Bowed Tendons

STEVE: A bow tendon, first of all you need to know where it is located. This is the front limb of a horse. Externally, on the outside here, we are looking in this area right here. This is the tendon the deep and superficial flexor tendon right here running down the back of the limb. Okay.

Now, internally, what we see is this structure right here, the red, is the superficial flexor tendon and where it goes down here and attaches on the pastern. And the yellow on the inside is the deep flexor tendon.

Typically, it goes all the way down the back here, originates out of the forearm or the radius of the horse and it goes all the way down at the base of the coffin bone. Its action is to flex the entire lower limb, and pull it backwards.

Superficial does the same thing except it doesn’t attach as nearly as far down, it touches along the pastern. So, what we see is that throughout cycling concussion or throughout many, many repetitive cycles on extension on bearing weight and bring the limbs back forward, what ends up happening is this tendon structure, mainly the superficial, gets overstretched.

And when it gets overstretched, it essentially loses some of its shape and creates some hemorrhage and edema in it. What we call a bow tendon is the external clinical symptom of enlargement of mainly the superficial and/or the deep flexor tendon. And that is clinically what a bow tendon is.

One of the behavioral signs of bow tendon is lameness. They typically, when they are extremely bowed, they are extremely lame. They will limp and they will nod and they will show that there is a tremendous gaipe deficit associated with the injury of an acute bow tendon. And the reason why is because it creates a quite a bit of pain on extension of the limb when they go to place it on extension.

And if these fibers shorten up quite a bit, and of course it is enlarged and flaming and sore and hot, visually, palpably uncomfortable to them, and clinically they, like I said, it creates a tremendous amount of discomfort to them. So therefore, they are lame.