Which nerve root injury can present with symptoms affecting the ulnar aspect of the forearm?

The correct response is based on the anatomy of the brachial plexus and the specific nerve root contributions to sensory innervation in the forearm and hand. The C8 and T1 nerve roots contribute to the ulnar nerve, which supplies sensation to the ulnar aspect of the forearm and the little finger and half of the ring finger.

In particular, the T1 nerve root is responsible for the innervation of the muscles and skin along this region, including the intrinsic muscles of the hand supplied by the ulnar nerve. Damage or injury to the T1 nerve root can lead to sensory loss or abnormal sensations in the ulnar distribution, including the inner aspect of the forearm, which correlates with the symptoms described in the question.

In contrast, injury to the other nerve roots C6, C7, and C8 may cause different patterns of sensory deficits that do not primarily impact the ulnar aspect of the forearm, highlighting the unique role that the T1 nerve root plays in this specific clinical context.