The Hospital for Sick Children, Division of Plastic and Reconstructive Surgery, University of Toronto, Department of Surgery, Toronto, Ontario, Canada.
J Plast Reconstr Aesthet Surg. 2012 Mar;65(3):363-6. doi: 10.1016/j.bjps.2011.09.026. Epub 2011 Oct 10.
The motor nerve to the masseter muscle is increasingly being used for facial reanimation procedures. However, many surgeons have been reluctant to use this versatile source of axons because of difficulty in locating it intraoperatively. In this study we conducted a detailed assessment of its gross and microscopic anatomy and develop a simple, reliable method for locating this nerve.
We defined the anatomy of the nerve to the masseter, in particular its relationship to common surgical landmarks such as the auricular tragus and the zygomatic arch, and determined its intramuscular anatomy. We also performed a histomorphometric analysis.
The anatomy of the motor nerve to the masseter was consistent. A convenient starting point for its dissection was found 3.16 ± 0.30 cm anterior to the tragus at a level 1.08 ± 0.18 cm inferior to the zygomatic arch. The nerve was located 1.48 ± 0.19 cm deep to the superficial muscular aponeurotic system (SMAS) at this point. Relative to the zygomatic arch, the nerve formed an angle of 50 ± 7.6° as it coursed distally into the masseter muscle. The distance from the arch to the first branch of the motor nerve to the masseter was 1.33 ± 0.20 cm. The histomorphometric analysis demonstrated that the motor nerve to the masseter contained an average of 2775 ± 470 myelinated fibers.
Successful intraoperative location of the motor nerve to the masseter is facilitated by knowledge of its anatomy relative to standard surgical landmarks. A consistent and convenient starting point for dissection of this nerve is found 3 cm anterior to the tragus and 1 cm inferior to the zygomatic arch. The nerve contains over 2700 myelinated fibers, demonstrating its usefulness as a source of motor innervation for facial reanimation.
咀嚼肌的运动神经越来越多地用于面部再生动手术。然而，由于术中定位困难，许多外科医生一直不愿意使用这种多功能的轴突来源。在这项研究中，我们对其大体和微观解剖结构进行了详细评估，并开发了一种简单、可靠的定位该神经的方法。
我们定义了咀嚼肌运动神经的解剖结构，特别是其与常见手术标志如耳屏和颧骨弓的关系，并确定了其肌内解剖结构。我们还进行了组织形态计量学分析。
咀嚼肌运动神经的解剖结构是一致的。在耳屏前 3.16 ± 0.30 cm 处，在颧骨弓下方 1.08 ± 0.18 cm 处找到了一个方便的起点，用于其解剖。在这个位置，神经位于浅肌肉腱膜系统（SMAS）深 1.48 ± 0.19 cm 处。相对于颧骨弓，神经在向咀嚼肌远端走行时形成 50 ± 7.6°的角度。从弓到咀嚼肌运动神经第一分支的距离为 1.33 ± 0.20 cm。组织形态计量学分析表明，咀嚼肌运动神经包含平均 2775 ± 470 条有髓纤维。
了解其相对于标准手术标志的解剖结构，有助于术中成功定位咀嚼肌运动神经。在耳屏前 3 cm 和颧骨弓下 1 cm 处找到了一个一致且方便的神经解剖起点。该神经包含超过 2700 条有髓纤维，证明其作为面部再生动用的运动神经支配源的有用性。
