Axial Skeleton Development

Question 1

Components of axial skeleton

Answer 1

the cranium (skull), vertebral column, ribs, and sternum

Question 2

Mesodermal cells from sclerotome migrate to condense

Answer 2

• Around notochord > centrum > vertebral body
• Around neural tube > vertebral arches > pedicles, laminae, spinous processes, articular and transverse processes
• In the body wall > costal processes > ribs

Question 3

Occipital bone formation

Answer 3

The caudal portion of the fourth occipital sclerotome fuses with the cranial portion of C1 sclerotome

Question 4

Mesenchymal cells

Answer 4

Contribute to the formation of intervertebral discs

Question 5

Notochord becomes…

Answer 5

nucleus pulposus

Question 6

Clinical condition that occurs when portions of the notochord persist as a tumor, usually in the cranial and lumbosacral regions

Answer 6

Chordoma

Question 7

Primary vertebral curves

Answer 7

Thoracic and sacral, form during fetal development

Question 8

Secondary vertebral curves

Answer 8

Cervical (lifting head) and lumbar (walking)

Question 9

Sternum develops from:

Answer 9

Somatic mesoderm

Question 10

Sternal bars

Answer 10

Primordial sternum, fuse cranial to caudal by week 8

Question 11

Spina bifida occulta

Answer 11

Failure of vertebral arches to form or fuse

Question 12

Scoliosis

Answer 12

represents lateral and rotational curvature of the vertebral column

Question 13

Hemivertebra

Answer 13

Most common cause of scoliosis, complete unilateral failure of the vertebral body to form

Question 14

VACTERL Association

Answer 14

Vertebral anomalies 
Anal atresia
Cardiovascular anomalies
Trachoesophageal fistula
Renal anomalies
Limb defects

Question 15

Spondylolisthesis

Answer 15

pedicles fail to fuse with vertebral body, resulting in lordosis (vertebral body moves anteriorly relative to vertebra below

Question 16

Sternal cleft

Answer 16

Sternal bars fail to fuse

Question 17

Precuts excavatum

Answer 17

most common chest anomaly = concave depression of the lower sternum, It is probably due to overgrowth of the costal cartilages, which displaces the lower sternum inward