The equine ear is notoriously difficult to examine. Peter Green MRCVS looks at a new technique that might one day change all that
Horses ears are blamed for all sorts of problems, including difficulties with getting the bridle on and head shaking.
Yet the ear is notoriously difficult to examine. Most horses hate having anything poked down there. Even strong sedation fails to abolish the reflex that makes a horse shake his head when you stimulate inside the ear. In addition, the ear canal takes a sharp right-hand bend into the bony tunnel at the side of the head before the eardrum.
Vets at Leipzig in Germany recently described a technique for proper examination of the ear. They worked out that it is important to numb the ear by injecting local anaesthetic around 2 nerves at its base. These can be identified by palpation and by scanning the side of the head with an ultrasound probe. When the ears were numb, they used a very narrow flexible endoscope to look down into the ear and around the corner to the eardrum.
The vets examined 23 warmbloods in this way, none with any history or suspicion of ear problems. The examination technique proved excellent, but what the vets found was surprising.
A third of the horses had an abnormal narrowing of the ear canal caused by excess bone. 3 had canals blocked by some kind of soft tissue growth and 3 had blockages caused by excessive wax and debris.
The results suggest that even apparently normal horses may have ear problems. We don’t know whether any of the discovered abnormalities affected hearing or caused irritation, but we do now have a reliable examination technique if such problems are suspected.