An ovoid joint, also known as an ellipsoidal or condyloid joint, is a type of synovial joint characterized by the articulation of a convex, oval-shaped surface of one bone with a concave cavity of another. This configuration allows for movement in two planes, making it a biaxial joint.
Characteristics of Ovoid Joints
- Synovial Joint: Ovoid joints are classified as synovial joints, meaning they possess a joint capsule, synovial membrane, and synovial fluid to lubricate and nourish the articular surfaces.
- Biaxial Movement: The primary feature of an ovoid joint is its ability to move in two planes:
- Flexion and Extension: Movement that decreases or increases the angle between bones.
- Abduction and Adduction: Movement away from or towards the midline of the body.
- Circumduction: Ovoid joints also allow for circumduction, which is a conical movement combining flexion, extension, abduction, and adduction. However, axial rotation is typically limited or absent.
Examples of Ovoid Joints
- Radiocarpal Joint (Wrist): This joint connects the radius bone of the forearm with the carpal bones of the wrist, allowing for flexion, extension, abduction, adduction, and circumduction of the hand.
- Metacarpophalangeal Joints (Knuckles): These joints connect the metacarpal bones of the hand with the phalanges (finger bones), enabling flexion, extension, abduction, adduction, and circumduction of the fingers.
- Metatarsophalangeal Joints (Toes): Similar to the knuckles, these joints connect the metatarsal bones of the foot with the phalanges (toe bones), allowing for flexion, extension, abduction, adduction, and circumduction of the toes.
Function and Importance
Ovoid joints play a crucial role in facilitating a wide range of movements necessary for daily activities. Their biaxial nature provides a balance between stability and mobility, allowing for controlled and coordinated movements of the limbs. Injuries to these joints can significantly impact function and require appropriate rehabilitation.
