出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/09/23 03:58:35」(JST)
The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In normal adults the plantar reflex causes a downward response of the hallux (flexion). An upward response (extension) of the hallux is known as Koch sign, Babinski response or Babinski sign, named after Joseph Babinski (1857–1932), a French[1] neurologist of Polish origin. The presence of the Babinski sign can identify disease of the spinal cord and brain in adults, and also exists as a primitive reflex in infants.[2][3]
The lateral side of the sole of the foot is rubbed with a blunt instrument or device so as not to cause pain, discomfort, or injury to the skin; the instrument is run from the heel along a curve to the toes[4] (metatarsal pads). Many reflex hammers taper at the end of the handle to a point which was used for testing the plantar response in the past, however, due to the tightening of infection control regulation this is no longer recommended. Either a single use orange stick or the thumb nail should be used.
There are three responses possible:
As the lesion responsible for the sign expands, so does the area from which the afferent Babinski response may be elicited. The Babinski response is also normal while asleep and after a long period of walking.
The Babinski sign can indicate upper motor neuron lesion constituting damage to the corticospinal tract. Occasionally, a pathological plantar reflex is the first (and only) indication of a serious disease process and a clearly abnormal plantar reflex often prompts detailed neurological investigations, including CT scanning of the brain or MRI of the spine, as well as lumbar puncture for the study of cerebrospinal fluid.
Babinski sign is an up-turning or extensor plantar response. Modifiers "upgoing, "downgoing, "positive," or "negative" should not be applied. The phrase "negative Babinski sign" is a misnomer for a "flexor plantar response."[5]
Infants will also show an extensor response. A baby's smaller toes will fan out and his big toe will dorsiflex slowly. This happens because the corticospinal pathways that run from the brain down the spinal cord are not fully myelinated at this age, so the reflex is not inhibited by the cerebral cortex. The extensor response disappears and gives way to the flexor response around 12 to 24 months of age.
Afferent: Nociception detected in the S1 dermatome and travels up the tibial nerve to the sciatic nerve to roots of L5,S1 and synapse in the anterior horn to elicit the motor response. Efferent: Motor response back through the L5,S1 roots to the sciatic nerve to its bifurcation. Toe flexors are innervated by the tibial nerve. Toe extensors (extensor hallicus longus, extensor digitorum longus) are innervated by the deep peroneal nerve. Loss of normal adult descending pyramidal control of the reflex arc to suppress extensor withdrawal results in the upgoing toes in the plantar reflex known as Babinski's sign. There is no such thing as a negative Babinski's sign.
The Hoffmann's reflex is sometimes described as the upper limb equivalent of the Babinski sign[6] because both indicate upper motor neuron dysfunction. Mechanistically, they differ significantly; the finger flexor reflex is a simple monosynaptic spinal reflex involving the flexor digitorum profundus that is normally fully inhibited by upper motor neurons. The pathway producing the plantar response is more complicated, and is not monosynaptic. This difference has led some[who?] neurologists to reject strongly any analogies between the finger flexor reflex and the plantar response.[citation needed]
The plantar reflex can be elicited in a number of ways, which were described in the late 19th and early 20th century. These have their own eponyms.[7]
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リンク元 | 「原始反射」「バビンスキー反射」「病的反射」 |
関連記事 | 「reflex」 |
中枢 | 消失時期 | 反射 | ||
脊髄 | ~生後3ヶ月 | magnet reflex | ||
歩行反射 | stepping reflex | |||
把握反射 | grasping reflex | |||
非対称性緊張性頚部反射 | asymmetrical tonic neck reflex | 背臥位にした新生児の頭を一方に向けると、顔の向いた方の上下肢は伸展し、後頭側の上下肢は屈曲する | ||
脊髄-橋 | ~生後6ヶ月 | モロー反射 | Moro reflex | 頭を持ち上げて急に落とす動作をした時に両上肢を開き、側方から正中方向に抱きつくような動き |
口唇探索反射 | rooting reflex | |||
緊張性頚反射 | tonic neck reflex | 腹位水平抱きまたは座位で頚を背屈すると上肢が伸展、背筋が緊張し、頚を前屈すると上肢が屈曲し、体幹のトーヌスが減弱する | ||
中脳 | 生後6ヶ月~5歳 | 立ち直り反射 | righting reflex | |
頚立ち直り反射 | ||||
体幹立ち直り反射 | ||||
視性立ち直り反射 | ||||
大脳皮質 中脳 |
生後8ヶ月~終生 | パラシュート反射 | 水平位にして、突然頭を下げると腕が伸びて身体を支えようとすること。 |
反射 | 出現 | 消失 | |
モロー反射 | Moro reflex | 生来 | 3~4 |
口唇探索反射 | rooting reflex | 生来 | 4~7 |
吸啜反射 | sucking reflex | 生来 | 4~7 |
手指把握反射 | palmar grasp reflex | 生来 | 6 |
足底反射 | plantar grasp reflex | 生来 | 10 |
バビンスキー反射 | Babinski reflex | 生来 | 24 |
緊張性頚反射 | tonic neck reflex | 2 | 6 |
Landau反射 | Landau reflex | 3 | 24 |
パラシュート反射 | 9 | 一生 |
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-バビンスキー徴候
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