@ GSA、SVE
@ Nuclei or Ganglion Related with the Trigeminal Nerve
1. Nucleus of the spinal trigeminal tract = Spinal trigeminal nucleus
(1) 接受Spinal trigeminal tract傳來的GSA fibers (Pain、Thermal sensation、Light touch)。Spinal trigeminal nucleus位於Tract的內側，上與Principal sensory nucleus合併，下則延伸入Substantia gelatinosa of the C1 and C2 spinal segments。Fibers進入Tract與Nucleus時，有Topographic organization，亦即Mandibular division Þ Most dorsal；Maxillary division Þ Intermediate；Ophthalmic division Þ Most ventral 。
(a) Ophthalamic division Þ 接受Forehead、Upper eyelid、Cornea、Conjunctiva、Dorsum of the nose、Mucous membranes of the nasal vestibule、Frontal sinus、Dura mater之感覺。
(b) Maxillary division Þ 接受Upper lip、Lateral and posterior portions of the nose、Upper cheek、Anterior portion of the temple、Mucous membranes of the nose、Upper jaw、Upper teeth、Roof of the mouth to the palatopharyngeal arch、Dura mater之感覺。
(c) Mandibular division Þ 接受Lower lip、Chin、Posterior portions of the cheek、Temple、External ear、Lower teeth、Lower jaw、Floor of the mouth、Anterior 2/3 of the tongue、Dura mater之感覺。
(d) Spinal trigeminal tract also contains small groups of GSA fibers from the facial (VII), glossopharyngeal (IX), and vagus (X) nerves which occupy dorsomedial regions.
(2) Spinal trigeminal nucleus含有三部份【Onion skin pattern】：
(a) Pars caudalis Þ 接受Entire anterior part of head的Light touch、Pain、Temperature之感覺。此區分為四層，相似於脊髓的Posterior gray horn：
(i) Lamina I Þ 相當於Posteromarginal nucleus。此區與Outer part of lamina II含有Substance P的神經纖維，故與Nociceptive information有關，對Pain與Thermal stimuli敏感。
(ii) Lamina II Þ 相當於Substantia gelatinosa。此區較深層處含有Enkephalin的神經纖維。
(iii) Laminae III & IV (= Magnocellular layers) Þ 相當於Proper sensory nucleus。
(b) Pars interpolaris Þ 接受Forehead、Cheeks、Angle of jaw、Tooth pulp的感覺。
(c) Pars oralis Þ 接受Mouth、Lips、Nose的Tactile之感覺。
(3) Spinal trigeminal nucleus發出軸突交叉到對側，形成Ventral trigeminothalamic tract，終止於Thalamic ventral posteromedial nucleus (VPM)，負責傳送頭前部的感覺。
2. Principal sensory nucleus = Pontine trigeminal nucleus
(1) 位於橋腦蓋的背外側，與三叉神經感覺纖維輸入處同高。接受GSA fibers，與Tactile (尤其是Two-point discrimination)、Pressure sense有關。
(2) Cells of the principal sensory nucleus have large receptive fields, show high spontaneous activity, and respond to a wide range of pressure stimuli with little adaptation.
(4) Dorsomedial part of the principal sensory nucleus發出一小束軸突直接上行，形成Dorsal trigeminothalamic tract，終止於Thalamic ventral posteromedial nucleus (VPM)。而Ventral part發出一大束軸突交叉到對側，加入Ventral trigeminothalamic tract。
3. Trigeminal ganglion = Semilunar ganglion = Gasserian ganglion
(1) 含Unipolar (GSA) cells，位於Petrous bone in the middle cranial fossa。
(2) 它們的Sensory root fibers進入Pons後會分叉：
(a) Ascending fibers Þ 終止於Principal sensory nucleus。
(b) Descending fibers Þ 形成Spinal trigeminal tract，終止於Spinal trigeminal nucleus。
4. Mesencephalic nucleus
(1) A slender cell column，含有Large unipolor (GSA) neurons，是唯一存留在CNS的Primary sensory neurons。不同於Dorsal root ganglial neurons的是Mesencephalic neurons並沒有Encapsulation。此核由Trigeminal motor nucleus層次開始出現，延伸至Rostral midbrain，位於Periaqueductal gray的Lateral margin。
(2) 接受從Teeth、Periodontium、Hard palate、TMJ capsules傳來的Pressure與Kinesthesis senses，以及從Stretch receptors in the muscles of mastication傳來的Proprioception。
(3) 這些Neurons的Peripheral process到達咀嚼肌的神經肌梭以及牙齒附近深部的本體感覺受器，而它們的Central process的Collateral branch則到達Trigeminal motor nucleus (= Mesencephalic tract of the trigeminal nerve)，因此形成了Two-neuron reflex arc － Jaw jerk reflex (頷反射)。
(4) 除此之外，Mesencephalic neurons亦能發出Collateral axons，經由Superior cerebellar peduncle到達Cerebellum。
5. Trigeminal motor nucleus Þ 位於Principal sensory nucleus的內側，其發出的軸突在周邊併入Mandibular division of the trigeminal nerve，為SVE fibers，去支配Muscles of mastication、Mylohyoid muscle、Anterior belly of the digastric muscle、Tensor tympani muscle、Tensor veli palatini muscle。
@ Trigeminal Nerve in the PNS
1. Ophthalmic division
(1) Meningeal branch
(2) Lacrimal branch
a. To lacrimal gland (parasympathetic supply derived from the facial nerve)
b. To superior eyelid (sensory supply)
(3) Frontal branch
a. Supraorbital nerve － To eyelid and scalp
b. Supratrochleal nerve － To eyelid, nose, and scalp
(4) Nasociliary branch (鼻睫枝)
a. Sensory root to ciliary ganglion (睫狀神經節的感覺根)
b. Long ciliary nerve (睫長神經) (It is a sensory supply to the eyeball but contains sympathetic fibers)
c. Posterior ethmoidal nerve (Sensory supply to the ethmoid and sphenoid sinuses)
d. Infratrochleal nerve － To nose, eyelid, lacrimal sac, and lacrimal caruncle
e. Anterior ethmoidal nerve
i. Meningeal branch
ii. To nasal cavity
iii. External nasal branch
2. Maxillary division
(1) Meningeal branch (in the cranial cavity)
(2) Pterygopalatine branch (翼腭枝) (via the pterygopalatine ganglion) (in the pterygopalatine fossa)
a. Orbital nerve
b. Greater palatine branch (through the greater palatine canal)
i. Posterior inferior nasal nerve
ii. Lesser palatine nerve (through the lesser palatine canal)
c. Posterior superior nasal branch ® through the sphenopalatine foramen ® Nasopalatine nerve ® through the incisive canal ® To the roof of the mouth
d. Pharyngeal nerve (through the pharyngeal canal)
(3) Zygomatic branch (in the infratemporal fossa)
a. Communication with the lacrimal nerve of the ophthalmic division
b. Zygomaticofacial nerve
c. Zygomaticotemporal nerve
(4) Posterior superior alveolar nerve (in the infratemporal fossa) － innervates the palatal and distal roots of the 3rd, 2nd, and 1st molar teeth
(5) Infraorbital branch (in the infraorbital groove first and then through the infraorbital canal and infraorbital foramen)
a. Middle superior alveolar nerve (in the infraorbital groove) － innervates the mesial root of the 1st molar tooth and the 2nd and 1st premolar teeth
b. Anterior superior alveolar nerve (in the infraorbital groove) － innervates the central and lateral incisor teeth and the canine tooth
c. Inferior palpebral nerve (on the face)
d. External nasal nerve (on the face)
e. Superior labial nerve (on the face)
3. Mandibular division
(1) Branches of the undivided trunk
a. Meningeal nerve (從Foramen ovale穿出Cranial cavity後，伴隨著Middle meningeal artery由Foramen spinosum又穿回Cranial vault)
b. Medial pterygoid nerve － To the medial pterygoid m. (翼內側肌)
c. To tensor tympani m. (鼓膜張肌)
d. To tensor veli palatini m. (腭帆張肌)
(2) Branches of the anterior division -- 又可稱為Muscular division
a. Buccal nerve － 為Sensory nerve，當位於Infratemporal fossa時，它介於Two heads of the lateral pterygoid m.，然後穿過Buccal pad去支配Buccal skin等。
b. Lateral pterygoid nerve － To the lateral pterygoid m. (翼外側肌)
c. Masseteric nerve － To the masseteric m. (咬肌) and the temporomandibular joint (sensory branch)
d. Anterior deep temporal nerve － To the temporalis m. (顳肌)
e. Posterior deep temporal nerve － To the temporalis m.
(3) Branches of the posterior division
a. Auriculotemporal nerve (顳耳神經) － 分為兩枝剛好夾住Middle meningeal artery。有分枝到：(a) the superior part of the auricle，(b) the superior part of the external auditory meatus and the lateral surface of the tympanic membrane，(c) the temporomamdibular joint，(d) the parotid gland (parasympathetic supply derived from the glossopharyngeal nerve)，(e) the skin over the parotid region，and (f) the skin on the side of the head。
b. Lingual nerve
c. Inferior alveolar nerve － 由Mandibular foramen鑽進Inferior alveolar canal，再由Mental foramen穿出。
i. Mylohyoid nerve (下頜舌骨神經) － To the mylohyoid m. (下頜舌骨肌) and the anterior belly of the digastric m. (二腹肌的前腹)
ii. Mental nerve (頦神經) (terminal branch) － Sensory supply to the lower lip and chin
@ Trigeminal Reflexes
2. Corneal reflex Þ 涉及到Ophthalamic division與Facial motor nucleus。
3. Lacrimal or tearing reflex Þ 涉及到Ophthalamic division與Lacrimal nucleus。
4. Sneezing reflex Þ 涉及到Maxillary division與Nucleus ambiguus、Respiratory centers in the reticular formation、Phrenic nerve nuclei、Anterior horn cells innervating the intercostals muscles。
5. Vomiting reflex Þ 涉及到Maxillary and mandibular divisions與Dorsal motor vagal nucleus、Nucleus ambiguus、Nucleus of solitary tract。
6. Salivary reflex Þ 涉及到Maxillary and mandibular divisions、Superior salivary nucleus與Inferior salivary nucleus。
7. Jaw-jerk reflex Þ 涉及到Maxillary and mandibular divisions與Trigeminal motor nucleus。
@ Frey’s Syndrome
此症是在Parotid gland受穿刺傷後所發生的有趣併發症。當創傷痊癒、神經再生後，原先在Auriculotemporal nerve內可支配Parotid gland的Parasympathetic postganglionic fibers，很有機會發生Cross reinnervation而進入Great auricular nerve of the cervical plexus去支配臉頰的汗腺，亦即此處的汗腺由原來的Sympathetic nerve supply變成Parasympathetic nerve supply。因此，在吃飯時Parotid gland受刺激而分泌唾液，另一方面也使臉頰處流下大量汗珠來。
@ Blood Supply of Dura Mater
1. 支配顱前窩的硬腦膜
(1) Meningeal branches from the cavernous portion of internal carotid artery
(2) Ethmoidal branches of ophthalamic artery (via ethmoidal foramina)
(3) Ascending pharyngeal artery (via foramen lacerum)
2. 支配顱中窩的硬腦膜
(1) Middle meningeal branch of maxillary artery (via foramen spinosum) Þ 最大且最重要。
(2) Accessory meningeal artery (via foramen ovale) Þ 可源自Maxillary artery或Middle meningeal artery，支配顱中窩的硬腦膜以及Trigeminal ganglion。
(3) Small branches from the lacrimal artery (via superior orbital fissure)
3. 支配顱後窩的硬腦膜
(1) Posterior meningeal branches from occipital artery via jugular foramen and hypoglossal canal
(2) Small meningeal branches from ascending pharyngeal artery via foramen lacerum and hypoglossal canal
(3) Minute branches from vertebral artery via foramen magnum
@ Nerve Supply of Dura Mater
1. Trigeminal nerve Þ 硬腦膜對伸展(Stretch)敏感，會產生頭痛的現象。當損傷並刺激到顱前窩的Supratentorial dura時，會引起同側Forehead皮膚的牽涉痛。
(1) Ophthalmic division Þ 支配小腦天幕和大腦鐮後部的硬腦膜。
(2) Anterior ethmoidal branch of ophthalamic division Þ 支配顱前窩及大腦鐮前部的硬腦膜。
(3) Tentorial branch of ophthalmic division of trigeminal nerve Þ 支配Tentorium cerebelli。
(4) Maxillary division Þ 支配一部分顱前窩，但主要支配顱中窩的硬腦膜。
(5) Mandibular division Þ 支配一部分顱前窩，但主要支配腦膜中動脈供應(顱中窩)的腦膜。
2. Vagus nerve Þ 支配Infratentorial dura，所以當刺激小腦天幕以下(顱後窩)的腦膜時，會在頸背及肩胛背產生牽涉痛。
3. Dorsal rami of C1－C3 spinal nerves Þ 取道Meningeal branch of hypoglossal nerve支配顱後窩的硬腦膜。