The Skeletal System
Articulations
Classification
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Classified based on the type of movement they allow.
3 major types:
Fibrous Joint – immovable and connected by fibrous
connective tissue (ex: plates in skull, periodontal
ligaments)
Cartilaginous Joint – slight movement and
fibrocartilage is between the 2 bones (ex: betw. spinal
vertebrae & pubic bones)
Synovial Joint – free motion no direct contact of
bones associated with synovial membranes (Ex: elbow,
ankle, shoulder)
Fibrous Joints: minimal movement
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Sutures: seams between bones, found
between skull bones, form fontanels in
children (e.g. coronal)
Syndesmoses: bones farther apart than in
a suture and are joined by ligaments (e.g.
radioulnar)
Gomphoses: specialized joints consisting of
pegs that fit in sockets (e.g. dentoaveolar)
Cartilaginous Joints: Growth
Synchondroses: 2 bones joined by hyaline
cartilage (e.g. epiphyseal platescartilaginous region betw. epiphysis &
diaphysis of a growing bone)
 Symphyses: fibrocartilage uniting 2 bones
(e.g. symphyses pubis, manubriosternal
(ribcage))
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Synovial Joints: Movable
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Plane or gliding: 2 opposed flat surfaces, movement
confined to one plane (e.g. intervertebral)
Saddle: 2 saddle-shaped articulating surfaces oriented
at right angles (e.g. carpometacarpel- wrist/hand)
Hinge: convex cylinder in one bone applied to a
corresponding concave portion on another bone (e.g.
elbow and knee)
Pivot: rotation around a single axis. A process that
rotates within a ring (e.g. atlantoaxial-neck)
Synovial Joints
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Ball and Socket: ball (head) at the end of
one bone and a socket on another bone
(e.g. coxal-hip and glenohumeralshoulder)
Ellipsoid: modified ball-and-socket the
head is more ellipsoid in shape rather
than round (e.g. atlanooccipitalbetw.head & neck i.e. allows nodding)
Types Movements
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Flexion (anterior or ventral direction) and extension (posterior or
dorsal direction)
Dorsiflexion (flex toes) and plantar flexion (point toes)
Abduction (away from midline) and adduction (toward midline)
Medial and lateral rotation (turning around long axis)
Circumduction (combination of flexion, extension, abduction, and
adduction)
Elevation (superior motion) and depression (inferior motion)
Protraction (moving in anterior direction) and retraction (moving in
posterior direction)
Supination (face up palm) and pronation (face down palm)
Opposition (thumb to finger) and reposition
Lateral excursion (bottom jaw lateral)
Inversion (ankle medial turn) and eversion (ankle lateral turn)