Section A: Applied Anatomy and Physiology 2. Joint type

Syllabus Definitions and examples of fibrous, cartilaginous and synovial joints The typical structure and features of a synovial joint The type of join and the bones which articulate at the following joints: Shoulder, elbow, radio-ulnar, wrist, hip, knee, ankle, spine

Joint Classification Structural classification is based on anatomical characteristics. Fibrous: no synovial cavity and bones are held together by fibrous connective tissue. Cartilaginous: no synovial cavity and the bones are held together by cartilage. Synovial: bones forming the joint have a synovial cavity. Held together by the articular capsule and often by accessory ligaments.

Fibrous Joint (Suture) Fibrous Joint (Suture) * the amount of movement is based on the length of the tissue fibres *

Fibrous Joint (Syndesmosis)

Cartilaginous Joint Types (Synchondroses) – temporary joints present in children E.g. epiphyseal plates in long bones (Sympheses) – permanent cartilaginous joints E.g. vertebral column

Temporary Joint

Permanent Joint

Synovial Joints There are 6 types These are categorized according to range of movement possible Movement determined by: Shape of articulating surfaces Position of ligaments Number of ligaments

Synovial Joint Features Common features include A joint (articular) capsule: unites the articulating bones. A joint cavity. A synovial membrane: secretes synovial fluid to reduce friction/absorb shock, supply nutrients. Articular (hyaline) cartilage.

Some Synovial Joints Also Have… Bursae Small sacs of synovial fluid located at points of friction Menisci Discs of cartilage between bone surfaces Pads of fat Added protection

Synovial Joints

Synovial Joints

Ball and Socket

Ball and Socket Joint Multiaxial Movement in all 3 planes Flexion/Extension Abduction/Adduction Circumduction Rotation

Hinge

Hinge Joint Uniaxial Only permits flexion and extension Examples are the knee, elbow and ankle

Pivot

Pivot Joints Uniaxial It allows rotation only around its own longitudinal axis Example is the atlanto-axial joint

Plane

Planar Joints Nonaxial The motion they allow does not occur around an axis or along a plane Examples are intercarpal joints, intertarsal joints etc

Saddle

Saddle Joints Biaxial Flexion/Extension Abduction/Adduction Circumduction Example is the carpometacarpal joint

Condyloid

Condyloid Joints Biaxial Flexion/Extension Abduction/Adduction Circumduction Examples are the wrist and metacarpophalangeal joints