Changes

*Due to acceleration of normal ageing process - wear and tear

*Due to acceleration of normal ageing process - wear and tear

*Destructive disease leading to:

*Destructive disease leading to:

**Loss of weight-bearing [[Joints - normal#Articular cartilage|articular cartilage]]

**Loss of weight-bearing [[Joints - Anatomy & Physiology#Articular cartilage|articular cartilage]]

**Erosion, fibrillation of cartilage

**Erosion, fibrillation of cartilage

***Clefts in the cartilage, perpendicular to the surface

***Clefts in the cartilage, perpendicular to the surface

*May or may not be symptomatic

*May or may not be symptomatic

*Pathogenesis:

*Pathogenesis:

**Not entirely clear but linked to loss of [[Joints - normal#Articular cartilage|proteoglycans]] and subsequent lubrication

**Not entirely clear but linked to loss of [[Joints - Anatomy & Physiology#Articular cartilage|proteoglycans]] and subsequent lubrication

**Increased water content due to improper binding -> softening of cartilage = chondromalacia

**Increased water content due to improper binding -> softening of cartilage = chondromalacia

[[Image:Intervertebral disc degeneration.jpg|right|thumb|100px|<small><center>Intervertebral disc degeneration (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

[[Image:Intervertebral disc degeneration.jpg|right|thumb|100px|<small><center>Intervertebral disc degeneration (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]

*Occurs mainly in dogs

*Occurs mainly in dogs

*Almost always '''dorsal''' protrusion due to eccentric position of [[Joints - normal#Fibrocartilagenous joints|''nucleus pulposus'']]

*Almost always '''dorsal''' protrusion due to eccentric position of [[Joints - Anatomy & Physiology#Fibrocartilagenous joints|''nucleus pulposus'']]

*Main sites are '''cervical and lumbar''' regions

*Main sites are '''cervical and lumbar''' regions

**Thoracic vertebrae have [[Joints - normal#Fibrocartilagenous joints|conjugal ligaments]]

**Thoracic vertebrae have [[Joints - Anatomy & Physiology#Fibrocartilagenous joints|conjugal ligaments]]

*Degeneration precedes protrusion (two patterns):

*Degeneration precedes protrusion (two patterns):

**'''Chondroid'''

**'''Chondroid'''

*Pathogenesis:

*Pathogenesis:

**Repeated abnormal movement between joints -> stress

**Repeated abnormal movement between joints -> stress

** -> Degeneration of [[Joints - normal#Fibrocartilagenous joints|''annulus fibrosis'']]

** -> Degeneration of [[Joints - Anatomy & Physiology#Fibrocartilagenous joints|''annulus fibrosis'']]

** -> [[Musculoskeletal Terminology - Pathology|Osteophyte]] formation

** -> [[Musculoskeletal Terminology - Pathology|Osteophyte]] formation

*In dogs usually no symptoms

*In dogs usually no symptoms