van Gijn J
University Department of Neurology, Academisch Ziekenhuis, Utrecht, The Netherlands.
Postgrad Med J. 1995 Nov;71(841):645-8. doi: 10.1136/pgmj.71.841.645.
The plantar response is a reflex that involves not only the toes, but all muscles that shorten the leg. In the newborn the synergy is brisk, involving all flexor muscles of the leg; these include the toe 'extensors', which also shorten the leg on contraction and therefore are flexors in a physiological sense. As the nervous system matures and the pyramidal tract gains more control over spinal motoneurones the flexion synergy becomes less brisk, and the toe 'extensors' are no longer part of it. The toes then often go down instead of up, as a result of a segmental reflex involving the small foot muscles and the overlying skin, comparable to the abdominal reflexes. With lesions of the pyramidal system, structural or functional, this segmental, downward response of the toes disappears, the flexion synergy may become disinhibited and the extensor hallucis longus muscle is again recruited into the flexion reflex of the leg: the sign of Babinski. A true Babinski sign denotes dysfunction of the pyramidal tract, and should be clearly distinguished from upgoing toes that do not belong to the flexion synergy of the leg. Correct interpretation of the plantar response depends only to a minor degree on the method or site of stimulation of the foot. It is therefore most important to assess the response in the entire leg.
跖反射是一种不仅涉及脚趾，还涉及所有使腿部缩短的肌肉的反射。在新生儿中，这种协同作用很活跃，涉及腿部的所有屈肌；其中包括脚趾“伸肌”，它们在收缩时也会使腿部缩短，因此在生理意义上是屈肌。随着神经系统的成熟以及锥体束对脊髓运动神经元的控制增强，屈曲协同作用变得不那么活跃，脚趾“伸肌”不再是其中一部分。由于涉及足部小肌肉和覆盖皮肤的节段性反射，类似于腹壁反射，此时脚趾通常向下而不是向上。锥体系统出现结构性或功能性病变时，这种脚趾的节段性向下反应消失，屈曲协同作用可能会解除抑制，拇长伸肌再次被纳入腿部的屈曲反射：巴宾斯基征。真正的巴宾斯基征表示锥体束功能障碍，应与不属于腿部屈曲协同作用的脚趾背伸明确区分。跖反射的正确解读在很大程度上仅取决于足部刺激的方法或部位。因此，评估整个腿部的反应最为重要。
