Chapter 8Articulations 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

• Uniaxial-movement @ 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 ExtensionAnterior/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 Depressionsuperior inferior

Protraction and Retraction

anterior

posterior

Inversion and Eversion

medial lateral

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

• 1st Degree- stretch• 2nd Degree- stretch & partial tear• 3rd 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