Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

Which dermatome corresponds to T7?

1. Xyphoid

2. Nipple

3. Medial upper arm

4. Thumb

The correct answer is: Xyphoid

The correct correspondence for the T7 dermatome is at the level of the xyphoid process. Dermatomes represent areas of skin that are innervated by sensory fibers from a single spinal nerve root, and T7 specifically relates to the thoracic region. The xyphoid process is located at the lower part of the sternum, which corresponds to the sensory innervation of the T7 spinal nerve. This is an important landmark in clinical practice, especially in assessments of referred pain or in surgical procedures. Understanding dermatomes helps in diagnosing potential nerve root issues and their effects on sensory perception, as well as guiding interventions and procedures that may be needed in areas corresponding to certain spinal nerves. In contrast, the nipple corresponds to T4, the medial upper arm typically relates to T1 to T2, and the thumb is associated with C6.