The anatomy of the tendons
The most important tendons are on the backside of the cannon bone. The most superficial one is, like the name says, the superficial flexor tendon. Directly beneath that is the deep flexor tendon.
When your horse has all his weight on the leg, the two tendons are hard to distinguish and feel like one cable. But if you lift the leg, you can feel the two tendons separate from each other.
In the top part of the cannon bone there is another ligament nearby the deep flexor tendon: the check ligament. This one merges about halfway through the leg with the deep flexor tendon.
Right beneath the two flexor tendons, behind the cannon bone, there is a tough cable: the suspensory ligament, or tendo interosseous.
When your horse uses his leg, it can almost be like bone. That’s how tough the structure feels like. The tissue of the suspensory ligament is more ligament than tendon.