Naming Muscles

Location

A muscle may be named for its actual location within the body relative to other body structures. Examples: Pectoralis: Chest muscle located within the pectoral girdle. Intercostal: Muscle located between ribs (intercostal literally means between ribs). Abdominis: Located in the abdominal area.

Attachment

Many muscles are named for the bones to which they are attached. The muscle name may combine more than one name when more than one bone is involved. Examples: Zygomaticus: Attached to the zygoma (bone of the face). Sternocleidomastoid: Attached to the sternum, clavicle, and mastoid process of the skull.

Shape

Muscle names are often derived from the actual physical shape of the muscle itself or a defining physical characteristic, such as the number of heads that it has. Examples: Rhomboideus: A muscle of the back that is shaped like a rhomboid. Triangularis: A muscle of the face that is triangular in shape. Triceps: A muscle with three (tri-) heads. Biceps: A muscle with two (bi-) heads.

Function

Muscles are responsible for movement. However, there are several different types of movements, and muscles are often classified according to the actual movement that they produce. Examples: Adductor: Movement to draw toward a medial plane. Extensor: General term for a muscle that extends a joint. Flexor: General term for a muscle that flexes a joint. Levator: A muscle that elevates or lifts an organ or structure.

Size

The actual size of the muscle or its relative size to a similar muscle may be used in naming a muscle. Examples: Maximus or Major: Both of these terms mean larger or largest. Minimus or Minor: Meaning smaller or smallest. Longus: Meaning long. Brevis: Meaning short.

Naming Muscles

There are seven (7) primary ways the names assigned to muscles are derived.

Relative position

These delineations contain basic directional planes and are used on similar muscles to designate a slightly different orientation. Often a "medial" will have a corresponding "lateral"; likewise, an "internal" will have a corresponding "external." Examples: Lateral: Something that is further from the midpoint or to the side. Medial: Something closer to the middle or the midline. Internal: Situated or occurring within or on the inside. External: Situated or occurring on the outside.

Orientation of fibers

This is the direction that the individual fibers of a muscle extend. Examples: Oblique: In a slanting or inclined direction. Rectus: Meaning straight. Transverse: Meaning across or placed crosswise.