The Pelvis (J/B/L/M)

Question 1

Describe the pelvic girdle and its function.

Answer 1

Made up of the sacrum, innominate bones (ilium/ischium/pubis). Function is weight-bearing, ambulation, protection of organs and muscle attachment points.

Question 2

Describe the Sacrum and its function.

Answer 2

Large, triangular shaped (keystone), pelvic surface is smooth/concave (anterior), dorsal surface is rough and convex and has 4 pairs of sacral foramen, inferior lateral edges and sacral sulcus. Has medial, intermediate, and lateral crests, L-shaped lateral surface and coccyx at the bottom (apex).

Question 3

Describe the Ilium and its function

Answer 3

A wide/flattened fan shape makes up 2/3rds of the hip bone. Consists of the gluteal surface, the sacro-pelvic surface, and the iliac fossa.

Question 4

Gluteal Surface

Answer 4

Lies on the ilium, faces posterior and lateral, rough, between the iliac crest and superior acetabulum, origin point for gluteal muscles, anterior/posterior/inferior lines.

Question 5

Iliac Fossa

Answer 5

Internal aspect of the ilium, faces anterior and medial. Origin for iliacus.

Question 6

Sacro-Pelvic Surface

Answer 6

Articulates with the sacrum to form the sacroiliac joint, covered in hyaline cartilage. Consists of the ischium which faces inferior/posterior and is L-shaped, and the pubis which consists of a body and 2 rami.

Question 7

Key Landmarks of the Innominate Bones (8)

Answer 7

Iliac Crest, ASIS, AIIS, PSIS, PIIS, GSN, Ischial Tuberosity, Ischial Spine

Question 8

Symphysis Pubis

Answer 8

A cartilaginous articular surface where the pubic bodies of each innominate bone meet (disc/crest/tubercle)

Question 9

Superior Pubic Ligament

Answer 9

O/I: Runs from pubic tubercle to pubic tubercle

A: Helps keep the innominate bones together

Question 10

Arcruate Pubic Ligament

Answer 10

O: Inferior borders of the pubic bones
I: Blends superiorly with the interpubic disc, and laterally with the inferior pubic rami

Question 11

Sacro-Iliac Joint

Answer 11

Where the ilium and the sacrum meet on both sides. Primary function is to unite the plevis and the spine to allow transfer of forces. Allows rotation, articular surfaces are the L-shaped surface of the sacro-pelvic surface and the posterior aspect of the wing of the sacrum.

Question 12

Interosseous Sacro-Iliac Ligament

Answer 12

Forms the major connection between the sacrum and innominate bone
O: Located posteriorly, covered by the dorsal SI ligament
I: Deep part has superior/inferior bands that run from posterior depressions to the sacral auricular surface
A: Resists anterior/inferior movement

Question 13

Dorsal Sacro-Iliac Ligament

Answer 13

Posterior to the interosseous SI ligament, megres laterally with the sacrotuberous ligament, merges medially with the TLF.
O: Intermidiate/lateral crests of sacrum
I: PSIS and internal lip of iliac crest

Question 14

Anterior Sacro-Iliac Ligament

Answer 14

O: Lateral crest of the sacrum
I: Posterior internal lip of the ilium
A:Strengthens the ventral portion of the capsule

Question 15

Iliolumbar Ligament (5 bands)

Answer 15

Runs between the iliac crest and the TP’s of L5.
O: ANT (ant/inf borders of TP’s of L5, POST (tips of TP’s to L5 and the ilium), SUP (ant/sup border of TP’s of L5), INF (lower border of L5 TP’s), VERT (ant/inf border of L5 TP’s down to iliopectineal line

Question 16

Sacrospinous Ligament

Answer 16

O: Lateral margin of the lower sacrum/coccyx
I: Lateral aspect of the ischial spine, blends with sacrotuberous ligament