The subzygomatic fossa: a practical landmark in identifying the zygomaticus major muscle.

OBJECTIVE To test the validity of the subzygomatic fossa as a possible landmark in identifying the origin of the zygomaticus major muscle (ZMM). METHODS Twenty-three fresh cadaver facial halves were dissected. Four references points were identified in each cadaver head: the zygomatic arch, the malar eminence, the modiolus, and the ZMM insertion notch. The ZMM insertion notch is a palpable landmark that is typically identified midway between the zygomatic arch and the malar eminience. A straight line was drawn from the ZMM insertion notch to the modiolus. An additional line was drawn from the malar eminence to the modiolus. An incision was made along the each line to the depth of the facial muscles. The presence or absence of the ZMM was recorded, and the location of the ZMM insertion notch was characterized in each cadaver. RESULTS The ZMM insertion notch was palpated and identified in 23 of 23 facial halves. It was accurate in identifying the course of the ZMM in all 23 facial halves. The line created by the malar eminence to the modiolus was inaccurate in all 23 facial halves. CONCLUSION The ZMM insertion notch is a reliable landmark for identification of the ZMM.