is inferior to pelvic inlet

false pelvis is superior inlet.

Question 5

pubic symphysis joint

Answer 5

secondary cartilage
fibrocartilage disc between two symphyseal surfaces of both the pubic bones.
limited movement

Question 6

sacroiliac joint

Answer 6

anterior - synovial plane
posterior - fibrous due to interosseous ligaments

articular surfaces - auricular surface of ilium and auricular surface of sacrum.

Question 7

ligaments of the sacroiliac joint

Answer 7

anterior:

• anterior sacroiliac ligament
• interosseous sacroiliac ligament
• iliolumbar ligament

all stabilise sacroiliac ligament and prevent anterior and inferior slide of sacrum

posterior:

• posterior sacroiliac ligament - stabilises
• sacrotuberous ligament - limit nutation
• sacrospinal ligament - limit nutation

Question 8

what are the forces that act on the pelvis

what mechanisms stabilize the joint

Answer 8

weight of trunk, head and arms
gravity

form closure - passive structures (joint surface alignment, joint surface configuration and ligaments being under tension).

force closure - active structures (muscles and fascia interacting together and acting on joints to enhance compression in order to increase stability).

Question 9

movements of pelvis in coronal plane

AP axis

Answer 9

pelvis drop (abduction) - ipsilateral gluteus medius and contralateral hip adductors.

pelvic life (adduction) - contralateral gluteus medius and ipsilateral hip adductors

Question 10

movements of pelvis in sagittal plane - transverse axis

Answer 10

anterior pelvis tilt - produced by hip flexion (hip flexors).

posterior pelvic tilt - produced by hip extension (hip extensors).

Question 11

movements of pelvis in horizontal plane

longitudinal axis

Answer 11

pelvis rotation to the right - left hip external rotators and right hip medial adductors

rotation to the left - right hip external rotators and left hip medial rotators.