There space over 600 muscles in the human being body. Finding out the muscular mechanism often involves memorizing details around each muscle, choose where a muscle attaches to bones and how a muscle helps relocate a joint. In textbooks and lectures this details about muscles are explained using specialized vocabulary that is difficult to understand. Right here is one example: The triceps brachii has actually three bellies with varying origins (scapula and also humerus) and also one insertion (ulna). It is a prime mover that elbow extension. The anconeus acts as a synergist in elbow extension.

You are watching: The origin of a muscle is on a stationary bone.

What walk all the textbook slang mean? The triceps brachii has four places where it attaches to the scapula, humerus, and also ulna. This muscle plays a big role (that’s what prime mover means) in prolonging the elbow joint from a bent come a directly position.

Keep reading to learn what all the various other muscle jargon means!

1. Muscles attach to Bones in ~ Locations referred to as Origins and also Insertions


A skeleton muscle attaches to bone (or periodically other muscles or tissues) at 2 or an ext places. If the ar is a bone that stays immobile for an action, the attachments is dubbed an origin. If the ar is ~ above the bone that moves during the action, the attachment is dubbed an insertion. The triceps brachii happens to have 4 points of attachment: one insertion top top the ulna and three origins (two on the humerus and also one top top the scapula).

2. Muscle Act ~ above Synovial Joints to relocate the Body

The muscles surrounding synovial joints room responsible for relocating the body in space. This muscle action are often paired, prefer flexion and extension or abduction and also adduction. Listed below the common terms are detailed and defined, through animations to aid you snapshot the muscles and also joints in motion.

Flexion and also extension are usually activities forward and backward indigenous the body, such together nodding the head.

Flexion: to decrease the angle between two skeleton (bending).

Extension: enhancing the angle between two skeletal (straightening a bend).

The triceps brachii and also anconeus are muscles that expand the elbow. The biceps brachii, brachialis, and also brachioradialis flex the elbow.


Abduction and also adduction space usually side-to-side movements, such as relocating the eight laterally when doing jumping jacks.

Abduction: relocating away native the body’s midline.

Adduction: relocating toward the body’s midline.

The gluteus medius, gluteus minimus, tensor fasciae latae, and also sartorius room muscles the abduct the hip. The pectineus, adductor longus, adductor brevis, adductor magnus, and also gracilis adduct the hip.


Pronation and supination

Describing the rotation that the forearm ago and forth requires special terms. Spread your fingers out and also look in ~ the palms of her hands and the fingers and also then revolve your palms to look at your nails. Currently look at her palms again. That’s forearm supination and pronation.

Pronation: rotating the forearm for this reason the palm is dealing with backward or down.

Supination: rotating the forearm so the palm is dealing with forward or up.


Elevation and also depression space up-and-down movements, such as chewing or shrugging your shoulders. Once you relocate the mandible down to open the mouth, it is mandible depression. Relocate the mandible earlier up, it is mandible elevation.

Elevation: relocating a body part up.

Depression: relocating a body component down.


Protraction and also retraction

By relocating your jaw earlier and forth in a jutting motion, you room protracting and also retracting her mandible.

Protraction: moving a bone forward without an altering the angle.

Retraction: moving a bone behind without changing the angle.


Inversion and also eversion

You invert her foot when you revolve it inward to check out what is grounding under her shoe. You evert her foot to placed the single of your shoe earlier on the floor.

Inversion: turning the single of the foot inward.

Eversion: turning the sole of the foot outward.

Dorsiflexion and also plantar flexion girlfriend dorsiflex her feet to walk on her heels, and plantar flex them come tiptoe.

Dorsiflexion: bringing your foot upward towards your shin.

Plantar flexion: depressing her foot.

3. Muscle Actions have Prime Movers, Synergists, Stabilizers, and Antagonists


While countless muscles might be connected in any kind of given action, muscle function terminology permits you to easily understand the miscellaneous roles different muscles beat in each movement.

Prime movers and antagonist

The prime mover, sometimes referred to as the agonist, is the muscle that gives the primary pressure driving the action. An antagonist muscle is in opposition to a element mover in the it provides some resistance and/or reverses a given movement. Prime movers and also antagonists are regularly paired up on opposite sides of a joint, through their element mover/antagonist duties reversing together the movement alters direction.

Synergists. One or more synergists space often associated in one action. Synergists room muscles that aid the prime mover in its role.

Stabilizers. Stabilizers action to save bones immobile once needed. Your back muscles, because that example, are stabilizers once they are keeping your attitude sturdy.

See more: Is Distance A Vector Or Scalar S, And Coordinate Systems, Velocity And Displacement — Vectors And Scalars

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External Sources

Muscle Premium by visible Body provides a considerable reference the musculoskeletal structures and function, plus typical injuries and also conditions.

Types of Muscle Contractions. This presentation explains in more detail 3 methods that bones muscles create force. College of California, san Diego: nationwide Skeletal Muscle research Center. Http://

This table, from a food at Marquette University focused on rehabilitation engineering, includes descriptions of straightforward movements and also explanations of vital muscle biomechanics and movement terminology. Biomechanics & motion Science. Jack M. Winters, Ph.D, Marquette Univeristy. Http://