Emergence Point of the Infratrochlear Nerve With Reference to the Nasion and Its Clinical Implications in Craniofacial Surgery
13 Dec 2025
09:15
09:30
Hyun Jin ShinKorea (Republic of)
Speaker
Emergence Point of the Infratrochlear Nerve With Reference to the Nasion and Its Clinical Implications in Craniofacial SurgeryAbstract
Infratrochlear nerve (ITN) block is widely utilized for achieving surgical anesthesia, reducing postoperative pain, and treating neuralgia. The aim of this study was to identify the emerging point of the ITN (EP-ITN) in the medial orbital margin with reference to the nasion in order to enhance the effectiveness of regional ITN block in craniofacial surgery. Thirty-eight hemifaces from 19 embalmed Korean cadavers were dissected. Measurements were made of the vertical distances from the EP-ITN to key landmarks such as the nasion, the inferior border of the trochlea, and the medial canthus. The study also analyzed facial morphology by measuring the horizontal and vertical dimensions of the midface and orbit. The spatial relationships between these landmarks and the EP-ITN relative to the dimensions of the midface and orbit were also evaluated. The distances from the EP-ITN to the nasion, trochlea, and medial canthus were 1.6±1.3 mm (mean±standard deviation), 19.7±1.7 mm, and 11.7±2.0 mm, respectively. The distance between the trochlea and the EP-ITN also tended to increase as the horizontal dimensions of the midface and orbit increased. However, the dimensions of the midface and orbit did not significantly affect the distance from the nasion to the EP-ITN. In conclusion, the nasion is located nearer to the EP-ITN than to other landmarks and maintains a consistent spatial relationship that is unaffected by variations in the size of the midface or orbit. This means that it can serve as a reliable external landmark for guiding the ITN block technique.