Joints
Joints (articulation)
• Defined: A point of contact
between bones, between
cartilage and bones, or between
teeth and bones.
– When two bones articulate
with one another we say
that the 2 bones form a joint.
• Arthrology = study of joints
• Kinesiology = study of
movement within the
human body
• Rheumatology = study of joint
diseases and related conditions
Joint Strength, Flexibility, & Movement
• Determined by:
– Shape of the articulating
bones
– Flexibility of the ligaments
that attach bone to bone
– Tension of tendons and
muscles of the articulating
bones
– Hormones
• Dislocation: When
articulating bones move from
their normal positions.
Joint Structure
• Classification:
– Type of connective
tissue that holds
the bones
together.
– The presence or
absence of a
synovial cavity
(space between
the articulating
bones).
Joint Function
• Classification:
– Relates to the amount of
movement allowed
• Types:
– Synarthrosis = Immoveable joint
• Ex. pelvis , sutures, teeth
– Amphiarthrosis = Slightly moveable joint
• Ex. epiphysis, tibia-fibula, vertebrae and pelvic symphysis
– Diarthrosis = A freely movable joint.
• All synovial joints fall into this category
• Come in many shapes
• Allow for different types of movements
Types of Fibrous Joints
• Fibrous joints are held together by fibrous connective tissue – bones
lack a synovial cavity = little to no movement.
1. Suture
• Unite the bones of the skull
• The irregular interlocking edges decrease chances of
fracturing
• Functionally classified as Synarthrosis = Immovable
Types of Fibrous Joints
2. Syndesmosis
• Contains dense fibrous
connective tissue
• Functionally classified as
amphiarthrosis = Slight
movement
• Ex. The distal articulation
between the tibia and the
fibula.
Types of Fibrous Joints
3. Gomphosis
• Cone shaped peg that
fits into a socket
• The only found in the
articulations of the
roots of the teeth with
the sockets of the
mandible & maxillae.
• Functionally classified
as synarthrosis =
Immovable
Types of Cartilaginous Joints
• Cartilagious joints are held
together by fibrocartilage or
hyaline cartilage
• Bones lack a synovial cavity
1. Synchondrosis
• A cartilage joint that
connects with hyaline
cartilage
• Ex. Epiphyseal plate that
connect the epiphysis and
the diaphysis of a bone.
• Functionally classified as
synarthrosis = Immovable
Types of Cartilaginous Joints
1. Symphysis
• A cartilage joint where ends of
the articulating bones are
covered with hyaline cartilage,
but the bones themselves
connect via fibrocartilage.
• Ex. Pubic symphysis &
between the bodies of
vertebrae.
• Functionally classified as
amphiarthrosis = Slightly
movable
Types of Synovial Joints
• Synovial joints
– Presence of a synovial
cavity
– Functionally classified as
diarthrosis = Freely
movable
– Epiphysis of bones are
covered by articular
(hyaline) cartilage
– Reduces friction
– Absorb shock
– Contain ligaments:
bundled fibers that
connect bone to bone and
give joints stability
Types of Synovial Joints
1. Planar AKA Plane or Gliding Joint
• Flat or slightly curved bones
• Allow for side to side & back
and forth gliding motion
2. Hinge Joint
• Concave surface meets the
convex surface of another bone
• Allow for opening & closing
motion like the hinge of a door
Types of Synovial Joints
3. Pivot Joint
• A rounded surface articulates
with a ring formed by another
bone or ligament.
• Allows for rotation around its
vertial axis.
4. Condyloid Joint
• Convex-oval shape of one
bone fits into the concaveoval shape of another.
• Allows for up & down and
side to side movement.
Types of Synovial Joints
5. Saddle Joint
• Allows for side to side and
back to forth movement.
6. Ball & Socket Joint
• Ball like surface of one
bone fits into the cup like
depression of another.
• Allows for free movement.
Joint Review Video
(click picture)