Anatomy and Histology of Sensorimotor Connections Between the Facial and Trigeminal Nerve in the Buccinator Muscle.

Abstract

Despite indications of a close interaction between the trigeminal (CN V) and facial nerve (CN VII) within the buccinator muscle, a combination of anatomical dissection and histological analysis has not been reported. Five formalin-fixed and fresh-frozen hemifaces were dissected to reveal the buccal fat pad, the buccinator muscle, and anastomotic connections between CN V and CN VII within it. Samples were taken for histological processing and immunostaining. Branches of CN V and CN VII formed pronounced sensorimotor anastomotic connections in and surrounding the buccinator muscle. These findings were histologically evident with close intramuscular coupling of sensory and motor fibers. There was an evident but gradual shift from motor to sensory fibers in the interconnections when analyzing them from the side of CN V toward the side of CN VII and vice versa. These results further elucidate connections between CN V and CN VII and their possible role in proprioception of the facial muscles.