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 -Sacral hiatus

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

Question 15

What is the shape of posterior coccyx

Answer 15

Convex

Question 16

What is the shape of anterior coccyx

Answer 16

Convex

Question 17

Sacroiliac Joint

Answer 17

• Between auricular surfaces of the scruk, and illium
• Synovial joint

Question 18

Functions of sacroiliac joint

Answer 18

• Control and distribute the forces from upper body into legs
• Shock absorber for the spine
• Allow spinal and thigh movements
• Support weight of the upper body
• More mobile in pregnancy and childbirth

Question 19

What are the primary movements of the sacroiliac joint movements?

Answer 19

Anterior-posterior and upward-downward

Question 20

Nutation

Answer 20

Anterior sacral tilt

Question 21

Counter-nutation

Answer 21

Posterior-sacral tilt

Question 22

Ligaments of sacroiliac joint

Answer 22

3 main:
- Anterior Sacro Iliac Ligament
- Posterior Sacro Iliac Ligament
- Interosseous Ligament

2 Accessory:
- Sacrospinous Ligament
- Sacrotuberous Ligament

Question 23

Anterior Sacroiliac Ligament

Answer 23

• Blends with fibres of the capsule
• Innervation of nociceptive fibres (significant source of pain)

Question 24

Posterior Sacroiliac Ligament

Answer 24

• Overlies interosseous sacroiliac ligament
• Contributes the most to SIJ mobility
• Ligament undergoes tension during transmission of forces from legs to upper body

Question 25

Interosseous Ligament

Answer 25

- Strongest ligament in the body - Short, strong bands, fibers detach from the bone Functions: - Prevents forward and downward movement of the sacrum - Prevents excessive backward movement

Question 26

Sacrospinous Ligament

Answer 26

- From ischial spine to sacrum - Prevents excess posterior movement of sacral apex - Transforms lesser sciatic notch into foramen

Question 27

Sacrotuberous Ligament

Answer 27

- Extends from posterior ilium and lateral sacrum and coccyx to the ischial tuberosity - Transforms greater sciatic notch into a foramen - Prevents posterior movement of sacral apex - Limits anterior movement of sacral base

Question 28

Sacrococcygeal Joint

Answer 28

- Articulation between the apex of of the sacrum, and base of the coccyx - Symphysis (2 bones lined by hyaline cartilage and connecte dby fibrous disc) - Slight mobility: flexion-extension

Question 29

Ligaments of sacrococcygeal

Answer 29

1. Anterior Sacrococcygeal ligament 2. Lateral sacrococcygeal ligament 3. Superficial posterior sacrococcygeal ligament 4. Deep posterior sacrococcygeal ligament 5. Intercornual ligament

Question 30

Anterior sacrococcygeal ligament

Answer 30

Extends from the anterior surface of the sacrum to the anterior surface of the apex coccyx

Question 31

Lateral Sacrococcygeal ligament

Answer 31

Attaches to inferolateral angle of the sacrum and the transverse processes of the coccyx

Question 32

Superficial posterior sacrococcygeal ligament

Answer 32

Arises from the margin of the sacral hiatus and attaches to the dorsal surface of the coccyx.

Question 33

Deep posterior sacrococcygeal ligament

Answer 33

Spans from the dorsal surface of the S5 to the dorsal surface of coccyx.

Question 34

Intercornual Ligament

Answer 34

A band that connects the cornua of the sacrum and coccyx

Question 35

Pelvic mechanism provides:

Answer 35

- Support for the trunk - Guides movement - Helps absorb compressive forces associated with locomotion and weight-bearing

Question 36

Acetabulofemoral Joint (Hip)

Answer 36

Formed by the pelvic bones and the femur Pelvis consisted of 3 bones: - Ischium - Ilium - Pubic

Question 37

What does triradiate cartilage do?

Answer 37

Separates the bons prior to puberty

Question 38

Ilium

Answer 38

- Largest and widest pelvic bone - Body forms the roof of acetabulum

Question 39

Pubis

Answer 39

- Most anterior portion of the hip bone Consists of: - Body - Superior Ramus - Inferior Pubic Ramus

Question 40

Ischium

Answer 40

- Forms posteroinferior part of the hip bone Consists of: - Body - Superior ramus - Inferior pubic ramu

Question 41

Ischial Spine

Answer 41

Posteromedial projection of bone near the junction of the superior ramus and ischium body

Question 42

Ischial tuberosity

Answer 42

- Posteroinferior aspect of the ischium

Question 43

The Acetabulum of Pelvis

Answer 43

- Cup-like depression located on the inferolateral aspect of the pelvis

Question 44

Male vs Female pelvis

Answer 44