1. Anatomy of the Horse Presentation Part 2: Muscular Structure #8893-A

2. Muscles Move by contracting and relaxing As muscle contracts, it pulls a bone The opposite muscle or muscles relax and allow the bone to move

3. Muscles

4. Muscles – Neck Neck muscles should be long, smooth, and flat – Increases ease and freedom of moment in forelegs

5. Muscles – Forearm Forearm muscles should be long and lean and attach close to the knee – Allows for long strides and freedom of movement

6. Muscles – Back and Loin Help support weight of riders Lack of muscling will lead to swayback

7. Muscles – Back and Loin Different breeds = Different types of muscling – Powerful quarterhorses – large, bulging muscles – Speedy thoroughbreds – long, tapering muscles Thoroughbred Quarterhorse

8. Muscles - Tendons Muscles are attached to bones by tendons As muscle contracts, tendon resist stretching and pulls on attached bone

9. Muscles - Tendons Must be strong and tight Responsible for moving horse ’ s feet Weak tendons = lameness and unsoundness

10. Organs of the Thoracic Cavity Thoracic – area between the neck and abdomen Ribs form the sides of the cavity Contains vital organs of the circulatory and respiratory system

11. Organs of the Thoracic Cavity

12. Thoracic Cavity - Heart Lies towards bottom of cavity inside the sternum 4 chambers

13. Thoracic Cavity - Heart Racehorses have larger hearts – Require more oxygen – Heart enlarges to pump more blood to supply oxygen

14. Thoracic Cavity - Lungs Lie to the sides of and behind the heart Fill most of thoracic cavity Exchange of oxygen and carbon dioxide takes place

15. Thoracic Cavity - Lungs Must be large and functional Efficiency allows horses to exercise long and hard