A 28-year-old motorcyclist sustains a brachial plexus injury. Clinical examination shows total anesthesia of the entire upper limb with a Horner's syndrome on the ipsilateral side. The most accurate diagnosis and its significance are:

• A Infraclavicular brachial plexus injury — surgical repair is straightforward
• B Preganglionic (root avulsion) injury at C8-T1 — Horner's confirms T1 involvement with a poor prognosis for direct nerve repair ✓
• C Postganglionic C5-C6 rupture — nerve grafting is the first line
• D Supraclavicular injury limited to upper trunk — sensation usually preserved

Explanation

Horner's syndrome (ptosis, miosis, anhidrosis) in the context of a brachial plexus injury indicates preganglionic avulsion of the T1 root (and often C8), because the sympathetic fibers to the eye travel via the T1 root and are avulsed from the spinal cord rather than torn in the periphery. Preganglionic injuries cannot be repaired by direct neurorrhaphy or nerve grafting since there is no viable proximal stump; management requires nerve transfer (neurotisation) from donor nerves (intercostal, phrenic, contralateral C7, accessory nerve) or tendon transfers. Total limb anesthesia indicates involvement of all roots (C5–T1), carrying a worse prognosis.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.