the pelvis

Question 1

2 functions of the pelvis

Answer 1

• girdle for lower limb attachment - force transduction

- basin to hold pelvic viscera

Question 2

force transduction

Answer 2

allows force to be transduced from the ground through bone

Question 3

pelvic girdle is made up of

Answer 3

sacrum and 2 os coxa

Question 4

os coxa

Answer 4

three bones that fuse during development

Question 5

broad pelvis

Answer 5

distance covered by momentum moving over a fixed limb is larger
increased the efficiency in bipedalism

Question 6

distance between acetabulum and the scare-iliac joint is short

Answer 6

centre of mass is vertically closer to the hip joint - easier to control and balance

Question 7

rickets

Answer 7

issues with the composition of the bone of the pelvis

bones can bend in pathological ways due to force transduction

Question 8

pelvic inlet/brim defines

Answer 8

true pelvis - beneath it

false pelvis - above it

Question 9

pelvic brim is the same as

Answer 9

pelvic inlet

Question 10

sacral promontory

Answer 10

part of the S1 vertebral body protruding into the pelvis

Question 11

pubic symphysis

Answer 11

anterior mechanical link between limbs
weaker than posterior link
bone on with side (pubic bone), N plate cartilage and fibrous cartilage in the middle
capsular ligaments thickened at the top and the bottom - superior and inferior pubic ligament

Question 12

joint cavities

Answer 12

• can be due to trauma
• common in multiparous women
• fibrous cartilage tears

Question 13

sacroiliac joint

Answer 13

synovial joint
auricular surfaces articulate
auricular cavity - not fully connected

Question 14

capsular ligaments in the sacroiliac joint

Answer 14

ventral sacroiliac - thin

dorsal interosseous sacroiliac - very thick, resists more forces

Question 15

sacrospinous ligament

Answer 15

between sacrum and spine off the ischium

Question 16

sacrotuberous ligament

Answer 16

from the sacrum to the ischial tuberosity

Question 17

iliolumbar

Answer 17

between L5 and the ilium

Question 18

coronal and forntal stability

Answer 18

keystone principle
SI joint can slip in the coronal plane - wedges itself
resisted by dorsal interosseous and iliolumbar ligament

Question 19

more slip of the SI joint

Answer 19

means more tension on the ligaments
holds ileum to sacrum more securely
limits further movement

Question 20

functional leg length discrepency

Answer 20

changes in where the joint is positioned

causes difference in legs length due to SI joint

Question 21

lumbosacral joint and sagittal stability

Answer 21

joint is steeply sloped
60 degrees for males and up to 80 in females
force on lumbar to slip anteriorly

Question 22

resistance to lumbar slipping

Answer 22

dorsal ligaments
iliolumbar ligaments
neural arch components (articular processes)

prevent arteries displacement

Question 23

tendency of the sacrum to rotate forwards relative to the ilium is resisted by

Answer 23

dorsal interosseous SI ligament
sacrotubuerous ligament
sacrospinous ligament

Question 24

greater sciatic foramen is formed by

Answer 24

sacrotuberous ligament

Question 25

lesser sciatic foramen is formed by

Answer 25

sacrospinous ligament

Question 26

what plugs up the obturator foramen

Answer 26

obturator muscles - internal and external | internus tendon passes through lesser sciatic foramen

Question 27

what covers obturator internus muscle

Answer 27

obturator fascia | forms attatchemtn for the pelvic diaphragm

Question 28

what passes through the obturator canal

Answer 28

obturator nerve and vessels

Question 29

what passes through the greater sciatic Foramen

Answer 29

- piritoforms muscle - sciatic nerve - gluteal nerves and vessels - pudendal nerves and vessels

Question 30

what passes through the lesser sciatic foramen

Answer 30

- obturator inernus tendon | - pedundal nerve and vessels

Question 31

what closes the pelvic outlet

Answer 31

pelvic floor - levator ani - all support abdomino pelvic viscera - elevates anal canal - made from 3 muscles - used to be 4

Question 32

levator ani is made up of

Answer 32

1. pubococcygeus 2. iliococcygeus 3. puborectalis

Question 33

sexual dimorphism in male pelvis

Answer 33

external features related to load bearing and muscle attachment tend to be bigger

Question 34

sexual dimorphism in female pelvis

Answer 34

internal diameters are larger - predict likelihood of successful vaginal delivery - creates larger and rounder pelvic cavity

Question 35

male pelvis internal morphology

Answer 35

has less variation - not an evolutionary pressure

Question 36

bipedalism changes pregnancy centre of mass issues

Answer 36

increased tendency to fall forwards the hormone relaxin makes ligament stretchier - decreases joint stability lordotic curve supports baby weight

Question 37

lordotic curve

Answer 37

adaptation made to avoid and reduce pressure of prolapse due to upright body position