What is a Riche-Cannieu anastomosis in the evaluation of ulnar neuropathy?

Updated: Jun 08, 2018
  • Author: Charles F Guardia, III, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

Another anomaly that can complicate diagnostic studies is the Riche-Cannieu anastomosis (see the image below).

Riche-Cannieu anastomosis is communication between Riche-Cannieu anastomosis is communication between recurrent branch of median nerve and deep branch of ulnar nerve in hand. Although it is present in 77% of hands, it yields highly variable degrees of detectable physiologic difference; in many hands, it contributes little and does not affect diagnostic findings at all. Most common effect is probably to give ulnar innervation to some muscles usually innervated by median nerve, median innervation to muscles usually innervated by ulnar nerve, or both. Most extreme version is so-called all-ulnar hand (very rare). Two examples of confusion this might cause are as follows. (1) Median lesion could cause denervation in typically ulnar muscle, such as adductor digiti minimi (adductor digiti quinti) or first dorsal interosseous muscle. (2) Ulnar lesion could cause denervation in typically median muscle, such as flexor pollicis brevis or abductor pollicis brevis.

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