Trigeminal nerve
Updates to Article Attributes
The trigeminal nerve is the fifth cranial nerve and its primary role is relaying sensory information from the face and head, although it does provide motor control to the muscles of mastication. It is both large and complicated and has multiple brainstem nuclei (sensory and motor) as well as many interconnections with other cranial nerves. It swaps parasympathetic fibres and taste fibres somewhat haphazardly, and divides into dozens of terminal branches.
Gross anatomy
Nuclei
There are three sensory and one motor nuclei. The sensory nuclei are arranged in a column which spans from the midbrain through the pons and medulla and into the upper cervical cord.
- mesencephalic nucleus: proprioceptive fibers for muscles of the face, orbit, mastication, and tongue
- main sensory nucleus: located in the upper pons, lateral to the motor nucleus is responsible for touch sensation for all three trigeminal divisions
- spinal nucleus: lower pons to upper cervical cord is responsible for pain and temperature; additionally it receives afferent fibers from the glossopharyngeal nerve and vagus nerve.
The motor nucleus is located in the upper pons and innervates the muscles of mastication as well as mylohyoid and tensor palati.
Intracranial component
The trigeminal nerve exits at the mid pons anteriorly, courses through the prepontine cistern (cisternal portion) to enter Meckel's cave (cavernous portion) where its fibers form the trigeminal (aka gasserian(a.k.a. Gasserian or semilunar) ganglion. It then divides into three main branches:
Ophthalmic division (V1)
Courses anteriorly in the lateral wall of the cavernous sinus superior to trochlear nerve. It then passes through the superior orbital fissure where it divides into the frontal, lacrimal, and nasociliary nerves in the superior orbit. The frontal nerve divides into the supraorbital and supratrochlear nerves. Nasociliary nerve branches include a communicating branch to the ciliary ganglion, short and long ciliary nerves, the posterior and anterior ethmoidal nerves (the latter divides into internal and external nasal branches), and the infratrochlear nerve.
Maxillary division (V2)
Courses anteriorly in the lateral wall of the cavernous sinus inferior to trochlear nerve. It then passes through the foramen rotundum to exit skull and never the pterygopalatine fossa. It continues anteriorly to enter the orbit through the inferior orbital fissure and the infraorbital canal. It emerges through the infraorbital foramen to become the infraorbital nerve. Hence following trauma and an orbital blow out fracturfracture, it is at risk of injury and loss of sensation over the maxilla.
Mandibular division (V3)
Courses inferiorly through the foramen ovale to exit the skull. It hence does not course through the cavernous sinus. It gives motor supply to the muscles of mastication.
Related pathology
-</ol><p>The <strong>motor nucleus</strong> is located in the upper <a href="/articles/pons">pons</a> and innervates the <a href="/articles/muscles-of-mastication">muscles of mastication</a> as well as <a href="/articles/mylohyoid">mylohyoid</a> and <a href="/articles/tensor-palati">tensor palati</a>.</p><h5>Intracranial component</h5><p>The trigeminal nerve exits at the mid pons anteriorly, courses through the prepontine cistern (cisternal portion) to enter Meckel's cave (cavernous portion) where its fibers form the trigeminal (aka gasserian or semilunar) ganglion. It then divides into three main branches:</p><h6>Ophthalmic division (V1)</h6><p>Courses anteriorly in the lateral wall of the cavernous sinus superior to <a href="/articles/trochlear-nerve">trochlear nerve</a>. It then passes through the <a href="/articles/superior-orbital-fissure">superior orbital fissure</a> where it divides into the frontal, lacrimal, and nasociliary nerves in the superior orbit. The frontal nerve divides into the supraorbital and supratrochlear nerves. Nasociliary nerve branches include a communicating branch to the ciliary ganglion, short and long ciliary nerves, the posterior and anterior ethmoidal nerves (the latter divides into internal and external nasal branches), and the infratrochlear nerve.</p><h6>Maxillary division (V2)</h6><p>Courses anteriorly in the lateral wall of the cavernous sinus inferior to <a href="/articles/trochlear-nerve">trochlear nerve</a>. It then passes through the <a href="/articles/foramen-rotundum">foramen rotundum</a> to exit skull and never the <a href="/articles/pterygopalatine-fossa">pterygopalatine fossa</a>. It continues anteriorly to enter the orbit through the <a href="/articles/inferior-orbital-fissure">inferior orbital fissure</a> and the infraorbital canal. It emerges through the <a href="/articles/infraorbital-foramen">infraorbital foramen</a> to become the infraorbital nerve. Hence following trauma and an <a href="/articles/orbital-blow-out-fracture">orbital blow out fractur</a>, it is at risk of injury and loss of sensation over the maxilla.</p><h6>Mandibular division (V3)</h6><p>Courses inferiorly through the <a href="/articles/foramen-ovale-head-1">foramen ovale</a> to exit the skull. It hence does not course through the cavernous sinus. It gives motor supply to the muscles of mastication.</p><h4>Related pathology</h4><ul>- +</ol><p>The <strong>motor nucleus</strong> is located in the upper <a href="/articles/pons">pons</a> and innervates the <a href="/articles/muscles-of-mastication">muscles of mastication</a> as well as <a href="/articles/mylohyoid">mylohyoid</a> and <a href="/articles/tensor-palati">tensor palati</a>.</p><h5>Intracranial component</h5><p>The trigeminal nerve exits at the mid pons anteriorly, courses through the prepontine cistern (cisternal portion) to enter Meckel's cave (cavernous portion) where its fibers form the trigeminal (a.k.a. Gasserian or semilunar) ganglion. It then divides into three main branches:</p><h6>Ophthalmic division (V1)</h6><p>Courses anteriorly in the lateral wall of the cavernous sinus superior to <a href="/articles/trochlear-nerve">trochlear nerve</a>. It then passes through the <a href="/articles/superior-orbital-fissure">superior orbital fissure</a> where it divides into the frontal, lacrimal, and nasociliary nerves in the superior orbit. The frontal nerve divides into the supraorbital and supratrochlear nerves. Nasociliary nerve branches include a communicating branch to the ciliary ganglion, short and long ciliary nerves, the posterior and anterior ethmoidal nerves (the latter divides into internal and external nasal branches), and the infratrochlear nerve.</p><h6>Maxillary division (V2)</h6><p>Courses anteriorly in the lateral wall of the cavernous sinus inferior to <a href="/articles/trochlear-nerve">trochlear nerve</a>. It then passes through the <a href="/articles/foramen-rotundum">foramen rotundum</a> to exit skull and never the <a href="/articles/pterygopalatine-fossa">pterygopalatine fossa</a>. It continues anteriorly to enter the orbit through the <a href="/articles/inferior-orbital-fissure">inferior orbital fissure</a> and the infraorbital canal. It emerges through the <a href="/articles/infraorbital-foramen">infraorbital foramen</a> to become the infraorbital nerve. Hence following trauma and an <a href="/articles/orbital-blow-out-fracture">orbital blow out fracture</a>, it is at risk of injury and loss of sensation over the maxilla.</p><h6>Mandibular division (V3)</h6><p>Courses inferiorly through the <a href="/articles/foramen-ovale-head-1">foramen ovale</a> to exit the skull. It hence does not course through the cavernous sinus. It gives motor supply to the muscles of mastication.</p><h4>Related pathology</h4><ul>
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