0:35 This is Dr. Adel Bunduk, professor of anatomy, Mansour University, Egypt. Today I will talk about the trigeminal nerve. Okay, I will start with the deep origin of the trigeminal nerve or the deep nuclei. The trigeminal nerve has four nuclei, one motor nucleus, and the three sensory nuclei. The motor nucleus is present in the pons and it supplies muscles of mastication. The three sensory nuclei, one in the midbrain, one in the pons, and one in the medulla, and each
1:24 one has a specific function. The one in the medulla transmits pain and temperature sensation from the face. The one in the pons transmits touch sensation from the face and the one in the midbrain transmits proprioception from the muscles of the face sense of movement and sense of position. So the first nucleus is present in the medulla. It's called spinal trigeminal nucleus and it transmits pain and temperature sensation from the face. It is called spinal trigeminal nucleus because it descends in the spinal cord and becomes continuous with the substantia gelatinosa of Rolandi.
2:12 The second one is present in the bones and it's called the main sensory nucleus and it transmits touch sensation from the face. The third one present in the midbrain and it is called the mesencephalic nucleus and it transmits proprioceptive sensation from the muscles of the face. Therefore, the three sensory nuclei, one in the midbrain, mesencephalic nucleus, one in the palms, main sensory nucleus, one in the medulla, spinal trigeminal nucleus. Mesencephalic nucleus transmits proprioception, main sensory nucleus transmits touch, and the spinal trigeminal nucleus transmits pain and temperature sensation.
3:02 This is the trigeminal nerve trunk, and this is the trigeminal ganglion, and this trigeminal ganglion gives the three branches, one, two, and three. The first branch is the offsalmic nerve, and this offsalmic nerve is going to the superior orbital fissure. Second branch is the maxillary nerve and this maxillary nerve is going to the foramen rotundum. The third branch is the mandibular nerve and it is going to foramen ovale. I mentioned before that the offsylbic and the maxillary nerves run in the lateral wall of the cavernous sinus. This is the cavernous sinus while the mandibular nerve runs
3:51 outside. the cavernous sinus. Start by the off-cellumic nerve. Again, this is the trigeminal nerve trunk. This is the trigeminal ganglion. This is the off-cellumic, maxillary, and mandibular. The off-cellumic and maxillary nerves are pure sensory. The mandibular nerve is mixed nerve. Therefore, the off-cellumic nerve arises from the trigeminal ganglion. This is the trigeminal ganglion of selenic nerve arises from the trigeminal ganglion. It passes in the lateral wall of the cavernous sinus. Before the superior orbital fissure, it divides into
4:38 three divisions. These three divisions are lacrimal nerve to the lacrimal gland, frontal nerve, which gives the supratrochlear and supraorbital nerves to the scalp and upper eyelid and the nasociliary nerve. In the cranial cavity, the ofhthalmic nerve gives the meningeal branch to the dura. So again, the ofhthalmic nerve arises from the trigeminal ganglion. It passes in the lateral wall of the cavernous sinus. It divides into three divisions which pass through superior
5:24 orbital fissure it gives a meningial branch in the cranial cavity and the three divisions are lacrimal nerve frontal nerve and the nasociliary nerve this is the ofcelmic nerve the first branch of the ofcelmic nerve in the cranial cavity this branch is a meningial branch then it divides into three branches This one is going to the lacrymal gland. This is the lacrymal gland. So this is the lacrymal nerve. Second one, this one is the frontal nerve. And this frontal nerve divides into supratrochlear and this is the frontal nerve. This one, it gives it supratrochlear and supraorbital nerves.
6:10 And the third one, this one, this one, the nesociliary nerve. and we can see that it gives a branch to the ciliary ganglion. It gives posterior ismoidal and anterior ismoidal branches. We'll talk about them in the next slide. The frontal nerve again gives two branches, supratrochlear nerve to the scalp and upper eyelid, supraorbital nerve again to the scalp and upper eyelid. So the four branches of the off-cellinic nerve, meningial branch in the cranial cavity, and the three divisions lacrimal, frontal and nasociliary. So again the ofcelmic nerve gives the three branches or three divisions.
7:01 Lacrimal nerve to the lacrimal gland and upper eyelid. Second branch in the frontal nerve, this frontal nerve it gives supraorbital and supratrochlear nerves. which supplies upper eyelid and scalp and then this one is the nasociliary nerve this is the nasociliary nerve gives sensory root to the ciliary ganglion we'll talk about it in the next slide it gives the long ciliary nerves to the iris and the cornea and the long ciliary nerves also carry sympathetic fibers to the dilator pupilli okay long ciliary nerves it gives a posterior ismoidal nerve this posterior ismoidal nerve
7:48 to the sphenoid and ismoidal sinuses and the dura mater it gives anterior ismoidal nerve to the nasal cavity and dura mater and it gives infratrochlear nerve to the skin of the nose again this is a nasociliary nerve this one this nasociliary nerve gives Okay, sensory root to the ciliary ganglion. This is the ciliary ganglion. Okay, sensory root. It gives the long ciliary nerves. This long ciliary nerves carry sympathetic fibers to the theylator pupillary muscle and the sensory fibers to the cornea
8:34 and the iris. It gives the posterior ismoidal nerve, this one, to the sphenoid. and the ismoidal sinuses and the dura mater. It gives anterior ismoidal nerve to the nasal cavity and the dura mater. It gives the infratrochlear nerve to the skin of the nose. So the nasociliary nerve gives sensory route to the ciliary ganglion, lung ciliary nerves, posterior ismoidal nerve, anterior ismoidal nerve, and the infratrochlear nerve.
9:29 the maxillary nerve again this is a trigeminal nerve trunk this is a trigeminal ganglion and the three branches of the trigeminal ganglion of salmock maxillary and the mandibular this is of salmock nerve it travels from the cranial cavity to the face so it has a long course so the first station is that it passes through foramen rotundum This is foramen rotundum. Then it enters the trigopalotene fossa. Then passes through the trigomaxillary fissure. This
10:16 fissure. To enter the infratemporal fossa. Then it passes through the inferior orbital fissure. to continue as the infraorbital nerve, this one, which runs in the infraorbital groove, then infraorbital canal, then infraorbital foramen, where it divides into three terminal branches. Again, the course of the maxillary nerve, foramen rotundum, of course, lateral wall of the cavernous sinus, foramen rotundum, trigopilatine fossa, trigomaxillary fissure, infratemporal fossa, inferior orbital fissure,
11:05 infraorbital groove, infraorbital canal, and infraorbital foeamen. Regarding the branches and the distribution of the maxillary nerve, this is the first branch in the cranial cavity, so it is a meningeal branch to the dura. In the trigopalatine fossa, it gives two branches. First one, these two branches to the sphenopalotene ganglion, ganglionic branches. So ganglionic branches to the sphenopalotene ganglion. These ganglionic branches carry sensory fibers from the maxillary nerve to the sphenopalotene ganglion. And they also
11:50 carry parasympathetic fibers from the sphenopalotene ganglion to the lacrimal gland. We'll talk about this. when I talk about the facial nerve. Okay, so ganglionic branches to sphenoplatin ganglion. And then this branch, zygomatic nerve. This zygomatic nerve enters the inferior orbital fissure. It divides into two branches, zygomatico-facial nerve and zygomatico-temporal nerve. Zygomatico-facial nerve supplies the face. Zygomatico-temporal nerve supplies the temple and communicates with the lacrimal nerve. So branches in the trigopalatine fossa,
12:40 ganglionic branches to sphenopalatine ganglion and zygomatic nerve. The ganglionic branches carry sensory fibers from the maxillary nerve to the sphenopalatine ganglion and carry parasympathetic fibers from the sphenopalatine ganglion to the lacrimal gland. Second branch in the trichoplatine fossa, the egomatic nerve. Then in the infrant temporal fossa, it gives this branch, posterior superior alveolar nerve. It supplies the upper molar teeth. Okay. And then anterior middle superior alveolar nerve. This middle superior alveolar nerve supplies the upper premolar teeth. This is the infraorbital nerve.
13:30 It gives this one anterior superior alveolar nerve. This anterior superior alveolar nerve supplies the incisors and the canine teeth. Therefore, the three superior alveolar nerves are posterior to the upper three molar, the middle to the premolar, and the anterior to the incisors and the canine. In the infraorbital foramen, it gives the three terminal branches. Palpebral branch to the lower eyelid, nasal branch to the side of the nose, and the labial branch or superior labial branch to the
14:15 upper lip. Okay, so again, branches of the maxillary nerve. In the cranial cavity, in the cranial cavity, meningeal branch, to the dura, in the trigopalotene fossa ganglionic branches to the sphenopalotene ganglion and the zygomatic nerve. This zygomatic nerve divides into zygomatico-facial and zygomatico-temporal nerves. Then three superior alveolar nerves, posterior superior alveolar to the upper molar teeth, middle superior alveolar to the upper premolar teeth, anterior-sphere alveolar to the incisors and the canine. Then the three terminal branches at the infraorbital
15:03 foramen, palpebral branch to the lower eyelid, nasal branch to the side of the nose, and labial branch to the upper lip. talk about the mandibular nerve, which is a mixed nerve, unlike the ophthalmic and the maxillary nerves. This is the mandibular nerve. It contains the motor and the sensory fibers. Therefore, the mandibular nerve arises by two roots. Motor root, the red
15:53 one, from the motor nucleus in the pons, and the sensory root from the trigeminal ganglion. The two roots unite to form the mandibular nerve, which passes through the foramen ovary. Then it immediately divides into anterior division and posterior division. Therefore, when talking about the branches, branches from the trunk, branches from the anterior division, and the branches from the posterior division. Again, mandibular nerve arises by two roots. Motor root,
16:43 small, arises from the motor nucleus in the pons. Sensor root, large, arises from the trigeminal ganglion. The two roots pass through the foramen ovally, form the trigeminal nerve trunk, divide the into anterior division and the posterior division. Then we'll talk about the branches of the trunk, branches of the anterior division, which is smaller than the posterior division, and the branches from the posterior division. Branches from the trunk. The trunk gives the two branches, one motor, this one, and one sensory. The motor branch is to the medial trigoid muscle.
17:33 This is the medial trigoid muscle. This nerve to medial trigoid supplies three muscles. Of course, it supplies the medial trigoid muscle. The two other muscles are tensor palatii, this one, and tensor tympanii in the middle ear cavity. The second branch is sensory branch. This one is going back to the cranial cavity. Through the foramen spinosum, it's called the nervous spinosis, it supplies the dura mater. Again, branches around the trunk are two, motor and sensory. Motor to medial trigoid, it supplies three muscles, medial trigoid, tensor palatii, tensor tympanii.
18:23 Nervous spinosis is sensory, it passes through foramen spinosum with the middle meningial artery to supply the dura mater. Then the anterior division. The anterior division is mainly motor. The sensory branch is the bachal branch. So the motor muscular to all muscles of mastication except medial teregoid. We have four muscles of mastication. So three of them are supplied by the anterior division. Masseter, temporalis, and lateral teregoid. Okay. the medial trigoid is supplied from the trunk the sensory branch is called the buccal nerve or buccal branch
19:12 it supplies the skin and the mucous membrane opposite the buccinator muscle again the anterior division gives the muscular branches and sensory branch the muscular branches to masseter nerve to masseter deep temporal nerves to temporalis Trigoid branch to the lateral trigoid. And the buccal nerve to the skin and the mucous membrane opposite or over the buccinator. Then the posterior division. This is the posterior division. And this one is anterior division. The posterior division gives the three branches. This is the first one, auriculo-temporal nerve.
20:03 second one inferior alveolar nerve and the third one is the lingual nerve so the posterior division gives auriculi temporal, inferior alveolar and lingual actually the lingual nerve is joined by this branch from the facial nerve which is the chorda tympani so talk about the auriculi temporal nerve this one talk about the origin and the distribution it arises by two roots surrounding the middle meningeal artery okay two roots surrounding the middle meningeal artery this
20:51 auriculo-temporal nerve from its name auriculo-ear temporal temporal region so number one it gives the branches sensory branches or sensory fibers to the scalp, temporal region of the scalp, auricle, external auditory mitis, and outer surface of tympanic membrane. It gives the branches to the parotid gland. It gives the branches to the temporomandibular joint. So the first branches of the auriculo-temporal nerve are the sensory branches, supply,
21:36 scalp, auricle, external deuterium, outer surface of tympanic membrane, perenchyma of the parotid gland, and the temporomandibular joint. Actually, the auriculo-temporal nerve carries the parasympathetic fibers from the otic ganglion to the parotid gland. So the auriculo-temporal nerve contains sensory fibers and the polysympathetic fibers. Second branch is this one, the inferior alveolar nerve. This inferior alveolar nerve passes through the mandibular canal and it gives the three branches. This is the inferior alveolar nerve. The first branch is motor branch,
22:23 nervetomyelohyoid. It supplies myelohyoid muscle and anterior belly of the digastric muscle myelohyoid anterior belly of the digastric second branch this one the mental branch mental nerve it passes through the mental foremen to supply the chin and lower lip it gives incisive branch to supply the incisors and the canine teeth So the inferior alveolar nerve gives the three branches. Nerve to myelohyoid, to myelohyoid and the anterior below the gastric. Mental nerve to the chin and lower
23:14 lip. Incisive branch to the incisors and canine. Then the inferior, the lingo nerve. This is the lingo nerve. Talk about the landmarks. It is joined by this nerve, this branch from the facial nerve, which is the chorda tympani. Okay, and it passes below the last molar tooth. That's why extraction of the wisdom tooth might lead to injury of the lingual nerve. Distribution of the lingual nerve, lingual nerve itself, and the distribution of the chorda tympani. Lingual nerve carries general sensory fibers. from the anterior to the third of the tongue and the chorda tympani carries test fibers from the anterior to the third of the tongue chorda tympani
24:04 synapses in the submandibular ganglion and from the submandibular ganglion parasympathetic fibers supply the submandibular and sublingual salivary glands again distribution of the lingual nerve lingual nerve itself and chorda tympani fibers lingual nerve general sensation from the anterior to the third of the tongue chorda tympani This sensation from the anterior to the sides of the tongue and the parasympathetic fibers to the submandibular and the sublingual salivary glands. These parasympathetic fibers synapse in the submandibular ganglion. Again, summary of the branches of the mandibular nerve branches from the trunk branches from the anterior division and the branches from the posterior division. Anterior division gives the motor branch and sensory branch. The motor branch is nerve
24:55 to medial tergoid. and the sensory branch is nervous spinuses. Nerve to medial trigoid supplies three muscles, medial trigoid, tensor temporae and tensor palae. Nerve to masseter, temporalis, deep temporal nerves and lateral trigoid, pterigoid branches and the sensory branch of the anterior division is the buccal nerve and this buccal nerve supplies the skin and the mucous membrane over the buccinator. The posterior division is mainly sensory. It gives three branches, auricular temporal nerve, lingual nerve
25:44 and inferior alveolar nerve. The motor fibers of the posterior division run with the inferior alveolar nerve, form nervotomial hyoid, supply myelohyoid and anterior belly of the digastric then the mental nerve to the chin and the lower lip incisive nerve to the incisors and the canine therefore the muscles supplied by the mandibular nerve are eight four muscles of mastication masseter temporalis medial trigoid lateral trigoid then two then the other four muscles are two and the two the first two tensor palatii and the tensor tympani the second two myelohioid and anterior belly of the gastric. And remember that distribution of the lingual nerve includes distribution of the lingual nerve itself
26:34 and fibers of the cordial tympani. Lingual nerve itself, general sensation from the anterior to the sides of the tongue, cordial tympani, test sensation from the anterior to the sides of the tongue, and parasympathetic fibers to the submandibular and the sublingual salivary glands. The intra-guminal nerve lesion will lead to motor and sensory signs, motor paralysis of all muscles of mastication on the same side and loss of sensation on the same side of the face. And finally, trigeminal neuralgia. Trigeminal neuralgia is severe pain along the distribution of the branches of the trigeminal nerve. This trigeminal neuralgia is usually due to compression or irritation of the trigeminal nerve by a tumor or cyst or blood vessel.
27:25 And thank you very much and have a nice day and good luck.
