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Morphologic observation for anomalous patterns of the flexor carpi radialis muscle and atypical insertions: a proposal for a new classification

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Abstract

In the present study, four types of variations of the flexor carpi radialis with accessory muscular bundles were classified depending on the origin of the accessory muscular bundle and relationships with the bicipital aponeurosis, biceps brachii, pronator teres, and coracobrachialis. Six types of insertions of the tendon of the flexor carpi radialis were also divided according to their inserted positions on the carpal and metacarpal bones. An accessory muscular bundle of the flexor carpi radialis was found in 4 (1 female and 3 males) of 68 cadavers (5.88%), with five examples in 136 arms (3.68%). It was bilateral in one cadaver and unilateral (two on the right and one on the left) in three. The insertion of the flexor carpi radialis tendon was not only on the proximal surface of the base of the second metacarpal bone but also on the third metacarpal bone, the tubercle of the trapezium, and the scaphoid. These findings and classifications are important in anatomical education, and have important significances in clinical diagnosis and therapies.

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Abbreviations

BA:

Bicipital aponeurosis

BB:

Biceps brachii muscle

BR:

Brachialis muscle

BT:

Biceps tendon

CbM:

Coracobrachialis muscle

FCR:

Flexor carpi radialis muscle

FCRt:

Tendon of flexor carpi radialis

FCU:

Flexor carpi ulnaris muscle

MII:

Second metacarpal bone

MIII:

Third metacarpal bone

MN:

Median nerve

PT:

Pronator teres muscle

Sca:

Scaphoid bone

TB:

Triceps brachii muscle

Tra:

Tubercle of trapezium bone

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Acknowledgements

The authors sincerely thank the members and their families of “Shiragiku-Kai” of Akita University Graduate School of Medicine who donated their bodies to medical science so that anatomical dissection and research can be performed. The authors totally agree with the anatomical journal editor’s recommendation expressing deep gratitude upon donor cadaver (Iwanaga et al. 2020): “The authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially increase mankind's overall knowledge that can then improve patient care. Therefore, these donors and their families deserve our highest gratitude.” We thank the staff of the Medical Technology Center for their technical assistance. We also thank our students Seiki T, Goto H, Kaneko R, Sasaki K, Watanabe I, Nakabayshi T, and Yoshimura G, who assisted in this study.

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Authors and Affiliations

  1. Department of Anatomy, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan

    Ming Zhou, Hideo Akashi, Ryoji Suzuki & Yoshio Bando

  2. Guidance Division, Kashiwa City Board of Education, 48-1 Oshimada, Kashiwa, 277-8503, Japan

    Akimitsu Ishizawa

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  1. Ming Zhou
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Correspondence to Ming Zhou.

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Zhou, M., Ishizawa, A., Akashi, H. et al. Morphologic observation for anomalous patterns of the flexor carpi radialis muscle and atypical insertions: a proposal for a new classification. Anat Sci Int 98, 99–106 (2023). https://doi.org/10.1007/s12565-022-00675-6

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  • DOI: https://doi.org/10.1007/s12565-022-00675-6

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