ll. pectoralis major (pectoral, L: "breast"; major, L: "larger")
- name refers to the fact that it is the largest muscle that covers the chest
- originates on the sternum and the second through sixth rib as well as a portion of the clavicle; inserts on the humerus
- flexes, adducts and rotates the upper arm
mm. pectoralis minor (pectoral, L: "breast"; minor, L: "smaller")
- the smaller muscle that covers the chest
- originates on the third through fifth rib; inserts on the scapula
- depresses the shoulder and elevates the rib if the shoulder is held steady
nn. latissimus dorsi (lati, L: "broad or wide"; dorsi, L: "the back")
- the broad, flat shape of this muscle that is found on covering a significant portion of the back gives this muscle its name
- originates from the spinal processes of the lower thoracic vertebrae and the lumbar vertebrae; inserts on the humerus
- flexes, adducts and rotates the upper arm medially

oo. trapezius (trapez, G: "a table")
- the diamond, or table shape of this muscle signifies the name
- originates from the occipital bone and thoracic vertebrae and inserts on the clavicle and scapula
- has many actions including the shrugging of the shoulders, and the extension of the head and neck backwards

pp. serratus anterior (serrat, L: "a saw"; anterior, L: "in front of")
- named for its saw-toothed appearance on the anterior portion of the body
- originates on the anterior surface of the first nine ribs and inserts on the scapula
- abducts and rotates the scapula medially

qq. diaphragm (dia, G: "across"; phragm, G: "a partition")
- named as a result of forming a partition between the thoracic and abdominal cavity
- primary muscle of inspiration

rr. external intercostals (extern, L: "outer"; inter, L: "between"; costal, L: "rib")
- name tells one where it can be found, as it is the outer muscle located between the ribs
- originates on the bottom of each rib; inserts on upper border of the rib below
- elevates the ribs (used for active inspiration)

ss. internal intercostals (intern: L: inner; inter, L: "between"; costal, L: "rib")
- name tells one where it can be found, as it is located between the ribs deep to the external intercostal muscles
- originates on the top of each rib; inserts on bottom border of the rib above
- depresses the ribs (used for active expiration)

tt. external oblique (extern, L: "outer"; oblique, L: "angling away from the midline")
- name tells one about the direction of its fibers in relation to the midline of the body
- originates on the lower eight ribs; inserts on connective tissue in the center of the abdomen
- compresses the abdomen

uu. internal oblique (intern, L: "inner"; oblique, L: "angling away from the midline")
- found underneath the external obliques
- originates on the connective tissue of the back; inserts on the lower ribs, sternum, and connective tissue in the center of the abdomen
- compresses the abdomen

vv. rectus abdominis (rectus, L: "straight"; abdominis, L: "refers to abdomen")
- this muscle obtained its name due to its fibers running straight up and down with the midline and its association with the abdomen
- originates on the pubis; inserts on the lower portion of the sternum
- flexes the vertebral column