Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, Louisiana, USA.
Division of Gross and Clinical Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.
Anat Rec (Hoboken). 2021 Feb;304(2):366-371. doi: 10.1002/ar.24406. Epub 2020 May 18.
The facial muscles have significant roles for vocalization, feeding, and facial expression in both human and non-human primates. Of these, the anatomy of the incisivus labii superioris (ILS) and incisivus labii inferioris (ILI), which are considered as the accessory bundle of the orbicularis oris (OO) in humans, has rarely been documented in the literature. Our current understanding of the function of the ILS and ILI is that they probably retract the upper and lower lips. Also, there is no account of these muscles in non-human primates in the current literature. The aim of this study was to reveal the ILS and ILI in non-human primates. Five Macaca fascicularis, one Macaca fuscata, one Macaca fuscata yakui, and one Pan troglodytes were dissected. Seven formalin-fixed cadavers and one fresh cadaver were included. Both the ILS and ILI were observed in all specimens. The ILS originated from the incisive fossa of the maxilla and inserted into the OO. The mentalis (MT) and ILI arose from the incisive fossa of the mandible and inserted into the OO and the skin of the chin area. The MT and ILI in the P. troglodytes examined were thicker than in the other three non-human species, and the ILS and ILI in the three macaques were similar in shape to those of humans. The difference of these muscles may result in different functions of the lip such as during vocalization, feeding, and facial expression.
面部肌肉在人类和非人类灵长类动物中对于发声、进食和面部表情都具有重要作用。在这些肌肉中，上唇鼻翼肌（ILS）和下唇鼻翼肌（ILI）的解剖结构很少在文献中被记录。我们目前对上唇鼻翼肌和下唇鼻翼肌功能的理解是，它们可能会使上唇和下唇回缩。此外，目前的文献中也没有关于这些肌肉在非人类灵长类动物中的描述。本研究的目的是揭示非人类灵长类动物中的上唇鼻翼肌和下唇鼻翼肌。我们解剖了 5 只猕猴（包括 1 只食蟹猴、1 只黑毛和冠猕猴、1 只黑毛和冠猕猴指名亚种），1 只短尾猴，1 只普通狨猴。研究中包含了 7 具福尔马林固定的尸体和 1 具新鲜尸体。所有标本均观察到了上唇鼻翼肌和下唇鼻翼肌。上唇鼻翼肌起源于上颌切齿窝，插入到口轮匝肌。下唇肌和下唇鼻翼肌起源于下颌切齿窝，插入到口轮匝肌和下巴区域的皮肤。研究的普通狨猴的下唇肌和下唇鼻翼肌比其他三种非人类物种的要厚，而三种猕猴的上唇鼻翼肌和下唇鼻翼肌的形状与人类相似。这些肌肉的差异可能导致嘴唇在发声、进食和面部表情等方面的功能不同。
