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Presence of accessory abductor digiti minimi muscle in two cadavers
Affiliations- Campbell University School of Osteopathic Medicine, Buies Creek, United States
- Department of Anatomy, Buies Creek, United States
open access
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.
Keywords
anatomy, dissection, variation, forearm, wrist, hand, palm, medicine
About this articleTitle
Presence of accessory abductor digiti minimi muscle in two cadavers
Journal
Issue
Article type
Case report
Pages
216-220
Published online
2022-01-17
Page views
3174
Article views/downloads
845
DOI
Pubmed
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)- Aleksenko D., Varacallo M. 2021 [Updated Jul 18]. Guyon Canal Syndrome. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK431063/.
- Berger P, Duerinckx J. Flexor pollicis longus tendon rupture after volar wrist plating : reconstruction with palmaris longus interposition graft. Acta Orthop Belg. 2017; 83(3): 467–472.
- Coraci D, Luchetti R, Paolasso I, et al. Intermittent ulnar nerve compression due to accessory abductor digiti minimi muscle: Crucial diagnostic role of nerve ultrasound. Muscle Nerve. 2015; 52(3): 463–464.
- Dimitriou C, Natsis K. Accessory abductor digiti minimi muscle causing ulnar nerve entrapment at the Guyon's canal: a case report. Clin Anat. 2007; 20(8): 974–975.
- Dodds GA, Hale D, Jackson WT. Incidence of anatomic variants in Guyon's canal. J Hand Surg Am. 1990; 15(2): 352–355.
- Doherty, T.J. 2021. Ulnar neuropathy at the elbow and wrist. Shefner J.M., Goddeau Jr. R.P., eds. UpToDate. Waltham, MA: UpToDate Inc. https://www.uptodate.com/contents/ulnar-neuropathy-at-the-elbow-and-wrist (Accessed on October 18, 2021).
- Lam DS, Ng JS, Cheng GP, et al. Autogenous palmaris longus tendon as frontalis suspension material for ptosis correction in children. Am J Ophthalmol. 1998; 126(1): 109–115.
- Liu Z, Ma K, Huang D. Treatment of mallet finger deformity with a modified palmaris longus tendon graft through a bone tunnel. Int J Burns Trauma. 2018; 8(2): 34–39.
- Lokanathan TH, Surendra M, Ajay N, et al. Unusual co-existence of biaponeurotic palmaris longus and accessory abductor digiti minimi in man. J Clin Diagn Res. 2014; 8(1): 146–147.
- 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.
- 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.
- Soldado-Carrera F, Vilar-Coromina N, Rodríguez-Baeza A. An accessory belly of the abductor digiti minimi muscle: a case report and embryologic aspects. Surg Radiol Anat. 2000; 22(1): 51–54.
- Yong MW, Yusof N, Rampal L, et al. Prevalence of absence of palmaris longus and its association with gender, hand dominance and absence of FDS tendon to little finger among malay population. J Hand Surg Asian Pac Vol. 2017; 22(4): 484–489.
- Zeiss J, Jakab E, Khimji T, et al. The ulnar tunnel at the wrist (Guyon's canal): normal MR anatomy and variants. AJR Am J Roentgenol. 1992; 158(5): 1081–1085.
