Chapter 9: Joints Study Notes

Joints are essential structural components that connect bones and allow for movement in the human body.

Temporomandibular Joint (TMJ)
- Type: Combined hinge and planar joint.
- Bones involved: Mandible and temporal bone.
- Unique attribute: Only movable joint between the skull bones.
Shoulder Joint
- Type: Ball-and-socket joint.
- Bones involved: Head of the humerus and the scapula.
Elbow Joint
- Type: Hinge joint.
- Bones involved: Humerus, ulna, and radius.
Hip Joint
- Type: Ball-and-socket joint.
- Bones involved: Femur and os coxae.
Knee Joint
- Type: Modified hinge joint.
- Characteristics: Largest and most complex joint in the body.

Impact of Aging on Joints
- Aging affects joints variably across individuals.
- By age 80, most individuals experience some form of degeneration in the knees, elbows, hips, and shoulders.
- Common age-related issues include:
- Osteoarthritis: At least partially related to age.
- Thinning of articular cartilage.
- Decreased production of synovial fluid in joints.
- Shortening and reduced elasticity of ligaments.
Joint Arthroplasty
- Definition: Surgical implantation of an artificial joint.
- Commonly replaced joints: Hips, knees, and shoulders.
- Partial Hip Replacements: Involves replacement of only the femur.
- Total Hip Replacements: Involves both the acetabulum and head of the femur.
- Visual aids:
- Diagram displaying components of an artificial hip joint:
  - Artificial acetabulum
  - Artificial femoral head
  - Artificial metal shaft.
Potential Complications of Arthroplasty
- Risks associated with joint replacement surgeries include:
- Infection
- Blood clots
- Nerve injury

An overview of the parts involved in the construction of an artificial knee joint and their functions will be detailed in subsequent sections.
- The information presented emphasizes the medical and surgical advancements in joint replacement therapies for aging populations and indicates ongoing developments in joint health management.