Encyclopedia entry

Rectus Abdominis

Version 1

Abstract

The rectus muscle of lower mammals extends further over the thorax than that of the human subject. In many of the lower primates, it reaches the first rib and the clavicle. It may rise to the fourth rib or even the third rib in humans, and in certain rare cases even higher. On the other hand, the slip attached to the fifth rib may be absent. The muscle usually inserts onto two or three ribs. In one study, six types of insertion were found. In 67%, the insertions were ribs 4 and 5; 4,5 and 6; 5 and 6; or 5, 6 and 7. In 20%, the insertions were ribs 6 and 7; and in 10%, ribs 6, 7 and 8.

The rectus muscle of lower mammals extends further over the thorax than that of the human subject. In many of the lower primates, it reaches the first rib and the clavicle. It may rise to the fourth rib or even the third rib in humans, and in certain rare cases even higher. On the other hand, the slip attached to the fifth rib may be absent. The muscle usually inserts onto two or three ribs. In one study, six types of insertion were found. In 67%, the insertions were ribs 4 and 5; 4,5 and 6; 5 and 6; or 5, 6 and 7. In 20%, the insertions were ribs 6 and 7; and in 10%, ribs 6, 7 and 8. Slender muscular slips are sometimes found between the rectus and the deep inguinal ring.

In the absence of pyramidalis, the inferior end of rectus abdominis is usually enlarged. Absence of a part or even the whole muscle has been reported. It may also be doubled.

A rectus lateralis abdominis has been described by Kelch, 2.5 cm. wide, located between external and internal oblique muscles, arising by a short tendon from the middle and edge of the tenth rib and extending over the edge of the eleventh rib to the edge of crest of the pubis.

The congenital absence of the abdominal muscles was first reported by Froumllich in 1839.

Syn.: Gerader Bauchmuskel, Grand droit (Cruveilhier).

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Riferimenti dell’opera originale

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  • Ando, T. (1938) On the rectus abdominis and the pyramidalis. Sotai taijino kaibogakuteki kenyu 2:1-30. In Japanese.
  • Chouke, K.S. (1927) The constitution of the sheath of the rectus abdominis muscle. Anat. Rec.61:341-349.
  • Dobson, G.E. (1883) Note on the rectus abdominis et sternalis muscle. J. Anat. physiol. 17:84-85.
  • Gruber, W. (1877) Tensor laminae posterioris vaginae musculi recti abdominis. Arch. Path. Anat. Physiol. Klin. Med. 69:400-403.
  • Gruber, W. (1879) Nachtrag zum Vorkommen des Musculus tensor laminae posterioris vaginae musculi recti abdominis. Arch. Path. Anat. Physiol. Klin. Med. 77:130-131.
  • Gruber, W. (1880) Tensor laminae posterioris vaginae musculi rectus abdominis. Arch. Path. Anat. Physiol. Klin. Med. 80:87-88.
  • Henle, J. (1871) Handbuch der Muskellehre des Menschen, in Handbuch der systematischen Anatomie des Menschen. Verlag von Friedrich Vieweg und Sohn, Braunschweig
  • Kita, T. (1931) On the rectus abdominis. Kaibogaku Zasshi 3:1491-1495. In Japanese.
  • Livini, F. (1905) Contribuzione alla morphologia des m. rectus abdominis e du m. supra-costalis nell'uomo. Arch. Ital. Anat. Embriol. 44:116-117.
  • Macalister, A. (1875) Observations on muscular anomalies in the human anatomy. Third series with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci. 25:1-130.
  • Milloy, F.J., Anson, B.J. and D.K. McAffee. (1960) The rectus abdominis muscle and the epigastric arteries. Surg., Gynec. Obstet. 110:293-302.
  • Morita, M. (1947) On the M. rectus abdominis, appendix, the length of the M. pyramidalis. Kaibogaku Zasshi 23:50-55. In Japanese.
  • Obata, T. and A. Sugiyama. (1943) The M. rectus abdominis and M. pyramidalis. Sotaiiji no Kaibogakuteki Kenkyu 4:155-185. In Japanese.
  • Sosa, G.C. , Liotta, D. and S. Liotta. (1952) La gaine des muscles grand droits del'abdomen considérations anatomiques dans les 3/4 supérieurs. L'Assoc. Anatomistes, Comptes Rendus. 39:329-338.

Anatomical classification

Systems:
Muscular system

Content provenance

Adaptation

Adaptation of «Rectus Abdominis — Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System» by Ronald A. Bergman, Adel K. Afifi, Ryosuke Miyauchi. Source: https://www.anatomyatlases.org/AnatomicVariants/MuscularSystem/Text/R/07Rectus.shtml Original work distributed under the CC BY-NC-SA 4.0 licence (https://creativecommons.org/licenses/by-nc-sa/4.0/deed.it). Adaptation by Redazione AIVA. Changes from the original: Testo originale inglese riprodotto integralmente e riorganizzato nel formato scheda del portale (sintesi, testo, riferimenti), senza modificarne le affermazioni. La traduzione italiana non è ancora stata eseguita, e la pagina lo dichiara. Le figure non sono state copiate: sono collegate alla pagina d’origine. This publication is not approved or endorsed by the authors of the original work.

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