Trigeminal Nerve Anatomy

Trigeminal Nerve - Maxillary Branch (V2)

• The maxillary branch (V2) is a division of the trigeminal nerve (CN V).
• It's a sensory nerve, meaning it carries information about touch, pain, and temperature.
• Its function also includes controlling muscles used in chewing.
• The trigeminal nerve is the largest cranial nerve.
• Knowledge of this nerve is vital for dental professionals.
• It has three divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3).

GDC Learning Outcomes

• Students should describe relevant dental, oral, craniofacial, and general anatomy.
• They should also explain how this anatomy applies to patient management.

Intended Learning Outcomes

• Describe the function of the maxillary branch of the trigeminal nerve (CN V).
• Outline the anatomical regions supplied by the maxillary branch.
• Explain the maxillary branch's relevance to dentistry.

Why Do I Need to Know This?

• Understanding the maxillary branch is crucial for dental procedures.

Resources

• Anatomy.tv (online resource)
• Acland's Video Atlas of Human Anatomy (online resource)
• Netter's Head and Neck Anatomy for Dentistry (book)
• Teach Me Anatomy (online resource)

Trigeminal Nerve

• The trigeminal nerve is the largest cranial nerve.
• It consists of three main divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3).
• The knowledge of the trigeminal nerve is very important in dentistry for professionals.

Nerve Roots

• Each trigeminal nerve is composed of two roots: a motor root (thinner) and a sensory root (thicker).
• Trigeminal nerves are responsible for sensing facial touch, pain, and temperature.
• Trigeminal nerves are also responsible for controlling muscles involved in chewing.
• The facial nerve (cranial nerve VII) controls other facial movements, which are distinct from the trigeminal nerve.

What is Supplied?

• Sensory (afferent) roots supply: Maxillary dentition, Mandibular dentition, Skin of the face and head, Oral mucosa, Nasal mucosa, Air sinuses, Meninges

• Motor (efferent) roots supply: Muscles of mastication (masseter, temporalis, medial pterygoid, lateral pterygoid, anterior belly of digastric), Mylohyoid, Tensor tympani, Tensor veli palatini

Brain Origin

• The trigeminal nerve originates from the pons of the brain stem.
• It has one motor nucleus and three sensory nuclei.

Pathway from Skull

• Ophthalmic branch exits the skull through the superior orbital fissure.
• Maxillary branch exits through the foramen rotundum, then the infraorbital canal into the infraorbital foramen.
• Mandibular branch exits via the foramen ovale.

Ganglion

• The three divisions of the trigeminal nerve connect at the Gasserian ganglion.
• Within the brainstem, signals travel through the trigeminal nerve to specialised clusters of neurons called the trigeminal nerve nucleus.

Ophthalmic Nerve (V1)

• The ophthalmic nerve is the smallest division of the trigeminal nerve.
• It's a sensory nerve that carries information to the brain through the superior orbital fissure of the sphenoid bone.
• It supplies the conjunctiva, cornea, eyeball, orbit, forehead, ethmoid/frontal sinuses, and portions of the dura mater.
• It has several branches (lacrimal, frontal, nasociliary).

Branches of Ophthalmic Nerve

• Lacrimal nerve: supplies conjunctiva and skin, responsible for tear production
• Frontal nerve: supplies mucous lining of frontal sinus, skin and conjunctiva of eyelid, forehead and scalp
• Nasociliary nerve: sensory to ciliary ganglion, long ciliary nerves, posterior ethmoidal nerve, anterior ethmoidal nerve, and infratrochlear nerve

Pterygo-maxillary Fissure

• The fissure is located between the maxilla and the pterygoid process of the sphenoid bone.
• It's a triangular gap between the lower ends of the medial and lateral pterygoid plates.
• The maxillary nerve passes through the pterygomaxillary fissure, entering through foramen rotundum.

Maxillary Nerve (V2)

• The maxillary nerve exits the skull via the foramen rotundum.
• It passes into the pterygopalatine fossa, dividing into branches: zygomatic, infraorbital, posterior superior alveolar, and pterygopalatine.
• It is only comprised of sensory fibres
• It supplies the maxillary teeth and supporting structures, hard and soft palates, and the maxillary sinus. Also supplies the skin covering the middle part of the face.

Infraorbital Nerve

• The terminal branch of the Maxillary nerve.
• It enters the orbit via the inferior orbital fissure.
• It runs in the infraorbital groove.
• Leaves the orbit through the infraorbital foramen.
• Branches include the middle superior alveolar nerve, anterior superior alveolar nerve, and terminal branches like palpebral, nasal, and labial.

Terminal Branches

• Palpebral nerve supplies skin of lower eyelid.
• Nasal nerve supplies skin of the side of the nose.
• Labial nerve supplies skin and oral mucosa of upper lip, labial gingivae, anterior maxillary teeth, and cheek overlying maxilla.

Posterior Superior Alveolar Nerve (C)

• It leaves pterygopalatine fossa through pterygomaxillary fissure.
• It runs to the tuberosity of the maxilla.
• It sends a branch to buccal gingivae of maxillary molars.
• It pierces bone to supply maxillary sinus and maxillary molar teeth.

Middle & Anterior Superior Alveolar Nerves (G)

• Arise from the infraorbital nerve in the orbit.
• Middle supplies the maxillary premolars and the mesiobuccal root of the first maxillary molar.
• Anterior supplies the maxillary incisors and canines.

Pterygopalatine Nerves

• The pterygopalatine nerves include greater palatine, lesser palatine, and nasopalatine nerves.
• They supply the hard palate, nasal cavity, and soft palate.

Greater Palatine Nerve

• Passes through greater palatine canal and greater palatine foramen.
• Supplies much of the mucosa on the hard palate and palatal gingiva.
• It has nasal branches that extend into the canal.

Lesser Palatine Nerve

• Passes through the greater palatine canal to reach the lesser palatine foramen.
• It supplies the soft palate.

Nasopalatine Nerve

• Enters nasal cavity via spheno-palatine foramen.
• Supplies a portion of the nasal septum.
• Passes through incisive canal on hard palate.
• Supplies oral mucosa around incisive papilla.

Zygomatic Nerve

• Travels anteriorly via inferior orbital fissure.
• Branches into zygomaticotemporal and zygomaticofacial nerves.
• innervates skin on prominence of cheek.

Summary of Trigeminal Nerve

• The trigeminal nerve has three main divisions: ophthalmic (V1), maxillary (V2), and mandibular (V3).
• The ophthalmic nerve travels through the superior orbital fissure.
• The maxillary nerve passes through the foramen rotundum.
• The mandibular nerve exits through the foramen ovale.

Trigeminal and Facial Nerve Examination

• A procedure to assess the trigeminal and facial nerves.

Quiz

• Students can use the provided link (https://app.sli.do/event/5tK3dJmSTbUD1sjvhsZiGc) for a quiz about the trigeminal nerve.

References

• Provided links for further study.

Test your knowledge of the trigeminal nerve (cranial nerve V). This quiz covers its branches (ophthalmic, maxillary, and mandibular), sensory and motor functions, and anatomical pathways through the skull. Learn about the innervation of the face, oral cavity, and related structures.