Definition of Joint
A joint is the location at which two or more
bones articulate or make contact. Some joints
like those of the skull are fixed and have no
movement, some like those of the vertebrae
can move slightly and some are freely
moveable like the joints of the limbs.
Fibrous joints connect bones without allowing any
movement. The bones of the skull and pelvis are held
together by fibrous joints. The union of the spinous
processes and vertebrae, joints between the teeth and
maxilla and mandible are the examples of fibrous
Cartilaginous joints are joints in which the bones are
attached by cartilage. In this type of joint, there is a
pad of fibro cartilage between the ends of bones
which form joints, where only some movement is
required. Joints at the pubic symphysis, joint between
the manubrium sterni and body of the sternum and
joints between the vertebral bodies are the examples
of cartilaginous joint.
2- Cartilagenous Joints
1) PRIMARY CARTILAGINOUS JOINT (synchondrosis)
*It does not allow any
* This type is
characterized by having a
plate of cartilage between
the epiphysis & diaphysis
of the same bone. It is not
a true permanent joint, but
it is a temporary plate of
hyaline cartilage which
disappears in adulthood by
i.e. It is represented by the
epiphysial plate of cartilage
intervening between the
epiphysis and diaphysis of
Structure of Intervertebral disc
Characteristics of synovial joint
1. The capsule The joint is enclosed and surrounded by fibrous tissue. This
keeps the bones together. The capsule is such, that, it protects the bones
and joint from injury and at the same time allows free movement.
2. Articular cartilage: hyaline cartilage lines the bones which form the joint
and which are in contact with each other. Hence, the articular surfaces are
smooth. The hyaline cartilage also bears the weight of the body. It reduces
friction of the joint..
3. Synovial membrane lines the capsule,
4. Synovial fluid is secreted by the synovial membrane into the joint cavity. It
provides nutrition to the structures within the joint cavity.
5. In addition to the capsule, the bones are also attached and held together by
strong-tough ligaments made of dense connective tissue. These
ligaments prevent dislocation during normal movement.
6. The articulating surfaces of adjacent bones are reciprocally shaped.
Diagram showing the main structures of the Synovial Joint
Synovial joint cavity
Articular disc or
The main movement of the synovial joints are
--- flexion: bending forward.
--- extension : means straightening or bending backward
--- abduction :- moving away from the midline of the body .
--- adduction :- moving towards the midline of the body .
--- rotation :- moving round the long axis of bone .
--- pronation :- turning the palm of the hand down .
--- supination :- turning the palm of the hand up .
--- circumulation :- combination of flexion , extension,
abduction , adduction ,
--- inversion :- turning the sole of the foot inwards.
--- eversion :- turning the sole of the foot outwards .
It is a ball and socket type of joint. The head of the humerus rotates within the glenoid
cavity of the scapula. It is also known as humero-scapular joint.
This joint is formed by
the lower end of the
humerus with the
upper ends of the
ulna and the radius. It
is a type of hinge
radioulnar joint is
formed by the rim of
the head of radius
rotating in the radial
notch of the ulna and
it has little movement.
The distal joint is
formed between the
distal end of the
radius and the head
of the ulna. It is a
This joint is formed by the distal end of the
radius and the proximal ends of the carpal
(wrist) bones. It is a condyloid joint.
Joints of wrist and fingers
These are joints between the carpal bones, between
carpal and metacarpal bones and between the
metacarpal bones and proximal phalanges and
between the phalanges. Intercarpal and carpal –
metacarpal joints are gliding joints.
Metacarpophalangeal joints are condyloid joints and
interphalangeal joints are hinge joints.
Coronal section through a metacarpophalangeal joint, a synovial joint. The
.collateral ligaments are thickenings of the joint capsule
Joints of the foot and toes
Joints are formed between the tarsal bones,
between the tarsal and the metatarsals,
between the metatarsal bones and the proximal
phalanges and between the phalanges. They
are all gliding type of joints.