Posterior superior alveolar nerve
Encyclopedia
The posterior superior alveolar branches (posterior superior dental branches) arise from the trunk of the maxillary nerve just before it enters the infraorbital groove
; they are generally two in number, but sometimes arise by a single trunk.
They descend on the tuberosity
of the maxilla
and give off several twigs to the gums and neighboring parts of the mucous membrane
of the cheek
.
They then enter the alveolar canals
on the infratemporal surface
of the maxilla
, and, passing from behind forward in the substance of the bone, communicate with the middle superior alveolar nerve
, and give off branches to the lining membrane of the maxillary sinus
and gingival and dental branches to each molar tooth from a superior dental plexus
; these branches enter the apical foramina at the roots of the teeth.
The posterior superior alveolar nerve innervates the second and third maxillary molars, and two of the three roots of the maxillary first molar (all but the mesiobuccal root). When giving a Posterior Superior Alveolar nerve block, it will anesthetize the mesialbuccal root of the maxillary first molar approximately 72% of the time.
Infraorbital groove
Not to be confused with the inferior orbital fissure, which is just lateral to the infraorbital groove.Also not to be confused with the infraorbital canal, into which the groove enters, nor the infraorbital foramen, which is the canal's opening on the other side.Near the middle of the posterior...
; they are generally two in number, but sometimes arise by a single trunk.
They descend on the tuberosity
Maxillary tuberosity
At the lower part of the infratemporal surface of the maxilla is a rounded eminence, the maxillary tuberosity, especially prominent after the growth of the wisdom tooth; it is rough on its lateral side for articulation with the pyramidal process of the palatine bone and in some cases articulates...
of the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
and give off several twigs to the gums and neighboring parts of the mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
of the cheek
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
.
They then enter the alveolar canals
Alveolar canals
The infratemporal surface of the maxilla is pierced about its center by the apertures of the alveolar canals, which transmit the posterior superior alveolar vessels and nerves....
on the infratemporal surface
Infratemporal surface of the body of the maxilla
The infratemporal surface is convex, directed backward and lateralward, and forms part of the infratemporal fossa.It is separated from the anterior surface by the zygomatic process and by a strong ridge, extending upward from the socket of the first molar tooth...
of the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, and, passing from behind forward in the substance of the bone, communicate with the middle superior alveolar nerve
Middle superior alveolar nerve
The middle superior alveolar nerve is a nerve that drops from the infraorbital portion of the maxillary nerve to supply the sinus mucosa, the roots of the maxillary premolars, and the mesiobuccal root of the first maxillary molar....
, and give off branches to the lining membrane of the maxillary sinus
Maxillary sinus
The pyramid shaped maxillary sinus is the largest of the paranasal sinuses, and drains into the nose. It is present at birth as rudimentary air cells, and develops throughout childhood.-General characteristics:...
and gingival and dental branches to each molar tooth from a superior dental plexus
Superior dental plexus
The superior dental plexus is a nerve plexus which supplies the upper jaw.Formed by posterior superior alveolar nerve, middle superior alveolar nerve, and anterior superior alveolar nerve....
; these branches enter the apical foramina at the roots of the teeth.
The posterior superior alveolar nerve innervates the second and third maxillary molars, and two of the three roots of the maxillary first molar (all but the mesiobuccal root). When giving a Posterior Superior Alveolar nerve block, it will anesthetize the mesialbuccal root of the maxillary first molar approximately 72% of the time.