Magendie made very important contributions to the understanding of reflexes and the reflex apparatus by showing that sensory (afferent) fibers enter the spinal cord as part of the posterior roots, while efferent fibers, such as motor ones, leave it as part of the anterior roots. This discovery ...
12 Rarely, a delay in the corneal reflex has been reported ipsilateral to a hemispheric lesion.13 A pathologic jaw jerk reflex may indicate dysfunction of afferent sensory or efferent motor V3 fibers. Afferent axons for the jaw jerk reflex are from stretch receptors (muscle spindles) within the...
4. Sympathetic stimulation also reduced the EMG activity evoked by the jaw jerk reflex, which may reflect a sympathetic effect on spindle afferents. After cessation of stimulation, a transient increase in EMG activity was observed, which may be due to efferent supply from the trigeminal ...
The classic reflex is the knee-jerk reflex, where a sharp tap to the knee evokes contraction in the thigh muscles and a brief lifting of the lower leg. In the jaw motor system, reflexes include the jaw-closing or jaw-jerk reflex, and the jaw-opening reflex. The jaw-closing reflex occur...
afferent pathway of the reflex is via the 1a motor fibers in the mandibular division, and theefferent pathwayconstitutes fibers traveling from the motor nucleus of the trigeminal nerve via the same mandibular division. An increasedjaw jerk reflexis seen in supranuclear lesions, and when exaggerated ...
jerk reflex. Themuscle spindleis thesensory receptorand the reflex pathway goes via the trigeminal mesencephalic nucleus to jaw-closing motoneurones and the jaw-closing musculature (Fig. 6.2B). The reflex is usually monosynaptic, but a polysynaptic pathway also exists. The jaw-jerk reflex differs ...
The afferent pathway of the reflex is via the 1a motor fibers in the mandibular division, and the efferent pathway constitutes fibers traveling from the motor nucleus of the trigeminal nerve via the same mandibular division. An increased jaw jerk reflex is seen in supranuclear lesions, and when ...