When the major divisions of the facial nerve are stimulated distally facial movement will be evident. After traversing the labyrinthine segment, the facial nerve changes direction to form the first genu ie, bend or knee , marking the location of the geniculate ganglion. Corinne Elisabeth Horn, J. By eliminating the offending electrodes, facial nerve stimulation can often be reduced or eliminated all together. The chorda tympani nerve can be exposed along its length and can be followed inferiorly and medially to its takeoff from the main trunk of the facial nerve. Retrieved from " https:
Pes anserinus facial nerve. It is primarily responsible for lower lip depression, pucker, and platysma function. Magnetic resonance imaging MRI is useful for identifying soft tissue abnormalities around the facial nerve, as seen in inflammatory disorders, neoplasms, and hemifacial spasm. It is composed of approximately 10, neurons, 7, of which are myelinated and innervate the muscles of facial expression. Temporal bone CT can detect deviations in the course and caliber of the intratemporal facial nerve, which can provide key information regarding facial nerve pathology and prove critical in surgical planning for otologic surgery.
Facial Nerve Anatomy: Overview, Embryology of the Facial Nerve, Central Connections
The facial nerve crosses lateral to the styloid process and enters the parotid gland. It is crucial to be aware of this if surgery in the submandibular region is being performed. In the parotid gland, the nerve divides into two major divisions at the so-called pes anserinus; ie, the superiorly directed temporofacial and the inferiorly directed cervicofacial divisions of the facial nerve. A conceptual understanding of the anatomy of the SMAS is important to the surgeon. You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. The facial nerve innervates all of the muscles of facial expression.
Brisk bleeding at this time may be a sign that the nerve is in close proximity; hemostasis should be obtained using bipolar electrocautery, and further dissection should proceed cautiously. Hemangiomas of the facial nerve typically occur at the geniculate ganglion and show avid contrast enhancement. The chorda tympani nerve can be exposed along its length and can be followed inferiorly and medially to its takeoff from the main trunk of the facial nerve. The labyrinthine segment travels anterior-laterally from the IAC and superior to the cochlea until it reaches the geniculate ganglion. Surgical landmarks to identify main trunk of facial nerve: Superiorly, the SMAS ends at the level of the zygoma because of attachments of the fascial layers to the zygomatic arch.