Sacrum

Question 1

What is the sacrum?

What is its function?

What is the sacrum made of

Answer 1

Large bone located at the base of the vertebral canal

Thick so aids in supporting transmitting the weight of the body

The fusion of the five sacral vertebrae

Question 2

What are the four constitutes of the sacrum?

Answer 2

Base- articulates superiorly with the five lumbar vertebrae and associated intervertebral disc

Apex- attatches with the coccyx inferiorly

Auricular sufaces- Lateral surfaces of the sacrum, shaped like an ear

Pelvic and Dorsal surfaces- Provide attatchment of ligaments and muscles

Question 3

Which side of the sacrum is rugged?

What arises from fusion of the spinous processes

Answer 3

The dorsal surface- due to the fusion of the vertebrae

Median sacral crest- gives attachment to the supraspinous ligament

Question 4

What attaches at the intermediate sacral crests?

What articulates with the superior articulating process of the coccyx?

Answer 4

Posterior sacroiliac ligaments

Sacral cornu

Question 5

What arises from the fusion of the transverse processes

What is found at the top of the pelvic surface of the coccyx

Answer 5

Lateral sacral crests- attachment point for the posterior sacroiliac ligaments as well the sacrotuberous ligament

Sacral promontory

Question 6

What muscles attach to the pelvic side of the pelvis

Answer 6

Piriformis- originates from the S2-S4 level of the pelvic surface. Acts to externally rotate, abduct, extend and stabilise hip joint

Coccygeus- inserts at lower sacrum. supports pelvic cavity and flexes coccyx

Iliacus- Distal attachment to the lesser trochanter of femus. Flexes thigh at hips and stabilises hip joint.

Question 7

What muscles attach to the dorsal side of the pelvis?

Answer 7

Multifundus lumborum- stabilses the spine

Erector spinae- extension and lateral bending of the head and vertebral column

Question 8

What is the cauda equina?

Answer 8

Bundle of spinal nerves that arise form the termination pf the spinal cord. Proximal fibres are contained in the dural sac which terminates at the level of S2

Question 9

What is filum terminale?

Answer 9

Continuation of the pia matter

Question 10

What supplies blood to the sacrum?

Answer 10

Median sacral artery- midline relation to the sacrum. It is a continuation of the abdominal aorta that arises posteriorly before its bifurcation.

Lateral sacral arteries a pair of bilateral vessels that run along the medial border of the sacral foramina