Pectoral muscles (colloquially referred to as "pecs") are the muscles that connect the front of the human chest with the bones of the upper arm and shoulder. This region contains four muscles that provide movements to the upper limbs or ribs. Gray411

Pectoralis major The pectoralis major () is a thick, fan-shaped or triangular convergent muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, ...

is a thick, fan-shaped or triangular

convergent muscle Muscle architecture is the physical arrangement of muscle fibers at the macroscopic level that determines a muscle’s mechanical function. There are several different muscle architecture types including: parallel, pennate and hydrostats. Force pr ...

, which makes up the bulk of the chest muscle. It lies under the

breast The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and sec ...

. It serves to

flex Flex or FLEX may refer to: Computing * Flex (language), developed by Alan Kay * FLEX (operating system), a single-tasking operating system for the Motorola 6800 * FlexOS, an operating system developed by Digital Research * FLEX (protocol), a com ...

, extend, and rotate the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a r ...

, the long bone of the upper arm. Pectoralis minor is a thin, triangular muscle located beneath the pectoralis major. It attaches to the ribs, and serves to stabilize the

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eith ...

, the large bone of the shoulder. The pectoral fascia is a thin layer of tissue over the pectoralis major, extending toward the latissimus dorsi muscle on the back. Along with the pectoralis major and pectoralis minor, the subclavius muscle forms the axilla or armpit. The subclavius moves the shoulder downward and forward. Serratus anterior is another muscle on the front of the chest. It moves the scapula forward around the torso, as when throwing a

punch Punch commonly refers to: * Punch (combat), a strike made using the hand closed into a fist * Punch (drink), a wide assortment of drinks, non-alcoholic or alcoholic, generally containing fruit or fruit juice Punch may also refer to: Places * Pu ...

. Between the ribs are various groups of intercostal muscles, which help with breathing.

References

* {{cite book, last1=Gray, first1=Henry, last2=Lewis, first2=Warren, year=1918, title=Anatomy of the Human Body, location=Philadelphia and New York, publisher=Lea and Feibiger, edition=twentieth, url=https://archive.org/details/anatomyofhumanbo1918gray, access-date=13 September 2016 Muscles of the torso Broad-concept articles Human anatomy