Regional nerve blocks
Four regional nerve blocks are commonly used to provide local analgesia to the different regions of the oral cavity. These
blocks have confusing nomenclature in that the block may refer to the region blocked or the actual nerve that is blocked.
This discussion suggests simplification and clarification of nomenclature to describe the region affected rather than the
Two blocks exist for the maxilla. The rostral maxillary infiltrates the infraorbital nerve prior to exiting the infraorbital
canal. The caudal maxillary anesthetizes both the infraorbital nerve and pterygopalatine nerve caudal to the second maxillary
molar. The regional mandibular blocks include two blocks as well. The caudal mandibular infiltrates the inferior alveolar
nerve on the lingual aspect of the mandible prior to its entry into the mandibular canal. The rostral mandibular anesthetizes
the inferior alveolar nerve within the mandibular canal via the mental foramen.
Photo 2: Rostral maxillary (infraorbital) block. Retraction of the infraorbital neurovascular bundle in a dorsal direction
allows for the needle to pass ventral to the bundle to enter the infraorbital foramen.
The regional nerve blocks for oral surgery are similar for the dog and the cat. Some anatomical differences do exist, however.
Variations in the approach to the cat will be described following the discussion of these four regional blocks for the dog.
The proposed new names are followed by the often-confusing traditional names of these blocks in parentheses.
Photo 3: Proper needle placement for the rostral maxillary block on a skull.
Rostral maxillary (infraorbital) regional block
The rostral maxillary block provides infiltration of the lidocaine/bupivicaine combination adjacent to the infraorbital nerve
and the rostral maxillary alveolar nerve within the infraorbital canal (Photos 2 and 3). The latter leaves the inferior alveolar
nerve within the canal to enter the incisivomaxillary foramen to innervate the canine and incisor teeth. In addition, the
first three premolar teeth, as well as the maxillary bone and surrounding soft tissue, are affected.
Photo 4: Caudal maxillary (maxillary) block. The mouth is opened wide and the needle passed into the mucosa caudal to the
maxillary second molar.
To perform this block, retract the lip dorsally. Palpate the infraorbital neurovascular bundle beneath the vestibular mucosa.
This is a large cylindrical band that exits the infraorbital canal dorsal to the distal root of the maxillary third premolar.
The thumb of one hand can be used to retract the bundle dorsally.
Photo 5: Cadaver specimen demonstrating needle placement for the caudal maxillary block. The needle is adjacent to the infraorbital
nerve and the pterygopalatine nerve and its ventral branches.
With the opposite hand, the needle is advanced close to the maxillary bone ventral to the retracted bundle in a rostral-to-caudal
direction to a point just inside the canal. The needle should pass without engaging bone. If bone is encountered, the needle
is withdrawn slightly and redirected until it passes resistance-free into the canal. Proper insertion can be confirmed by
gentle lateral movement of the syringe whereby the needle will meet resistance with the lateral canal wall.