PMC5655409_01
Exposure of the FN main trunk and its bifurcation in relation with the RMV.
gr1.jpg
PMC5655409_01_gr1.jpg
fig0005
When surgeons elevated the superficial lobe of the parotid gland and they exposed carefully the operative field, they observed that the FN bifurcated into the cervicofacial(inferior) division and the upper bigger temporofacial division. (Fig. 1)The main trunk was carefully isolated in order to avoid nerve injury and subsequent severe morbidities.
1) mandibular/2) cervical nerve branches/RMV: retromandibular vein/FN: facial nerve trunk/SD: superior division/ID: inferior division.
gr2.jpg
PMC5655409_01_gr2.jpg
fig0010
While performing descending dissection of the FN, they unexpectedly identified that the RMV passed superficially to both the mandibular and the cervical branch of the inferior division of the FN. (Fig. 2)The surgeons retracted the superficial RMV gently with a vessel loop for better exposure of the FN branches and for avoidance of accidental damage of the vein and bleeding.
The superior division of the FN. 1: temporal/2: zygomatic/3: buccal nerve branches.
gr3.jpg
PMC5655409_01_gr3.jpg
fig0015
Apart from the previously mentioned anatomic variation, surgeons incidentally detected that a single buccal branch, originating from the temporofacial division of the FN, coursed deeper, rather than superficial to the RMV, although the temporal and zygomatic branch, overlied the vein, as commonly (Fig. 3, Fig. 4).