- A 3-month-old paint colt presents to you after flipping over backward while being led by the owner the previous day. Clinical signs at the time of presentation are shown in the image (head tilt, flaccid ear, muzzle deviation). Based on the history and clinical signs, what cranial nerves are damaged and what is the most likely diagnosis?
- Ans??
- Cranial nerves VII and VIII (left side); fracture of the basisphenoid bone
- The correct answer is damage to cranial nerves VII (facial nerve) and VIII (vestibular nerve) on the left side caused by fracture of the basisphenoid bone. This is a common injury when a fractious young foal rears up and falls backward on the poll. The basisphenoid bone becomes injured resulting in injury to cranial nerves VII and VIII. Damage to the facial nerve results in the muzzle deviation (opposite direction of the side of injury, in this case deviated to the right), ptosis of the left eye and drooping of the left ear. Damage to the vestibular nerve results in the head tilt.