|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
| The Pectoralis minor (Fig. 411) is a thin, triangular muscle, situated at the upper part of the thorax, beneath the Pectoralis major. It arises from the upper margins and outer surfaces of the third, fourth, and fifth ribs, near their cartilage and from the aponeuroses covering the Intercostalis; the fibers pass upward and lateralward and converge to form a flat tendon, which is inserted into the medial border and upper surface of the coracoid process of the scapula.|
Variations.Origin from second, third and fourth or fifth ribs. The tendon of insertion may extend over the coracoid process to the greater tubercle. May be split into several parts. Absence rare.
| Pectoralis minimus, first rib-cartilage to coracoid process. Rare.|
FIG. 411 Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (See enlarged image)
| The Subclavius (Fig. 411) is a small triangular muscle, placed between the clavicle and the first rib. It arises by a short, thick tendon from the first rib and its cartilage at their junction, in front of the costoclavicular ligament; the fleshy fibers proceed obliquely upward and lateralward, to be inserted into the groove on the under surface of the clavicle between the costoclavicular and conoid ligaments.|
Variations.Insertion into coracoid process instead of clavicle or into both clavicle and coracoid process. Sternoscapular fasciculus to the upper border of scapula. Sternoclavicularis from manubrium to clavicle between Pectoralis major and coracoclavicular fascia.
| The Serratus anterior (Serratus magnus) (Fig. 411) is a thin muscular sheet, situated between the ribs and the scapula at the upper and lateral part of