Back 2 Flashcards
Internal “Epidural” Venous Plexus
- Drains blood from surface of spinal cord and Basilateral vein (from vertebral body)
- neither of these have valves
- tributaries with veins in pelvis and thoracic wall
- communicates with veins in cranial cavity
Membranes surrounding spinal cord
- Dura Mater
- Arachnoid Mater
- Pia Mater
Subarachnoid Space
- Space beneath arachnoid mater containing 1) spinal cord 2) spinal nerve roots 3) dorsal ganglia
Epidural Space
- Contains adipose tissue and Internal venous plexus
Types of vessels needed for spinal cord perfusion
- Longitudinal
- Feeder (enter IV foramen)
Longitudinal Vessels
- 1 anterior spinal artery
- 2 posterior spinal arteries
Spinal arteries
- arise from posterior intercostal arteries
- enter IV foramen
Radicular arteries
- Arise from spinal arteries
- perfuse dorsal and ventral roots
Segmental medullary arteries
- Large spinal arteries
- merge with and reinforce longitudinal spinal arteries
Posterior intercostal arteries
- from aorta
- give rise to spinal arteries
Path to dorsal/ventral root perfusion
Aorta –>Posterior intercostal artery–>spinal artery–> radicular artery
OR
Aorta–>Posterior intercostal artery–>segmental medullary artery–>longitudinal spinal arteries (anterior and posterior)
Great anterior segmental artery
- “Artery of Adamiewicz”
- largest segmental medullary artery
- rises from lower intercostals
- reinforces 2/3 of cord circulation
Things vertebral canal houses
- Meninges
- spinal cord
Number of pairs of spinal nerves
31
spinal cord is continuation of…
medulla oblongata
length of spinal cord
base of skull to ~L2
proportion of vertebral canal occupied by spinal cord
2/3
longest nerve roots (and reason)
- Lumar and sacral/coccygeal
- bony vertebrae grow faster than nerves
Conus medullaris
Tapered end of spinal cord (~ L2)
internal filium terminale
extends from end of conus medullaris to interior end of dural sac
external filium medullaris
extends from edge of dural sac to sacrum and provides stability to spinal cord
Two spinal cord enlargements
- Cervical enlargement - innervates upper limbs
- Lumbosacral enlargement - innervates lower limbs
Cauda Equina
- nerve roots from sacral and lumbar roots extending to their appropriate vertebrae
Dural Sleeve
- lateral extension of dura mater/dural sac along ventral and dorsal roots
