Joints

1
Joints

• Chapter 9

2
Objectives

• Be able to define an articulation and arthrology
• Know the four main categories of articulations
  and their sub categories
• Understand how a lever works and what mechanical
  advantage is
• Be able to describe selected joints of the body

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Articulations

• Any point where two bones meet
• Arthrology
• Science of joint structure, function, and
  dysfunction
• Classified into four main categories
• Bony
• Synostosis
• Immovable joint formed when two separate bones
  fuse to form one
• Ex. Frontal, mandible, epiphyseal line
• Fibrous
• Cartilaginous
• Synovial

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Fibrous

• Synarthrosis
• Adjacent bones bound by collagen fibers that
  penetrate into both bones
• Three kinds
• Sutures
• Serrate, lap, and plane
• Gomphoses
• Teeth in socket
• Syndesmoses
• Bones held by longer collagen fibers that allow
  for a greater range of motion
• Interosseous membrane between ulna and radius

pc.maricopa.edu
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Cartilaginous

• Amphiarthrosis
• Two bones are linked by cartilage
• Two types
• Synchondroses
• Bones joined by hyaline cartilage
• Epiphyseal discs
• Symphysis
• Bones are joined by fibrocartilage
• Pubic symphysis, intervertebral discs

6
Synovial Joints

• Diarthrosis
• Articulation of bones surrounded by a joint
  capsule
• Articular hyaline cartilage at ends of bones
• Synovial fluid
• Articular disc and meniscus
• Bursa and tendon sheaths
• Exhibit the widest range of motion

zoology.ubc.ca
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Lever Systems

• Enhance speed or power of limb movements
• Rigid, elongated object that pivots on a fixed
  point called the fulcrum
• forces resistance and effort
• Long bones and joints
• Mechanical advantage
• Ratio of output force to input force
• MA LE/LR
• Lever can provide one of two types of advantages
• Exert more force on the object than what is being
  applied to the lever
• Move the resistance arm farther or faster than
  the effort arm

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Lever Systems

• Mechanical advantage
• If gt 1.0
• Lever produces more force, but less speed and
  distance, than force applied to it
• High mechanical advantage, high power
• If lt 1.0
• Lever produces more speed or distance, less force
  than force applied to it
• Low mechanical advantage, low power

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Types of Levers
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Classes of Synovial Joints

• Six types based on shape of articular surface and
  degree of mobility
• Ball and socket
• Shoulder and hip joints
• Wide range of motion
• Condylar (ellipsoid)
• Radiocarpel joint, metacarpophalangeal
• Saddle
• Trapezialmetacarpal joint
• Sternoclavicular joint
• Plane (gliding)
• Carpals and tarsals, vertebral articular
  processes
• Hinge
• Knee and elbow
• Pivot
• Atlantoaxial and radioulnar joints

iupucbio2.iupui.edu
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Movements of Synovial Joints

• Flexion and extension
• Abduction and adduction
• Elevation and depression
• Protractions and retraction
• Circumduction
• Rotation
• Pronation and supination

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The Shoulder Joint

• Glenohumoral joint
• Shallow joint, allows wide range of motion
• Glenoid labrum
• Tendon of long head of bicep brachii
• Rotator cuff
• Tendons of muscles
• Five principal ligaments
• Glenohumeral (3)
• Coracohumeral
• Transverse humeral

aftabphysio.blogspot.com
aidmypain.com
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The Knee Joint

• Tibiofemoral joint
• Two intracapsular ligaments
• Acl, pcl
• Two extracapsular ligaments
• Lateral collateral, medial collateral
• Two menisci
• Lateral and medial

badknees.net
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The Ankle Joint

• Talocrural joint
• Two articulations
• Tibia and talus
• Fibula and talus
• Anterior and posterior tibiofibular ligaments
• Binds tibia to fibula
• Medial (deltoid) ligament
• Binds tibia to foot
• Lateral (collateral) ligaments
• Bind fibula to foot

medical-dictionary.thefreedictionary.com
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cedars-sinai.edu
chiropractic-books.com