Part 20: Pelvic Joints and Ligaments

Question 1

What are the joints of the pelvis?

Answer 1

Sacroiliac, Sacrococcygeal and pubic symphysis

Question 2

What type of joint is sacroiliac, what is it supported by?

Answer 2

Synovial joint (atypical) with fibrocartilage and jagged edges which help prevent movement. Very strong posterior ligaments and weak anterior. Ventral SI ligament - flat band, joins bones above and below pelvic brim. Posterior consists of interosseous SI and dorsal SI ligaments. Stability of sacroiliac joint is achieved through ligaments alone.

Question 3

What type of joint is sacrococcygeal? What are its ligaments?

Answer 3

Symphysis with fibrocartilage. Short ventral SC ligament units bones at front, 2 dorsal SC ligaments posterior (deep and superficial). lateral SC ligaments from transverse process of coccyx to sacrum (completes foramen for anterior rami 5th sacral nerve)

Question 4

What type of joint is the pubic symphysis?

Answer 4

Secondary cartilaginous joint. Each pube is covered with hyaline cartilage joined by mass of transverse fibres. Reinforced by superior pubic ligament above and arcuate pubic ligament below

Question 5

Where does the sacrotuberous ligament run?

Answer 5

From posterior ilium between PSIS and PIIS to transverse tubercles of sacrum and upper transverse tubercles of coccyx. Continuation from this wide area to medial surface of ischial tuberosity.

Question 6

Where does the sacrospinous ligament run?

Answer 6

Broad base at lower part of sacrum/upper coccyx. Narrows as passes laterally to spine of ischium.

Question 7

What ligaments enclose the lesser sciatic foramen?

Answer 7

Sacrotuberous and sacrospinous

Question 8

Where does the iliolumbar ligament run?

Answer 8

Shaped like V lying sideways. Apex is attached to transverse process of L5. Upper band passes to iliac crest and lower band runs lateral to blend with SI ligament