E Q U I N E D E N T I S T RY — A N I N T R O D U C T I O N
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How to perform nerve blocks
Dental blocks
Infraorbital nerve block
The infraorbital nerve is a sensory continuation of the maxillary branch of the trigeminal nerve. This nerve
supplies sensory innervation to the ipsilateral upper lip, cheek, and nostril as well as the upper incisors, canines
and premolars. Desensitisation of this nerve can greatly enhance procedures involving dental conditions and
has been advocated as a diagnostic aid in the evaluation of headshaking horses 4 .
The infraorbital foramen can be found in most horses by placing the ring finger on the rostral aspect of the facial
crest and the thumb in the nasal notch, dividing this distance in half with the middle and index finger the dorsal
rim of the foramen can usually be palpated two finger widths above dorsal to this line. In some horses the levator
naso labialis muscle will need to be pushed dorsally to palpate the foramen. There is great variation on the
diameter of the opening so it is beneficial to spend sometime palpating to determine how easy passing a needle
into the foramen is likely to be. The nerve block involves direct stimulation of the nerve while the practitioner is
directly in front of or near the front of the horse. Hence proper preparation and safety is essential to avoid serious
injury. The horse should be sedated and an opiod should be administered, it is advisable to place the horse in a
crush if available and a nasal twitch should ALWAYS be used. The horses head