Intermediate Anatomy: Skeleton

You're in a dressage lesson and your coach tells you your horse is bending at the third vertebrae. Do you smile and thank her celebrating because it's finally working after months of effort? Or do mutter "yeah I know" under your breath while surreptitiously trying to fix it before she has to tell you *again*? To answer that question you need to know two things: the basic skeleton of the horse, and dressage theory 101. We only have time for the skeleton today -- dressage theory will be another Thursday, so for now I'll just tell you you're probably not celebrating. Perhaps, once you know the skeleton, you'll be able to figure out why.



Unfortunately the diagram was way to crowded with labels, so had to go with numbers. It's all good though cause now I have all the room in the world for explanations!

First of all, the skeleton (205 bones total -- I'm only expecting you to remember 29 -- aren't you lucky!) is divided into two groups:

The Axial Skeleton - which gives the horse its shape
The Appendicular Skeleton - which is the basis for locomotion.
Take a look at the skeleton and see if you can ascertain which numbers fall into which group. Yes of course I'll tell you eventually, but you're more likely to remember if you at least try to think of it yourself first!

1 - Skull (houses a fist-sized brain. This one should be a gimmie... Alas, poor Yorick... Imagine how different that scene would be with this skull!)
2 - Mandible (basically the jaw -- slightly bigger than yours, but same concept!)

Numbers 3-7 comprise the vertebral column. But some sections have more flexibility than others so it's important to know how they divide up. Also, anybody taking riding or PC tests I would be willing to wager it will eventually be a test question. Examiners love it.

3 - Cervical Vertebrae (7)
4 - Thoracic Vertebrae (18)
5 - Lumbar Vertebrae (6)
6 - Sacral (5) -- not sacred as I once saw on a test!
7 - Caudal Vertebrae (15-21)
8 - Ribs. 18 pairs of them to be precise. And just to complicate things, there are 8 "true" pairs and 10 "false". The true ribs are attached to the sternum while the false are not. I remember that from my once rather cynical viewpoint that there are more false people in the world than true... Sad, but true? Either way I never have to look it up.
9 - Sternum

You are now at the end of the Axial Skeleton. Were you right? Did you even think about it at all? If so, congrats! You're in the minority :) And we all know that's where the kewl kids hang out!

So if the Axial Skeleton is comprised of all that is above, it follows that all below will be the Appendicular Skeleton.

10 - Humerus (points to the elbow. Funny bone anybody?)
11 - Scapula
12 - Ulna
13 - Radius (again following basic human anatomy of the arms)
14 - Carpal bones (7 or 8 of them)
15 - Metacarpal bones (3 of them -- more commonly known as the cannon bone and 2 splint bones)
16 - P1 (aka first phalanx)
17 - P2 (aka 2nd or middle phalanx)
18 - take a guess, I dare ya >;-P Yes indeed, it's P3 (aka any of: third phalanx, coffin bone, pedal bone ) This bone is entirely in the hoof along with the navicular bone and P2.
19 - anywhere??? oh my I appear to have lost 19. It's a sad, sad day in the world of Theory Thursdays. I evidently can't count to 20, but I can ride a horse *really* well >;-P On the plus side, it's one less bone for you to memorize. Woohoo! Maybe we can pretend Navicular was 19. The arrow would be pointing to the other side of the hoof from 18.
20 - Sesamoid bones (x 2)

21 through 23 are all really fused together to form the hip. But that's another of those silly exam questions people love so just-in-case, I've included them anyway (after all, have to make up for the missing 19!)

21 - Ilium
22 - Pubis
23 - Ischium
24 - Femur (so now we're doing the legs)
25 - Patella
26 - Fibula
27 - Tibia
28 - Tarsal bones (6)
29 - Metatarsal bones (3) - again with the cannon and 2 splints.

Et al - all the various Px of the hindleg are the same as the front leg, so I'm going to be kind and only have you memorize them once :) You're welcome!

Now that you know all that, what's the point? The skeleton has several functions:

• provide rigidity and form
  
• provide protection to vital organs
  
• facilitate movement
  
• allow locomotion to take place

Well now that was fun and exciting wasn't it?