Arm - Dermatomes, Peripheral Inn., Myotomes

Question 1

If there is sensation loss involves the dermatome, that indicates

Answer 1

proximal lesion/root level

(spine!!)

Question 2

If there is sensation loss in only a patch of skin, this indicates

Answer 2

distal lesion/peripheral cutaneous nerve

(problem somewhere along nerve pathway!)

Question 3

The superior lateral brachial cutaneous branch is a branch of…

Answer 3

axillary n

Question 4

the inferior lateral brachial cutaneous branch is a branch of….

Answer 4

radial n

Question 5

the lateral antebrachial cutaneous is the terminal portion of what nerve?

Answer 5

musculocutaneous n

Question 6

the posterior antebrachial cutaneous is a branch of…

Answer 6

radial n

Question 7

the superficial radial n is a branch of…

Answer 7

radial n

Question 8

the posterior antebrachial cutaneous supplies the…

Answer 8

posterior lateral forearm

Question 9

The superficial branch (of the radial n) supplies the…

Answer 9

dorsum of the hand from the first IP joint to the lateral half of the third DIP

***(in hand, radial nerve has superficial branch and dorsal digital branches)

Question 10

What two branches of the radial n supply the dorsum of the hand from the first IP joint to the lateral half of the third DIP?

Answer 10

superficial branch

dorsal digital branches

Question 11

What does the median nerve supply?

Answer 11

Dorsal tips of digits 1-3 and lateral 1/2 of the 4th digit

Palmar aspect of the hand covering digits 1-3 and the lateral half of the 4th digit

***(made up of palmar branch and palmar digital branches)

Question 12

What does the ulnar nerve supply?

Answer 12

Palmar medial hand from the medial 1/2 of the 4th digit including all of the 5th digit

Dorsal medial hand covering the medial half the 3rd digit up to the DIP, the entire 4th digit (EXCEPT the lateral tip past the DIP – median n), and all of the 5th digit

Question 13

What does the medial brachial cutaneous supply?

Answer 13

medial aspect of the distal arm (primarily T1)

Question 14

What does the medial antebrachial cutaneous supply?

Answer 14

skin of the anteromedial aspect of the forearm down to the level of the wrist

Question 15

What is a myotome?

Answer 15

group of mm innervated by a single nerve root

Question 16

supply synovial joints of the vertebral column, deep muscles of the back and overlying skin segmentally

Answer 16

posterior/dorsal rami of spinal nerves

Question 17

supply the much larger remaining area of the anterior/lateral regions of the trunk and upper and lower limbs. The distribution to the upper and lower limbs form plexuses (brachial and lumbosacral).

Answer 17

anterior/ventral rami of spinal nerves

Question 18

transmits the
sensation for touch, pain, temperature, and position from sensory receptors to the brain

Answer 18

somatic sensory (afferent)

Question 19

innervates only skeletal muscle (voluntary and reflexive movement); signals course from the brain to the muscle

Answer 19

somatic motor (efferent)

Question 20

What is a dermatome?

Answer 20

area of skin innervated by one spinal cord segment (i.e. one root level, one spinal nerve)

Question 21

What is peripheral cutaneous innervation?

Answer 21

Innervation by specific cutaneous nerves (or cutaneous branches of other nerves)

Question 22

In the UE, all peripheral innervation is transmitted through the…

Answer 22

brachial plexus

Question 23

Supplies the skin over the lower part of the posterior deltoid and lateral mid arm

Answer 23

superior & inferior lateral brachial cutaneous n.

Question 24

Supplies skin of the lateral forearm and wrist

Answer 24

lateral antebrachial cutaneous n.

Question 25

Supplies cutaneous innervation to the dorsal & lateral arm, forearm, & dorsal lateral hand

Answer 25

radial n.