Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made.
Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students.
A synovial joint, also known as a diarthrosis, is the most common and most movable type of joint in the body of a mammal. Synovial joints achieve movement at the point of contact of the articulating bones. Structural and functional differences distinguish synovial joints from cartilaginous joints (synchondroses and symphyses) and fibrous joints (sutures, gomphoses, and syndesmoses). The main structural differences between synovial and fibrous joints are the existence of capsules surrounding the articulating surfaces of a synovial joint and the presence of lubricating synovial fluid within those capsules (synovial cavities).
Several movements may be performed by synovial joints. Abduction is the movement away from the midline of the body. Adduction is the movement toward the middle line of the body. Extension is the straightening of limbs (increase in angle) at a joint. Flexion is bending the limbs (reduction of angle) at a joint. Rotation is a circular movement around a fixed point.
There are six types of synovial joints. Some are relatively immobile, but are more stable. Others have multiple degrees of freedom, but at the expense of greater risk of injury. The six types of joints include:
Gliding joints - only allow sliding movement
Hinge joints - allow flexion and extension in one plane
Pivot joints - allow bone rotation about another
Condyloid joints - flexion, extension, abduction, and adduction movements
Saddle joints - permit the same movement as condyloid joints (and condylar joints and saddle joints combine to form compound joints)
Ball and socket joints - allow all movements except gliding