Your pectoralis major is a large and powerful chest muscle that’s shaped like a fan. It starts from two sections: your breastbone (sternum) and your collarbone (clavicle). The two sections come ...

The rhomboid major muscle is located in the back region and helps keep the scapula, or shoulder blade, attached to the ribcage. It also rotates the scapula and retracts it towards the spinal column.

Limb muscles are remarkably complex and evolutionarily labile. Although their anatomy is of great interest for studies of the evolution of form and function, their homologies among major amniote ...