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

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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 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°.

RESULTS

Accessory 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.

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 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.

Article Information

Correspondence Amgad Hanna: University of Wisconsin, Madison, WI. ah2904@yahoo.com.

INCLUDE WHEN CITING Published online July 5, 2019; DOI: 10.3171/2019.4.JNS19516.

Disclosures The author reports no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.

Headings

Figures

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    Types of palmar recurrent branch of the median nerve based on zone of origin. From lateral to medial, zones 1–4 correspond to types I–IV, respectively. The more medial the origin, the riskier it is for iatrogenic injury. Copyright Amgad Hanna. Published with permission.

  • View in gallery

    Types of palmar recurrent branch based on the angle it makes with the axial plane of the median nerve in both axial (A) and oblique axial (B) views. Type A = 0°, type B = 45°, type C = 60°, and type D = 90°. The most dangerous type is type D. Copyright Amgad Hanna. Published with permission.

  • View in gallery

    Specimen 34, right. Dual nerve supply of the thenar muscles. One branch (white arrow) type IB (zone 1, 45°) and the other (black arrow) type IIID (zone 3, 90°).

  • View in gallery

    Specimen 8, left. Four branches are supplying the thenar muscles. Two (white arrow) type IA (zone 1, 0°), and 2 (black arrow) type IIB (zone 2, 45°).

  • View in gallery

    Specimen 6, right, showing a single branch (arrow) type IC (zone 1, 60°). This is fairly safe because of how lateral it is originating from the median nerve.

  • View in gallery

    Specimen 29, right, demonstrating a single palmar recurrent branch (arrow) type IID (zone 2, 90°). This is a dangerous type because of the angle.

References

  • 1

    Entin MA: Carpal tunnel syndrome and its variants. Surg Clin North Am 48:109711121968

  • 2

    Graham WP III: Variations of the motor branch of the median nerve at the wrist. Case report. Plast Reconstr Surg 51:90921973

  • 3

    Hurwitz PJ: Variations in the course of the thenar motor branch of the median nerve. J Hand Surg Br 21:3443461996

  • 4

    Jegal MWoo SJLee HIShim JWShin WJPark MJ: Anatomical relationships between muscles overlying distal transverse carpal ligament and thenar motor branch of the median nerve. Clin Orthop Surg 10:89932018

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Lanz U: Anatomical variations of the median nerve in the carpal tunnel. J Hand Surg Am 2:44531977

  • 6

    Linburg RMAlbright JA: An anomalous branch of the median nerve. A case report. J Bone Joint Surg Am 52:1821831970

  • 7

    Mackinnon SEDellon AL: Anatomic investigations of nerves at the wrist: I. Orientation of the motor fascicle of the median nerve in the carpal tunnel. Ann Plast Surg 21:32351988

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Mannerfelt LHybbinette CH: Important anomaly of the thenar motor branch of the median nerve. A clinical and anatomical report. Bull Hosp Jt Dis 33:15211972

    • Search Google Scholar
    • Export Citation
  • 9

    Poisel S: Ursprung und Verlauf des Ramus muscularis des Nervus digitalis palmaris communis I (N. medianus). Chir Praxis 18:4714741974

    • Search Google Scholar
    • Export Citation
  • 10

    Rasulić LSavić AVitošević FSamardžić MŽivković BMićović M: Iatrogenic peripheral nerve injuries—surgical treatment and outcome: 10 years’ experience. World Neurosurg 103:841851851.e1–851.e6 2017

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Samarakoon LBGuruge MHJayasekara MMalalasekera APAnthony DJJayasekara RW: Anatomical landmarks for safer carpal tunnel decompression: an experimental cadaveric study. Patient Saf Surg 8:82014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Schultz RJEndler PMHuddleston HD: Anomalous median nerve and an anomalous muscle belly of the first lumbrical associated with carpal-tunnel syndrome. J Bone Joint Surg Am 55:174417461973

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Stancić MFEskinja NStosić A: Anatomical variations of the median nerve in the carpal tunnel. Int Orthop 19:30341995

  • 14

    Trachani ERigopoulou AVeltsista DGavanozi EChrysanthopoulou AChroni E: Occurrence of bifid median nerve in healthy and carpal tunnel syndrome patients. J Electromyogr Kinesiol 39:77802018

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Vinding MTTarnowski JRBenyahia M: A rare anatomical variant of the thenar branch discovered during open decompression of the median nerve. J Plast Surg Hand Surg 44:3223242010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Werschkul JD: Anomalous course of the recurrent motor branch of the median nerve in a patient with carpal tunnel syndrome. J Neurosurg 47:1131141977

    • Crossref
    • Search Google Scholar
    • Export Citation

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