The mechanical behaviour of the mandibles of Pan and Macaca during mastication was compared using finite element modelling. Muscle forces were calculated using species-specific measures of physiological cross-sectional area and scaled using electromyographic estimates of muscle recruitment in Macaca. Loading regimes were compared using moments acting on the mandible and strain regimes were qualitatively compared using maps of principal, shear and axial strains. The enlarged and more vertically oriented temporalis and superficial masseter muscles of Pan result in larger sagittal and transverse bending moments on both working and balancing sides, and larger anteroposterior twisting moments on the working side. The mandible of Pan experiences higher principal strain magnitudes in the ramus and mandibular prominence, higher transverse shear strains in the top of the symphyseal region and working-side corpus, and a predominance of sagittal bending-related strains in the balancing-side mandible. This study lays the foundation for a broader comparative study of Hominidae mandibular mechanics in extant and fossil hominids using finite element modelling. Pan's larger and more vertical masseter and temporalis may make it a more suitable model for hominid mandibular biomechanics than Macaca.

使用有限元建模比较了Pan和Macaca咀嚼过程中下颌骨的力学行为。使用特定物种的生理横截面积测量来计算肌肉力量，并使用Macaca中肌肉募集的肌电图估计进行缩放。使用作用在下颌骨上的力矩比较加载状态，并使用主、剪切和轴向应变图对应变状态进行定性比较。Pan的扩大和更垂直的颞肌和浅表咬肌导致工作侧和平衡侧的矢状和横向弯曲力矩更大，工作侧的前后扭转力矩更大。下颌骨潘在支和下颌突出处经历更高的主应变幅度，在联合区顶部和工作侧体部的横向剪切应变更高，并且在平衡侧下颌骨中的矢状弯曲相关应变占优势。这项研究为使用有限元建模对现存和化石原始人的原始人科下颌力学进行更广泛的比较研究奠定了基础。潘的更大和更垂直的咬肌和颞肌可能使其成为比猕猴更适合人类下颌生物力学的模型。