Anatomical Variations of the Pectoralis Major Muscle: Notes on Their Impact on Pectoral Nerve Innervation Patterns and Discussion on Their Clinical Relevance

Figure 4

Anatomy of the tendon of the pectoralis major muscle with a separate clavicular part. (a) The tendon of the right pectoralis major muscle seen from behind. Posterior lamina (PL) of the pectoralis major muscle tendon constitutes place of attachment for the lower fibers of the sternocostal (STC) part of the muscle. (b) The tendon of the pectoralis major muscle seen from behind. Posterior lamina (PL) of the pectoralis major muscle has been separated and reflected to expose the posterior view to the anterior lamina (AL) of the tendon. The AL is a place of attachment for the clavicular part (CL), as well as for the upper and middle fibers of the sternocostal (STC) part of the pectoralis major muscle. (c) Anterior view to the tendon of the PM. (d) Inferior view to the tendon of the pectoralis major muscle. Black arrowheads show twisting of the lower fibers of the sternocostal part of the pectoralis major muscle.

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