Spine & Spinal Cord

Question 1

At what vertebral level does the hyoid bone lie? Which bones does it articulate with?

Answer 1

• the hyoid bone sits at the C3 level

- it does NOT directly articulate with any other bones

Question 2

What passes through the transverse foramina of cervical vertebrae?

Answer 2

• the vertebral arteries

Question 3

What part of axis (C2) allows for axial rotation between C1 and C2?

Answer 3

• the odontoid peg (the dens)

Question 4

What are the four natural curves in the vertebral column? Which are primary curves and which are secondary?

Answer 4

• cervical lordosis (a secondary curve)
• thoracic kyphosis (a primary curve)
• lumbar lordosis (a secondary curve)
• sacral kyphosis (a primary curve)

Question 5

What is the normal number of vertebrae?

Answer 5

• 7 cervical
• 12 thoracic
• 5 lumbar
• 5 fused sacral
• 4 fused coccygeal

Question 6

What are the major general features of a vertebrae?

Answer 6

• vertebral arch w/ 1 spinous and 2 transverse processes; superior and inferior articular processes
• vertebral foramen (forms the vertebral canal)
• vertebral body
• inferior and superior vertebral notches (these form the intervertebral foramina from which the spinal nerves exit)

Question 7

What are the parts of an intervertebral disc?

Answer 7

• a gel-like nucleus pulposus surrounded by a tough capsule (the anulus fibrosus)
• (note that only the outer 1/3 of the anulus fibrosus is innervated)

Question 8

What are joints involving adjacent vertebrae (via their articular processes) called?

Answer 8

• zygapophysial joints

Question 9

What are the major defining characteristics of the cervical vertebrae?

Answer 9

• small body
• vertebral foramen is large and triangular
• C1-C6 have bifid spinous processes
• presence of transverse foramina (for the vertebral arteries to ascend through)

Question 10

What are the major defining characteristics of the thoracic vertebrae?

Answer 10

• large heart shaped body
• vertebral foramen is more round
• spinous processes are long and slender
• costal/rib facets on the body and transverse processes

Question 11

What are the major defining characteristics of the lumbar vertebrae?

Answer 11

• very large kidney shaped body
• vertebral foramen is triangular
• large spinous processes
• long, slender transverse processes
• lack of unique features of the other vertebrae

Question 12

What are the major features of C1 and C2?

Answer 12

• C1 (atlas): lack of a body; fovea for articulation of C2’s dens; articular surfaces for the occipital bone (for nodding)
• C2 (axis): dens (odontoid peg) for articulation with C1 (for rotating head)

Question 13

What are the major features of the sacrum?

Answer 13

• S1’s ala (superior surface) with the auricular surfaces
• fusion of the spinous processes into the median sacral crest
• sacral foramina (no longer called vertebral foramina)
• sacral canal and sacral hiatus (found on posterior side)

Question 14

Which major ligaments are involved in the atlantoaxial joint?

Answer 14

• apical ligament (between C2 and occipital)
• alar ligaments (between C2 and foramen magnum)
• transverse ligament (forms part of the cruciate ligament)

Question 15

Which major ligaments are involved in forming the vertebral column?

Answer 15

• anterior longitudinal ligament
• posterior longitudinal ligament
• ligamentum flavum
• interspinous ligament
• supraspinous ligament
• ligamentum nuchae (posterior aspect of cervical vertebrae only)

Question 16

Back muscles are also known as what? How many layers of these muscles are there?

Answer 16

• post-vertebral muscles; 3 layers
• deep layer containing the true intrinsic back muscles
• intermediate layer (serratus posterior, rhomboids)
• superficial layer (trapezius, latissimus dorsi)

Question 17

What is the superficial layer of the deep intrinsic back muscles made up of? Which muscle lies at the upper end of this layer?

Answer 17

• superficial (of deep): erector spinae muscles (most superior is the splenius capitis)
• (these muscles run straight and longitudinally)
• these are the extensors of the spine

Question 18

What is the largest group of muscles making up the deep layer of the deep intrinsic back muscles?

Answer 18

• deep layer (of deep): multifidus
• (these muscles run obliquely)
• these are the rotators of the spine

Question 19

At what vertebral level does the spinal cord end? What structures arise at its termination?

Answer 19

• ends at L1/L2 (tapered end part is the conus medullaris)
• from here meninges and spinal nerves continue to form the cauda equina
• additionally, the thin filum terminale (made up of pia mater) extends to the coccyx

Question 20

What is the blood supply to the spinal cord?

Answer 20

• the single median anterior spinal cord and the bilateral posterior spinal arteries

Question 21

What is a denticulate ligament?

Answer 21

• a ligamentous structure connecting the pia mater and arachnoid mater
• a denticulate ligament is found between the dorsal and ventral spinal roots at each level

Question 22

What muscles are involved in the sub-occipital triangle?

Answer 22

• (these muscles are just deep to the splenius capitus)
• lateral border: obliquus capitis superior
• inferior border: obliquus capitis inferior
• medial border: rectus capitilis posterior major and minor (major is INFERIOR to minor)

Question 23

What important structures are found in the sub-occipital triangle?

Answer 23

• the vertebral artery
• greater occipital nerve
• C1 and its roots are located in this area