Lecture 5

Question 1

Sacrum Base

Answer 1

Sits at an oblique angle forming the lumbo-sacral angle that measures 30 degrees +/- 10 in 95% of cases studied

Question 2

Lumbosacral Articular facets/surface

Answer 2

orientate posteriorly articulate with Inferior facets of L5

Question 3

Sacral apex

Answer 3

(formed by the S5 vertebra)
articulates with the coccyx

Question 4

Sacral Alar (wings)

Answer 4

articulates with Ilium

Question 5

Transverse ridges of Sacrum Anterior Surface

Answer 5

Middle portion has 4 transverse ridges- correspond to 5 sacral
bodies

Question 6

Anterior Sacral foramina

Answer 6

• Anterior sacral foramina 4 on each side
• First 4 sacral nerves exit here, arteries enter here

Question 7

Sacrum posterior surface

Answer 7

Convex, narrower, highly
irregular

Question 8

Posterior Sacral canal

Answer 8

Runs down the center of the
sacrum and represents the
end of the vertebral canal.

Question 9

Posterior sacral foramina (4
pairs)

Answer 9

sacral nerve fibres exit from
the sacral canal to these
foramina

Question 10

Posterior Surface - Sacral Crest

Answer 10

• Median crest (due to fusion of
  spinous processes S1-S3)
• Intermediate crest (due to fusion of articular processes L5-S4),
• Lateral crest (due to fusion of transverse processes)

Question 11

Posterior Surface -

Answer 11

• The opening present at the
  caudal end of sacral canal as SP
  and lamina do not form in the S5
  and leave a hole =sacral hiatus

Question 12

Posterior Surface - Sacral Cornu

Answer 12

Remnants of the inferior
articular process, lie on each
side of the sacral hiatus

Question 13

Coccyx Anatomy

Answer 13

• Terminal point of the vertebral
  column Known as tail bone
• Usually 3-5 bones
• Comprised of four fused coccygeal vertebrae

Question 14

Coccyx Landmarks

Answer 14

• Base (oval)
• Apex (rounded)
• Anterior surface
• Posterior surface
• Lateral surface