Plantar reflex
Encyclopedia
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 Babinski response, Babinski sign, or Koch sign, named after Joseph Babinski
(1857–1932), a French
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 infant
s.
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 toe
s (metatarsal
pads). Many reflex hammer
s 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 "flexor plantar response."
s will also show an extensor response. A baby's smaller toes will fan out and their big toe will dorsiflex
slowly. This happens because the corticospinal pathways
that run from the brain
down the spinal cord
are not fully myelin
ated 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.
Efferent: Motor response back through the L5,S1 roots to the sciatic nerve to its bifurcation. Toe flexors are innervated by 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.
equivalent of the Babinski sign 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 neurologists to reject strongly any analogies between the finger flexor reflex and the plantar response.
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
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
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
(flexion
Flexion
In anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
). An upward response (extension
Extension (kinesiology)
In kinesiology, extension is a movement of a joint that results in increased angle between two bones or body surfaces at a joint. Extension usually results in straightening of the bones or body surfaces involved. For example, extension is produced by extending the flexed elbow. Straightening of...
) of the hallux
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
is known as Babinski response, Babinski sign, or Koch sign, named after Joseph Babinski
Joseph Babinski
Joseph Jules François Félix Babinski was a French neurologist of Polish descent. He is best known for his 1896 description of the Babinski sign, a pathological plantar reflex indicative of corticospinal tract damage....
(1857–1932), a French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
neurologist
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
of Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
origin. The presence of the Babinski sign can identify disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
of the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
and brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
in adults, and also exists as a primitive reflex
Primitive reflexes
Primitive reflexes are reflex actions originating in the central nervous system that are exhibited by normal infants but not neurologically intact adults, in response to particular stimuli. These reflexes disappear or are inhibited by the frontal lobes as a child moves through normal child...
in infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
s.
Methods
Sole (foot)
The sole is the bottom of the foot.In humans the sole of the foot is anatomically referred to as the plantar aspect. The equivalent surface in ungulates is the hoof.- Human sole :...
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 toe
Toe
Toes are the digits of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being digitigrade. Humans, and other animals that walk on the soles of their feet, are described as being plantigrade; unguligrade animals are those that walk on hooves at the tips of...
s (metatarsal
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
pads). Many reflex hammer
Reflex hammer
A reflex hammer is a medical instrument used by physicians to test deep tendon reflexes. Testing for reflexes is an important part of the neurological physical examination in order to detect abnormalities in the central or peripheral nervous system....
s 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
Infection control
Infection control is the discipline concerned with preventing nosocomial or healthcare-associated infection, a practical sub-discipline of epidemiology. It is an essential, though often under-recognized and under-supported, part of the infrastructure of health care...
regulation this is no longer recommended. Either a single use orange stick or the thumb nail should be used.
There are three responses possible:
- Flexor: the toes curve inward and the foot evertsEversion (kinesiology)Eversion is the movement of the sole of the foot away from the median plane. It occurs at the subtalar joint.Peroneus longus and peroneus brevis evert. Both muscles are innervated by the superficial fibular nerve....
; this is the response seen in healthy adults. - Indifferent: there is no response.
- Extensor: the halluxHalluxIn tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
dorsiflexesDorsiflexionDorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
, and the other toes fan out; this is Babinski's sign, which indicates damage to the central nervous systemCentral nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
.
As the lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
responsible for the sign expands, so does the area from which the afferent
Afferent nerve
In the nervous system, afferent neurons , carry nerve impulses from receptors or sense organs towards the central nervous system. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneurons...
Babinski response may be elicited. The Babinski response is also normal while asleep and after a long period of walking.
Interpretation
Upper motor neuron
Upper motor neurons are motor neurons that originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway, that is, any motor neurons that are not directly responsible for stimulating the target muscle...
lesion constituting damage to the corticospinal tract
Corticospinal tract
The corticospinal or pyramidal tract is a collection of axons that travel between the cerebral cortex of the brain and the spinal cord....
. 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
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
investigations, including CT scanning
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
of the brain or MRI
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
of the spine, as well as lumbar puncture
Lumbar puncture
A lumbar puncture is a diagnostic and at times therapeutic procedure that is performed in order to collect a sample of cerebrospinal fluid for biochemical, microbiological, and cytological analysis, or very rarely as a treatment to relieve increased intracranial pressure.-Indications:The...
for the study of cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
.
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
Misnomer
A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...
: for "flexor plantar response."
In infants
InfantInfant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
s will also show an extensor response. A baby's smaller toes will fan out and their big toe will dorsiflex
Dorsiflexion
Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
slowly. This happens because the corticospinal pathways
Corticospinal tract
The corticospinal or pyramidal tract is a collection of axons that travel between the cerebral cortex of the brain and the spinal cord....
that run from the brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
down the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
are not fully myelin
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
ated at this age, so the reflex is not inhibited by the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
. The extensor response disappears and gives way to the flexor response around 12 to 24 months of age.
Pathways
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 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.
Relationship to Hoffmann reflex
The Hoffmann's reflex is sometimes described as the upper limbUpper limb
The upper limb or upper extremity is the region in an animal extending from the deltoid region to the hand, including the arm, axilla and shoulder.-Definition:...
equivalent of the Babinski sign because both indicate upper motor neuron
Upper motor neuron
Upper motor neurons are motor neurons that originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway, that is, any motor neurons that are not directly responsible for stimulating the target muscle...
dysfunction. Mechanistically, they differ significantly; the finger flexor reflex is a simple monosynaptic spinal reflex
Reflex arc
A reflex arc is a neural pathway that controls an action reflex. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord...
involving the flexor digitorum profundus
Flexor digitorum profundus muscle
- References :...
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 neurologists to reject strongly any analogies between the finger flexor reflex and the plantar response.
Babinski-like responses
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.Abnormal reflex seen as extension of the big toe
- Bing signBing's signBing's sign or Bing's reflex is a clinical sign in which pricking the dorsum of the foot or toe with a pin causes extension of the great toe. It is seen in patients with pyramidal tract lesions of the lower limbs....
– multiple pinpricks on the dorsumDorsum (biology)In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
of the foot - Cornell signCornell's signCornell's sign is a clinical sign in which scratching along the inner side of the extensor hallucis longus tendon elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– scratching along the inner side of the extensor hallucis longusExtensor hallucis longus muscleThe Extensor hallucis longus is a thin muscle, situated between the Tibialis anterior and the Extensor digitorum longus that functions to extend the big toe, dorsiflex the foot, and assists with foot inversion....
tendon - Chaddock signChaddock reflexChaddock reflex is a diagnostic reflex similar to the Babinski reflex. It is designed to identify lesions of the pyramidal tract, via stimulation of the skin over the lateral malleolus.It was identified by Charles Gilbert Chaddock in 1911....
– stroking the lateral malleolus - Gorda signGonda's signGonda's sign is a clinical sign in which flexing and then suddenly releasing the 4th toe elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– flexingFlexionIn anatomy, flexion is a position that is made possible by the joint angle decreasing. The skeletal and muscular systems work together to move the joint into a "flexed" position. For example the elbow is flexed when the hand is brought closer to the shoulder...
and suddenly releasing the 4th toe - Gordon signGordon's signGordon's sign is a clinical sign in which squeezing the calf muscle elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses.The sign is named after Alfred Gordon....
– squeezing the calf muscle - Moniz signMoniz signMoniz sign is a clinical sign in which forceful passive plantar flexion of the ankle elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– forceful passive plantar flexionPlantarflexionPlantarflexion is the movement which increases the approximate 90 degree angle between the front part of the foot and the shin, as when depressing an automobile pedal...
of the ankle - Oppenheim signOppenheim's signOppenheim's sign is dorsiflexion of the big toe elicited by irritation downward of the medial side of the tibiaPositive sign indicates a damage to the pyramidal tract.It is named for Hermann Oppenheim....
– applying pressure to the medial side of the tibiaTibiaThe tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones.... - Schaeffer signSchaeffer's signSchaeffer's sign is a clinical sign in which squeezing the Achilles tendon elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– squeezing the Achilles tendonAchilles tendonThe Achilles tendon , also known as the calcaneal tendon or the tendo calcaneus, is a tendon of the posterior leg. It serves to attach the plantaris, gastrocnemius and soleus muscles to the calcaneus bone.- Anatomy :The Achilles is the tendonous extension of 3 muscles in the lower leg:... - Stransky signStransky's signStransky's sign is a clinical sign in which vigorous abduction followed by the sudden release of the little toe causes an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– vigorously abductingAbduction (kinesiology)Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...
and suddenly releasing the little toeFifth toeThe fifth toe is the outermost and usually the smallest toe of the foot.It is associated with many medical conditions, largely due to the use of shoes.... - Strümpell signStrümpell's signStrümpell's sign is a clinical sign in which the patient's attempt to flex the knee against resistance elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– patient attempts to flex the knee against resistance - Throckmorton reflexThrockmorton's reflexThrockmorton's reflex is a clinical sign in which pressure over the dorsal side of the metatarsophalangeal joint of the big toe elicits a plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– percussion over the metatarsophalangeal jointMetatarsophalangeal articulationsThe metatarsophalangeal articulations are the joints between the metatarsal bones of the foot and the proximal bones of the toes...
of the big toe
Abnormal reflex seen as flexion of toes
- Bekhterev-Mendel reflexBekhterev-Mendel reflexThe Bekhterev-Mendel reflex, also known as the Mendel reflex or Mendel-Bekhterev reflex, is a clinical sign found in patients with pyramidal tract lesions...
– flexion of the 2nd to 5th toes on percussion of the dorsum of the foot - Rossolimo signRossolimo's signRossolimo's sign is a clinical sign in which percussion of the tips of the toes causes an exaggerated flexion of the toes. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses....
– exaggerated flexion of the toes induced by rapid percussion on the tips of the toes