Anatomically [Figure 1], the SOF, which is a pear-shaped structure with the broadest part at the nasal side, is bound laterally by the greater wing of the sphenoid, medially by the lesser wing of sphenoid, and superiorly by the frontal bone, lying at the apex of the orbit and at the border between the roof and the lateral orbital wall. The SOF serves as a pathway that allows communication between the orbit and the middle cranial fossa, thereby transmitting the oculomotor, trochlear, and abducens nerves (cranial nerves III, IV, and VI), as well as the first three branches of the trigeminal nerve: the frontal, lacrimal, and nasociliary
The ophthalmic division further divides into the nasociliary
, frontal, and lacrimal branches, of which the frontal nerve is most commonly involved with HZO.
The nasal tip receives its main sensory supply from the external nasal branch of the anterior ethmoid nerve, which is a branch of the nasociliary
Sympathetic fibres travel via the nasociliary
nerve and the long ciliary nerves until they reach the ciliary body and dilator pupillae muscle.
Ramus superior runs forward to the orbital region and gives off branches that accompany lacrimal, frontal and nasociliary
The sensory nerves reach the eye through the nasociliary
branch of the ophthalmic nerve , which branches typically into two long ciliary nerves, one nasal and the other temporal, which course directly to the posterior pole of the eye, and a communicating branch carrying sensory fibers to the ciliary ganglion .
(7) Materials such as calcium sulfate (gypsum), calcium carbonate (calcite), crystalline silica, and fibrous glass--which were released during the removal of rubble and debris--are known to inhibit nasociliary
action and cause nasal irritation.
This involvement of the external nasal nerve (the terminal branch of the nasociliary
branch of the ophthalmic division of the trigeminal nerve) implies a high risk of involvement of the earlier ciliary branches supplying intra-ocular structures.
Note the whole nasociliary
dermatome, The Hutchinson sign--the appearance of skin lesions along the side of the nose, which represents the dermatome of the nasociliary
nerve--is a useful prognostic factor for subsequent ocular inflammation for patients with acute ophthalmic zoster.
However, an intra-orbital nasociliary
block is described for the treatment of "short lasting unilateral neuralgic pain with conjunctival tearing and /or infection ('SUNCT', the Charlin syndrome)".
facial trochlear optic phrenic axon dendrite occipital hypoglossal frontal mandibular nasociliary
ophthalmic tibial laryngeal hillock bouton median splanchnic hypogastric femoral genitofemoral plexus pudendal myelin trigeminal abducens oculomotor vagus glossopharyngeal vestibulocochlear accessory auricular maxillary lacrimal supraorbital ethmoidal peroneal endoneurium synapse ganglion antebrachial acetylcholine ramus iliohypogastric subcostal obturator ilioinguinal oligodendrocyte nerve astrocyte
palpebrales A14.2.01.025 Nasociliary
nerve A14.2.01.026 Communicating Branch with ciliary ganglion; Sensory root of ciliary; Nasociliary
root of ciliary ganglion.