Articulations CH 8

Outline Anatomical design Joint Classifications Movements Degree of joint motion Type of motion Degree of joint stability Joint Classifications Structural joints Functional joints Movements Synovial Joint Classification

Articulations “artic” = Joint Union of articulating bone Bone-bone interactions Direct Indirect Cartilage, fibrous CT, fluid Anatomical design determines Degree of joint motion Type of motion Degree of joint stability

Degree of Joint Motion

Type of Motion

Mobility vs Stability Inversely related

Joint Classifications 2 categorizations of joints Structural classification Space between bones Amount of space Contents of space Functional classification Degree of motion

Structural Classification Categorization based on amount of space and contents of space 4 categories Bony fusion Fibrous joint Cartilaginous joint Synovial joint

Bony Fusion Space Space contents Degree of motion Example No space between bones No joint cavity Space contents None, bones completely fused Degree of motion No movement Very stable Example Portions of Coxal bone & sacrum Frontal bone

Bony Fusion

Fibrous Joint Space Space contents Degree of motion Example Little space No joint cavity Space contents Fibrous CT Degree of motion Immovable to slightly movement Stable Example Cranial sutures, pelvis (sacrum/ coxal bone) No Mobility

Fibrous Joint Virtually no mobility

Cartilaginous Joint Space Space contents Degree of motion Example Little space No joint cavity Space contents Cartilage Degree of motion Immovable to slightly movable Stable Example Intervertebral joints, pubic symphysis, sternocostal

Cartilaginous Joint

Synovial Joint Space Space contents Degree of motion Example Yes! Joint cavity Space contents Synovial fluid Held together w/ bands of dense regular CT- ligaments Degree of motion Freely moveable Least stable- high motility Example Knee, elbow, fingers, shoulder

Synovial Joint

Functional Classification Categorization based on motility of joint 3 Categories Synarthrosis Amphiarthrosis Diarthrosis

Synarthrosis “syn” together “arthr” joint Motility none

Amphiarthrosis “amphi” both sides Motility Slightly movable

Diarthrosis “dia” Through Motility Structural classification Freely movable Structural classification Synovial joints (6) Hip, knee, shoulder, elbow

Synovial Joints 6 types Categorized based on Shape of articulating surfaces Movements produced

Movements Gliding Angular Rotation Misc Flexion/ extension Abduction/ adduction Circumduction Rotation Medial/ lateral Misc Elevation/ depression Protraction/ retraction Inversion/ eversion Pronation/ supination Dorsiflexion/ plantar flexion Opposition

Gliding Linear motion One plane of motion 2 opposing surfaces pass one another Examples Clavicle & sternum

Angular Changes in longitudinal position of bone Flexion/ Extension Abduction/ Adduction Circumduction

Flexion/ Extension/ Hyperextension Anterior plane Flexion decrease in angle btw bones Extension increase in angle btw bones Hyperextension extension beyond the standard anatomical position

Flexion/ Extension/ Hyperextension

Flexion/ Extension/ Hyperextension

Abduction/ Adduction Frontal plane Abduction Adduction Movement away from midline Adduction Movement toward midline

Abduction/ Adduction

Circumduction Combination of movements Flexion Extension Abduction Adduction

Rotation Spin along a longitudinal axis Medial rotation Anterior surface Rotates toward the midline Lateral rotation Posterior surface Rotates away from the midline

Rotation

Elevation & Depression Superior & inferior bone movement Ex. Scapula, mandible

Protraction & Retraction Anterior & posterior bone movement Ex. Mandible

Inversion & Eversion Inversion Eversion Inward movement of functional surface Sole of foot Eversion Outward movement of functional surface

Pronation & Supination Posterior of functional surface ie eversion of foot, medial rotation of forearm Supination Anterior rotation of functional surface ie Inversion of foot, lateral rotation of forearm

Dorsiflexion & Plantar Flexion Dorisiflexion Movement of the foot upward Plantar flexion Movement of the foot downward

Synovial Joint Classification Gliding joint Hinge joint Pivot joint Ellipsoidal joint Saddle joint Ball & socket joint

Gliding Joint Movement Examples Linear movement Sternum & clavicle Tarsals Ribs & vertebrae Carpals

Hinge Joint Movement Examples Flexion/ extension/ hyperextension Elbow Knee

Pivot Joint Movement Example Medial/ lateral rotation Axis & atlas Radius & ulna

Ellipsoidal Joint Aka Condylar Articulating surface- rounded surface articulates w/ a depression Movement Flexion/ Extension Adduction/ abduction Circumduction Example Wrist- radius & carpals Phalanges & metacarpals

Saddle Joint Articulating surface- saddle shaped Movement Example Flexion/ extension Adduction/ abduction Circumduction Opposition Example Metacarpals I & carpal I (pollex)

Ball & Socket Joint Articulating surface- round surface & depression Movement Flexion/ extension Adduction/ abduction Circumduction Rotation Example Shoulder Hip