CT examination of the guttural pouch (auditory tube diverticulum) in Przewalski’s Horse (Equus przewalskii).

The research article discusses a CT examination of the guttural pouch in Przewalski’s Horse, a unique wild horse variety, and compares its structure to the guttural pouch in a domestic horse.

Introduction to the Study

• The research paper revolves around a study conducted to analyze the structure of the guttural pouch, or auditory tube diverticulum, in Przewalski’s Horse (Equus przewalskii). This particular breed was selected for its distinction as the only true wild horse species currently in existence.
• The guttural pouch in horses is a saccate (or bag-like) bulge of the auditory tube and is typically symmetrical in structure.
• The researchers utilized computerized tomography (CT) scans to obtain an in-depth look at the guttural pouch of Przewalski’s Horse.

Findings from CT Examination

• The CT examination revealed that like its domestic counterpart, Przewalski’s Horse retains significantly large and symmetrical guttural pouches.
• These guttural pouches feature division into medial and lateral compartments, with the stylohyoid bone acting as the separator.
• In contrast to the domestic horse, the right and left guttural pouches in Przewalski’s horse meet at the middle to form a thin septum instead of separate fully-enclosed spaces.
• Closer examination towards the occipital condyle part of the CT sections demonstrated the disappearance of the lateral compartment. Simultaneously, the medial compartment size gradually receded until reaching the base of the skull.

Conclusions

• The diminution of the medial compartment towards the base of the skull and absence of the lateral compartment near the occipital condyle region implies a lack of development of the nuchal-basal section of the medial compartment in Przewalski’s Horse, in comparison to the domestic horse.
• This difference highlights the physiological variations in the structure of the auditory tube diverticulum between wild and domestic horse breeds.