Page 181 - Manual of Equine Field Surgery
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Nerve Blocks for Ophthalmic Procedures 177
needle, inject 3 to 5 mL of 2o/o lidocaine along the
lateral third of the orbital rim. The zygomatic
nerve block is performed in the same manner, but
along the ventrolateral third of the orbital rim.
Zygomatic n.
The infratrochlear nerve is blocked by injecting 2
to 3 mL of 2% lidocaine over a notch palpated
along the ventromedial aspect of the orbital
•
rim.
The supraorbital foramen is located by grasp-
ing the rostral and caudal borders of the supraor-
bital process of the frontal bone using the thumb
and middle fingers. Moving the thumb and
middle finger medially as the process widens, the
index finger is used to palpate the depression of
the supraorbital foramen approximately halfway
Figure 32-1 Schematic demonstrating innervation between the middle finger and thumb. A 25-ga11ge
of the eyelids by the lacrimal, zygomatic, frontal and needle is passed subcutaneously to the opening of
infratrochlear nerves. the supraorbital foramen or into the supraorbi-
Palpebral n.
Figure 32-2 Schematic demonstrating palpebral nerve anatomy in relationship to the zygomatic arch and orbital
rim. F, Frontal; I, infratrochlear; L, lacrimal; Z, zygomatic.
