There space over 600 muscle in the person body. Discovering the muscular system often entails memorizing details around each muscle, favor where a muscle attaches come bones and how a muscle helps relocate a joint. In textbooks and also lectures this details around muscles are described using specialized vocabulary that is difficult to understand. Below is an example: The triceps brachii has actually three bellies with varying origins (scapula and also humerus) and one insertion (ulna). That is a prime mover that elbow extension. The anconeus acts together a synergist in elbow extension.

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

Keep analysis to discover what all the various other muscle jargon means!

1. Muscles connect to Bones at Locations called Origins and Insertions


A skeletal muscle attaches to bone (or occasionally other muscles or tissues) at 2 or an ext places. If the location is a bone that continues to be immobile for an action, the attachment is referred to as an origin. If the location is on the bone the moves throughout the action, the attachments is referred to as an insertion. The triceps brachii wake up to have four points that attachment: one insertion ~ above the ulna and also three origins (two top top the humerus and one top top the scapula).

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

The muscles bordering synovial joints are responsible for relocating the human body in space. These muscle plot are often paired, choose flexion and extension or abduction and also adduction. Listed below the typical terms are noted and defined, through animations to aid you snapshot the muscles and also joints in motion.

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

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

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

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


Abduction and adduction space usually side-to-side movements, such as moving the eight laterally as soon as 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 sartorius space muscles the abduct the hip. The pectineus, adductor longus, adductor brevis, adductor magnus, and gracilis adduct the hip.


Pronation and also supination

Describing the rotation the the forearm back and forth calls for special terms. Spread out your finger out and also look in ~ the palms of your hands and the fingers and then turn your palms to look at her nails. Now look at her palms again. It is forearm supination and pronation.

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

Supination: rotating the forearm for this reason the palm is facing forward or up.


Elevation and depression room up-and-down movements, such together 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: moving a body component up.

Depression: relocating a body part down.


Protraction and retraction

By moving your jaw ago and soon in a jutting motion, you are protracting and retracting your mandible.

Protraction: moving a bone forward without transforming the angle.

Retraction: relocating a bone behind without changing the angle.


Inversion and eversion

You invert her foot when you turn it inward to view what is grounding under her shoe. Girlfriend evert your foot to put the single of your shoe ago on the floor.

Inversion: transforming the sole of the foot inward.

Eversion: transforming the single of the foot outward.

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

Dorsiflexion: bringing your foot upward toward your shin.

Plantar flexion: depressing your foot.

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


While countless muscles may be involved in any type of given action, muscle function terminology permits you to easily understand the miscellaneous roles different muscles pat in each movement.

Prime movers and antagonist

The element mover, sometimes called the agonist, is the muscle that gives the primary pressure driving the action. One antagonist muscle is in opposition to a element mover in that it offers some resistance and/or reverses a given movement. Element movers and also antagonists are often paired up on opposite political parties of a joint, with their prime mover/antagonist duties reversing together the movement alters direction.

Synergists. One or more synergists are often associated in an action. Synergists space muscles that help the prime mover in that role.

Stabilizers. Stabilizers action to store bones immobile once needed. Your earlier muscles, because that example, room stabilizers once they are maintaining your posture sturdy.

See more: Is The Ring-Like Muscle That Controls The Flow From The Stomach To The Small Intestine.

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External Sources

Muscle Premium by visible Body uses a substantial reference of musculoskeletal structures and also function, plus usual injuries and also conditions.

Types that Muscle Contractions. This presentation describes in much more detail 3 means that bones muscles create force. College of California, san Diego: national Skeletal Muscle study Center. Http://

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