Chapter 8 Articulations and Movement

Articulations or Joints Articulation or Joint –Place where two bones come together –Freely moveable to limited to no apparent movement –Structure correlated with movement

Classes of Joints Structural: Based on major connective tissue type that binds bones –Fibrous –Cartilaginous –Synovial Functional: Based on degree of motion –Synarthrosis: Nonmoveable –Amphiarthrosis: Slightly moveable –Diarthrosis: Freely moveable

Fibrous Joints Characteristics –United by fibrous connective tissue –Have no joint cavity –Move little or none Types –Sutures –Syndesmoses –Gomphoses

Syndesmoses Bones farther apart than suture and joined by ligaments (holds bone to bone) Some movement may occur

Gomphoses Specialized joints Pegs that fit into sockets Inflammations –Gingivitis –Periodontal disease

Cartilaginous Joints Unite two bones by means of cartilage Types –Synchondroses Joined by hyaline Little or no movement –Symphyses Fibrocartilage uniting two bones

Concept Check 1.What is articulation? -point of contact b/n two bones 2.What type of joint is gomphoses? symphyses? -Fibrous Joint in jaw (holds teeth); Fibrous Joint 3.What is the difference b/n synarthrosis, amphiarthrosis, & diarthorsis? -non-moveable; slightly moveable, and freely moveable

Synovial Joints Allow considerable movement Most joints that unite bone of appendicular skeleton Complex –Articular cartilage and disks –Joint cavity and capsule –Synovial membrane and fluid –Ligments and menisci Bursae –Pockets of synovial fluid *reduces friction* –Bursitis

Types of Synovial Joints Plane or gliding Saddle Hinge Pivot Ball-and-socket Ellipsoid *See Table 8.2 pg. 247

Types of Synovial Joints 1 axis & 1 plane Biaxial- 2 perpendicular axis & 2 perpendicular planes Multiaxial- 3 or more axes & 3 or more planes

Plane and Pivot Joints Plane or Gliding Joints –Monoaxial/Slight Movement –Example: Articular processes between vertebrae (intervertebral) Sacroiliac Pivot Joints –Monoaxial/Rotation –Example: Articulation between dens of axis and atlas Radius w/ ulna

Saddle and Hinge Joints Saddle Joints –Biaxial/Slight Movement –Example: Thumb Hinge Joints –Monoaxial –Example: Elbow, Knee –Multiaxial –Example: Ankle-One predominates

Ellipsoid and Ball-and-Socket Joints Ellipsoid –Modified ball-and- socket –Biaxial –Example: Atlantooccipital Joint Ball-and-Socket –Multiaxial –Examples: Shoulder and Hip joints

Types of Movement Gliding Angular –Flexion and Extension Hyperextension Plantar and Dorsiflexion Circular –Rotation –Pronation and Supination –Circumduction

Flexion and Extension Anterior/Ventral Posterior/Dorsal

Dorsiflexion and Plantar Flexion heel toes

Abduction and Adduction “take away” “bring together”

Rotation and Pronation and Supination “face down” “lying face up”

Circumduction Combination of flexion, extension, abduction, & adduction

Special Movements Unique to only one or two joints –Types Elevation and Depression Protraction and Retraction Inversion and Eversion

Elevation and Depression superiorinferior

Protraction and Retraction anterior posterior

Inversion and Eversion mediallateral

Concept Check How are joints classified? –Structural; Degree of movement What type of joint makes up most of the appendicular skeleton? –Synovial Joints What components make up a synovial joint? –Synovial membrane, joint cavity, joint capsule, articular cartilage, ligaments, tendons, menisci, bursae

Knee Joint Modified hinge joint Menisci: Fibrocartilage articular disks –Pad of cartilage b/n bone of a synovial joint –Cup-shaped for stability; cushion; guide; shock absorber Cruciate ligaments: ACL and PCL Collateral ligaments: Fibular and tibial

Parts of the Knee Bones: Femur, Patella, Tibia, Fibula Muscles: Quadriceps, Hamstrings Actions: Flexion, Extension Ligaments: –Anterior Cruciate: prevents forward movement of tibia (ACL) –Posterior Cruciate: prevents forward movement of femur (PCL) –Lateral Collateral- (Fibula) LCL –Medial Collateral- (Tibia) MCL Tendons: Patellar Tendon (Tibia) Cartilage (Fibrous Articular Cartilage): – Medial Meniscus- shock absorber –Lateral Meniscus- shock absorber

Knee Injuries and Disorders Football injuries Bursitis Chondromalacia –Softening of cartilage Hemarthrosis –Blood accumulation w/n joint cavity –Acute; swollen knee “Water on the knee” –Slower accumulation of fluid may be caused by bursitis

Other Knee Disorders Osgood Schlatter- patellar tendon pulls away from tibia causing fracture & new bone growth –Associated w/ younger athletes Unhappy Triad  - MCL, ACL, & Medial Meniscus –Caused by posterior, lateral blow or hit Dislocated Patella- medial forced w/ slightly flexed knee –Patella flips over Bucket Handle Tear- meniscus tears & piece fills in cavity

Knee Repair Arthroscopy- using tools & camera to see inside of joint –Ligament of cartilage repair, doesn’t need full open exposure to repair Arthroplasty- knee replacement –Diseased or damaged joint

Sprains/Strains Sprain- ligaments Strain- muscle tendons 1 st Degree- stretch 2 nd Degree- stretch & partial tear 3 rd Degree- complete tear

Joint Disorders Arthritis –Osteoarthritis: Wear and tear –Rheumatoid: Caused by transient infection or autoimmune disease Joint infections –Lyme disease: Bacterial infection; Tick vector Gout –Metabolic disorders of unknown cause (idiopathic; arising spontaneously - cause unknown)

Effects of Aging on Joints Tissue repair slows Production of synovial fluid declines Ligaments and tendons become less flexible Decrease in ROM (Range of Motion) 

Concept Check What is the function of menisci? –Cup shaped to help with stability, cushion, & guide the knee What is the difference b/n a ligament & a tendon? –Ligaments connect bone to bone; Tendons connect muscle to bone What is the difference b/n arthroplasty arthroscopy? –Arthroscopy: using tools/camera to see inside the joint; Arthoplasty: knee replacement