Joints are classified structurally based on how bones connect and functionally based on degree of movement. Structural types are fibrous, cartilaginous, and synovial. Fibrous joints allow little movement, cartilaginous more than fibrous but less than synovial. Synovial joints have the most mobility and include ball-and-socket, hinge, and gliding joints. Functionally, joints are synarthrosis (no movement), amphiarthrosis (slight movement), and diarthrosis (varied movement like flexion). Key parts of joints are articular cartilage, synovial cavity, articular capsule, synovial fluid, and ligaments.
3. DEFINITION
A joint is the location at which two or more bones
make contact. They are constructed to allow
movement and provide mechanical support, and
are classified structurally and functionally.
Structural classification is determined by how the
bones connect to each other, while functional
classification is determined by the degree of
movement between the articulating bones
5. Cartilaginous
Cartilaginous are connected entirely by
cartilage. Cartilaginous joints allow more
movement between bones than a fibrous joint
but less than the highly mobile synovial joint.
6. Synovial
Synovial joints have a space between the
articulating bones for synovial fluid. This
classification contains joints that are the most
mobile of the three, and includes the knee and
shoulder.
7. FIBROUS JOINTS
• 1. Sutures or
synostoses are found
between bones of the
skull. In fetal skulls the
sutures are wide to
allow slight movement
during birth. They later
become rigid
(synarthrodial).
8. FIBROUS JOINTS
• 2. Syndesmosis are
found between long
bones of the body, such
as the radius and ulna
in forearm and the
fibula and tibia in leg.
Unlike other fibrous
joints, syndesmoses
are moveable
(amphiarthrodial), but
not to such degree as
synovial joints.
9. FIBROUS JOINTS
• 3. Gomphosis is a joint
between the root of a
tooth and the sockets in
the maxilla or mandible.
10. CARTILAGENOUS JOINTS
Cartilaginous joints are connected entirely by
cartilage. Cartilaginous joints allow more
movement between bones than a fibrous joint
but less than the highly mobile synovial joint.
An example would be the joint between the
manubrium and the sternum. Cartilaginous
joints also form the growth regions of
immature long bones and the
intervertebral discs of the spinal column.
11. CARTILAGENOUS JOINTS
Primary cartilaginous
joints - Known as
"synchondroses". Bones are
connected by hyaline
cartilage or fibrocartilage,
sometimes occurring
between ossification
centers. This cartilage may
ossify with age. These joints
usually allow no movement,
or minimal movement in the
case of the manubriosternal
and first manubriocostal
joints.
12. CARTILAGENOUS JOINTS
Examples in humans
are the joint between
the first rib and the
manubrium of the
sternum, and the
"growth plates"
between ossification
centers in long bones.
13. CARTILAGENOUS JOINTS
Secondary cartilaginous joints - Known as "symphyses".
Fibrocartilaginous joints, usually occurring in the midline.
Examples in human anatomy would be the intervertebral
discs, and the pubic symphysis. Articulating bones at a
symphasis are covered with hyaline cartilage and have a
thick, fairly compressable pad of fibrocartilage between them.
14. SYNOVIAL JOINTS
Synovial
Synovial joint
Synovial joints have a space between the
articulating bones for synovial fluid. This
classification contains joints that are the most
mobile of the three, and includes the knee
and shoulder. These are further classified
into ball and socket joints, condyloid joints,
saddle joints, hinge joints, pivot joints, and
gliding joints.
15. SYNOVIAL JOINTS
Ball and Socket - such as the shoulder or the hip
and femur.
Hinge - such as the elbow.
Pivot - such as the radius and ulna.
Condyloid (or ellipsoidal) - such as the wrist
between radius and carpals, or knee
Saddle - such as the joint between carpal thumbs
and metacarpals.
Gliding - such as between the carpals.
25. FUNCTIONAL CLASSIFICATION
1. Synarthrosis
Synarthroses permit little or no mobility. Most
synarthrosis joints are fibrous. They can be
categorised by how the two bones are joined
together:
A.Synchondroses are joints where the two bones
are connected by a piece of cartilage.
26. FUNCTIONAL CLASSIFICATION
B. Synostoses are where two bones that are
initially separted eventually fuse together,
essentially becoming one bone. In humans the
plates of the cranium fuse together as a child
approaches adulthood. Children whose
craniums fuse too early may suffer deformities
and brain damage as the skull does not
expand properly to accommodate the growing
brain, a condition known as craniostenosis.
27. FUNCTIONAL CLASSIFICATION
2. Amphiarthrosis
Amphiarthroses permit slight mobility. The
two bone surfaces at the joint are both
covered in hyaline cartilage and joined by
strands of fibrocartilage. Most amphiarthrosis
joints are cartilaginous.
28. FUNCTIONAL
CLASSIFICATION
3. Diarthroses
Permit a variety of movements (e.g. flexion,
adduction, pronation). Only synovial joints are
diarthrodial. They can be divided into six classes:
Ball and Socket - such as the shoulder or the hip and
femur.
Hinge - such as the elbow.
Pivot - such as the radius and ulna.
Condyloid (or ellipsoidal) - such as the wrist between
radius and carpals, or knee
Saddle - such as the joint between carpal thumbs and
metacarpals.
Gliding or plane- such as between the carpals.
29. BIOMECHANICAL
CLASSIFICATION
Joints can also be classified based on their
anatomy or on their biomechanical
properties. According to the anatomic
classification, joints are subdivided into
simple and compound, depending on the
number of bones involved, and into complex
and combination joints:
30. BIOMECHANICAL
CLASSIFICATION
Simple Joint: 2 articulation surfaces (eg.
shoulder joint, hip joint)
Compound Joint: 3 or more articulation
surfaces (eg. radiocarpal joint)
Complex Joint: 3 or more articulation
surfaces and an articular disc or meniscus
(eg. knee joint)
31. ANATOMICAL CLASSIFICATION
Anatomical
The joints may be
classified anatomically
into the following
groups:
articulations of hand
wrists
elbows
axillary articulations
sternoclavicular joints
vertebral articulations
temporomandibular joints
sacroiliac joints
hip joints
knee
articulations of foot
32. TERMS RELATING TO JOINT
MOVEMENTS
Extension Increasing the angle. In the
anatomical position everything is extended.
Hyperextension To increase the angle beyond
the anatomical position.
Flexion Decreasing the angle.
Plantar Flexion To point the toe.
Dorsiflexion Pulls the toes up.
Abduction Moving a limb away from the trunk of
the body.
33. TERMS RELATING TO JOINT
MOVEMENTS
Adduction Moving a limb toward the trunk of the
body.
Rotation Movement of a bone around an axis.
Circumduction Circular movement of the distal
end of a limb.
Supination The palm in the anatomical position
(palms forward).
Pronation Palms backward.
Inversion Turning the sole of the foot inward.
Eversion Turning the sole of the foot outward.
34. PARTS OF A JOINT
A). Articular Cartilage
B). Synovial (joint) cavity
C). Articular Capsule
D). Synovial Fluid.
E). Reinforcing Ligaments
F). Fatty Pads or Articular Discs
G). Bursae Flattened sacs that contain synovial fluid.
Function to reduce friction
H).Tendon Sheath A bursa that wraps around a
tendon that is subject to friction.