Topic 10 Flashcards
what are the functions of the pelvis
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.
what does the pelvic inlet house
what is its function
pubic crest
pectineal line
arcuate line
sacral alar and promontary
communicates with abdominal cavities.
what is the pelvic outlet
function
cocyx
ischial tuberosities
pubic symphysis
provides a passageway for child birth.
where is the true and false pelvis
true pelvis is inferior to pelvic inlet
false pelvis is superior inlet.
pubic symphysis joint
secondary cartilage
fibrocartilage disc between two symphyseal surfaces of both the pubic bones.
limited movement
sacroiliac joint
anterior - synovial plane
posterior - fibrous due to interosseous ligaments
articular surfaces - auricular surface of ilium and auricular surface of sacrum.
ligaments of the sacroiliac joint
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
what are the forces that act on the pelvis
what mechanisms stabilize the joint
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).
movements of pelvis in coronal plane
AP axis
pelvis drop (abduction) - ipsilateral gluteus medius and contralateral hip adductors.
pelvic life (adduction) - contralateral gluteus medius and ipsilateral hip adductors
movements of pelvis in sagittal plane - transverse axis
anterior pelvis tilt - produced by hip flexion (hip flexors).
posterior pelvic tilt - produced by hip extension (hip extensors).
movements of pelvis in horizontal plane
longitudinal axis
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.