#lower limb anatomy

[chaoticneutraltee]

[pkmedlectures-blog]

Hey everyone! come check out our latest video going over a standard model of the muscles, arteries and nerves of the foot!!

(via https://www.youtube.com/watch?v=uKhVXGh0eLk)

[pkmedlectures-blog]

Check out our latest video on cutaneous vessels of the lower limb!!

(via https://www.youtube.com/watch?v=f4YidSBk_-c)

[thescienceofequus]

Equine Navicular Syndrome

Navicular syndrome describes chronic forelimb lameness caused by pain stemming from the navicular bone.

[SOURCE]

Equine researchers and veterinarians speculate that approximately 90% of lameness in horses stems from the foot and that navicular syndrome is one of the most common causes of forelimb lameness in horses, But what exactly is navicular syndrome?

According to the Merck Veterinary Manual, navicular syndrome (or disease) is also called palmar foot pain, which simply refers to pain localized to the back of the foot. In fact, veterinarians use navicular syndrome as a "catch-all" phrase to describe horses with either ongoing recurrent pain stemming from the navicular bone and/or related structures. 

WHAT (AND WHERE) IS THE NAVICULAR BONE?

Despite its small size the navicular bone has a surprisingly complex structure function. In terms of anatomy, the navicular bone is a small, cartilage-covered, boat-shaped bone located at the back of the foot (palmar/plantar aspect) behind the coffin bone (third phalanx) and under the small pastern bone (second phalanx). The navicular bone, together with its synovial fluid filled bursa (a "sac" containing synovial/joint fluid), provides a fulcrum for the deep digital flexor tendon (DDFT) as it courses down the back of the foot. The tendon changes direction at the navicular bone before attaching to the bottom of the coffin bone. Several ligaments, such as the impar (distal sesamoidean) and collateral sesamoidean ligaments also help support the navicular bone. 

THE "FACE" OF NAVICULAR SYNDROME

Navicular syndrome is typically diagnosed in mature horses 4-15 years old. Geldings of Quarter Horse, Thoroughbred, and Warmblood breeds appear to be more commonly afflicted. Researchers believe a genetic component is involved, which may be linked to heritable conformation traits. A ban on breeding severely affected Warmblood stallions decreased the occurrence of navicular in Warmblood breeds.

MANY CAUSES OF NAVICULAR DISEASE

Enlarged synovial invaginations (pockets) in the navicular bone;

Erosion of the flexor surface of the navicular bone;

Bone loss or thinning of the distal margins of the navicular bone

A. Healthy navicular bone, B. Diseased navicular bone [ SOURCE ]

Fluid within the navicular bone;

Adhesions between the navicular bone and the DDFT or navicular bursa;

Adhesions between the DDFT and the impar ligament or suspensory ligament of the navicular bone;

Synovial proliferation and excessive fluid in the navicular bursa;

Fiber disruption (injury) or degeneration in the DDFT; and

Desmopathy (disease) of the collateral ligament of the distal interphalangeal joint (DIP, coffin joint).

Download the free PDF to read more about the many causes of navicular syndrome, its clinical signs, how navicular disease is diagnosed, and the treatment options available.