Classification of the variations of the palmar recurrent branch of the median nerve with special emphasis on angulation

Abstract

OBJECTIVEIatrogenic nerve injuries are devastating to both the patient and the surgeon. This study focuses on the anatomical relationship of the palmar recurrent branch with the parent median nerve in an attempt to identify higher risk types.METHODSThe palmar recurrent branch was dissected in 75 embalmed cadavers. The median nerve was divided into 4 sections from lateral to medial, defined as zones 1–4. The angle to the axial plane of the median nerve was also measured and classified as 0°, 45°, 60°, and 90°.RESULTSAccessory recurrent branches were found in 36.2% of cases. The recurrent branch originated from zone 1 in 32.42%, zone 2 in 61.54%, zone 3 in 6.04%, and zone 4 in 0%. These are respectively classified as types I, II, III, and IV. The motor branch made an angle with the median nerve of 0° in 17% of cases, 45° in 37.4%, 60° in 26.4%, and 90° in 19.2%. These are respectively classified as types A, B, C, and D.CONCLUSIONSClose attention should be paid to the potential anatomical variabilities when performing nerve surgeries. For the palmar recurrent branch, the more medial the origin and the greater the angle it makes with the median nerve, the more dangerous it is. This classification is helpful in unifying the language and comparing results.