Carpus and distal thoracic limb

Joint capsule

-outer fibrous membrane

-inner synovial membrane-makes fluid

Articular cartilage

Joint cavity

Synovial fluid

What are the components of a synovial joint

Different levels of articulations. Different small joints within one larger joint group

Individual synovial compartments at each small joint

Common fibrous capsule that surrounds all the joints in the group

What is the genera structure of a compound or composite joint

Antebrachiocarpal joint (most movement)

Midcarpal joint

Carpometacarpal joint (least movement)

What are the synovial joint compartments of the equine carpus

Antebrachiocarpal joint does not communicate

Midcarpal and carpometacarpal joints communicate- fluid flows freely between them

What is the communication between the different synovial compartments in the equine carpus

Extensor retinaculum- holds together extensor tendons

Flexor retinaculum- holds together flexor tendons

What are the retinacula of the equine carpus

Prevents friction of the tendon as it glides overtop of a bony structure

What is the purpose of a tendon sheath

Flexor carpi ulnaris

Ulnaris lateralis short tendon (long tendon DOES have one)

Both insert on accessory carpal bone. No need for sheaths since they don't move over anything causing friction

What tendons of the equine carpal region do NOT have synovial tendon sheaths

Sheath: surrounds a decent portion of the tendon- no friction for tendons passing over an extended length surface

Bursa: small area of cushioning. Good for tendons passing over a small piece of bone

What is the difference between a synovial tendon sheath and a synovial bursa

Superficial digital flexor tendon

Deep digital flexor tendon

What structures are found inside the carpal canal

Located on the palmar aspect of the carpus

Contains SDF and DDF

Tendons are surrounded by carpal synovial sheath

Deep boundary (closest to bones): palmar carpal ligament

-smooths out caudal surface of carpal bones

Superficial boundary (closest to skin): flexor retinaculum

What is the structure of the carpal canal

Common digital extensor-> extensor process of P3

Lateral digital extensor

Interosseus muscle- suspensory ligament-> proximal sesamoid bones

Extensor branch of interosseus- fuses to common digital extensor tendon- indirect insertion on P3 extensor process

DDF-> flexor surface of P3

SDF-> distal end of P1, proximal end of P2

What are the tendons of the metacarpal area (6)

Suspensory ligament

-inserts on proximal sesamoid bones

Extensor branch of interosseus

-fuses to the common digital extensor tendon

-indirect insertion on P3 extensor process

What structures arise from the interosseus muscle

Extensor process of P3

Area of insertion for common digital extensor

Flexor surface of P3

Area of insertion for DDF

Distal end of P1

Proximal end of P2

Area of insertion for SDF

Palmar annular ligament- holds flexor tendons at fetlock level

Proximal digital annular ligament- x-shaped

Distal digital annular ligament- crescent-shaped

What are the annular ligaments of the metacarpal area

Palmar annular ligament

Suspensory ligament (from interosseus muscle)

Palmar ligament (intersesmoidean ligament)

Oblique sesamoidean ligament- to phalanges

Straight sesamoidean ligament- on midline

Cruciate sesamoidean ligaments

What are the ligaments of the fetlock region

Intersesamoidean ligament

Passes between proximal sesamoid bones

What is the palmar ligament

Triangular, sheet-like ligament

Goes to the phalanges

Deep to straight sesamoidean ligament

What is the oblique sesamoidean ligament

Located on the midline

Superficial to oblique sesamoidean ligament

What is the straight sesamoidean ligament

Originate from proximal sesamoid bones

Cross over to insert on the opposite proximal P1

X-shaped

Stabilize the fetlock

What are the cruciate sesamoidean ligaments

Digital cushion

Structure on the palmar aspect that cushions impact

Navicular bursa

(Bursa podotrochlearis)

Structure that reduces friction between the navicular bone and the DDF tendon

Bursa podotrochlearis

Lies between the navicular bone and DDF tendon

Reduces friction

What is the navicular bursa

Degenerative disease

Causes intermittent lameness

Can be chronic or acute

Can affect the navicular bone, navicular bursa, and/or DDF tendon-> inflammation

What is navicular syndrome

Navicular syndrome

Degenerative disease that can affect the navicular bone, bursa, and/or DDF tendon and cause intermittent lameness

Inflammation of the navicular bursa

Inflammatory process

Can cause lameness

Often due to penetrating wounds

What is navicular bursitis

Navicular bursitis

Inflammation of the navicular bursa

Strain and overexertion of the thoracic limb tendons

Requires rest to reduce swelling and pain

What are bowed tendons

Bowed tendons

Strain and overexertion of thoracic limb tendons