The zygomatic branch of the auriculopalpebral nerve: can it be normally palpated in the live horse?

This study provides a technique to locate and touch the zygomatic branch of the auriculopalpebral nerve in horses, which can be used to administer local anaesthetic for eye examinations and treatments.

Objective of the Research

• The study aims to provide a detailed method to locate and palpate (touch) the zygomatic branch of the auriculopalpebral nerve in live horses. This nerve is subcutaneous, meaning it is situated or applied under the skin.

Methodology

• The researchers designed a method and tested it on ten adult horses. They were able to successfully locate and touch this nerve in nine out of these ten horses.

Results and Applications

• Once the nerve is located, veterinarians can inject a local anaesthetic with precision along the nerve branch at the indicated location.
• The successful application of anaesthetic results in akinesis – loss of muscle movement – of the m. orbicularis oculi, a muscle in the eyelid that controls blinking.
• This also causes the elimination of the blink reflex, the automatic closing of the eye when it is touched or when a sudden movement is detected.
• This facilitation is crucial for performing thorough ophthalmologic examinations. It also assists in the treatment of certain eye conditions, as it allows for easier access and less discomfort for the horse during the process.

Conclusions

• The research introduces a practical method for veterinary ophthalmology to administer local anaesthetic to horses, improving the efficiency and efficacy of eye examination and treatment procedures. Yet, based on the findings, the technique may not be applicable to all horses as it didn’t work in 1 of the 10 subjects tested.