The posterior superior alveolar branches (posterior superior dental branches) arise from the trunk of the

maxillary nerve In neuroanatomy, the maxillary nerve (V) is one of the three branches or divisions of the trigeminal nerve, the fifth (CN V) cranial nerve. It comprises the principal functions of sensation from the maxilla, nasal cavity, sinuses, the palat ...

just before it enters the

infraorbital groove The infraorbital groove (or sulcus) is located in the middle of the posterior part of the orbital surface of the maxilla. Its function is to act as the passage of the infraorbital artery, the infraorbital vein, and the infraorbital nerve. St ...

; they are generally two in number, but sometimes arise by a single trunk. They descend on the

tuberosity In the skeleton of humans and other animals, a tubercle, tuberosity or apophysis is a protrusion or eminence that serves as an attachment for skeletal muscles. The muscles attach by tendons, where the enthesis is the connective tissue between the ...

of the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

and give off several twigs to the

gums The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health. Structure The gums are part of the soft tissue lin ...

and neighboring parts of the

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...

of the

cheek The cheeks ( la, buccae) constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the insi ...

. They then enter the

alveolar canals The alveolar canals are apertures in the center of the infratemporal surface of the maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two max ...

on the infratemporal surface of the

, and, passing from behind forward in the substance of the bone, communicate with the

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. It is not al ...

, and give off branches to the lining membrane of the

maxillary sinus The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210 Structure It i ...

and gingival and dental branches to each

molar tooth The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

from a

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. See also * Inferior dental plexus The inferior denta ...

; these branches enter the

apical foramina In dental anatomy, the apical foramen, literally translated "small opening of the apex," is the tooth's natural opening, found at the root's very tip—that is, the root's apex—whereby an artery, vein, and nerve enter the tooth and commingle w ...

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.

See also

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References

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