Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study

BACKGROUND: The authors aimed to understand the considerable variations in the number of adult extensor tendons at the dorsal side of the wrist and hand. MATERIALS AND METHODS: The authors examined histological sections from 30 human foetuses of gestational age 7–39 weeks and crown-rump length 22–...

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Main Authors: Chun-Ai Li, Shogo Hayashi, Zhe Wu Jin, Masahito Yamamoto, Yoko Ueda, Gen Murakami
Format: Article
Language:English
Published: Via Medica 2025-01-01
Series:Folia Morphologica
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Online Access:https://journals.viamedica.pl/folia_morphologica/article/view/101833
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author Chun-Ai Li
Shogo Hayashi
Zhe Wu Jin
Masahito Yamamoto
Yoko Ueda
Gen Murakami
author_facet Chun-Ai Li
Shogo Hayashi
Zhe Wu Jin
Masahito Yamamoto
Yoko Ueda
Gen Murakami
author_sort Chun-Ai Li
collection DOAJ
description BACKGROUND: The authors aimed to understand the considerable variations in the number of adult extensor tendons at the dorsal side of the wrist and hand. MATERIALS AND METHODS: The authors examined histological sections from 30 human foetuses of gestational age 7–39 weeks and crown-rump length 22–323 mm. RESULTS: At the carpal level, earlier or smaller foetuses showed a simpler configuration with fewer tendon slips, whereas later or larger foetuses had a greater number of tendon slips with considerable variations in number and topographical relationships. Tendon slips of the early extensor digitorum to the middle and ring fingers were always 1 or 2, but were seven or more at late term. A tendon of the extensor digitorum to the little finger could not be distinguished from other tendons at the carpal bone level. At the metacarpal bone level, however, it extended from the ring finger tendon toward two slips of the extensor digiti minimi tendon. At the distal carpal level at midterm and late term, in which the tendon sheath was lost, each of the extensor digitorum tendon slips further divided to provide a mediolateral linear cluster of thin bundles. This large number of tendon components joined and united together to provide a single tight tendon at the level of the metacarpophalangeal joints. The extensor pollicis longus tendon usually lost a membranous septation when it crossed the extensor carpi radialis brevis tendon. CONCLUSIONS: Tendon slips in the fourth and fifth canals of the sheath are most likely to reduce in number after birth, depending on the mechanical demand.
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spelling doaj-art-8bc3380c833641b8919a91db561d828c2025-08-20T13:27:48ZengVia MedicaFolia Morphologica0015-56591644-32842025-01-0184210.5603/fm.101833Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological studyChun-Ai Li0Shogo Hayashi1https://orcid.org/0000-0003-0302-7658Zhe Wu Jin2https://orcid.org/0000-0002-6789-2977Masahito Yamamoto3https://orcid.org/0000-0001-9683-6678Yoko Ueda4Gen Murakami5https://orcid.org/0000-0001-7181-5475Department of Radiology, Yanbian Second People’s Hospital, Yanji, ChinaDepartment of Anatomy, Division of Basic Medicine, Tokai University School of Medicine, Isehara, JapanDepartment of Anatomy, Wuxi School of Medicine, Jiangnan University, Wuxi, ChinaDepartment of Anatomy, Division of Basic Medicine, Tokai University School of Medicine, Isehara, JapanDepartment of Anatomy, Division of Basic Medicine, Tokai University School of Medicine, Isehara, JapanDivision of Internal Medicine, Iwamizawa Asuka Hospital, Iwamizawa, JapanBACKGROUND: The authors aimed to understand the considerable variations in the number of adult extensor tendons at the dorsal side of the wrist and hand. MATERIALS AND METHODS: The authors examined histological sections from 30 human foetuses of gestational age 7–39 weeks and crown-rump length 22–323 mm. RESULTS: At the carpal level, earlier or smaller foetuses showed a simpler configuration with fewer tendon slips, whereas later or larger foetuses had a greater number of tendon slips with considerable variations in number and topographical relationships. Tendon slips of the early extensor digitorum to the middle and ring fingers were always 1 or 2, but were seven or more at late term. A tendon of the extensor digitorum to the little finger could not be distinguished from other tendons at the carpal bone level. At the metacarpal bone level, however, it extended from the ring finger tendon toward two slips of the extensor digiti minimi tendon. At the distal carpal level at midterm and late term, in which the tendon sheath was lost, each of the extensor digitorum tendon slips further divided to provide a mediolateral linear cluster of thin bundles. This large number of tendon components joined and united together to provide a single tight tendon at the level of the metacarpophalangeal joints. The extensor pollicis longus tendon usually lost a membranous septation when it crossed the extensor carpi radialis brevis tendon. CONCLUSIONS: Tendon slips in the fourth and fifth canals of the sheath are most likely to reduce in number after birth, depending on the mechanical demand.https://journals.viamedica.pl/folia_morphologica/article/view/101833extensor digitorumextensor pollicis longustendon sheathhand and wristhuman foetus
spellingShingle Chun-Ai Li
Shogo Hayashi
Zhe Wu Jin
Masahito Yamamoto
Yoko Ueda
Gen Murakami
Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
Folia Morphologica
extensor digitorum
extensor pollicis longus
tendon sheath
hand and wrist
human foetus
title Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
title_full Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
title_fullStr Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
title_full_unstemmed Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
title_short Foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand: a histological study
title_sort foetal development and growth of extensor tendons and their sheaths in dorsal side of wrist and hand a histological study
topic extensor digitorum
extensor pollicis longus
tendon sheath
hand and wrist
human foetus
url https://journals.viamedica.pl/folia_morphologica/article/view/101833
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