muscular

Flexion

Decreases joint angle; e.g., bending elbow or knee.

Extension

Increases joint angle; e.g., straightening elbow.

Hyperextension

Extension beyond anatomical position.

Abduction

Movement away from midline.

Adduction

Movement toward midline.

Circumduction

Cone-like circular motion; involves flexion, extension, abduction, adduction.

Dorsiflexion

Lifting foot toward shin.

Plantar flexion

Pointing toes down.

Inversion

Turning foot inward.

Eversion

Turning foot outward.

Supination

Palm faces forward; radius and ulna parallel.

Pronation

Palm faces backward; radius crosses ulna.

Opposition

Thumb touches fingertips.

Prime mover

Main muscle causing movement.

Antagonist

Muscle opposing prime mover.

Synergist

Assists prime mover, stabilizes movement.

Fixator

Specialized synergist that stabilizes the origin of prime mover.

Origin

Attached to an immovable or less movable bone; usually proximal.

Insertion

Attached to a movable bone; usually distal.

Fascicle Arrangement: Circular

Surround openings (e.g., orbicularis oris).

Fascicle Arrangement: Convergent

Broad origin, converge to tendon (e.g., pectoralis major).

Fascicle Arrangement: Parallel

Fibers run parallel (e.g., sartorius).

Fascicle Arrangement: Fusiform

Spindle-shaped; wider belly (e.g., biceps brachii).

Fascicle Arrangement: Pennate

Short fibers obliquely attach to central tendon: unipennate, bipennate, multipennate types.

Muscle Naming: Direction of fibers

Rectus (straight), oblique (angled).

Muscle Naming: Size

Maximus (largest), minimus (smallest), longus (long).

Muscle Naming: Location

Temporalis (temporal bone).

Muscle Naming: Number of origins

Biceps (two), triceps (three).

Muscle Naming: Origin and insertion

Sternocleidomastoid (sternum, clavicle, mastoid).

Muscle Naming: Shape

Deltoid (triangular).

Muscle Naming: Action

Flexor, extensor, adductor.

Motor control development

Matures superior to inferior and proximal to distal.

Effects of exercise

No activity leads to atrophy; vigorous activity leads to hypertrophy.

Aging and muscles

Muscle mass decreases, becomes more sinewy; exercise can slow or reduce these effects.

Five Golden Rules for understanding skeletal

With a few exceptions, all skeletal muscles cross at least one joint.

2.Typically, the bulk of a skeletal muscle lies proximal to the joint crossed.

3.All skeletal muscles have at least two attachments: the origin and the insertion.

4.Skeletal muscles can only pull; they never push.

5.During contraction, a skeletal muscle insertion moves toward the origin.