Fusion of the musculocutaneous nerve with the median nerve in a Japanese raccoon dog (Nyctereutes procyonoides viverrinus)

Various patterns of the relationship between the musculocutaneous and median nerves have been reported. This is the first report in Canidae, a Japanese raccoon dog, of the musculocutaneous nerve fused into the median nerve in the brachial plexus. The musculocutaneous nerve gave rise to the only branch to the coracobrachialis muscle and fused into the median nerve. The median nerve sent a branch to the biceps brachii muscle, the medial antebrachial cutaneous nerve, and a branch to the brachialis muscle. This case report may provide clues to understanding the phylogeny and embryology of the brachial plexus in Canidae.