Spinal Cord Flashcards
What is the conus medullaris?
Terminal point of the spinal cord @ ~L1-L2
What are the meningeal coverings of the SC
Brown - dura mater
Green = arachnoid mater
Red = pia mater
Describe the spaces in the SC
Red = epidural space (fat and venous plexus)
Yellow = subarachnoid space (CSF and spinal blood vessels)
What are denticulate ligaments
Thickening of pia and glial elements that form ribbons along lateral surface of SC
What is the filum terminalae
Extension of pia and supporting cells that connects the conus medullaris to the coccyx bone
Label the following
Posterior (posterolateral sulcus) – where sensory info enters
Posterior median fissure
Anterolateral sulcus – where motor info exits
Anterior median fissure
Differences between SC sections at cervical, thoracic and lumbar segments?
- Cervical and lumbar have the most grey matter because they innervate the limbs
- Cervical white matter > thoracic > lumbar because motor information from all spinal segments is carried at the most caudal sections
Two sources of spinal cord blood supply
- Vertebral basilar system
* PICAs and vertebral arteries join to form the posterior spinal artery and anterior spinal artery - Segmental arteries
- Posterior brances of intercostal arteries give rise to segmental spinal arteries
- Segmental spinal arteries branch to form either (a) radicular arteries that supply roots at each level of SC or (b) segmental medullary arteries which supply either the PSA or the ASA
- Segmental p
Where do segmental spinal arteries originate
Anterior intercostal arteries
What originates from segmental spinal arteries
1) Radicular arteries (supplies roots)
2) Segmental medullary arteries (supply the ASA or the PSA)
Describe the blood supply from the ASA and PSA to the SC
- The ASA supplies the anterior 2 thirds of the SC, including the base of the posterior horns
- The PSAs supply the posterior 1/3 of the SC
What is the composition of a spinal nerve
1) Sensory root (afferent) to posterolateral sulcus
2) Motor root (efferent) exiting from anterolateral sulcus
Number of cervical vertebrae and nerves
CI - CVII (7 vertebrae)
C1-C8 (8 nerves)
Number of thoracic nerves and vertebrae
TI - TXII (12 vertebrae)
T1-T12 (12 nerves)
Number of lumbar nerves and vertebrae
LI-LV (5 vertebrae)
L1-L5 (5 nerves)