Congenital Oculonasal Synkinesis: Botulinum Toxin A in the Treatment of a Pure Facial Synkinesis

Oculonasal synkinesis (ONS) refers to involuntary contractions of the orbicularis oculi and the compressor narium minor muscles (CNMM). In this phenomenon, blinking triggers simultaneous depression of alar complex. The etiology of congenital type ONS is unknown and has not been investigated in depth. Anomalous connections between zygomatic and buccal branches of the facial nerve are attributed to the etiology.^1,2