Spinal Nerve Basis
How many pairs of spinal nerves are in the human body?
31 pairs
A dermatome is an area of skin supplied by what?
A single spinal nerve
A mytome is a group of muscles supplied by what?
A single spinal nerve root
Which direction does snesory (afferent) information travel?
Toward the spinal cord/brain
If a person loses sensation over the shoulder, which spinal nerve is likely affected?
C5
What is the name of the bundle of spinal nerves below the end of the spinal cord?
Cauda equina
The thumb corresponds to which dermatome?
C6
Which myotome controls elbow flexion?
C5-C6
Which direction does motor (afferent) information travel?
Away from the spinal cord to muscles
Weakness in wrist extension could indicate a problem with which spinal level?
C6
Which part of the spinal nerve carries sensory information INTO the spinal cord?
Dorsal (posterior) root
The umbilicus (belly button) corresponds to which dermatome?
T10
Which myotome controls knee extension?
L3-L4
The dorsal horn of the spinal cord processes what information?
Sensory
Loss of knee relfex and having trouble straightening the knee suggest damage at which level?
L3-L4
Which part of the spinal nerve carries motor information OUT of the spinal cord?
Ventral (anterior) root
Loss of feeling on the lateral leg and top of foot indicates damage to which dermatome?
L5
Which mytome controls ankle dorsiflexion (lifting up your foot)?
L4-L5
The ventral horn of the spinal cord sends out which type of signals?
Motor
Loss of ankle reflex and difficulty walking on tiptoes point to which level?
S1
Which structure joins the dorsal and ventral roots to form a mixed spinal nerve?
Spinal nerve trunk
Why do adjacent dermatomes overlap slightly?
To prevent total sensory loss if one root is damaged
Which myotome allows you to wiggle your toes?
S2
Which part of the spinal nerve contains both sensory and motor fibers?
The mixed spinal nerve
Why is it important for therapists to know dermatomes and myotomes?
To help localize spinal nerve or root injuries to help guide the rehabiliation process