Bones and joints of the pelvis Flashcards
What type of joint is the sacroiliac joint?
Synovial
What type of joint is the pubic symphysis?
Secondary cartilaginous
What lies above and below thse obturator foramen?
Above: superior pubic ramus
Below: inferior pubic ramus
How do the pubic crest and pubic tubercle relate to the pubic body?
Pubic tubercle is lateral edge of pubic crest
Pubic crest is superior margin of pubic body
What does the pectineal line lie on?
Superior pubic ramus
Which bony landmark dermarcates the greater and lesser sciatic notches?
Ischial spine
Describe the bony features of the sacrum?
What are the lateral masses of the sacrum formed by?
Transverse processes fusing on each side
Describe the line of demarcation of the true and false pelvis?
Pubic crest, pectineal line, arcuate line of ilium, anterior margin of ala, sacral promontroy
Iliopectineal lie
List the pelvic types?
Which are most common in males and females?
Gynaecoid typical in women (val, wider transversely)
Android most common in males, followed by anthropoid (wider AP)
Describe the difference in pelvic inlet and outlet between males and females?
Inlet: wider transversely in females
Outlet: diamon shaped in both
Describe the borders of the pelvic outlet?
Inferior margin of pubic symphysis anteriorly
Tip of coccyx posteriorly
Ischial tuberosities either side
Describe the plane of least dimensions in the pelvis?
Through ischial spine, S4 and base of pubis
One of the points where baby rotates during birth
Describe the ligaments of the sacroiliac joint?
Anterior and posterior sacroiliac ligaments
Interosseous sacroiliac ligament: strongest, locks in rotation
Accessory: iliolumbar, sacrotuberous and sacrospinous
Describe the sacrotuberous and sacrospinous ligaments?
Sacrotuberous: sacrum to ischial tuberosity
Sacrospinous: sacrum to ischial spine
Accessory ligaments of SIJ
Form greater and lesser sciatic foraminae
Describe nutation and counter-nutation?
How are these movements limited?
Nutation: top of sacrum moves forwards, closes inlet and opens oultet
Counter-nutation: top of sacrum moves backwards, opens inlet and closes outlet
Limited by all ligaments in pelvis
Describe the ligaments of the pubic symphysis?
Superior pubic ligament
Inferior arcuate ligament
Prevent separation and resist compressive forces
How are the ligaments of the pubic symphysis reinforced?
Criss-crossing fibres from :
oblique abdominal muscles
rectus sheath
adductor longus
