Muscle Movement

Fulcrum

The pivot point in a lever system.

Pull (in levers)

The load with respect to levers.

Class 1 Lever

A lever system where the fulcrum is located between the pull and weight.

Atlanto-occipital joint lever class

Class 1 lever example

Class 2 Lever

A lever system where the weight is located between the fulcrum and pull.

Temporomandibular joint lever class

Class 2 lever example

Class 3 Lever

A lever system where the pull is located between the fulcrum and weight.

Most common lever class in muscles

Class 3 lever.

Biceps acting on the elbow joint lever class

Class 3 lever example

Origin (muscle)

The fixed, less movable attachment point of a muscle on a bone.

Insertion (muscle)

The movable attachment point of a muscle

Tendon

A cord-like band of dense connective tissue connecting muscle to bone.

Aponeurosis

A broad, flat sheet of fibrous connective tissue connecting or surrounding muscles.

Epicranial aponeurosis (Galea aponeurotica)

The aponeurosis on the superior portion of the skull.

Linea Alba

A fibrous structure extending from the xiphoid process to the pubic symphysis.

Agonist muscle

A muscle performing a specific movement.

Antagonist muscle

A muscle that opposes a specific joint movement.

Fixator

A muscle that assists in holding a joint immobile to maintain posture.

Prime mover

The muscle most responsible for a specific joint movement.

Synergist muscles

Muscles that work together to perform a specific movement.

Prime mover in a biceps curl

Brachialis muscle.

Synergist in a biceps curl

Biceps brachii muscle.

Antagonist during the lifting phase of a biceps curl

Triceps muscle.