Vertbral Column & Spinal Cord

Question 1

What are the 3 Atlanto-axial joints?

Answer 1

Movement at all three Atlanta-axial joints. Permits the head to be turned from the side to side to indicate disapproval (the ‘no’ movement). Here, the cranium and C1 rotate as a unit over C2. When the head rotates to the side, the dens of C2 is the axis point or pivot that is held in a socket formed anteriorly by the anterior arch of the atlas and posteriorly by the TRANSVERSE LIGAMENT OF THE. ATLAS

Question 2

What is the transverse ligament of atlas?

Answer 2

This ligament is a thick, strong band, which arches across the ring of the atlas, and surrounding the odontoid process at this bone articulates with the atlas

Question 3

Where are the superior and inferior ligaments bands of the Cruciate ligament?

Answer 3

These pass from the transverse ligament to the occipital bone superiorly and inferiorly to the bidy of C2

Question 4

Describe ligament support for atlas and axis

Answer 4

Cruciate ligament- hold dens in place during rotation of the head. Has 3 bands

Alar ligaments- laterally from dens to skull

Apical ligaments- is deep to the Cruciate ligament, attaching the dens to the skull

Question 5

Contrast primary and secondary curvature development on the spinal cord

Answer 5

Primary curvature- they develop during the fetal period in relaxation to the (flexed) fetal position

Secondary curvature- they result from extension from the flexed fetal position and are maintained by the differences in thickness between anterior and posterior parts of IV discs. Control of head (1-2 months), sitting at about 6 months and walking about 1 year old

Question 6

What is kyphosis?

Answer 6

Hunchback

Is an abnormal increase in thoracic curvature, leading to a posterior protrusion of the vertebral column

Question 7

What is lordosis?

Answer 7

Is characterized by an anterior tilting of the pelvis (the upper sacrum is flexed or rotate antero-inferiorly) with increased inward curve of the spine

Question 8

What is scoliosis?

Answer 8

Common in young adults - is characterized by an abnormal lateral curvature that is accompanied by rotation of the vertebrae

Question 9

What is the spinal cord?

Answer 9

• Part of the CNS
• zconduction pathway between body and brain
• protected by vertebral column, meninges and CSF

Question 10

What are the enlargements of the spinal column?

Answer 10

Cervical and lumbosacral

Question 11

What is the cauda equina?

Answer 11

Segment of the spinal cord that continues into lumbar cistern

Question 12

What are the spinal nerves?

Answer 12

31 of them

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

Question 13

What are the main sources of arterial blood to the spinal cord?

Answer 13

Longitudinal artery- originate from vertebral artery

Location:one anterior, two posterior

Question 14

Describe the segmental blood supply to the spinal cord

Answer 14

Feeder arteries enter through the IV Foramina

Originate from body wall arteries at each segment of the spinal cord

Two types:
-Segmental medullary arteries which anastomose with the longitudinal spinal arteries

-Segmental Radicular branches that supply the dorsal and ventral roots

Question 15

Explain the significance of the Artery of Adamkiewicz for blood supply to the spinal cord

Answer 15

• Great anterior segmental medullary artery (Artery of Adamkiewicz)
• Largest segmental medullary artery
• Arises from the lower thoracic or upper lumbar region
• Important source of blood supply to lower lumbar and sacral roots (conus medullaris) of the spinal cord8

The spinal cord may suffer circulatory impairment if there is damage to segmental medullary arteries

Question 16

Artery of Adamkiewicz is important for…

Answer 16

Circulation to lumbar & sacral parts of the spinal co4d

Question 17

What veins drain the spinal cord?

Answer 17

Anterior and posterior spinal cord veins

Question 18

What is the significance of Baston’s plexus?

Answer 18

Spinal veins drain into internal vertebral (Batson’s). plexus
-located in the epidural space

• communicates with pelvic veins dural venous sinuses of the cranial vault and external vertebral venous plexus
• can serve as collateral pathway For venous flow to systemic vein (caval & azygos veins)
• vessels are valveless so blood, and thus infection or metastases of tumors may travel from the pelvic region to vertebrae and to the cranial vault . The reverse is also possible

Question 19

What is the spinal meninges function?

Answer 19

Protective membranes covering the spinal cord

Continuous with cranial meninges covering the brain

Question 20

What are the layers of the spinal cord?

Answer 20

1. Dura mater(tough mater)- subdural space(potential space)
2. Arachnoid mater (spider web )- subarachnoid space (actual space containing CSF )
3. Pia mater- (gentle mater)

Question 21

Where is the epidural space?

Answer 21

Surrounds the dura mater and contains spinal nerve roots, loose fatty tissue, small arteries , and the internal vertebral venous plexus of batson

Question 22

What is the dural sac?

Answer 22

Dural sac/lumbar cistern- contains cauda equina (dorsal & ventral roots of spinal nerves), filum terminale and CSF

Question 23

What are denticulate ligaments?

Answer 23

21 pairs of fibrous strips of pia mater that extends from the craniovertebral junction to T12 (superior fibers), and inferior fibers run from conus medullaris to T12 and L1

Each ligament features 18- 20 triangular extensions of pia mater that attach to the dura at their apices

Question 24

What is the function of denticulate ligaments?

Answer 24

Separates the ventral and dorsal rootlets from each other and helps to hold the spinal cord

Question 25

What is a lumbar puncture?

Answer 25

Procedure to draw out CSF from the lumbar cistern for diagnostic and/or therapeutic reasons

Site for an adult- between L3/L4 or L4/L5

approaches -median and paramedian

Question 26

What is the site for lumbar puncture in children?

Answer 26

L4/L5 for LP in children

Question 27

How to prepare for a lumbar puncture ?

Answer 27

The skin covering the lower lumbar vertebrae is anesthetizes and a lumbar puncture needle is inserted in the midline between the spinous processes of L4 and L5 at the supracristal line

After 4-6 cm the needle pops through the Ligamentum flavum and then “pops” again when penetrates the dura to enter the lumbar cistern

Lumbar puncture is not performed in the presence of increased intracranial pressure

Question 28

What are the layers through which a needle must pass through for a lumbar puncture?

Answer 28

Midline approach

• skin
• subcutaneous tissue

Supraspinous ligament

Interspinous ligament

Ligamentum flavum

Epidural space

Dura mater

Arachnoid mater

Subarachnoid mater