Sonographic characteristics of the facial nerve in healthy volunteers.
BACKGROUND
Peripheral nerve ultrasound has become an effective imaging technique. However, imaging of cranial nerves, especially in healthy volunteers, has received minimal attention. The objectives of this study were to describe the sonographic characteristics of the facial nerve and to establish average values of its diameter.


METHODS
The extra-cranial part of the facial nerve was scanned bilaterally along its longitudinal axis inside the parotid gland using a 13-MHz probe in 50 healthy adults. The diameter was measured at the nerve's thickest region.


RESULTS
The facial nerve appeared as a thin, tubular, hypoechoic structure inside the parotid gland. The mean facial nerve diameter was 0.5 ± 0.1 mm, and the mean side-to-side difference in diameter was 0.1 ± 0.1 mm.


CONCLUSIONS
The average facial nerve diameter values may provide help with identification of nerve abnormalities using ultrasound.
Department of Physical Medicine & Rehabilitation, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Eman A
EA
Tawfik
D000328:Adult; D005154:Facial Nerve / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography; D055815:Young Adult
cranial nerve; facial nerve; imaging; nerve diameter; neuromuscular ultrasound