Anatomy & Kinesiology – Page 1 Vocabulary

Vocabulary flashcards covering directional terms, planes of motion, muscle attachments, lever principles, basic biomechanics, muscle physiology, and common muscles from Page 1 notes.

Superior

Toward the head or upper part of a structure.

Inferior

Toward the feet or lower part of a structure.

Cranial

Toward the head (skull direction).

Caudal

Toward the tail or posterior end.

Ipsilateral

On the same side of the body.

Contralateral

On the opposite side of the body.

Sagittal plane

Divides the body into left and right portions; flexion/extension occur in this plane.

Frontal (coronal) plane

Divides the body into anterior (front) and posterior (back) parts; abduction/adduction occur here.

Transverse (horizontal) plane

Divides the body into superior and inferior parts; rotation occurs here.

Flexion

Bending that decreases the joint angle.

Extension

Straightening that increases the joint angle.

Abduction

Movement away from the midline of the body.

Adduction

Movement toward the midline of the body.

Rotation

Twisting around a central axis.

Origin

The proximal attachment of a muscle; typically less movable and acts as an anchor.

Insertion

The distal attachment of a muscle; the part that moves during contraction.

Palpation

Using touch to identify structures beneath or on the surface of the body.

Surface anatomy

Features that are palpable or visible on the surface.

Frontal axis

Axis running side-to-side; rotation about this axis occurs in the sagittal plane.

Sagittal axis

Axis running front-to-back; rotation about this axis occurs in the frontal plane.

Vertical axis

Axis running top-to-bottom; rotation about this axis occurs in the transverse plane.

Open-chain

Distal segment moves freely; examples: swimming, running.

Closed-chain

Distal segment fixed on a surface; examples: push-ups, squats.

Proximal

Closer to the trunk.

Distal

Farther from the trunk.

Passive insufficiency

Lengthening across multiple joints where a multi-joint muscle cannot be stretched further.

Active insufficiency

Inability of a multi-joint muscle to shorten sufficiently across all joints it crosses.

1st class lever

Fulcrum between effort and load; example: neck (seesaw).

2nd class lever

Load between fulcrum and effort; example: wheelbarrow (or ankle).

3rd class lever

Effort between fulcrum and load; example: bicep curl.

Newton's first law (Law of Inertia)

An object at rest stays at rest, and an object in motion stays in motion unless acted on by an external force.

Newton's second law (F = ma)

Acceleration is proportional to net force and inversely proportional to mass.

Newton's third law (Action-Reaction)

For every action, there is an equal and opposite reaction.

Stress

The amount of external force applied to a material.

Strain

The deformation or change in length resulting from stress.

Elasticity

Ability of a material to stretch and return to its original shape.

Lengthening

The process of muscle lengthening during a contraction (eccentric).

Shortening

The process of muscle shortening during a contraction (concentric).

Skeletal muscle (striated)

Muscle tissue that is attached to bones and is under voluntary control.

Myofibril

Long cylindrical strands of contractile proteins within a muscle fiber.

Sarcomere

Contractile unit of a muscle, between Z-discs.

Z-disc

Discs that delineate sarcomeres and anchor actin filaments.

Actin

Thin filaments; a major contractile protein.

Myosin

Thick filaments; motor proteins that pull on actin.

Motor unit

A single motor neuron and all the muscle fibers it innervates; follows the all-or-none principle.

All-or-none principle

Motor units fire completely or not at all.

Muscle spindles

Sensory receptors that detect changes in muscle length and rate of lengthening.

Golgi tendon organs

Sensory receptors that detect muscle tension.

Isometric contraction

Muscle length does not change while tension develops.

Isotonic contraction

Muscle changes length with a constant tension (includes concentric and eccentric).

Eccentric contraction

Muscle lengthens while producing force.

Concentric contraction

Muscle shortens while producing force.

Slow-twitch fibers (Type I)

Fibers for endurance; fatigue-resistant and suited for posture and long, steady activities.

Fast-twitch fibers (Type II)

Fibers for power and speed; fatigue more quickly.

Agonist (prime mover)

Muscle that initiates and drives a movement by contracting.

Antagonist

Muscle that opposes the prime mover and relaxes or lengthens during movement.

Synergist

Muscle that assists the prime mover to perform a movement.

Rectus femoris

Two-joint muscle crossing hip and knee; sagittal-plane action (knee extension, hip flexion).

Sartorius

Two-joint muscle crossing hip and knee; spans multiple planes; longest muscle in the body.