There space over 600 muscle in the human being body. Finding out the muscular device often entails memorizing details around each muscle, like where a muscle attaches to bones and how a muscle helps relocate a joint. In textbooks and lectures these details about muscles are described using specialized vocabulary the is difficult to understand. Here is one example: The triceps brachii has actually three bellies through varying origins (scapula and also humerus) and also one insertion (ulna). The is a prime mover the elbow extension. The anconeus acts together a synergist in elbow extension.

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What does all that textbook jargon mean? The triceps brachii has 4 places wherein it attaches to the scapula, humerus, and ulna. This muscle dram a big role (that’s what element mover means) in prolonging the elbow joint from a bent come a straight position.

Keep reading to discover what every the various other muscle slang means!

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


A bones muscle attaches to bone (or occasionally other muscle or tissues) at two or much more places. If the place is a bone that continues to be immobile for an action, the attachments is dubbed an origin. If the location is on the bone that moves throughout the action, the attachments is referred to as an insertion. The triceps brachii happens to have four points of attachment: one insertion on the ulna and also three origins (two on the humerus and one ~ above the scapula).

2. Muscle Act top top Synovial Joints to move the Body

The muscles surrounding synovial joints space responsible for relocating the human body in space. These muscle actions are frequently paired, choose flexion and also extension or abduction and also adduction. Below the usual terms are detailed and defined, v animations to help you snapshot the muscles and joints in motion.

Flexion and extension space usually motions forward and backward native the body, such as nodding the head.

Flexion: diminish the angle between two skeleton (bending).

Extension: boosting the angle between two bones (straightening a bend).

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


Abduction and also adduction room usually side-to-side movements, together as moving the arm laterally as soon as doing jumping jacks.

Abduction: relocating away indigenous the body’s midline.

Adduction: moving toward the body’s midline.

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


Pronation and supination

Describing the rotation the the forearm back and forth requires special terms. Spread your finger out and also look at the palms of your hands and the fingers and then turn your palms come look at your nails. Now look at your palms again. It is forearm supination and pronation.

Pronation: rotating the forearm so the palm is facing backward or down.

Supination: rotating the forearm therefore the palm is facing forward or up.


Elevation and depression room up-and-down movements, such as chewing or shrugging your shoulders. Once you relocate the mandible under to open up the mouth, that’s mandible depression. Relocate the mandible back up, it is mandible elevation.

Elevation: relocating a body part up.

Depression: relocating a body part down.


Protraction and retraction

By moving your jaw earlier and forth in a jutting motion, you space protracting and retracting your mandible.

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

Retraction: relocating a bone backward without an altering the angle.


Inversion and also eversion

You invert her foot when you rotate it inward to see what is stuck under her shoe. Friend evert your foot to placed the sole of her shoe earlier on the floor.

Inversion: turning the sole of the foot inward.

Eversion: transforming the sole of the foot outward.

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

Dorsiflexion: bringing your foot upward towards your shin.

Plantar flexion: depressing her foot.

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


While countless muscles might be connected in any given action, muscle role terminology allows you to easily understand the miscellaneous roles different muscles play in every movement.

Prime movers and also antagonist

The prime mover, sometimes dubbed the agonist, is the muscle that gives the primary force driving the action. One antagonist muscle is in opposition to a prime mover in that it gives some resistance and/or reverses a offered movement. Element movers and antagonists are regularly paired up on opposite political parties of a joint, through their element mover/antagonist functions reversing together the movement changes direction.

Synergists. One or much more synergists space often involved in an action. Synergists space muscles that assist the prime mover in the role.

Stabilizers. Stabilizers act to save bones immobile when needed. Your earlier muscles, for example, room stabilizers when they are maintaining your posture sturdy.

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External Sources

Muscle Premium by clearly shows Body provides a an extensive reference the musculoskeletal structures and function, plus typical injuries and conditions.

Types the Muscle Contractions. This presentation describes in much more detail 3 ways that skeleton muscles create force. College of California, mountain Diego: national Skeletal Muscle research study Center. Http://

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