During an airway exam, a 53-year-old patient mentions that his right thumb tingles and then becomes numb if he extends his head for more than a few seconds. This symptom most likely represents

During an airway exam, a 53-year-old patient mentions that his right thumb tingles and then becomes numb if he extends his head for more than a few seconds. This symptom most likely represents

• A. Unstable c-spine
• B. Lhermitte's phenomenon
• C. C6 nerve root irritation
• D. C8 radiculopathy

Answer: (C)

The patient’s symptom points to irritation of a cervical nerve root affecting the thumb region. The sensation in the thumb is carried mostly by the C6 dermatome, so tingling and then numbness in the thumb with neck extension suggests C6 nerve root involvement. Neck extension can narrow the intervertebral foramina or stretch a affected root, provoking radicular symptoms when the C6 nerve root is irritated or compressed (for example, by degenerative changes or a disc issue at the C5–C6 level). Lhermitte’s phenomenon, by contrast, is an electric shock-like sensation that occurs with neck flexion and is classically associated with cervical myelopathy or demyelinating disease like multiple sclerosis, not a focal radiculopathy triggered by extension. C8 radiculopathy would more likely involve the little finger and medial hand, not the thumb. Unstable cervical spine would present with unstable pain and movements and not specifically a thumb-focused sensory change.

The patient’s symptom points to irritation of a cervical nerve root affecting the thumb region. The sensation in the thumb is carried mostly by the C6 dermatome, so tingling and then numbness in the thumb with neck extension suggests C6 nerve root involvement. Neck extension can narrow the intervertebral foramina or stretch a affected root, provoking radicular symptoms when the C6 nerve root is irritated or compressed (for example, by degenerative changes or a disc issue at the C5–C6 level).

Lhermitte’s phenomenon, by contrast, is an electric shock-like sensation that occurs with neck flexion and is classically associated with cervical myelopathy or demyelinating disease like multiple sclerosis, not a focal radiculopathy triggered by extension. C8 radiculopathy would more likely involve the little finger and medial hand, not the thumb. Unstable cervical spine would present with unstable pain and movements and not specifically a thumb-focused sensory change.