Synovial joints are the most mobile joints of the skeleton.
Each contains a cavity filled with lubricating fluid that allows
the articulating bones to glide smoothly against one another. A
strong fibrous capsule surrounds the joint, lined internally by
a synovial membrane, while the bone surfaces are covered by a
layer of smooth articular cartilage.
Key Features
Joint cavity: Space filled with synovial
fluid that reduces friction.
Articular cartilage: Hyaline cartilage
protecting the bone ends.
Joint capsule: Fibrous outer layer with an
inner synovial membrane.
Ligaments: Reinforce and stabilize the
joint capsule.
Wide range of motion: Movement depends on
the specific joint type.
Common Types
Hinge – e.g., elbow and knee
Pivot – e.g., radioulnar joint
Condyloid – e.g., wrist (radiocarpal
joint)
Saddle – e.g., thumb (first
carpometacarpal)
Plane – e.g., intercarpal joints
Ball-and-socket – e.g., shoulder and
hip
Synovial joints enable most everyday motions, from walking
and gripping to swinging a bat. Their design balances mobility
with stability through supportive ligaments and surrounding
muscles.