EQUINE ANATOMY AND PHYSIOLOGY

1) Time led to a horse that had a lot of strength and endurance with a tremendous 
    ability to run. -Able to cover large distances for food and water and elude predators
2) Very unique skeletal structure 
    a) Long thin legs with sloping shoulders and buttocks for running 
    b) Hard strong hooves for covering many miles 
    c) Small diameter legs take a lot of pounding, twisting, turning and jumping which
     makes lameness and injury very common-Fractures, founder, navicular disease, 
     tendon and ligament injuries.

Wide, deep chest and abdomen
1) Heart and lung capacity
2) Storage of a large volume of feed for energy

Relatively small brain ruling a very, very powerful body
    -Don't assume horses will reason.  They can be extremely dangerous.

Gastrointestinal System
1) Massive molars for chewing
    -Grinding action breaks food down into small easily digestable particles
2) Single stomach with a large cecum for bacterial fermentation 
    a) Allows them to digest massive amounts of grass (cellulose) 
    b) Horses need to eat constantly to obtain enough energy fo work They like to graze
     ~ 18 hours per day.
3) Horses have a very long intestinal system 
    a) -70 feet of small intestine 
    b) ~ 25-30 feet of large intestine
4) Long intestinal system can lead to problems- Colic 
    a) Horses cannot vomit- only one way for feed material to go 
    b) Many twists and turns with wide and narrow spots 
         -Predisposed to obstruction (clogging up)

Head/Skull 
1) Teeth 
    a) Incisors- 12 total, 6 upper and 6 lower- Used for tearing grass 
    b) Molars- 24 total,+/-wolf teeth 
        1) Not all horses have wolf teeth 
        2) Wolf teeth have very short roots making them easily irritated by a bit
2) Eyes 
    a) Very good vision 
    b) Blindspot- directly in front and directly behind them. 
    c) Nasolacrimal Duct-For drainage of tear production

Vertebral Column
1) 7 Cervical vertebrae (neck)
2) 18 Thoracic vertebrae (back)
3) 6 Lumbar vertebrae (loin)
4) 5 Sacral vertebrae (croup)
5) 18 coccygeal vertebrae (tail)

Ribs-18 total
1) 8 True ribs- attached to sternum
2) 10 Floating ribs- attached to one another

Thoracic Limb (front leg)- Bears 65-70% of horses weight
1) Scapula- shoulder blade
2) Humerus
3) Radius/Ulna 
    a) Radius (forearm) 
    b) Ulna (elbow)
4) Carpus (knee of horse) comparable to human wrist 
    -7 or 8 individual bones
5) Metacarpus III (cannon bone) 
    -Metacarpus II and IV (splint bones)
6) Sesmoid bones
    - Act as a fulcrum for tendons
7) First Phalanx (long pastern bone)
8) Second Phalanx (short pastern bone)
9) Third Phalanx (coffin or pedal bone)
10) Navicular bone

* Large muscle mass down to the level of the knee. Below the knee is composed primarily of skin, tendons, and ligaments.
* Most important structures run down the back of the leg, with the exception of joints.

Pelvic Limb- Bears 30-35% of weight- Primarily for propulsion forward
1) Pelvis
2) Femur
3) Stifle joint (human knee)
4) Patella (knee cap)
5) Tibia (Fibula also present in some horses)
6) Hock- 4 joints 
    -Most important joint in the horse- Source of majority of rearlimb lameness
* All structures below the hock are the same as on the front leg

Hoof- Most important structure on the horse.
("No Foot, No Horse") Growth ~ 1/8-1/4" per month
Source of majority of front leg lameness
1) Toe
2) Quarter
3) Heel
4) Wall- Bears most of the weight
5) Sole- should be concave (dished)
6) Bar- Adds more support to the hoof (stabilizer)
7) Frog- Acts to pump blood in and out of the hoof, absorbs concussion, and helps 
    prevent slipping.
8) White Line- Junction of wall and sole Neutral zone between sensitive and 
    non-sensitive tissue (Horseshoe nails go thru)

Back