| + | The trachea begins at the larynx and ends at the hilus, where it divides into the left and right mainstem bronchi. The average length of the trachea in horses is 75-85cm and diameter is 5-6cm. It is comprised of 50-60 cartilagenous rings, which are incomplete dorsally. Between each ring is a '''tracheal annular ligament'''. The '''dorsal tracheal membrane''' lies on the inner surface of the cartilages and is composed of smooth muscle, mucosa and adventitia. Most of the trachea is cylindrical in shape, but the cervical part is flattened dorsally due to contact with the ‘’longus colli’’ muscle. |