Nerves

Nervus intermedius (part of the facial nerve)

• Two fibre types
• Secretomotor fibres from the superior salivatory nucleus (lacrimatory)
• Sensory fibres leading to the nucleus of the solitary tract
• Enters the internal acoustic meatus
• Passes through the middle ear
• Meets the geniculate ganglion (a sensory ganglion)

• The chorda tympani leaves the nerve within the middle ear to supply secretomotor fibres to the submandibular ganglion for the sublingual and submandibular glands and sensory fibres to the anterior two thirds of the tongue

• The greater petrosal nerve arises at the level of the geniculate ganglion

• Contains parasympathetic fibres which travel to the lacrimal gland via the pterygopalatine ganglion

Trigeminal nerve

Anatomy

• Trigeminal ganglion lies at the apex of the petrous part of temporal bone

• Emerges from the brainstem at the junction between the pons and the middle cerebellar peduncle as separate sensory and motor roots

• Spinal nucleus extends throughout the length of the medulla

Functions

• Supplies the muscles of mastication
• Supplies all the teeth of the upper jaw