Peterson’s Nerve Block Eye enucleation is a fairly common procedure in cattle, and this technique will provide analgesia of the eye and orbit and immobilization of the globe. Indications : Surgical management of conditions of eyeball, eye lid and horns. Following nerves except for the optic nerve, pass through the orbital foramen and can be blocked by this technique..  Auriculopalpebral branch (motor) of the facial nerve (VII).  Oculomotor (III), trochlear (IV), and abducens (VI) nerves - motor innervation to the ocular muscles.  Maxillary branch of the trigeminal nerve (V).– sensory, innervates lower eyelid, soft and hard palate, the nasal cavity, maxilla and adjoining bones, the maxillary sinus, and the region supplied by the infraorbital nerve.  Ophthalmic branch of the trigeminal nerve – sensory, innervates the horn, upper eyelid, third eyelid, medial canthus, caudal part of nasal septum, cornea sclera, and frontal sinus.  Optic nerve (II). Technique  Anesthetic is deposited anterior to orbital foramen.  Locate the notch formed by the supraorbital process, the zygomatic arch, and the coronoid process of the mandible.  Insert a 12-15 cm l8 gauge needle at this notch and direct it horizontally for 7-11 cm until it strikes the pterygopalatine fossa (make sure the needle is kept horizontal and that it is directed perpendicular to a sagittal plane through the head.) Withdraw the needle slightly and deposit l5 mL of 2% lidocaine. An additional l5 ml of lidocaine should be deposited slightly caudodorsally.  This does not block the auriculopalpebral nerve so to keep the animal from blinking this nerve should be anesthetized separately.  The animal will be blind in the blocked eye and will not blink. The upper eyelid will droop and the globe will protrude.  If the eye is not being removed, an ophthalmic ointment should be applied to the eye.