WHAT IS A JOINT ?
- → A JOINT CARTICULATION) → PLACE WHERE TWO OR BONES MEET
- →FUNCTION → ALLOW MOVEMENT OR STABILITY OF THE SKELETON
CLASSIFICATION OF JOINTS
A) FIBROUS JOINTS
SYNARTHROSES ↳ IMMOVABLE
- → BONES JOINED BY FIBROUS TISSUE (NO JOINT CAVITY)
- → MOVEMENT : NONE OR VERY LITTLE
EXAMPLES
- SUTURES — IN SKULL [e.g, CORONAL SUTURE]
- SYNDESMOSIS – LIGAMENT CONNECTION BETWEEN BONES [e.g, BETWEEN TIBIA AND FIBULA]
- GOMPHOSIS - TOOTH IN SOCKET
C) SYNOVIAL JOINT
DIARTHROSES -FREELY MOVABLE
- → MOST COMMON TYPE
- → HAVE A JOINT CAVITY FILLED WITH SYNOVIAL FLUID.
- → ALLOW WIDE RANGE OF MOVEMENTS
B) CARTILAGINOUS JOINT
AMPHIARTHROSES- SLIGHTLY MOVABLE
- → BONES JOINED BY CARTILAGE
- → TWO TYPES
- 1. PRIMARY CARTILAGINOUS [SYNCHONDROSIS]- JOINED BY HYALINE CARTILAGE [TEMPORARY, LATER OSSIFIES]
- EXAMPLE : EPIPHYSEAL PLATE (GROWING BONE]
- 2. SECONDARY CARTILAGINOUS [SYMPHYSIS] - BONES JOINED BY FIBROCARTILAGE (PERMENANT, SLIGHTLY MOVABLE).
- EXAMPLE : PUBIC SYMPHYSIS, INTERVERTEBRAL DISC
TYPES OF SYNOVIAL JOINTS (WITH EXAMPLES)
- 1) PLANE (GLIDING) – FLAT SURFACES SLIDE [e.g, INTERCARPAL JOINTS]
- 2) HINGE – MOVEMENT IN ONE PLANE (FLEXION / EXTENSION). [e.g ELBOW, KNEE]
- 3) PIVOT – ROTATION AROUND AXIS (e.g. ATLAS - AXIS JOINT, RADIOULNAR]
- 4) CONDYLOID (ELLIPSOID) - MOVEMENT IN 2 PLANES (FLEXION / EXTENSION, ABDUCTION / ADDUCTION) [e.g. WRIST]
- 5) SADDLE – LIKE RIDER ON A SADDLE , MOVEMENT IN 2 PLANES + CIRCUMDUCTION [e.g , THUMB JOINT – 1st CARPOMETACARPAL]
- 6) BALL AND SOCKET - MOVEMENT IN ALL DIRECTIONS (MULTIAXIAL) (e.g. SHOLDER, HIP]