Anatomy Lesson, Part 2

If you caught yesterday’s MSL (Anatomy Lesson, Part 1), you’ll know we examined anatomical nomenclature. And now that you’re all whizzes on the names that describe “where” specific anatomy of the horse occurs, it’s time to jump into the horse’s skeletal system.

Today I also thought it might be helpful to identify the parts of the horse’s skeletal structure and see how its frame compares to that of the human skeleton. Of course, large differences occur (for example, our two legs compared to that of the horse’s four,) but there are several bones in our bodies that perform similar functions to those of the horse.

So without further adieu, let’s get to it!

   Common Name                                     Anatomical Term
Forearm                                                       Radius
Knee                                                             Carpal Joint (Carpus)
Cannon Bone                                             3rd Metacarpal
Splint Bones                                              2nd & 4th Metacarpal
Fetlock                                                       Metacarpolphalangeal Joint
Pastern                                                       Interphalangeal Joint
Long Pastern Bone                                  1st Phalanx (Proximal)
Short Pastern                                           2nd Phalanx (Middle)
Coffin Bone                                              3rd Phalanx (Distal)

Radius – The larger of the two bones of the forearm. The radius is the main central bone that attaches to the humerus at the approximal end and articulates with the carpal bones at the distal end.

Knee – The horse’s knee/carpus is made up of 2 rows of bones with four bones in each row. These bones are located very close to the horse’s skin and there is very little movement within the bones. As humans, we have carpal bones as well, but ours are located in our wrist.

Cannon Bone – This is the strongest bone in the horse’s body. Articulates with the 2nd row of carpal bones and forms the carpal/metacarpal joint. Distally articulates with the long pastern bone and joins with the fetlock joint.

Splint Bones – These bones in the horse are rudimentary structures and although they are present, they don’t serve much of a useful purpose anymore as a result of evolution. The splint bones are attached by the interosseous ligaments to the cannon bone. As humans, we have metacarpal bones in our hands.

Fetlock – The fetlock serves as an attachment part for the distal part of the suspensory ligament and is subject to a lot of stress and strain.

Pastern – The portion of the horse’s foot occupied by the first and second phalanges (#7 Long Pastern Bone and #8 Short Pastern). As humans, we have phalanges too: our fingers and toes.

Coffin Bone – Or 3rd phalanx, is entirely enclosed by the hoof. The general shape of the bone conforms to the hoof itself and it is intimately related to the deep digital flexor tendon.