Joints and Articulations

Anatomy & Physiology and Articulations: Junctions between bones.

• Types/Categories – Fibrous Joints – Cartilaginous Joints – Synovial Joints Functions

• Bind parts of the skeleton. • Allow for bone growth. • Permit changes of skeleton during childbirth. • Allow for movement. • Vary considerably in structure and function. • Classified based on degree of movement. AND/OR • The type of tissue that bonds the bones together. Quick Fact There are 230 joints/articulations in the body! Fibrous Joints • Connect bones that are very close to one another. • A thin layer of connective tissue joins the bones together. • No measurable movement occurs at this . • Example: sutures between bones of the skull. Cartilaginous Joints

• Use of hyaline cartilage to connect bone. • Allows limited movement. • Absorbs shock. • Example: intervertebral discs.

Synovial Joints

• Most joints fit into this category. • Permits free movement. • Structurally complex. • Ends of bones are covered with smooth cartilage = allows for gliding and prevents bones from rubbing together. • Surrounds a filled with fluid to lubricate joints. • Some have flatened shock absorbing pads called . • Some have a bursae that allows for tendons to glide smoothly over the joint. Types of Synovial Joints

• Ball-and-socket • Condyloid • Gliding • Hinge • Pivot • saddle Ball-and-Socket

• Bone with a rounded (ball-shaped) end that articulates with a cup- shaped cavity. • WIDE range of motion • Example: Shoulder and Hip Condyloid Joint

• Oval shaped bone extension fits into a shallow cavity. • Can move in different directions but NOT rotate. • Example: between metacarpals (bone of palm) and phalanges (fingers). Gliding Joint

• Articulations on an almost flat plane. • Allow for sliding or twisting motion. • Examples: – Between carpal () and tarsal (ankle) bones. – Sternum and ribs. – Sacrum and pelvis

• Convex surface of one bone fits into concave surface of another bone. • Resembles the hinge of a door. • Examples: – Joints of the phalanges – Elbow

• Cylindrical surface of one bone rotates in the ring formed between another bone and a . • Permits rotation. • Example: – Radius and ulna – Cervical vertebrae (neck) and skull.

• BOTH bone surfaces have both a concave and convex surface. • Bone fits like a puzzle piece. • Allows for a variety of movement. • Example: bones between metacarpal (hand) and thumb. Special Considerations

• Arthritis: inflammation of one or more joints that results in pain, swelling, stiffness, and limited movement Special Considerations • Arthrocentesis: removal of fluid from the joint capsule to alleviate pressure and swelling. Special Considerations • Arthrodesis: surgical union of a joint; fusing two or more bones together

Surgical Union of Lumbar (lower back) Vertebrae. Meniscus Tears • Meniscus are found in the knee joint. • They assist in stabilizing the knee and limiting motion that could cause injury. • Most injuries require surgical correction. • Becoming more common in young athletes.