Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

Which area does Dermatome C7 cover?

1. Thumb

2. Index finger

3. Ring/little finger

4. C4 region

The correct answer is: Ring/little finger

The correct coverage of the C7 dermatome includes the sensations in the middle finger, as well as parts of the index and ring fingers. Specifically, the C7 nerve root is primarily responsible for sensation in the middle finger, while also covering parts of the ring finger and sometimes the index finger. It is often localized to the palmar surface of the fingers extending up to the lateral aspect of the hand. The ring and little fingers are specifically associated with the C8 dermatome rather than the C7. The C7 dermatome does not cover the thumb, which is the territory of the C6 dermatome, nor does it encompass the area corresponding to the C4 region, which primarily covers the upper shoulders and neck. Recognizing the dermatomes is important in clinical practice, as it helps in diagnosing conditions related to nerve root compression and other neurological disorders. Understanding the distribution of the C7 dermatome can aid in providing targeted therapies and understanding the anatomy concerning neurologic assessments.