Spinal Cord and Spinal Nerves Flashcards
There are 31 pairs of spinal nerves, which are part of the
Peripheral Nervous System
Named by the spinal nerves emanating from it
Spinal Cord segments
Exit ABOVE the vertebra
C1-C7
Exits BELOW C7
C8
The remaining spinal nerves exit below the
Vertebra
The only spinal nerves to exit ABOVE the vertebra are
C1-C7
The spinal cord ends at
L1 at conus medullaris (tip of spinal cord)
Comprises spinal nerves below the conus medullaris
Cauda Equina
Contained within the lumbar cistern (duralsac)
Cauda Equina
The sympathetic nervous system originates only from
T1-L3
Contains cell bodies of motor neuron, sensory neurons, interneurons
Spinal Cord Gray Matter
Has connections between neurons for reflexes, processing sensory and motor input, and relaying information into tracts
Gray matter
Made up of long and short (between segments) pathways
Spinal cord white matter
Spinal cord injury disrupts the
-Leads to paralysis
Long Pathway
Interruption of long pathways leads to motor and sensory loss where?
BELOW the level of the lesion
The amount of spinal cord white matter decreases as we move from
Cranial to Caudal
What is the primary blood supply for the spinal cord?
Anterior spinal artery and posterior spinal arteries (2)
Located in the ventral median fissure and supplies the anterior 2/3 of spinal cord
Anterior spinal artery
Located in the posteriolateral sulci and supplies the posterior 1/3 of the spinal cord
Posterior spinal arteries
Branches from the anterior and posterior spinal arteries that encircle the spinal cord
Vasocorona
Anterior and posterior radicular arteries arise from
Segmental Arteries
Branches of aorta or internal iliac arterat each spinal levelto serve respective roots and ganglia
Segmental Arteries
Extensions of radicular arteries that penetrate dura to augment the spinal cord blood supply
Medullary Arteries
Major artery at T9-11 in 75% of people.
-Supplies majority of lumbar and sacral spinal cord
Great radicular Artery of Adamkiewicz
Fracture dislocations of vertebra can interfere with spinal cord
Blood supply
Arterial disease can obstruct the
Great Radicular artery
Occlusion of aorta during surgery can produce ischemic damage and lead to
Paralysis
Located at endpoints between major vessels
-susceptible to ischemia
T4-T9 watershed area
Susceptible to ischemia with low blood pressure, cardiac arrhythmias, and vessel occlusion
-Most susceptible is central cord
T4-T9 watershed area
Region of skin innervated by the spinal nerves
Dermatomes
Touching the skin stimulates a specific spinal nerve and spinal cord segment
Dermatomes
Most common cause of damage to a spinal nerve
Herniated Discs
Spinal nerve damage due to herniated disc can happen in any part of the vertebral column. But the most common regions are
C5-6, C6-7, L4-L5, and L5-S1
Most herniated discs resolve in
8 Weeks
Most disc herniations are
Lateral
T1 or T2 radiculopathy interupts the sympthetic pathway to the eye and can cause a
Horner’s Syndrome
What are the three symptoms of the Horner’s Syndrome caused by T1 or T2 radiculopathy
Constricted pupil (miosis), Anhidrosis (decreased sweating), and ptosis (drooping of eyelid)
Any herniation below C7 will affect the spinal nerve corresponding to the
LOWER vertebral body
For example, a disc herniation between T5-T6 will affect the
T6 spinal nerve
