Dogs
The following is a list of the muscles in the dog, along with their origin, insertion, action and innervation. Extrinsic muscles of the thoracic limb and related structures: Descending superficial pectoral: originates on the first sternebrae and inserts on the greater tubercle of the humerus. It both adducts the limb and also prevents the limb from being abducted during weight bearing. It is innervated by the cranial pectoral nerves. Transverse superficial pectoral: originates on the second and third sternebrae and inserts on the greater tubercle of the humerus. It also adducts the limb and prevents the limb from being abducted during weight bearing. It is innervated by the cranial pectoral nerves. Deep pectoral: originates on the ventral sternum and inserts on the lesser tubercle of the humerus. It acts to extend the shoulder joint during weight bearing and flexes the shoulder when there is no weight. It is innervated by the caudal pectoral nerves. Sternocephalicus: ...