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The trigeminal nerve (Figs 56.4 and 57.1–3) arises from the brain at the
nasal septum, to the incisive fossa to supply the hard palate. The pos-
side of the pons by a motor and a sensory root. The sensory root carries
terior superior dental nerve enters the back of the maxilla and supplies
the trigeminal ganglion which consists of the cell bodies of the sensory
the teeth. The maxillary nerve leaves the sphenopalatine fossa via the
axons and lies in a depression on the petrous temporal bone. It then palates, the sphenopalatine nerve to the nasal cavity and thence via the
divides into ophthalmic, maxillary and mandibular divisions. The inferior orbital fissure, travels in the floor of the orbit where it gives the
motor root forms part of the mandibular division. middle and anterior superior dental nerves, and emerges onto the face
through the infraorbital foramen as the infraorbital nerve. All branches
(a) The ophthalmic division (Fig. 57.1) of the maxillary division are sensory.
This traverses the cavernous sinus and enters the orbit via the superior
orbital fissure where it divides into frontal, lacrimal and nasociliary (c) The mandibular division (Fig. 57.3)
branches. The frontal nerve lies just under the roof of the orbit and This leaves the cranial cavity through the foramen ovale and immedi-
divides into supraorbital and supratrochlear nerves which emerge ately breaks up into branches. These are: the mainly sensory inferior
from the orbit and supply the front of the scalp. The lacrimal nerve lies alveolar nerve, which enters the mandibular foramen to supply the
laterally and supplies the skin of the eyelids and face. It also carries teeth before emerging onto the face as the mental nerve. This nerve
parasympathetic secretomotor fibres from the sphenopalatine ganglion does have one motor branch, the mylohyoid nerve, which supplies the
to the lacrimal gland. The nasociliary nerve crosses the optic nerve and mylohyoid and the anterior belly of the digastric. The lingual nerve lies
runs along the medial wall of the orbit to emerge onto the face as the close to the mandible just behind the third molar and then passes for-
infratrochlear nerve. It gives off the ethmoidal nerves to the ethmoidal wards to supply the tongue. It is joined by the chorda tympani which
sinuses and the long ciliary nerves to the eye which carry sensory fibres carries taste fibres from the anterior two-thirds of the tongue and
from the cornea and sympathetic fibres to the dilator pupillae. All parasympathetic secretomotor fibres to the submandibular and sublin-
branches of the ophthalmic division are sensory. gual salivary glands. These synapse in the submandibular ganglion
which is attached to the lingual nerve. The auriculotemporal nerve sup-
(b) The maxillary division (Fig. 57.2) plies sensory fibres to the side of the scalp. It also carries parasympath-
This leaves the cranial cavity through the foramen rotundum and enters etic secretomotor fibres, which have synapsed in the otic ganglion, to
the pterygopalatine fossa. It has the sphenopalatine ganglion attached the parotid gland. The buccal nerve carries sensory fibres from the face.
to it which transmits parasympathetic fibres to the lacrimal gland via There are muscular branches to the muscles of mastication, including
communications with the lacrimal nerve. The branches of the maxillary the deep temporal nerves which supply temporalis. The mandibular
nerve are the greater and lesser palatine nerves to the hard and soft division thus contains both motor and sensory branches.

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