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

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

Muscles

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

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

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

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

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

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

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

Organs of the Thoracic Cavity

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

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

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

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