# Assessing Salivary Ductal Structures of the Donkey (Equus asinus) Using Conventional Sialography and Its Practical Guide

## TL;DR

This study describes the salivary duct structures in donkeys using imaging and dissection to help diagnose and treat salivary gland issues in veterinary medicine.

## Contribution

The study provides the first detailed documentation of sialoradiography and macroanatomy of donkey salivary ducts.

## Key findings

- Lateral sialograms clearly outline the ductal structures of the parotid and mandibular glands in donkeys.
- The parotid duct opens against the crowns of the third and fourth premolar teeth and forms a single major duct.
- The study's findings can aid in diagnosing salivary gland pathologies and performing sialography in live donkeys.

## Abstract

Sialoradiography is an imaging technique that assesses the ducal macroanatomy and function of the major salivary glands (MSGs). Despite reports of salivary diseases in donkeys, no studies have documented detailed information on sialoradiography of the ductal structures. Therefore, this investigation aimed at describing the technique and ductal macroanatomy of the MSGs using sialoradiography, as well as the in situ macroanatomy of the salivary ductal structures in donkeys. Survey radiology and sialoradiography were conducted in lateral and dorsoventral oblique views, followed by cadaver dissection with colored latex injection to outline the MSGs' topographic macroanatomy in fourteen half-heads and the proximal cervical region of seven donkeys. The technique of cannulation, contrast media injection, and positioning for the sialoradiography in the donkey was thoroughly described. The extra- and intraglandular salivary ductal structures of the parotid and mandibular glands were clearly outlined only in lateral sialograms. Key macoanatomical findings included the rostral situation of the mandibular gland, a straight caudal edge of the parotid salivary gland (PSG), the absence of perforation of the PSG lateral aspect and its substance by the maxillary vein, and the superficial situation of the parotid duct (PD) on the body of the lower jaw rostral to in front of the masseter muscle, situation of the PD opening against the crowns of the third and fourth premolar teeth, and the formation of the single major PD at the rostrolateral aspect of the dorsal portion of PSG. The images and data reported in the current investigation may be utilized as basic information for veterinary clinicians, surgeons, and radiologists for (1) diagnosis of the MSGs pathologies and (2) aiding in performing sialography in live donkeys.