Reimann R, Anderhuber F, Gerold J
Anatomischen Institut, Karl-Franzens-Universität Graz.
Gegenbaurs Morphol Jahrb. 1988;134(3):351-80.
2 series of models demonstrate the geometrical shape of the human trochlea tali. We have changed step by step the shape of the 2 flanking articular facets of the trochlea, the course of the edges of the trochlea, and the length of their radii, and so we have found a model responding to the biomechanic conditions of the trochlea tali. The convex surface of this model (corresponding to the superior articular surface, i.e. the facies superior trochleae tali) is a torse, the medial flanking facet (corresponding to the medial articular facet of the trochlea, i.e. the facies malleolaris medialis) is a flat cone, the lateral flanking facet (corresponding to the lateral articular facet of the trochlea, i.e. the facies malleolaris lateralis) is a screwed (helicoidal) face. The resulting model shows the 2 completely different phases of motion in the ankle joint: During dorsiflexion (motion setting out from the neutral position towards the final position of dorsiflexion), the internal malleolus leads the talus, whereas the external malleolus is pushed outwards by the screwed lateral articular facet of the trocheal. The trochlea is moved like a hinge. In the final position of dorsiflexion, the malleoli tightly embrace the 2 flanking facets of the trochlea, whilst an obvious cleft appears dorsally and medially between the superior articular surface of the trochlea and the tibial roof (i.e. the facies articularis inferior tibiae). During plantarflexion (motion setting out from the neutral position towards the final position of plantarflexion), the external malleolus leads the talus, whereas the medial articular facet of the trochlea withdraws from the internal malleolus. The trochlea is moved like a screw. In the final position of plantarflexion, the superior articular surface of the trochlea closely contacts the tibial roof, whilst an obvious cleft appears between the medial articular facet of the trochlea and the internal malleolus.
两组模型展示了距骨滑车的几何形状。我们逐步改变了滑车两侧关节面的形状、滑车边缘的走向以及它们半径的长度，从而找到了一个符合距骨滑车生物力学条件的模型。该模型的凸面（对应于上关节面，即距骨滑车上面）是一个环面，内侧侧翼小面（对应于滑车的内侧关节面，即内踝关节面）是一个平锥面，外侧侧翼小面（对应于滑车的外侧关节面，即外踝关节面）是一个螺旋面。所得模型展示了踝关节运动的两个完全不同阶段：在背屈过程中（从中立位向背屈最终位置的运动），内踝引导距骨，而外踝被滑车的螺旋状外侧关节面推向外。滑车像铰链一样移动。在背屈最终位置，内外踝紧密包绕滑车的两侧小面，而在滑车的上关节面与胫骨顶（即胫骨下关节面）之间的背侧和内侧出现明显的间隙。在跖屈过程中（从中立位向跖屈最终位置的运动），外踝引导距骨，而滑车的内侧关节面从内踝处缩回。滑车像螺丝一样移动。在跖屈最终位置，滑车的上关节面紧密接触胫骨顶，而在滑车的内侧关节面与内踝之间出现明显的间隙。
