Which dermatome corresponds to sensory loss or numbness over the medial aspect of the forearm?
Solution
Correct Answer: Option B
The dermatome corresponding to the medial aspect of the forearm is innervated by the T1 spinal nerve. This region covers the skin over the medial side of the forearm extending towards the elbow.
- The C8 dermatome primarily supplies the little finger and the medial side of the hand, along with a portion of the medial forearm but not the entire medial forearm area.
- The T1 dermatome specifically covers the medial aspect of the forearm, which is distinct from the hand.
- The T2 dermatome innervates the axilla and upper medial arm.
- The C7 dermatome corresponds to the middle finger and the posterior aspect of the forearm.
In summary, sensory loss or numbness over the medial (inner) aspect of the forearm indicates involvement of the T1 dermatome. This knowledge helps in localizing the level of nerve root injury or compression in clinical neurology and physical examinations.
Reference: Gray’s Anatomy, 42nd Edition, Volume 2, Chapter 7/Skin Innervation
- The C8 dermatome primarily supplies the little finger and the medial side of the hand, along with a portion of the medial forearm but not the entire medial forearm area.
- The T1 dermatome specifically covers the medial aspect of the forearm, which is distinct from the hand.
- The T2 dermatome innervates the axilla and upper medial arm.
- The C7 dermatome corresponds to the middle finger and the posterior aspect of the forearm.
In summary, sensory loss or numbness over the medial (inner) aspect of the forearm indicates involvement of the T1 dermatome. This knowledge helps in localizing the level of nerve root injury or compression in clinical neurology and physical examinations.
Reference: Gray’s Anatomy, 42nd Edition, Volume 2, Chapter 7/Skin Innervation
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