APPLIED ANATOMY OF MAXILLARY

NERVE

Presented by Anirban Mallik(B.D.S. 3rd year)

INTRODUCTION

It is the nerve of maxillary process, that differentiates from first pharyngeal arch.

It is purely sensory; and is intermediate in size between ophthalmic and mandibular nerve.

ORIGIN

Sensory root fibers of trigeminal nerve comprises of the central processes of ganglion cells located in trigeminal ganglion.

Sensory root fibers enter the concave portion of each crescent and the three sensory divisions of trigeminal nerve exit from the convexity.

The 2nd sensory division among these three is Maxillary Nerve.

It originates from the middle part of trigeminal ganglion in middle cranial fossa.

Fig 1: Origin and Course of Maxillary nerve

COURSE

It gives off meningeal branch in middle cranial fossa which is sensory.

The nerve runs forwards through lower part of lateral wall of cavernous sinus.

The lateral wall here fuses with endosteal layer of dura mater at lateral margin of foramen rotundum.

It has a short course below the root of pterygopalatine fossa to inferior orbital fissure.

As it crosses pterygopalatine fossa, it gives off its main branches to pterygopalatine ganglion, posterior superior alveolar nerve and zygomatic branches.It then angles laterally in a groove on posterior surface of maxilla, entering the orbit through inferior orbital fissure.

Within the orbit it occupies the infraorbital groove and becomes infraorbital nerve which courses anteriorly into the infraorbital canal.

The maxillary nerve emerges on anterior surface of face through infraorbital foramen.

INNERVATION Lo

wer

ey

elid

an

d ch

eek

Nose

Upper

lip

Maxillary

teeth,

Nasal mucos

a,Hard palate Pharynx, tonsil.

Maxillary,

ethmoid and

sphenoid sinuses, m

enin

ges.SENSORYINNERVATION

BRANCHES

Maxillary nerve gives off branches in four regions:

1. Within the cranium2. In the pterygopalatine

ganglion3. In the infraorbital canal

4. On the face.

Branches Within the Cranium: Middle Meningeal Nerve: Immediately after separating from

trigeminal ganglion, the maxillary nerve gives off a small branch, middle meningeal nerve.

It travels with middle meningeal artery. It provides sensory innervation to the dura mater of anterior half of middle cranial fossa.

Branches in the Pterygopalatine Fossa:

i. Pterygopalatine nerves

ii. Zygomatic nerves

iii. Posterosuperior alveolar nerves.

Pterygopalatine nerves: Two short nerves, that suspend the pterygopalatine ganglion.

They pass through the ganglion into its branches and also serve as a communication between pterygopalatine ganglion and maxillary nerve.

By way of ganglion, the maxillary nerve hasthe four branches carrying sensory,secretomotor and sympathetic fibers.

1.Orbital branches: Supply periosteum of orbit. 2.Nasal branches: Supply mucous membranes superior and middle conchae, the lining of

posterior ethmoidal sinus and posterior portion of nasal septum. These convey postganglionic parasympathetic fibers from pterygopalatine ganglion to nasal glands.

I. Nasopalatine nerve (long sphenopalatine nerve)II. Posterior superior lateral nasal nerves (short

sphenopalatine nerves)3. Palatine branches:

a. Greater palatine nerves (or anterior palatine nerves) b. Lesser palatine nerves (or middle and posterior palatine nerves).

These branches provide sensory innervation to hard and soft palate. These branches also convey postganglionic parasympathetic fibers from pterygopalatine ganglion to palatal glands.

4. Pharyngeal branch: It provides sensory innervation to nasopharynx.

Zygomatic Nerves: It provides sensory innervation to skin over zygomatic region.

These nerves also convey postganglionic parasympathetic fibers from pterygopalatine ganglion to lacrimal nerve and glands.

It is a terminal branch. The zygomatic nerve enters zygomatic

bone anddivides into two branches

a. Zygomaticotemporal nerve: It perforates temporal surface of zygomatic bone, pierces

temporalis fascia and supplies skin above zygomatic arch (skin of side of forehead or the “hairless” skin of temple).b. Zygomaticofacial nerve: It perforates the facial surface of zygomatic bone and supplies skin over the bone (skin over the prominence of cheek). It carries secretomotor fibers from pterygopalatine ganglion for lacrimal gland.

Posterosuperior Alveolar Nerves:

These nerves are two to three in number. These descend from the main trunk of the

maxillary nerve in the pterygopalatine fossa just before the mandibular division enter inferior alveolar canal.

They emerge through the pterygomaxillary fissure.

One of it’s branch provides sensoryinnervation to buccal gingiva in maxillary molar region and adjacent facial mucosal surfaces.

Other branch enters maxilla (along with a branch of internal maxillary artery) through the posterior or posterolateral wall of maxillary sinus, and provides sensory innervation to mucous membrane of sinus.

Continuing downward, this second branch provides sensory innervation to alveoli, periodontal ligaments and pulpal tissues ofmaxillary molars, with the exception of (25%) patients of mesiobuccal root of first molar.

Branches in the Infraorbital Canal:In the infraorbital canal, the maxillary division gives two branches: 1. Middle superior alveolar nerve 2. Anterior superior alveolar nerveIt supplies multiple small branches through orbital plate of maxilla to roof of maxillary sinus. 1. Middle superior alveolar nerve: It supplies adjacent mucosa of maxillary sinus; two premolars and mesiobuccal root of first molar, periodontal tissues, buccal soft tissue and bone in premolar region.

2.Anterior superior alveolar nerve: It is relatively larger branch. Within the anterior wall of maxillary sinus, provides innervation to central and lateral incisors and the canines as well as sensory innervation to periodontal tissues, buccal bone and buccal gingiva of these teeth. In patients where middle superior alveolar

nerve is absent, the anterior superior alveolar nerve provides sensory innervation to premolars and occasionally the mesiobuccal root of first molar.

Branches on the Face:

Infraorbital nerve emerges on the face through infraorbital foramen, lies between levator labii superioris and levator anguli oris, divides into its terminal branches.

i. Inferior palpebral supply skin of lower eyelid with sensory innervation to both surfaces of conjunctiva.

ii. External nasal/lateral nasal provides sensory innervation to skin on lateral aspect of nose

iii. Superior labial provides sensory innervation to skin and mucous membrane of whole of upper lip (and sometimes also the adjacent gingiva from midline to second premolar teeth).

Infraorbital nerve has many communications with local branches of 7th cranial nerve, i.e. facial nerve, these are for proprioceptive supply of nearby facial muscles.

APPLIED ANATOMY

Maxillary nerve has an important role in Anesthesia.

Maxillary Anesthesia is of three types- 1.Local Infiltration 2.Field Block 3.Nerve Block

Small terminal nerve endings in the area of the

dental treatment are flooded with local anesthetic

solution.

Incision is then made into the

same area in which the local anesthetic has been deposited

1.Local Infiltration

Local anesthetic is deposited

near the larger terminal nerve

branches.

Incision is then made into an

area away from the site of

injection of the anesthetic.

Maxillary injections administered above the apex of the tooth to be treated are properly termed field blocks

2.Field Block

Local anesthetic is deposited close to a main nerve trunk,

usually at a distance from the site of operative intervention.

Posterior superior alveolar, inferior alveolar, and

nasopalatine injections are examples of maxillary nerve

blocks.

3.Nerve Block

Types of Injections:

Supraperiosteal (infiltration)Periodontal ligament (PDL, intraligamentary)Intraseptal injectionPosterior superior alveolar nerve blockMiddle superior alveolar nerve blockAnterior superior alveolar nerve blockGreater (anterior) palatine nerve blockNasopalatine nerve blockMaxillary (second division) nerve blockAnterior middle superior alveolar nerve blockPalatal approach-anterior superior alveolar nerve block

Supraperiosteal Injection

Nerves anesthetized– terminal branch of dental plexus

Areas anesthetized Entire region innervated by the large

terminal branches of this plexus

Posterior superior alveolar nerve block Nerves Anesthetized-

Posterior superior alveolar and its branches Areas Anesthetized-

1) Pulps of the maxillary 3rd , 2nd and 1st molars 2) Buccal periodontium and bone overlying these

teeth

Anterior superior alveolar(ASA) nerve block Nerves anaesthetized

1. ASA nerve2. MSA nerve3. Infraorbital nerve – inferior palpebral -- lateral nasal -- superior labial

Areas anaesthetized1. Pulps of maxillary C.I. through canine on the injected side2. Pulps of maxillary premolars(72% of patients) &

mesiobuccal root of the molar

Middle Superior Alveolar Nerve BlockNerves anaesthetized: MSA & terminal

branchAreas anaesthetized

1. Pulps of maxillary 1st & 2nd premolar & mesiobuccal root of 1st molar(28%)

2. Buccal periodontal tissues & bone of these teeth

Greater palatine nerve block

Nerves anesthetized Greater palatine nerve

Areas anesthetized Posterior portion of the hard palate &

its overlying tissues Anteriorly as far as the 1st premolar

& medially to the midline

Nasopalatine Nerve Block

Nasopalatine nerve block is an invaluable technique for palatal pain control.

In this administration of a minimum volume of anesthetic solution (maximally, one quarter of a cartridge), a wide area of palatal soft tissue anesthesia is achieved, thereby minimizing the need for multiple palatal injections.

Anterior middle superior alveolar nerve block

Nerves anesthetized1. ASA nerve2. MSA nerve3. Subdural dental nerve plexus of the ASA & MSA

Areas anesthetized1. Pulpal anesthesia of maxillary C.I. canines & premolars2. Buccal attached gingiva of these same teeth3. Attached palatal tissues from midline to free gingival margin on

the associated teeth

Maxillary nerve block

Nerve Anesthetized Maxillary division of the trigeminal nerve.

Areas Anesthetized 1. Pulpal anesthesia of the maxillary teeth on the

side of the block2. Buccal periodontium and bone overlying these

teeth3. Soft tissues and bone of the hard palate and

part of the soft palate, medial to midline 4. Skin of the lower eyelid, side of the nose, cheek,

and upper lip.

Fig: Maxillary nerve block, High-tuberosity approach

Palatal Approach-Anterior Superior Alveolar

Nerves Anesthetized: Nasopalatine, Anterior branches of the ASA

Areas Anesthetized: Pulps of the maxillary central incisors, the

lateral incisors, the canines Facial periodontal tissue associated with these

same teeth Palatal periodontal tissue associated with these

same teeth

Fig: Palatal Approach-Anterior Superior Alveolar Area of needle insertion

THE END