Thoracic outlet syndrome may lead to weakness in muscles supplied by which nerve roots?

Thoracic outlet syndrome (TOS) is a condition characterized by the compression of neurovascular structures passing through the thoracic outlet, which is the space between the collarbone and the first rib. This compression primarily affects the brachial plexus, which is formed by ventral rami from the lower cervical (C5-C8) and upper thoracic (T1) nerve roots.

In the context of TOS, the weakness in muscles supplied by specific nerve roots corresponds to the areas innervated by the brachial plexus. The correct answer highlights the importance of the C8 and T1 nerve roots, which innervate muscles in the hand and forearm, including intrinsic muscles that control fine motor actions. Weakness in these regions can result from the compression that occurs in TOS, affecting the motor function of muscles such as the thenar and hypothenar muscles as well as the interossei.

Understanding the involvement of C8 and T1 in thoracic outlet syndrome is crucial for both diagnosis and management. In contrast, other nerve roots like C5 and C6 primarily impact the shoulder and upper arm areas and would not account for the specific weakness observed due to TOS, which predominantly influences the lower segments of