Communication between the facial and auriculotemporal nerves

The communication between the auriculotemporal and the facial nerves, i.e. the communicating auriculotemporal nerves (CATN), was studied in 55 facial sides from Thai cadavers. CATN only joined the temporofacial (upper) division of the facial nerve. CATN patterns were classified as follows: (1) the facial nerve was joined by 1 CATN (20.7%), (2) by 2 separate CATN branches (60.4%), (3) by 3 separate CATNs (15.1%); (4) several CATNs ran parallel to the zygomatic and buccal nerves to the muscles of facial expression (3.8%). The 4 types of CATN pattern showed further variations according to the site of union with the facial nerve. The superficial temporal artery was crossed by CATN branches anteriorly in 47.1%, posteriorly in 18.9%, and anteriorly and posteriorly in 34.0% of the cases. The facial nerve branches that were joined by CATNs were observed to supply the upper muscles of facial expression, i.e. frontalis, orbicularis oculi and zygomaticus major. Some offshoots from CATNs were seen to innervate orbicularis oculi. On the basis of our results we suggest that CATNs may convey proprioceptive impulses from orbicularis oculi.