Day 39 (intervertebral disc functions, classification & embryology, anterior longitudinal ligament, posterior longitudinal ligament)

Question 1

How does the intervertebral disc attach to the vertebral body?

Answer 1

Sharpey’s fibers from the outer lamellae of the annulus fibrosus are firmly embedded into the epiphyseal rims of the adjacent vertebral bodies

Question 2

Based on histology, what is the classification of the intervertebral disc?

Answer 2

a cartilaginous (amphiarthrosis) symphysis

Question 3

What are the divisions of the embryonic somite?

Answer 3

the sclerotome, myotome, and dermatome

Question 4

What structure is formed following migration of sclerotomes to surround the notochord?

Answer 4

the perichordal blastema

Question 5

What is formed within the perichordal blastema between the sclerotomites?

Answer 5

the intrasclerotomal fissure or fissure of von Ebner

Question 6

What does the intrasclerotomal fissure or fissure of von Ebner become?

Answer 6

the perichordal disc

Question 7

What structure forms following migration and subsequent mixing of the sclerotomites?

Answer 7

the vertebral blastema

Question 8

What parts of the intervertebral disc will the notochord form?

Answer 8

the nucleus pulposus

Question 9

What will the dense sclerotomite become?

Answer 9

the upper part of the vertebral segment forming above

Question 10

What part of the intervertebral disc will the perichordal disc form?

Answer 10

the annulus fibrosus

Question 11

What is the earliest indicator of the position of the adult intervertebral disc?

Answer 11

the intrasclerotomal fissure or fissure of von Ebner

Question 12

What vertebral levels will the anterior longitudinal ligament attach to?

Answer 12

those between occiput and S3 inclusive are traditionally indicated

Question 13

What is the lowest extent of the anterior longitudinal ligament based on recent studies

Answer 13

L3

Question 14

What is believed to form the anterior longitudinal ligament in the lumbar spine?

Answer 14

the tendon of the crura of the diaphragm

Question 15

What innervates the anterior longitudinal ligament?

Answer 15

the anterior neural plexus formed by fibers from the ventral primary ramus and sympathetic postganglionic fibers from the paravertebral ganglia

Question 16

What is the function of the anterior longitudinal ligament?

Answer 16

it brakes or limits dorsi-flexion or hyperextension of the vertebral column

Question 17

What was ossification of the anterior longitudinal ligament in the lumbar region identified as?

Answer 17

Forestier’s Disease

Question 18

What is ossification of the anterior longitudinal ligament in the lumbar region now identified as?

Answer 18

Diffuse Idiopathic Skeletal Hyperostosis or DISH

Question 19

Newer research suggests what regional variation in the posterior longitudinal ligament?

Answer 19

prominent in the cervicals, occasional in the thoracics, rare in the lumbars

Question 20

What is the relationship of the posterior longitudinal ligament to the vertebral foramen?

Answer 20

it forms the anterior boundary of the spinal canal

Question 21

What is the innermost layer of the posterior longitudinal ligament called?

Answer 21

the perivertebral ligament

Question 22

What is the function of the posterior longitudinal ligament?

Answer 22

it brakes or limits flexion of the vertebral column

Question 23

Where is ossification of the posterior longitudinal ligament most commonly identified?

Answer 23

the cervical spine with an 80% incidence

Question 24

What is the clinical sign of posterior longitudinal ligament ossification in the cervical spine?

Answer 24

a loss of hand and finger dexterity

Question 25

What is the clinical sign of posterior longitudinal ligament ossification in the lumbar spine?

Answer 25

faltering gait

Question 26

What is the gender, age, and ethnic bias associated with ossification of the posterior longitudinal ligament?

Answer 26

it is greater in males over 50 and has a higher incidence in Japanese