American Society for Peripheral Nerve

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Classification of the Variations of the Palmar Recurrent Branch of the Median Nerve with Special Emphasis on Angulation
Amgad S Hanna, MD, University of Wisconsin, Madison, WI

Objective: Iatrogenic 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.

Methods:The palmar recurrent branch was dissected in 130 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 0o, 45o, 60o, and 90o.

Results:Accessory recurrent branches were found in 36.2%. 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 0o in 17%, 45oin 37.4%, 60oin 26.4%, and 90oin 19.2%. These are respectively classified as types A, B, C, and D.

Conclusions:Close 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 more angle it makes with the median nerve, the more dangerous it is. This classification is helpful in unifying the language and comparing results.

Key Words: carpal tunnel; complications; iatrogenic; median nerve; nerve injury; palmar recurrent; thenar

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