Lecture 30: Spinal Cord Structure and Function

Question 1

spinal nerve types

Answer 1

• cranial nerves: C1-C8
• thoracic: T1-T12
• lumbar: L1-L6
• sacral: S1-S6
• coccygeal: C0

Question 2

nerves of the plexuses

Answer 2

• cervical plexus: C1-C5
• brachial plexus: C5-T1
• lumbar plexus: L1-L4
• sacral plexus: L4-S4

Question 3

distribution of spinal nerves

Answer 3

• cervical enlargement (C4-T1): control shoulder girdle and upper limbs
• lumbar enlargement (T9-T12): pelvis and lower limbs
• cauda equina: extension of nerves exiting from the end of the spinal cord

Question 4

Internal Anatomy of Spinal Cord (gray matter)

Answer 4

• central canal: small opening at the center of spinal cord (contains CSF)
• posterior horns: cell bodies of somatic and visceral sensory neurons
• gray commissure: connects posterior horns
• know structure

Question 5

Internal Anatomy of Spinal Cord (white matter)

Answer 5

• posterior columns: sensory tracts (ascending)
• lateral columns: motor and sensory tracts
• anterior columns: motor tracts (descending)
• anterior white commissure: connects white matter on left and right side of spinal cord
• know structure

Question 6

Input and Output of the Spinal Cord

Answer 6

-dorsal root of spinal nerve: carries sensory info
-dorsal root ganglion: cluster of sensory cell bodies outside the CNS
-ventral root: carries motor info to anterior portion of the cord
spinal nerves: join dorsal and ventral roots (mixed nerves), 31 exit spinal cord, about 2 cm long
*know structure