open access

Vol 60, No 3 (2001)
ORIGINAL ARTICLES
Published online: 2001-05-29
Submitted: 2012-02-06
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A study on the morphology of the coracobrachialis muscle and its relationship with the musculocutaneous nerve

Mostafa M El-Naggar
Folia Morphol 2001;60(3):217-224.

open access

Vol 60, No 3 (2001)
ORIGINAL ARTICLES
Published online: 2001-05-29
Submitted: 2012-02-06

Abstract

Thirty-six arms from embalmed adult cadavers were utilised for this investigation. Coracobrachialis muscle was carefully examined to record variations in its attachments, morphology and its relationship with the musculocutaneous nerve. The results of the present work identified the presence of two heads of origin for the coracobrachialis muscle, which are situated superficial (anterior) and deep (posterior) to the musculocutaneous nerve. The superficial head arises mainly from most of the medial border of the tendon of the short head of the biceps brachii muscle. The deep head arises from the apex of the coracoid process of the scapula and the adjoining lateral border of the tendon of the short head of the biceps brachii muscle. The musculocutaneous nerve provides a separate branch for each head. In cases where the coracobrachialis muscle was not pierced by the musculocutaneous nerve, the muscle was formed of one head that has an origin analogous to that of the superficial head. One case showed a splitting of the deep head into two bellies shortly after its origin, where the muscle appeared as being formed of three heads. Variations in the insertion were present as an additional aponeurotic insertion above the usual insertion and an aponeurotic extension to the deep fascia on the medial aspect of the arm. Variations in the musculocutaneous nerve were in the form of lower origin from the lateral root of median nerve and a nerve with a short course after which it united with the median nerve. This investigation supplied evidence of the double heads of origin for the coracobrachialis muscle. The detected variability in insertion and association of the muscle with the musculocutaneous nerve further supports the idea that the coracobrachialis muscle is a complex muscle.

Abstract

Thirty-six arms from embalmed adult cadavers were utilised for this investigation. Coracobrachialis muscle was carefully examined to record variations in its attachments, morphology and its relationship with the musculocutaneous nerve. The results of the present work identified the presence of two heads of origin for the coracobrachialis muscle, which are situated superficial (anterior) and deep (posterior) to the musculocutaneous nerve. The superficial head arises mainly from most of the medial border of the tendon of the short head of the biceps brachii muscle. The deep head arises from the apex of the coracoid process of the scapula and the adjoining lateral border of the tendon of the short head of the biceps brachii muscle. The musculocutaneous nerve provides a separate branch for each head. In cases where the coracobrachialis muscle was not pierced by the musculocutaneous nerve, the muscle was formed of one head that has an origin analogous to that of the superficial head. One case showed a splitting of the deep head into two bellies shortly after its origin, where the muscle appeared as being formed of three heads. Variations in the insertion were present as an additional aponeurotic insertion above the usual insertion and an aponeurotic extension to the deep fascia on the medial aspect of the arm. Variations in the musculocutaneous nerve were in the form of lower origin from the lateral root of median nerve and a nerve with a short course after which it united with the median nerve. This investigation supplied evidence of the double heads of origin for the coracobrachialis muscle. The detected variability in insertion and association of the muscle with the musculocutaneous nerve further supports the idea that the coracobrachialis muscle is a complex muscle.
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Keywords

anomaly; muscles of arm; two heads; variation

About this article
Title

A study on the morphology of the coracobrachialis muscle and its relationship with the musculocutaneous nerve

Journal

Folia Morphologica

Issue

Vol 60, No 3 (2001)

Pages

217-224

Published online

2001-05-29

Bibliographic record

Folia Morphol 2001;60(3):217-224.

Keywords

anomaly
muscles of arm
two heads
variation

Authors

Mostafa M El-Naggar

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