open access

Vol 82, No 1 (2023)
Case report
Submitted: 2021-10-25
Accepted: 2021-12-23
Published online: 2022-01-17
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Presence of accessory abductor digiti minimi muscle in two cadavers

C. D. Hamacher1, B. J. Browning1, J. C. Barton1, N. F. Chase1, R. E. Larson12, D. J. Green12
·
Pubmed: 35099047
·
Folia Morphol 2023;82(1):216-220.
Affiliations
  1. Campbell University School of Osteopathic Medicine, Buies Creek, United States
  2. Department of Anatomy, Buies Creek, United States

open access

Vol 82, No 1 (2023)
CASE REPORTS
Submitted: 2021-10-25
Accepted: 2021-12-23
Published online: 2022-01-17

Abstract

During routine cadaveric dissection, accessory hypothenar muscles were incidentally discovered in two cadavers, both males, aged 86 and 92. Both muscles originated from the palmaris longus tendon in the distal portion of the forearm and were identified as accessory abductor digiti minimi (AADM) muscles, based on their association with abductor digiti minimi. While AADM is a common variant in the antebrachium, it is less typical for them to originate from the palmaris longus tendon. The presence of such an AADM could complicate surgical procedures requiring resection of the palmaris longus tendon. Moreover, the surrounding neurovasculature — namely the ulnar nerve as it passes through the ulnar canal between the pisiform and hook of the hamate — could be compressed by contractions of an AADM with such a proximal origin. This can manifest as ulnar neuropathies resulting in pain, weakness, or protracted flexion of the fourth and fifth digits (ulnar claw). Our description of these muscles adds to previous accounts of variation of the palmaris longus and abductor digiti minimi muscles while considering potential clinical implications.

Abstract

During routine cadaveric dissection, accessory hypothenar muscles were incidentally discovered in two cadavers, both males, aged 86 and 92. Both muscles originated from the palmaris longus tendon in the distal portion of the forearm and were identified as accessory abductor digiti minimi (AADM) muscles, based on their association with abductor digiti minimi. While AADM is a common variant in the antebrachium, it is less typical for them to originate from the palmaris longus tendon. The presence of such an AADM could complicate surgical procedures requiring resection of the palmaris longus tendon. Moreover, the surrounding neurovasculature — namely the ulnar nerve as it passes through the ulnar canal between the pisiform and hook of the hamate — could be compressed by contractions of an AADM with such a proximal origin. This can manifest as ulnar neuropathies resulting in pain, weakness, or protracted flexion of the fourth and fifth digits (ulnar claw). Our description of these muscles adds to previous accounts of variation of the palmaris longus and abductor digiti minimi muscles while considering potential clinical implications.

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Keywords

anatomy, dissection, variation, forearm, wrist, hand, palm, medicine

About this article
Title

Presence of accessory abductor digiti minimi muscle in two cadavers

Journal

Folia Morphologica

Issue

Vol 82, No 1 (2023)

Article type

Case report

Pages

216-220

Published online

2022-01-17

Page views

3176

Article views/downloads

846

DOI

10.5603/FM.a2022.0002

Pubmed

35099047

Bibliographic record

Folia Morphol 2023;82(1):216-220.

Keywords

anatomy
dissection
variation
forearm
wrist
hand
palm
medicine

Authors

C. D. Hamacher
B. J. Browning
J. C. Barton
N. F. Chase
R. E. Larson
D. J. Green

References (14)
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  10. Rixey A, Wenger D, Baffour F, et al. Accessory abductor digiti minimi muscle, less muscular than thought: an update on prevalence, morphology, and review of the literature. Skeletal Radiol. 2021; 50(8): 1687–1695.
  11. Slavchev S, Georgiev G. Aberrant abductor digiti minimi muscle found during open surgical decompression of the carpal tunnel: case report. Revista Argentina de Anatomía Clínica. 2016; 5(2): 88–91.
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