Mowlavi Arian, Wilhelmi Bradon J
Plastic Surgery Institute, Southern Illinois University, School of Medicine, Springfield, IL 62794, USA.
Ann Plast Surg. 2004 Apr;52(4):353-7. doi: 10.1097/01.sap.0000099712.80882.6b.
Extended superficial musculoaponeurotic system (SMAS) rhytidectomy has been advocated for improving nasolabial fold prominence. Extended subSMAS dissection requires release of the SMAS typically from the upper lateral border of the zygomaticus major muscle and continued dissection medial to this muscle. This maneuver releases the zygomatic retaining ligaments and achieves more effective mobilization and elevation of the ptotic malar soft tissues, resulting in more dramatic effacement of the nasolabial crease. Despite its presumed advantages, few reports have suggested greater risk of nerve injury with this technique compared with other limited sub-SMAS dissection techniques. Although the caudal extent of the zygomaticus muscle insertion to the modiolus of the mouth has been well delineated, the more cephalad origin has been vaguely defined. We attempted to define anatomic landmarks which could serve to more reliably identify the upper extent of the lateral zygomaticus major muscle border and more safely guide extended sub-SMAS dissections. Bilateral zygomaticus major muscles were identified in 13 cadaver heads with 4.0-power loupe magnification. Bony anatomic landmarks were identified that would predict the location of the lateral border of the zygomaticus major muscle. The upper extent of the lateral border of the zygomaticus major muscle was defined in relation to an oblique line extending from the mental protuberance to the notch defined at the most anterior-inferior aspect of the temporal fossa at the junction of the frontal process and temporal process of the zygomatic bone. The lateral border of the zygomaticus major muscle was observed 4.4 +/- 2.2 mm lateral and parallel to this line. More accurate prediction of the location of the upper extent of the lateral border of the zygomaticus major muscle using the above bony anatomic landmarks may limit nerve injury during SMAS dissections in extended SMAS rhytidectomy.
扩大的表浅肌肉腱膜系统（SMAS）除皱术已被提倡用于改善鼻唇沟的明显程度。扩大的SMAS下分离需要从颧大肌的上外侧缘开始松解SMAS，并在此肌肉内侧继续分离。此操作可松解颧部固定韧带，更有效地移动和提升下垂的颧部软组织，从而更显著地消除鼻唇沟。尽管其具有假定的优势，但与其他有限的SMAS下分离技术相比，很少有报告表明该技术导致神经损伤的风险更高。虽然颧大肌插入口角蜗轴的尾侧范围已被明确界定，但更头侧的起点却定义模糊。我们试图确定一些解剖标志，以便更可靠地识别颧大肌外侧缘的上界，并更安全地指导扩大的SMAS下分离。在13个尸体头部使用4倍放大镜识别双侧颧大肌。确定了可预测颧大肌外侧缘位置的骨性解剖标志。颧大肌外侧缘的上界是相对于一条从颏隆突延伸至颧骨额突与颞突交界处颞窝最前下方所定义切迹的斜线来界定的。观察到颧大肌外侧缘位于该线外侧4.4±2.2 mm处且与之平行。使用上述骨性解剖标志更准确地预测颧大肌外侧缘上界的位置，可能会在扩大的SMAS除皱术的SMAS分离过程中减少神经损伤。
