Joint structure and movements

Fibrous joints

Joints joined by dense fibrous connective tissue with no joint cavity

Suture

Rigid, interlocking fibrous joints found exclusively between skull bones. (Example: Sagittal suture between parietal bones)

Gomphosis

A "peg-in-socket" fibrous joint where a tooth is held in its bony socket by the periodontal ligament. (Example: Teeth in the mandible or maxilla)

Syndesmosis

A fibrous joint where bones are connected exclusively by ligaments or an interosseous membrane. (Example: Joint between the distal tibia and fibula)

Cartilaginous joints

Joints where articulating bones are united by cartilage

Synchondrosis

A cartilaginous joint where bones are united specifically by hyaline cartilage. (Example: Epiphyseal plates in growing long bones)

Symphysis

A cartilaginous joint where fibrocartilage unites the bones, acting as a shock absorber. (Example: Intervertebral discs)

Synovial joints

Freely movable joints characterized by a fluid-filled joint cavity, articular cartilage, and a protective joint capsule. (Example: Knee, shoulder, or hip)

Plane

Flat articular surfaces that allow for short, gliding or slipping movements. (Example: Intercarpal joints in the wrist)

Hinge

A cylindrical end of one bone fits into a trough-shaped surface of another, allowing uniaxial bending and straightening. (Example: Elbow joint between humerus and ulna)

Pivot

A rounded end of one bone conforms to a "sleeve" or ring of another, allowing uniaxial rotation. (Example: Atlantoaxial joint between C1 and C2 vertebrae)

Condylar

An oval condyle of one bone fits into a complementary oval depression of another, allowing biaxial movement. (Example: Metacarpophalangeal joints / knuckles)

Saddle

Articular surfaces have both concave and convex areas shaped like a saddle, allowing greater biaxial freedom. (Example: First carpometacarpal joint at the base of the thumb)

Ball and socket

The spherical head of one bone fits into a cuplike socket of another, allowing multiaxial movement. (Example: Shoulder or hip joint)

Synarthrosis

An immovable joint. (Example: Sutures of the skull)

Amphiarthrosis

A slightly movable joint. (Example: Pubic symphysis or intervertebral joints)

Diarthrosis

A freely movable joint. (Example: All synovial joints like the shoulder, knee, and hip)

Flexion

A movement that decreases the angle of the joint and brings the articulating bones closer together. (Example: Bending the elbow or knee)

Lateral flexion

Bending the trunk or neck sideways in the coronal plane. (Example: Tilting your torso to the side at the waist)

Extension

A movement that increases the angle between articulating bones, typically straightening a flexed joint. (Example: Straightening the knee from a bent position)

Hyperextension

Extension of a joint beyond its normal anatomical position, typically beyond 180 degrees. (Example: Tilting the head backward to look at the ceiling)

Abduction

Movement of a limb away from the midline or median plane of the body. (Example: Raising the arm laterally away from the torso)

Adduction

Movement of a limb toward the midline or median plane of the body. (Example: Bringing an outstretched arm back down to rest against the thigh)

Circumduction

Moving a limb so that it describes a cone in space

Rotation

The turning of a bone around its own longitudinal axis. (Example: Shaking the head "no" at the atlantoaxial joint)

Gliding

One flat, or nearly flat, bone surface slips or glides over another without appreciable angulation or rotation. (Example: Intercarpal joints in the wrist when waving your hand side-to-side)

Supination

Rotating the forearm laterally so that the palm faces anteriorly/upward and the radius and ulna are parallel. (Example: Turning your hand over to hold a bowl of soup)

Pronation

Rotating the forearm medially so that the palm faces posteriorly/downward and the radius crosses over the ulna. (Example: Dribbling a basketball)

Elevation

Lifting a body part superiorly/upward. (Example: Shrugging your shoulders)

Depression

Moving an elevated body part inferiorly/downward. (Example: Dropping your shoulders back down after a shrug, or opening your mouth)

Dorsiflexion

Lifting the foot so that its superior surface approaches the shin. (Example: Walking on your heels)

Plantar flexion

Depressing the foot downward, pointing the toes away from the shin. (Example: Standing up on your tiptoes or pressing a gas pedal)

Inversion

Turning the sole of the foot medially, inward toward the other foot. (Example: Tilting your foot to look at the bottom of your shoe)

eversion

Turning the sole of the foot laterally, outward away from the midline. (Example: Tilting the feet outward to shift weight to the inner arches)

Protraction

Nonangular anterior/forward movement of a bone in a transverse plane. (Example: Jutting your lower jaw outward)

Retraction

Nonangular posterior/backward movement of a bone in a transverse plane. (Example: Pulling your jaw back into its normal position after pretending it)

Excursion

Side-to-side movement of the mandible. (Example: Moving your lower jaw to the left or right while chewing)

Opposition

The movement of the thumb touching the tips of the other fingers on the same hand. (Example: Pinching a coin or picking up a pen)

Reposition

The movement that returns the thumb to its anatomical position next to the index finger. (Example: Opening your hand flat after making a fist)