muscles of the front

Pectoralis major

Superficial muscles of the chest and front of the arm

Pectoralis major

Flexes the humerus, adducts the humerus, draws scapula anteriorly and inferiorly

Pectoralis minor

Depresses and protractw shoulder, rotates scapula downwar, elevates ribs

Subclavius

A small triangular muscle, placed between the clavicle and the first rib. Along with pectoralis major and pectoralis minor, it makes up the anterior wall of the axilla

Subclavius

Depression of clavicle elevation of first rib

Subscapularis

Internally rotates and adducts humerus; stabilizes shoulder

Supraspinatus

Abduction of arm and stabilizes humerus

Infraspinatus

Lateral rotation of arm and stabilizes humerus

Serratus anterior

Protracts shoulder and rotates scapula upward

External intercostal muscles

Origin/insertion: lower border of a rib ventrocaudally to the upper border of the rib below

Internal intercostal muscles

Origin: upper border of rib; Insertion: Ventrocranially at the lower border of the rib above

Innermost intercostal muscles

Separate from the the internal intercostal muscles; insertion: Behind the costal grooves

Rectus abdominis

Flexes vertebral column, depresses ribs and compresses abdomen

External abdominal oblique

Compresses abdomen; depresses ribs; flexes, laterally flexes or rotates vertebral column

Internal abdominal oblique

Action same as external abdominal oblique

Transversus abdominis

Compresses abdomen