Types of Body Movements

Body movements occur at synovial (diarthrodial) joints — where two bones are separated by an articular cavity filled with synovial fluid. These movements are classified based on the plane and axis in which they occur. — Gray's Anatomy for Students

1. Flexion

Definition: A movement that decreases the angle between two body parts, bringing them closer together. It occurs in the sagittal plane around a transverse axis.

Example: Bending the elbow (humeroulnar joint) brings the forearm toward the upper arm — a hinge joint permitting only flexion and extension.

2. Extension

Definition: A movement that increases the angle between two body parts, returning a flexed part back to the anatomical position (or beyond, which is called hyperextension).

Example: Straightening the knee from a bent position; hyperextension occurs when the neck is tilted backward.

3. Abduction

Definition: Movement of a body part away from the midline of the body, in the frontal (coronal) plane.

Example: Raising the arm laterally away from the body (at the shoulder/glenohumeral joint). For digits, abduction means spreading the fingers apart away from the middle finger.

4. Adduction

Definition: Movement of a body part toward the midline of the body, opposite to abduction.

Example: Bringing the raised arm back down to the side of the body. Closing the spread fingers together is adduction of the digits.

5. Rotation

Definition: Movement of a bone around its own longitudinal axis without any displacement of that axis.

Medial (internal) rotation — rotating toward the midline
Lateral (external) rotation — rotating away from the midline

Example:

The atlantoaxial (pivot) joint (between C1 and C2) allows the head to turn left and right — pure rotation around a vertical axis.
At the shoulder, turning the arm inward (medial rotation) and outward (lateral rotation) demonstrates this movement. — Gray's Anatomy for Students

6. Circumduction

Definition: A combination of flexion, extension, abduction, and adduction performed in sequence, so that the distal end of the limb traces a cone shape. It does not involve axial rotation.

Example: Swinging the arm in a full circle at the shoulder joint (a ball-and-socket joint), or moving the index finger to trace a circle — classic circumduction. Also possible at the wrist (condylar joint) and hip joint. — Gray's Anatomy for Students

7. Special Movements

Beyond the above general movements, certain joints perform unique movements:

Movement	Definition	Example Joint
Pronation	Rotating the forearm so the palm faces posteriorly/downward	Radioulnar joint
Supination	Rotating the forearm so the palm faces anteriorly/upward	Radioulnar joint
Dorsiflexion	Flexing the foot upward (toward the shin)	Ankle (talocrural) joint
Plantar flexion	Pointing the foot downward (like standing on tiptoe)	Ankle joint
Inversion	Turning the sole of the foot inward (medially)	Subtalar/midtarsal joints
Eversion	Turning the sole of the foot outward (laterally)	Subtalar/midtarsal joints
Protraction	Moving a part anteriorly in the horizontal plane (e.g., jutting jaw forward)	Temporomandibular joint
Retraction	Moving a part posteriorly in the horizontal plane	Temporomandibular joint
Elevation	Moving a part superiorly	Mandible (closing the mouth)
Depression	Moving a part inferiorly	Mandible (opening the mouth)
Opposition	Touching the thumb pad to another fingertip	Carpometacarpal joint of thumb (saddle joint)

Summary Table

Movement	Plane	Axis	Example
Flexion	Sagittal	Transverse	Elbow bending
Extension	Sagittal	Transverse	Knee straightening
Abduction	Frontal	Sagittal	Arm raised sideways
Adduction	Frontal	Sagittal	Arm returned to side
Rotation	Transverse	Longitudinal	Head turning (atlantoaxial)
Circumduction	Multiple	Multiple	Arm circling
Pronation/Supination	Transverse	Longitudinal	Palm down/up
Dorsi/Plantar flexion	Sagittal	Transverse	Foot up/down

Key point: Ball-and-socket joints (hip, shoulder) permit the greatest range — flexion, extension, abduction, adduction, circumduction, and rotation. Hinge joints (elbow, knee) are restricted to flexion and extension only. Pivot joints (atlantoaxial) permit rotation alone. — Gray's Anatomy for Students

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