Joints

What is an articulation?  They are joints and occur wherever two bones meet

Are there a plethora of joints?  Joints classified by range of motion  First type-Synarthroses- immovable joint (no movement allowed)  A) Suture- between bones of the skull  B) Gomphosis- ligament binds each tooth within a bony socket

 Second type- Amphiarthroses-slightly movable joints (permits very limited movement)  Bones connected by collagen fibers or cartilage

Examples of amphiarthroses  A) Sydesmosis- connected by ligament (joint between tibia and fibula)  B) Symphysis- bones are separated by a pad of fibro cartilage (joint between spinal vertebrae, pubic symphysis)

 Third type- Diarthroses (synovial)- wide range of motion  Categorized according to type of movement allowed

Categories of Synovial Joints  Gliding joints- flat articular surfaces slide across one another. Permits slight movement  Example-ends of clavicles; between carpals; between tarsals

 Hinge Joints  Permit movement in one plane only  Example- atlas and occipital bone; elbow; knee; and interphalangeal joints)

 Pivot Joints  Permit only rotational movements  Example- atlas and axis, radius and ulna

 Angular (ellipsoidal)  Allows motion in two planes  Example- metacarpal- phalangeal joint

 Saddle  Specialized joint between carpals and metacarpals at the thumb.  Allows angular motion but prevents rotation

 Ball and Socket  Allows for all combinations of movement  Example- shoulder and hip joints

Types of Synovial Joints  Gliding joint  Hinge joint  Pivot joint  Ellipsoidal joint  Saddle joint  Ball and Socket joint

Structure of Synovial Joints  Joint Capsule- surrounds joint and is lined by synovial membrane  Ends of long bones are covered in articular cartilage to prevent bone on bone movement  Synovial membrane is lined with synovial fluid  Fluid provides lubrication to reduce friction within the joint

Joints Continued  Knee joint- requires more support structures  Menisci- fibro cartilage pads that act as shock absorbers

 Fat pad- protect articular cartilage

 Ligaments  Located either inside or outside of the joint capsule  Provides extra support to joint

 Bursae  Small pockets containing synovial fluid  Form at areas of friction within joint  Found in shoulder, elbow, and knee

Types of Joint Movements  Flexion- movement in the sagittal plane that decreases the angle between the two bones

 Extension- movement in the anterior/posterior plane that increases the angle between the two bones

 Abduction- movement away from the midline of the body in the frontal plane

 Adduction- movement toward the midline of the body in the frontal plane

 Circumduction- movement of arm in a loop

 Rotation- moving a bone around the longitudinal axis of the body or limb  Supination- turning hand palm side up  Pronation- turning hand palm side down

Joint Disorders  Rheumatism  General term describing pain and stiffness that affect the skeletal or muscular systems  SEVERAL TYPES OF RHEUMATISM

Types of Rheumatism  Arthritis- disease that affects all of the synovial joints  Always involves damage to the articular cartilages  Cause of this damage can vary  Bacterial or Viral infection  Injury to the joint  Metabolic problems  Severe physical stress

Types of Rheumatism  Osteoarthritis (Degenerative arthritis, Degenerative joint disease)  Affects individuals 60 years of age or older  Caused by wear and tear on joint surfaces  Also caused by genetic

Types of Rheumatism  Rheumatoid arthritis  Inflammatory condition that affects roughly 2.5 percent of the adult population  Cases involve immune system response attacking joint tissues  Allergies, bacteria, viruses, and genetic factors are possible triggers

 Wearing away of articular cartilage (bone on bone articulation)  Very painful  Treated by medication  Extreme cases treated with surgery