Key points at a glance:
- The equine skeleton consists of approximately 205 bones and forms the basis for all movement
- Horses do not have a collarbone—the rib cage is connected to the forelimbs only by muscles
- The thoracic sling musculature is crucial for allowing a horse to carry a rider in a healthy way
- Tendons transmit muscular force to the bones, while ligaments stabilize the joints
- A basic understanding of anatomy helps prevent training errors and supports long-term equine health
The musculoskeletal system: a fascinating interaction
Anyone who wants to ride and train a horse in a healthy way cannot avoid basic anatomical knowledge. The equine musculoskeletal system is a complex network of bones, joints, muscles, tendons, and ligaments that must work together in perfect coordination. Every movement, every step, and every exercise places demands on this system—and only by understanding how it functions can overload be avoided and the horse’s long-term health be preserved.
The skeleton: more than just a framework
The skeleton of an adult horse consists of approximately 205 bones connected by joints. It fulfills several essential functions: it gives the body shape and stability, protects vital organs such as the heart and lungs, and serves as the attachment point for muscles. At the same time, the joints between the bones allow the mobility the horse needs for its natural movement patterns.
The spine forms the central element of the skeleton. It consists of seven cervical vertebrae, 18 (17–19) thoracic vertebrae, six (5–rarely 7) lumbar vertebrae, five (rarely 4 or 6) fused sacral vertebrae, and 15 to 21 caudal vertebrae. While the cervical spine is highly mobile and allows the horse to move its head in all directions, the thoracic and lumbar spine are significantly more stable and only moderately flexible. This stability is essential for carrying the rider’s weight without excessive strain on the spine.
A unique feature: horses have no collarbone
One anatomical feature makes the horse truly unique: it has no collarbone. While in humans and many other mammals the collarbone connects the shoulder girdle to the rib cage, in horses the entire rib cage is suspended between the shoulder blades solely by muscles, tendons, and ligaments. This construction is known as the thoracic sling.
This unique anatomy has far-reaching consequences for training. The rib cage hangs, so to speak, in a muscular corset between the forelimbs. For a horse to carry a rider in a healthy way, this musculature must be strong enough to lift and stabilize the rib cage. If the thoracic sling musculature is too weak, the rib cage sinks between the shoulder blades—with serious consequences for the horse’s overall posture and health.
Muscles: the most important groups for training
For training purposes, the horse’s musculature can be roughly divided into three particularly relevant groups:
The thoracic sling musculature consists mainly of the abdominal muscles, the chest muscles, and the so-called wither lifters. These muscles are responsible for lifting and stabilizing the rib cage. They must work actively for the horse to be able to round its back and carry the rider’s weight in a healthy way. A well-developed thoracic sling is the fundamental prerequisite for sound riding.
The back muscles, especially the long back muscle (longissimus dorsi) running along both sides of the spine, are—contrary to common belief—not weight-bearing muscles but movement muscles. They contract alternately as the horse moves its limbs forward and should work in a relaxed, elastic manner. If they remain constantly tense and are forced to support weight because the thoracic sling is too weak, serious back problems will result.
The hindquarter muscles include the muscles of the croup, thigh, and lower hind limb. They form the engine of the horse and are responsible for the propulsion that moves the horse forward. Well-developed hindquarter musculature enables the horse to take on weight and achieve collection.
Tendons and ligaments: connection and stability
Tendons are fibrous structures that connect muscles to bones. They transmit the force generated by the muscle to the skeleton, enabling movement. Tendons are highly resistant to tension but also susceptible to overload. The flexor tendons of the limbs, in particular, are frequently affected by injuries when horses are trained too intensively or incorrectly.
Ligaments, on the other hand, connect bones to each other and stabilize the joints. One especially important ligament system is the nuchal–supraspinous ligament system, which runs from the poll along the entire spine to the sacrum. It plays a central role in allowing the horse to round its back. When the horse lowers its head and stretches forward and downward, the nuchal ligament is stretched, and this tension is transferred to the supraspinous ligament. As a result, the spine is stabilized and the back can lift—an essential prerequisite for carrying the rider in a healthy way.
Why anatomical knowledge matters in daily training
Understanding these anatomical foundations is not theoretical knowledge reserved for veterinarians or physiotherapists—it has very practical implications for everyday training. Those who know that the thoracic sling musculature, rather than the back muscles, carries the horse will structure training differently. Those who understand that the nuchal–supraspinous ligament system must be stretched to allow the back to lift will recognize the importance of the stretching posture. And those who are aware of the limits of tendons and ligaments will avoid overloading their horse.
Many training mistakes and health problems in horses arise from a lack of understanding of anatomical relationships. A horse that consistently moves with a high head and hollow back will inevitably develop problems because it is working against its anatomy. A young horse that is subjected to too much weight too early, before its musculature is sufficiently developed, will suffer long-term damage. Anatomy sets clear boundaries—and those who know and respect them can give their horse a long, healthy life as a riding partner.
