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Regional morphology of the transversus abdominis and obliquus internus and externus abdominis muscles

Version 2 2024-06-06, 11:12
Version 1 2015-08-28, 13:22
journal contribution
posted on 2024-06-06, 11:12 authored by DM Urquhart, PJ Barker, PW Hodges, IH Story, CA Briggs
BACKGROUND: The mechanisms by which the abdominal muscles move and control the lumbosacral spine are not clearly understood. Descriptions of abdominal morphology are also conflicting and the regional anatomy of these muscles has not been comprehensively examined. The aim of this study was to investigate the morphology of regions of transversus abdominis and obliquus internus and externus abdominis. METHODS: Anterior and posterolateral abdominal walls were dissected bilaterally in 26 embalmed human cadavers. The orientation, thickness and length of the upper, middle and lower fascicles of transversus abdominis and obliquus internus abdominis, and the upper and middle fascicles of obliquus externus abdominis were measured. FINDINGS: Differences in fascicle orientation, thickness and length were documented between the abdominal muscles and between regions of each muscle. The fascicles of transversus abdominis were horizontal in the upper region, with increasing inferomedial orientation in the middle and lower regions. The upper and middle fascicles of obliquus internus abdominis were oriented superomedially and the lower fascicles inferomedially. The mean vertical dimension of transversus abdominis that attaches to the lumbar spine via the thoracolumbar fascia was 5.2 (SD 2.1) cm. Intramuscular septa were observed between regions of transversus abdominis, and obliquus internus abdominis could be separated into two distinct layers in the lower and middle regions. INTERPRETATION: This study provides quantitative data of morphological differences between regions of the abdominal muscles, which suggest variation in function between muscle regions. Precise understanding of abdominal muscle anatomy is required for incorporation of these muscles into biomechanical models. Furthermore, regional variation in their morphology may reflect differences in function.

History

Journal

Clinical biomechanics

Volume

20

Pagination

233-241

Location

Amsterdam, The Netherlands

ISSN

0268-0033

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2004, Elsevier

Issue

3

Publisher

Elsevier