Temporal & infratemporal regions II
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The trigeminal nerve divides into three major branches - ophthalmic, maxillary, and mandibular nerves. These branches innervate the face and associated structures. The maxillary nerve passes through multiple foramina and fossae, supplying structures like the orbit, palate, nasal cavity and upper lip. The mandibular nerve divides into anterior and posterior branches that innervate muscles like the masseter and tissues of the lower face and oral cavity. Key ganglia like the pterygopalatine and otic relay parasympathetic fibers to glands like the parotid.
Temporal & infratemporal regions II
- 1. Temporal & Infratemporal Regions II Dr. Prabhakar Yadav Associate Professor Department of Human Anatomy B.P. Koirala Institute of Health Sciences
- 2. Course of the Trigeminal Nerve • Leaves anterior aspect of the pons as a small motor root and a large sensory root. • Passes forward out of the posterior cranial fossa and rests on the upper surface of the apex of the petrous part of the temporal bone in the middle cranial fossa. • Sensory root expands to form Trigeminal ganglion, which lies within a pouch of dura mater called trigeminal or Meckel cave.
- 3. Course of Trigeminal Nerve • Ophthalmic, maxillary, and mandibular nerves arise from anterior border of the ganglion . • V1,V2 contains only sensory fibers and leaves skull through superior orbital fissure & foramen rotundum respectively • V3 contains both sensory and motor fibers and leaves skull through the foramen ovale. • V1 & V2 runs in lateral wall of cavernous sinus.
- 4. V2: • run in wall of cavernous sinus • leave through rotundum • enter pterygopalatine fossa • enter orbit through inferior orbital fissure & acquires name- Infra orbital nerve • leave orbit through infraorbital foramen & • emerge on face. Maxillary div supply: lower eyelid, conjunctiva, skin of cheek, maxillary sinus mucosa, nasal cavities mucosa, upperlip, incisior canine & molar upper. Superior part of palate.
- 5. In Midddle cranial fossa: Middle meningeal nerve In pterygopalatine fossa: Ganglionic branch Zygomatic ----- a. zygomaticotemporal; b.Zygomaticofacial Posterior superior alveolar In infraorbital canal: a. Middle superior alveolar , b.Anterior superior alveolar On face: a. Plapebral, b. Nasal, c.Labial
- 6. In Middle Cranial Fossa Meningeal branch: Supplies dura mater of middle cranial fossa. In Pterygo-palatine Fossa Ganglionic branches: two in number to pterygopalatine ganglion.
- 7. In Pterygo-palatine Fossa Zygomatic nerve: enters the orbit through inferior orbital fissure and divides into: (a) zygomaticotemporal branch: supply skin of temple (b) zygomaticofacial branch: supply skin of face. Posterior superior alveolar nerve: supplies mucus membrane of maxillary air sinus. Form superior dental plexus, which supplies molar teeth & adjoining part of the gum. superior dental plexus: Formed by posterior,middle, and anterior superior alveolar nerves. Situated in alveolar process of maxilla above the sockets of the teeth.
- 8. In the Orbit (infraorbital canal) Middle superior alveolar nerve: supplies premolar teeth. Anterior superior alveolar nerve: divides into dental and nasal branches: (a) Dental branches: supply canine & incisor teeth. (b) Nasal branches: supply mucosa of lateral wall and floor of the nasal cavity.
- 9. On the Face 1. Palpebral branches: supply skin of lower eyelid 2. Nasal branches: supply skin of side of nose & mobile part of nasal septum. 3. Superior labial branches: supply skin and mucus membrane of upper lip.
- 10. MANDIBULAR NERVE : -Largest divisions of trigeminal nerve. -- -Mixed nerve & nerve of first pharyngeal arch. -Sensory root arises from lateral part of trigeminal ganglion & leaves cranial cavity through foramen ovale. -Motor root lies deep to trigeminal ganglion, passes through foramen ovale to join sensory root just below foramen, forming the main trunk. -Main trunk lies in infratemporal fossa, on tensor veli palatini, deep to lateral pterygoid. -Main trunk divides into a small anterior trunk & large posterior trunk
- 11. Mandibular Nerve: Trunk: 1.Meningeal(Nervus-spinosus) 2. Nerve to medial pterygoid Anterior division: 1. Masseteric 2. Deep temporal 3. Lateral pterygoid 4. Buccal Posterior division: 1. Auriculotemporal 2. Lingual 3. Inferior alveolar 4. Nerve to mylohyoid
- 13. Meningeal Branch or Nervus Spinosus: Supplies- dura mater of middle cranial foss Nerve to Medial Pterygoid Supplies-medial pterygoid It gives a motor root to otic ganglion which does not relay & supplies tensor veli palatin & tensor tympani Masseteric Nerve. Supplies- masseter, temporomandibular joint Deep Temporal Nerves: Supplies-temporalis. Nerve to Lateral Pterygoid: Buccal Nerve supplies – skin & mucous membrane related to buccinator - labial aspect of gums of molar & premolar teeth
- 14. Auriculotemporal Nerve: Distribution: (a) Auricular branches- skin of tragus, upper part of pinna, external auditory meatus & tympanic membrane. (b) Articular branches - temporomandibular joint. (c) Superficial temporal branches- skin of temple. (d) It’ssecretomotor fibres - parotid gland.
- 15. Lingual Nerve Terminal branches of posterior division of mandibular nerve. Distribution: (a) Provides sensory supply to floor of mouth, lingual surface of the gum and anterior two-third of tongue (b) Carries preganglionic secretomotor fibres to submandibular & sublingual salivary glands.
- 16. Inferior alveolar nerve: Larger terminal branch of posterior division of mandibular nerve. It is a mixed nerve Branches: (a) Nerve to mylohyoid: It pierces sphenomandibular ligament to reach mylohyoid groove. It supplies mylohyoid and anterior belly of digastric muscle. (b) Dental branches supply molar and premolar teeth. (c) Mental nerve: supply skin of chin and skin & mucus membrane of lower lip. (d) Incisive branch: supplies canine and incisor teeth.
- 17. OTIC GANGLION: Parasympathetic ganglion, located at infra- temporal fossa, just below foramen ovale. Topographically related to mandibular nerve but functionally related to glossopharyngeal nerve. It provides a relay station to the secretomotor fibres to the parotid gland. Relations Lateral: Mandibular nerve. Medial: Tensor palati muscle. Posterior: Middle meningeal artery. Anterior: Medial pterygoid muscle.
- 18. Connections and Branches: secretomotor or Parasympathetic root: formed by lesser petrosal nerve. Preganglionic parasympathetic fibres arise from inferior salivatory nucleus, passes successively through glossopharyngeal nerve, tympanic branch of glossopharyngeal nerve (Jacobson’s nerve), tympanic plexus, and lesser petrosal nerve to relay in the ganglion. Postganglionic parasympathetic fibres from ganglion pass through auriculo-temporal nerve to supply parotid gland.
- 19. Connections and Branches: •Sympathetic root: - vasomotor in function • derived form plexus on middle meningeal artery which contains post ganglionic fibres arising in superior cervical ganglion. •Fibres pass through otic ganglion without relay and reach parotid gland via auriculotemporal nerve •Sensory root: sensory to the parotid gland- from auriculotemporal nerve •Somatic motor: Nerve to medial pterygoid passes through ganglion without relay to supply medial pterygoid, tensor palati, and tensor tympani muscles.
- 20. Pterygopalatine Ganglion (Sphenopalatine Ganglion) Ganglion of Hay fever: •Largest parasympathetic peripheral ganglion. Location upper part of the pterygopalatine fossa, suspended from maxillary nerve by two short roots. Relations Behind: Pterygoid canal. Above: Maxillary nerve. Medial: Sphenopalatine foramen.
- 21. •serves as a relay station for secretomotor fibres to lacrimal gland & mucus glands of nose, palate, pharynx & paranasal sinuses. •Topographically, related to the maxillary nerve, but functionally connected to facial nerve through greater petrosal nerve
- 23. Connections: Motor or parasympathetic root : formed by nerve of pterygoid canal. It carries preganglionic fibres from superior salivatory & lacrimatory nuclei. Preganglionic fibrs pass through facial nerve, geniculate ganglion, greater petrosal nerve & nerve of pterygoid canal to reach ganglion. Postganglionic fibres arise in ganglion to supply secretomotor nerves to lacrimal gland and to mucous glands of the nose, palate, pharynx & paranasal sinuses.
- 24. Sympathetic root: formed by nerve of pterygoid canal. It contains postganglionic fibres from superior cervical sympathetic ganglion which pass through the internal carotid plexus, deep petrosal nerve and the nerve of the pterygoid canal to reach the ganglion. Postganglionic fibres pass through the ganglion without relay and provide vasomotor supply to the mucus membrane of the nose, palate, pharynx, and paranasal air sinuses.
- 25. Sensory root: is derived from maxillary nerve and passes through the ganglion without relay to be distributed through the branches of the ganglion.
- 26. Branches Branches of the ganglion are actually branches of the maxillary nerve. They also carry parasympathetic and sympathetic fibres which pass through the ganglion. Orbital branches: pass through inferior orbital fissure supply - periosteum of orbit, and orbitalis muscle Palatine branches: Greater palatine – pass through greater palatine canal Supply- Hard palate & labial aspect of upper gums . Lesser & posterior palatine nerves: supply- soft palate & tonsil
- 27. Nasal branches (posterior superior nasal nerves ): pass through sphenopalatine foramen to enter nasal cavity. divided into two sets- lateral and medial. Lateral set supply lateral wall of nasal cavity Medial set supply roof & nasal septum. •Nasopalatine/ sphenopalatine nerve – Longest branch of medial set. Runs anteroinferiorly on the nasal septum and leaves the nasal cavity through incisive foramen. Enter oral cavity & supplies anterior part of hard palate. pharyngeal branch: passes through palatovaginal canal supply- nasopharynx.
- 28. Lacrimal branch: Postganglionic fibres pass back into maxillary nerve to leave it through its zygomatic nerve and its zygomaticotemporal nerve, a communicating branch to lacrimal nerve to supply secretomotor fibres to the lacrimal gland.
- 29. Applied Anatomy: The allergic conditions eg. cold, cause irritation of nerve of pterygoid canal/pterygopalatine ganglion, which causes congestion of glands of the nose and palate, and lacrimal gland producing running nose & lacrimation. The condition is called hay fever. Inferior alveolar nerve block (1A block): most common nerve block performed in dentistry to carry out dental procedures on the mandibular teeth. Anesthetic agent is injected slightly superior to the entry of inferior alveolar nerve into the mandibular foramen.