Hand motor functional deficits due to pure T1 radiculopathy: illustrative cases.

BACKGROUND: Pure T1 radiculopathy is very rare. Furthermore, it is difficult to differentiate between C8 radiculopathy and T1 radiculopathy because the C8 and T1 nerve roots are joined at the lower brachial plexus. OBSERVATIONS: The authors report on 2 cases of T1 radiculopathy. Case 1 involved a 47-year-old man with a herniated disc at T1-2 whose symptoms improved after conservative treatment. Case 2 involved a 20-year-old woman with a schwannoma in the T1-2 intervertebral foramen whose symptoms improved after surgical treatment. Both patients presented with numbness, radiating pain, and decreased grip strength in the left upper limb. LESSONS: Weakness of the flexor digitorum profundus (first digit) that is innervated by the median nerve is characteristic of T1 radiculopathy and may be used to differentiate T1 radiculopathy from C8 radiculopathy. https://thejns.org/doi/10.3171/CASE25599.