To evaluate morphological properties of the zygomaticus major (ZMj) and demonstrate its detailed anatomical relationships with the orbicularis oculi (OOc) and the parotid duct (PD).
Fifteen formalin fixed adult cadaver heads (7 males /8 females) aged between 45 and 92 years were dissected to reveal the ZMj, OOc, PD. Shape, lengths and thickness of the ZMj, positional relationships of the ZMj with respect to the OOc and PD (overlap, neighboring, being separate) were determined. Topographic localization of the ZMj according to lateral and medial canthi, tragus, mental tubercle and angle of mandible was evaluated.
The shape of the ZMj was observed as band like in 15/29 (51%), fan like in 10/29 (34%) and bifid in 4/29 (13%) sides. Position of the ZMj with respect to the OOc and distal part of the PD was not constant. The ZMj was overlapped by the OOc in 15/29 (52%) sides while they were adjacent in 14/29 (48%) sides. The ZMj overlapped the distal part of PD in 16/29 (%55) sides. They were separate in 10/29 (35%) sides and adjacent in 3/29 (10%) sides. Topographic location of the ZMj with respect to lateral and medial canthii, tragus, angle of mandible and mental tubercle was demonstrated. No statistically significant relationships were found between the ZMj measurements with head circumference and face length. No statistically significant differences were found between sides and gender in terms of the ZMj morphology (P > 0.05).
This study demonstrates the morphological features and topography of the ZMj along with its relationships with the OOc and PD that would be essential for clinical implications.