1. Chapter 3 Articular System

2. Purposes of Joints
Allow motion
Bear weight
Provide stability

3. Types of Joints Fibrous Cartilaginous Synovial Synarthrosis
Nonaxial
Uniaxial
Biaxial
Triaxial
Synarthrosis
Syndesmosis
Gomphosis
Types – based on structure or amount of motion allowed
Fibrous – 3 types
Synarthrosis – suture joints; skull; no motion; shape & strength
Syndesmosis – ligamentous; distal tib-fib; small amount of twisting or stretch; distal radial ulnar joint;
Gomphosis – bolting together; tooth in socket
Cartilaginous – amphiarthrodial; some motion; either hyaline or fibrocartilage; first sternocostal joint; IV disks; symphysis pubis
Synovial – diathrodial; free motion; hip, elbow, knee, etc. – see Table 3-1 & 3-2 page 23
Nonaxial – linear; planar; intercarpals
Uniaxial – hinge; elbow & knee; pivot – A/A jt; radius/ulna
Biaxial – condyloid/ellipsoidal; flex/ext & abd/add; wrist; MP; or saddle – flex/ext, abd/add/rotation; Thumb CMC
Triaxial/multiaxial – ball & socket; flex/ext, abd/add, rot; shoulder, hip

7. Joint Structure Bone Ligament Capsule Synovial fluid Cartilage Tendon
Outer layer
Inner layer (synovial membrane)
Synovial fluid
Cartilage
Tendon
Bursa
Cartilage – hyaline or articular cartilage = ends of bones; fibrocartialge = shock absorbers, discs, menisci; elastic = maintains shape – ear, larynx
Bursa – natural or acquired;
Aponeurosis – broad flat tendonous sheath; linea alba, biceps, lats

8. Planes and Axes Planes Axes Saggital plane Frontal plane
Transverse plane
Axes
Sagittal axis
Frontal axis
Vertical axis
Frontal aka coronal; transverse plane aka horizontaL
COG = where the three cardinal planes intersect; anterior to S2 vertebrae
Joint Movement = around an axis that is always perpendicular to its plane ( in a plane around an axis); Thumb is exception

9. Degrees of Freedom Number of planes in which joint can move
Uniaxial joint has one degree of freedom
Biaxial joint has two degrees of freedom
Triaxial joint has three degrees of freedom

10. Common Pathological Terms
Dislocation
Subluxation
Osteoarthritis
Sprain
Tendonitis
Synovitis
Tenosynovitis
Bursitis
Capsulitis
Sprain/Strain – mild, moderate, severe