OBJECTIVE: The study adds important information regarding the descriptive anatomy of a very rarely reported unilateral chondrocoracoideus muscle (of Wood). Additionally it highlights the concomitant muscular and neural alterations.CASE REPORT: The current case presents the occurrence of a chondrocoracoideus muscle situated left-sided, as an extension of the abdominal portion of the pectoralis major muscle (PM). The chondrocoracoideus coexisted with a contralateral atypical PM, partially blended with the clavicular fibers of the deltoid muscle. There was an accessory head of the biceps brachii while the palmaris longus was absent on the right side of a 78-year-old Greek male cadaver.CONCLUSION: The above mentioned muscular abnormalities are shown as disturbances of embryological pectoral muscle development, and their documentation is essential in order to increase awareness among clinicians of their potential impact on the diagnosis and treatment of several pathologies.