Question

a) Draw diagrams of fibrous, cartilaginous and synovial joints ensuring that they are fully annotated.

b) Explain, with examples, the structure of each of these types of joint and how this relates to different types of movement that are associated with them.

Answer 1

1. Fibrous joint - in this type, articulating surfaces are connected by fibrous tissue. Depending upon the length of fibrous tissue, there may be some degree of movement or no movement at all.

Ex: sutures between bones of vault of the skull.

2. Cartilaginous joint - Here articulating ends are connected by a piece of cartilage. This may be primary or secondary.

A) primary - a piece of cartilage is interposed between articulating surfaces. These are temporary joints and are replaced by bony union.

Ex: between diaphysis and epiphysis of a growing bone

B) secondary- articulating surfaces are covered by thin hyaline cartilage and connected by fibrous cartilage. Degree of movement depends on physical quality of fibrocartilage.

Ex: usually midline joints: symphysis pubis

3.synovial joint- articular surfaces are covered by a thin hyaline cartilage and separated by synovial cavity. Cavity is enclosed within fibrous capsule. Inner surface of capsule and non articular parts of articulating ends of bones inside the capsule are lined by synovial membrane. Articulating surfaces are lubricated by synovial fluid.

In certain joints, an articular disc made of fibrocartilage is interposed into joint. They are found in joints where movements occur in two planes.

Classification

1.ball and socket joint- movement take place around many axes. Ex: shoulder joint, knee joint

2.hinge joint- movement occurs in one plane

Ex: ankle

3.pivot joint- movements occur around longitudinal axis

Ex: radioulnar joint

4.condyloid joint- biaxial joint

Ex: wrist

5.Saddle shaped joint- movement occurs in all planes

Ex: carpometacarpal joint of thumb

6.plane variety- movements restricted to gliding, tilting and rotation

Ex: joints between articulating surfaces of thoracic vertebra