Right and left pouches are separated dorsomedially by rectus capitis ventralis and longus capitis muscles. The medial retropharyngeal lymph node lies between the pharynx and ventral wall of the pouches. The floor lies mainly on the pharynx and beginning of the Oesophagus. It is covered laterally by the Pterygoid muscles, parotid and mandibular glands. The Guttural Pouch is located below the cranial cavity, towards the caudal end of the skull/wing of atlas. The auditory tube connect the nasal cavity and middle ear and the diverticulum dilates to form pouches which can have a capacity of 300-500ml in the domestic horse. The guttural pouches are paired ventral diverticulae of the eustachian (auditory) tubes, formed by escape of mucosal lining of the tube through a relatively long ventral slit in the supporting cartilages. The Guttural Pouch is present only in members of the order Perissodactyla (nonruminant ungulates: horses, tapirs, rhinoceros) and another small band of small mammals including Hyraxes, certain bats and a South American mouse.
