Horse muscles rely on their skeletal framework for support. This diagram gives an overview of the bones that make up your horse’s body.
The axial skeleton comprises the skull, vertebral column, sternum, and ribs. Muscles often act in pairs: one flexes a joint while the other extends it.
Chest
The chest area of a horse, which houses and protects their lungs, is supported by 18 sets of ribs that connect between neighboring thoracic vertebrae via synovial joints. Of these 18 pairs, eight pairs are considered true ribs because they attach directly to the sternum, while the remaining ten pairs are known as false ribs. The sternum allows expansion and contraction as it breathes while protecting viscera such as its heart, which lies equidistant from both ends of its chest cavity.
The stomach lies between the esophagus and small intestine, entirely within the rib cage, and has an average capacity of 5-15 liters in horses. Its interior contains glandular layers that produce acid to aid digestion, while it’s surrounded by non-glandular regions where microbes thrive.
Horses are obligate nasal breathers, meaning that they cannot breathe through their mouth, which helps explain why they cannot vomit. Air enters through the nostrils into the nasopharynx, which passes into the larynx and then the trachea before entering the lungs, supported by the rib cage and diaphragm muscle, which extends across the chest.
As the horse moves forward, its hindquarters weight is transferred to its forequarters through its lumbar spine. This spine features up to 30 centimeter-long spinous processes at its top that can be felt as knobbly bumps along its length, creating the withers. These processes serve as extensive attachment points for muscle and ligament attachment as well as acting as pivot points that enable movements at their withers.
Horse limbs, with their long, strong bones and wide pads, are perfectly designed for fast running, making long strides possible when running. Each stem possesses 20 bones in its appendicular skeleton, while the axial skeleton includes the skull, spinal column, sternum, and ribs – protecting vital organs while providing structure to soft parts of their bodies while also being capable of storing minerals and producing red blood cells.
Barrel
The barrel area of a horse spans from behind its withers to its hindquarters, comprising large muscles prone to injury due to their size and use. A horse’s gait relies heavily on this muscle group for balance; with proper knowledge of this region’s anatomy and usage, staff can more accurately communicate any changes or injuries experienced with an animal to a veterinarian.
The esophagus, the portion of the throat that brings food to the stomach, measures four or five feet long. This organ is connected with its target organ by a muscular ring known as the cardiac sphincter that connects at an oblique angle to allow horses to expel food through swallowing rather than vomiting; horses, therefore, must drink water to remove any debris clogging their throats and expel what has become lodged within it.
Horses’ digestive systems feature a relatively sizeable small intestine divided into the duodenum, jejunum, and ileum. Their stomach contains digestive juices as well as various acids and the enzyme pepsin, which help break down food into amino acid chains – another critical reason why horses must have access to clean water sources.
Contrary to humans, horses don’t connect the back of their leg to its fetlock joint through a tendon; instead, it is attached by a bone called the coffin bone, which can become vulnerable to deformities like cow hocks and founder. When this occurs inside their hoof, it causes extreme lameness that requires extensive vet care for rehabilitation.
Tendons are cords of connective tissue that connect muscles to bones and cartilage, transmitting muscle force into movement through their attachment. Some tendons only flex or extend one joint; others, like those on horses’ front legs (flexor tendons), can flex multiple joints (e.g., flexion of fetlock, pastern, coffin joint). Unfortunately, horses may experience issues like rotator cuff disease or tendonitis that causes their tendons to lose elasticity over time.
Flank
As a horse owner, understanding equine anatomy is critical to providing your horses with optimal training. Knowing their physique allows you to notice any anomalies more quickly and provide more effective care. Equine anatomy encompasses numerous body systems; understanding how they all interact is essential for maintaining normal body functions. Gaining some basic knowledge will enable you to better take care of the horses you reside with while giving them safe and comfortable lives.
Humans refer to this area of their flank as their withers. The components that compose it include the scapula (shoulder blade), radius, and ulna. The scapula is an oval flat bone with the ability to flex upward to 80 degrees at its shoulder joint (scapulohumeral joint), while its elbow joint enables downward angling up to 45 degrees. Meanwhile, the radius connects directly with the humerus via the elbow joint; additionally, the ulna forms part of this area as part of its wither formation.
A horse’s chest should be firm but not prominent; otherwise, it could weigh down and fatigue quickly, becoming slower in performance as a result. Furthermore, having too narrow a chest can be detrimental in terms of efficiency as it indicates poor nutrition or development.
Just like humans, horses breathe through their noses. Air enters nasal passageways before traveling through larynxes to the lungs via the larynx. Their head structure includes the crown of the head (top part of the skull) and neck. Mane and forelock cover this part while eyes sit directly in front.
The hind legs of horses are powerful, enabling them to move faster and jump farther. Shorter than their front counterparts, these back legs are supported by the fetlocks connected to kneecaps (carpus) in their legs; additionally, the hock is composed of nine bones that come together into three joints that allow limb extension/flexion freely.
Ribs
The horse rib area is another critical aspect of their body. While humans only possess 12 pairs of ribs, horses have 18 compared to just 12 for humans. These 18 pairs of ribs attach at their topmost points to 8 of the chest vertebrae and bottom ends to the sternum; these help the horse breathe by creating a protective bony cage around their heart and lungs, vital for optimal health. Eight out of 18 of these ribs feature cartilage, while two solid ones connect directly with their respective sternums; these 18 pairs form part of their health as a whole!
Like other parts of a horse’s anatomy, its ribs move and can be compressed by tight saddles and overly large girths. Ribs also contain muscles that help breathe easily – together with an active diaphragm; healthy ribcages enable horses to run, jump and play freely.
Other key areas include the neck, which has seven cervical vertebrae that join at the withers; croup, the space between hind feet that contains five interconnected vertebrae that cannot bend; and tail, which hangs down from behind pelvis with 15-20 tail vertebrae.
Horse front legs resemble human legs in several respects, yet are more significant due to more joints and their unusual carpus or knee joint structure that comprises two rows of three primary bones arranged on either side. This intricate joint, featuring multiple facets for stability and balance, plays an integral part in maintaining soundness and athleticism among horses.
Horse hoofs are much larger than human feet but made from the same protein-rich solid substance- keratin-which gives it its resilience and toughness. Each hoof wall supports the second and third phalanx of each lower leg phalanx, similar to what humans see with fingernails or toenails; however, this wall is thicker and more resilient so that it can withstand more pressure than human ones.
