4 Surgical Anatomy of the Temporal Migraine Headaches
The trigeminal ganglion is the main source of sensory supply for the majority of the face, including the temporal area.
The maxillary branch of the trigeminal nerve leaves the cranium through the foramen rotundum and enters the pterygopalatine fossa.
After providing branches to the pterygopalatine ganglion, it divides into the infraorbital and the zygomatic nerves.
The zygomatic nerve leans toward the lateral orbital wall and divides into the zygomaticotemporal and the zygomaticofacial branches.
The temporal and malar areas are supplied by the zygomaticotemporal and the auriculotemporal nerve branches.
The zygomatic nerve is divided into the zygomaticotemporal and the zygomaticofacial nerves inside the orbit; each of these nerves passes through the malar bone.
The zygomaticotemporal branch of the trigeminal nerve (ZTBTN) enters the temporal fossa deep to the temporalis muscle.
After entering the temporal fossa, the ZTBTN travels toward the surface of the muscle and pierces the deep temporal fascia.
The nerve exits the deep temporal fascia 16 to 17 mm lateral and 6.5 mm cephalic to the later canthus.
The ZTBTN does not travel within the muscle in 50% of the study specimens.
The auriculotemporal nerve branches from the main mandibular trunk after it exits the foramen ovale.
After exiting the foramen, the nerve divides into two roots that go around the middle meningeal artery and then unite under the lateral pterygoid muscles on the surface of the tensor veli palatini.
The nerve then passes between sphenomandibular ligament and the neck of the mandible and then runs laterally behind the temporomandibular joint toward the upper portion of the parotid gland.
The nerve travels superficially at the level of the temporoparietal fascia caudally and the subcutaneous tissue cephalically.
In the temporal region, the nerve is divided into the anterior and posterior branches and is accompanied by the superficial temporal artery and vein.
There is a watershed effect between the anterior branch of the trigeminal nerve and the posterior branch of the ZTBTN.
The temporal area is one of the most common trigger sites for migraine headaches. Since the introduction of migraine surgery in the early 2000s, our understanding of the anatomy of the nervous system in this area and its contribution to migraine headache and subsequently the surgical techniques for its treatment has evolved. There are a few small sensory nerves in the temple area that can trigger migraine headaches. A clear understanding of soft-tissue anatomy and facial and trigeminal nerve branches, along with safe surgical access to this area, plays an integral role in successful and safe surgery.
4.2 Central Nervous System Anatomy
The trigeminal ganglion is the main source of sensory supply for the majority of the face, including the temporal area; it spans from the superior part of pons to the medulla (►Fig. 4.1). This nucleus has a small motor portion, which supplies the muscles of mastication, mylohyoid, anterior belly of digastric muscle, tensor veli palatini, and tensor tympani.
The sensory part of the nuclei, which is the topic of this chapter, constitutes the majority of the nucleus.
The nerve leaves the brain in separate sensory and motor bundles with the sensory bundle being significantly larger than the motor bundle. Next, the sensory branch enters the trigeminal ganglion and the ganglion gives three branches:
The ophthalmic nerve (V1) leaves the cranium through the superior orbital fissure and continues to the frontal nerve. It also branches to the nasociliary ganglion and lacrimal gland.
The frontal branch divides itselfinto the supraorbital and supratrochlear nerves, which travel under the orbital roof to the orbital rim. These nerves will be discussed in a separate chapter.
The maxillary nerve (V2) leaves the cranium through the foramen rotundum and enters the pterygopalatine fossa. After providing branches to the pterygopalatine ganglion, it divides into the infraorbital and zygomatic nerves. The zygomatic nerve leans toward the lateral orbital wall and divides into the zygomaticotemporal and zygomaticofacial branches.
The mandibular nerve (V3) leaves the cranium through the foramen ovale, medial to the temporomandibular joint, and divides into the lingual, buccal, and inferior alveolar auriculotemporal nerves.
Motor branches also leave the cranium through the foramen ovale and supply muscles of mastication.