Changes

===Carpal Joint===

===Carpal Joint===

The carpal joint is a compound joint composed of:

*The '''synovial membranes''' form three compartments corresponding to each joint. The proximal is the largest whilst the middle carpal and carpometacarpal sacs communicate and extend into the intermetacarpal articulations.

*The '''antebrachiocarpal joint''' between the radius/ulna and the proximal carpal bones

*The fibrous joint capsule is common to all three joints and  attaches to the individual bones and various intercarpal ligaments.

*The '''middle carpal joint''' between the two rows of carpal bones

*The '''extensor retinaculum''' is fibrous collagenous tissue on the dorsal aspect that allows passage of the extensor tendons.

*The '''carpometacarpal joint''' between the distal carpal bones and the proximal metacarpals

*On the palmar aspect lies the '''palmar carpal fibrocartilage''' that provides attachment for some metacarpal bones.

 

*Paired '''collateral ligaments''' bridge the sides of the three main articulations.

The joint is a synovial joint, comprised of a common outer fibrous capsule and three inner synovial pouches, one for each joint.  Numerous ligaments add to the stability of the joint and ensure movement is largely limited to the [[Planes and Axes - Anatomy & Physiology|sagittal plane]], although no collateral ligaments exist in the dog between the radius and the proximal metacarpals.  This allows a very small amount of rotation.

*The '''flexor retinaculum''' is the carpal fascia on the palmar aspect and lies between the accessory carpal bone and the medial aspect of the carpus. This with the joint capsule and medial surface of the accesory carpal bone makes up the '''carpal canal'''. It houses just the deep digital flexor tendon in the dog.

===Metacarpal Joint===

===Metacarpal Joint===