Human Biology
Types of Joints (Chapter 13)
Joints are regions of union between bones OR cartilages in the skeleton.
They consist of:
1.
Rigid immovable joints, such as the connections between the bones of the skull.
2.
Slightly movable joints, such as the junction of the bones making up the front of the pelvis
3.
Movable joints, such as the meeting of the bones of the limbs with those of the trunk.
Immovable joints are held together by bone or by strong fibrous cartilage.
Slightly movable joints are held together by elastic
cartilage.
Movable joints consist of an external layer of fibrous cartilage giving rise to strong ligaments that support the separate bones.
The bones of movable joints are covered with smooth cartilage and are lubricated by a thick fluid, called

synovial fluid, produced between the bones in membranous sacs, known as bursae.
Bursitis, or inflammation of the bursae, is a common
painful condition of movable joints.
The human body has several types of movable joints.
Ball-and-socket
The hip and shoulder are ball-and-socket joints, which allow free movement in all directions.
Hinge
The elbows, knees, and fingers are hinge joints, allowing movement in one plane only.
Pivot
Pivot joints, permitting rotation only, are found between the first two vertebrae; the head rotates from side to side on a joint of this type called the axis.
Gliding
Gliding joints, in which the surfaces of the bones move a short distance over each other, are found between the various bones of the wrist and ankle. Also, the sternum and clavicle and the scapula and clavicle.
Saddle
Thumb joins the hand. Allows side-to-side and back-andforth movement.