2. Joint
• The point at which two bones articulate with each other (with or without the ability to move) is called a joint
• Cartilage is a connective tissue which keeps two adjacent bones to come in contact
• They are constructed to allow different degrees and types of movement
• The estimated number of joints in the human body is between 250 and 350
• Joint consists of various structures:
Cartilage (covers the surface of the ends of the bone, reduces friction during movement)
Synovial membrane (lines the joint and seal it)
Ligaments (tough elastic connective tissue surrounds the joint to give support and limit joint
movement also connects bones together)
Tendons (tough connective cord that connects muscle to bones)
Bursas (fluid filled sacs between bones and ligaments, acts as cushion to prevent friction)
Synovial fluid (clear sticky fluid secreted by synovial membrane)
Meniscus (C-shaped fibrocartilage between thighbone and shinbone and act as shock absorber)
3. Classification of Joint
• According to structure/binding tissue
Fibrous
Cartilaginous
Synovial joint
• According to function/ degree of movement
Synarthrosis/ Immovable
Amphiarthrosis/ Slightly movable
Diarthrosis/ Freely movable
4. Fibrous Joint
• Bound by tough dense fibrous connective tissue
• No cavity or space present between the bones
• Negligible movement
• Further subdivided into:
Sutures (skull, pelvic bone, rib cage)
Gomphoses (tooth and socket)
Syndesmoses (radioulnar joint and tibiofibular joint)
5. Cartilaginous Joint
• Bound by fibrocartilage or hyaline cartilage
• Further subdivided into:
Synchondroses (1° cartilaginous) connected by hyaline cartilage and are immovable. E.g. joint between
epiphysis and diaphysis of a growing bone
Symphyses (2° cartilaginous) united by a layer of fibrocartilage and is slightly movable. E.g. pubic
Symphysis and vertebral bodies
6. Synovial Joint
• Presence of a fluid filled joint cavity within a fibrous capsule
• articulating surfaces have no direct contact with each other
• Freely movable
• Most of the upper and lower limb joints are synovial Further subdivided into:
Hinge joint permits movement in one plane usually flexion and extension e.g. knee, elbow, ankle joint
Saddle joint is characterize by concave-convex shape opposing articular surface e.g. carpometacarpal joint
Plane or gliding joint are relatively flat, allowing the bones to glide over one another e.g. acromioclavicular
joint
Pivot joint allows rotation only e.g. radioulnar joints, atlantoaxial joint
Condyloid or ellipsoid joints contains a convex surface which articulates with a concave elliptical cavity e.g.
wrist joint, metacarpophalangeal joint
Ball and socket joint where ball-shaped surface of one rounded bone fits into the cup-like depression of
another bone. It permits free movement in numerous axis e.g. hip joint, shoulder joint
