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) * 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