topic 24: skin inervation

Question 1

dermatomes

Answer 1

Dermatomes are specific areas of the skin supplied by individual spinal nerves. In the upper limb, dermatomes from cervical and thoracic spinal nerves provide sensory innervation.

C4: Innervates a small area over the upper shoulder.
C5: Supplies the lateral aspect of the upper arm.
C6: Innervates the lateral aspect of the forearm and thumb.
C7: Provides sensation to the middle finger.
C8: Supplies the medial aspect of the forearm and little finger.
T1: Innervates the medial aspect of the upper arm.

Question 2

cutaneous nerves

Answer 2

Radial Nerve: Provides sensory innervation to the posterior aspect of the arm, forearm, and hand, including the dorsum of the hand and fingers, except for the medial one and a half fingers.

Median Nerve: Innervates the palmar aspect of the thumb, index finger, middle finger, and half of the ring finger. It also provides sensory innervation to the palmar aspect of the hand and fingers, excluding the little finger.

Ulnar Nerve: Supplies sensory innervation to the medial aspect of the hand and fingers, including the little finger and half of the ring finger, both palmar and dorsal aspects.

Axillary Nerve: Innervates a small area over the shoulder and the lateral aspect of the upper arm.

Musculocutaneous Nerve: Provides sensory innervation to the lateral aspect of the forearm.

Medial Brachial Cutaneous Nerve: Supplies the skin over the medial aspect of the upper arm.

Medial Antebrachial Cutaneous Nerve: Innervates the skin over the medial aspect of the forearm.

Lateral Antebrachial Cutaneous Nerve: Supplies the skin over the lateral aspect of the forearm.

Question 3

Palmar Cutaneous Branches:

Answer 3

Median Nerve: Provides sensory innervation to the skin of the thenar eminence and the proximal palm.

Ulnar Nerve: Supplies sensory innervation to the skin of the hypothenar eminence.