Implications of Anomalous Pectoralis Muscle in Reconstructive Breast Surgery

The Oblique Pectoralis Anterior

Katherine Marie Huber, BS; Travis Guthrie Boyd, BS; Amy R Quillo, MD; Bradon J Wilhelmi, MD

ePlasty. 2012;12

Results

Muscular coverage of the implant from pectoralis major and the oblique pectoralis anterior muscle approximated 70%. The remaining lower pole of the implant was covered by soft tissue, as in any other submuscular implant. The patient was left with a satisfactorily cosmetic result, despite the challenges presented by her anomalous chest wall musculature.

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Table 1. Anatomical descriptions of anomalous pectoralis musculature reported in the literature
Name	Origin	Insertion	Description	Reference
Chondrohumeralis	Normal, part of pectoralis major medially	Superficial to axillary neurovascular bundle into fascia of biceps	Muscular slip	9
Axillary arch of Langer	Anterior border of latissimus dorsi	Superficial to axillary neurovascular bundle into fascia of biceps, or into pectoralis major	Can be a single band or multiple bands
Sternalis	From the inferior costal region, often from the aponeurosis of the external oblique	The infraclavicular region, often on the sternal tendon of the sternocleidomastoid	Also called anomalous sterni, parasternal, rectus sternalis, etc… Fibers run vertically parallel to the sternum	1,13
Rectus thoracis bifurcalis	External oblique aponeurosis	Merges with sternocleidomastoid bilaterally	Splits into "Y" shape at sternal angle	15
Pectoralis minimus	Second costal cartilage	Superior surface of the coracoid process	Deep to pectoralis major and superomedial to pectoralis minor, becomes tendinous laterally	10
Pectoralis quartus	Costochondral junction of the fifth and sixth ribs	Intertubercular groove of the humerus	Extends laterally under the border of pectoralis major	11
Pectoralis intermedius	Third and fourth ribs	United with tendon of short head of biceps brachii	Fleshy slip between pectoralis minor and pectoralis quartus	11
Anomalous pectoralis major	Inferiorly from serratus anterior	Intertubercular groove of the humerus	An accessory head of pectoralis major arising inferiorly	12