Pocket watch

YOU probably won’t hear about your horse’s guttural pouches until they cause a problem. Unique to a small number of animal species, these pockets of air are out-pouches of the eustachian tube – the duct that connects the middle ear to the pharynx (throat).

One pouch is located either side of the horse’s head, each with a volume of around 300 to 500ml, and in the healthy horse they contain nothing but air. They are lined with a thin membrane, under which lie some critical structures – major arteries, namely the internal and external carotids; four major cranial nerves; the stylohyoid bone, which divides each