With disease of the corticospinal or pyramidal system, certain abnormalities are found in the reflex pattern. This is true whether the disorder is in the motor cortex itself or anywhere along the descending tracts. The superficial reflexes may be decreased or absent, and deep reflexes are exaggerated.
Clonus. If the muscle tonus is markedly increased, there is also a pathologic response in the form of clonus – a series of rhythmic involuntary muscular contractions induced by the sudden passive stretching of a muscle or tendon.
The most frequently are occurred ankle clonus, patellar clonus.
Corticospinal tract responses in the upper extremities. The corticospinal tract responses in the upper extremities occur more rarely than those found in the lower extremities.
In the Rossolimo sign, flexion of the fingers and supination of the forearm follow either percussion of the palmar aspect of the metacarpophalangeal joints or tapping the volar surface of the patient's fingertips. Flexion of the fingers and hand may follow not only stimulation of the flexor tendons on the velar surface of the forearm, but also percussion of the dorsal aspect of the carpal and metacarpal areas (the Mendel-Bechterev sign). Jukovski sign caused by hammer impact on a sole on a palm under fingers; response is flexing of II-V fingers. Jackobson-Laske reflex. It’s caused by hammer impact on processus styloideus. The thumb is flexing.
Corticospinal tract responses in the lower extremities. The corticospinal tract responses in the lower extremities are more constant and more clearly defined than those in the upper limbs and may be elicited with more ease. They may be classified as those characterized in the main by dorsiflexion of the toes, and those characterized by plantar flexion of the toes.
Corticospinal responses characterized in the main by extension (dorsiflexion) of the toes. The Babinski Sign (Fig 2.3). In disease of the corticospinal system there is an inversion of the plantar reflex, the Babinski sign or extensor plantar response. Stimulation of the plantar surface of the foot is followed by dorsiflexion of the toes, especially of the great toe, together with a separation or fanning of the toes. The Babinski sign has been called the most important sign in clinical neurology. It is considered to be one of the most significant indications of disease of the corticospinal system at any level from the motor cortex through the descending pathways. It is the most delicate, the first to be evident in the presence of disease, and the one that occurs most frequently.
The Oppenheim sign is elicited by applying heavy pressure with the thumb and index finger to the anterior surface of the tibia, mainly on its medial aspect, and stroking down from the infrapatellar region to the ankle. The response is a slow one and usually occurs toward the end of stimulation.
The Gordon sign is obtained by squeezing or applying deep pressure to the calf muscles. The Schaefer sign is produced by deep pressure on the Achilles tendon.
Corticospinal tract responses characterized by plantar flexion of the toes. There is a group of reflexes in which the pathologic response is one of plantar flexion of the toes.
The Rossolimo sign is elicited by tapping to the tips of the toes.
The Mendel - Bechterev sign is elicited by tapping or stroking the outer aspect of the dorsum of the foot in the region of the cuboid bone. Plantar flexion of the toes may also be elicited by application of the stimulus to other portions of the foot and ankle. Bechterew found that percussion of the middle of the sole or of the heel was followed by a plantar flexion response.
Reflexes of spinal automatism. The reflexes of spinal automatism are also termed defense reflexes. Like the corticospinal tract signs, they become manifest when the inhibiting action of the higher centers has been removed, and thus indicate, in part at least, a release from such inhibition.
The Flexion Spinal Defense Reflex (or the Marie–Foix–Bechterev) sign most frequently may be evoked by an uncomfortable or nociceptive irritation. Pricking, pinching the skin on the dorsal aspect of the foot or sharp flexion of the foot may initiate the response, as may squeezing the toes or extreme passive plantar flexion of the toes or foot.