The plantar reflex is a

reflex In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...

elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In healthy adults, the plantar reflex causes a downward response of the

hallux Toes are the digits (fingers) 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 '' pl ...

( flexion). An upward response (

extension Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * E ...

) of the

is known as the Babinski response or Babinski sign, named after the neurologist Joseph Babinski. The presence of the Babinski sign can identify

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

and

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

in adults, and also exists as a primitive reflex in

infant An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

s. While first described in the medical literature by Babinski in 1896, the reflex has been identified in art at least as early as

Botticelli Alessandro di Mariano di Vanni Filipepi ( – May 17, 1510), known as Sandro Botticelli (, ), was an Italian painter of the Early Renaissance. Botticelli's posthumous reputation suffered until the late 19th century, when he was rediscovered ...

's '' Virgin and Child with an Angel'', painted in the mid-

15th century The 15th century was the century which spans the Julian dates from 1 January 1401 ( MCDI) to 31 December 1500 ( MD). In Europe, the 15th century includes parts of the Late Middle Ages, the Early Renaissance, and the early modern period. M ...

Methods

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 Toes are the digits (fingers) 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 ''plant ...

s ( 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; due to the tightening of infection control regulation this is no longer recommended. Either a single use device or the thumb nail should be used. There are three responses possible: * Flexor: the toes curve down and inwards, and the foot inverts; this is the response seen in healthy adults. * Indifferent: there is no response. * Extensor: the

dorsiflexes, and the other toes fan out; this is Babinski's sign, which indicates damage to the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

if elicited in an adult, but normal reflex if elicited in infants (see below). As the

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

responsible for the sign expands, so does the area from which the

afferent Afferent may refer to: Anatomical structures Meaning "conveying towards a center": * Afferent arterioles, blood vessels that supply the nephrons * Afferent lymphatic vessels, lymph vessels that carry lymph to a lymph node * Afferent nerve fiber ...

Babinski response may be elicited. The Babinski response is also normal while asleep and after a long period of walking.

Interpretation

The Babinski sign can indicate upper motor neuron lesion constituting damage to the

corticospinal tract The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. There are more than one million neur ...

. 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 (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal ...

investigations, including

CT scanning A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

of the brain or MRI of the spine, as well as

lumbar puncture Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to ...

for the study of

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...

. The phrase "negative Babinski sign" is sometimes used for the normal flexor plantar response.

In infants

Infant An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

s will usually show an extensor response. In one study of 256 healthy infants, the response to testing was extensor in 73.8%, flexor in 8.9%, and equivocal in 17.3% This extensor response occurs because the corticospinal pathways that run from the

down the

are not fully

myelin Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be ...

ated at this age, so the reflex is not inhibited by the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

. The extensor response usually disappears – giving way to the flexor response – by 12 months of age. Its persistence beyond age 2–3 indicates a problem in the brain or spinal cord.

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 the tibial nerve. Toe extensors (extensor hallucis 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.

Relationship to Hoffmann's reflex

The Hoffmann's reflex is sometimes described as the

upper limb The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulde ...

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 The flexor digitorum profundus is a muscle in the forearm of humans that flexes the fingers (also known as digits). It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm. Together t ...

that is normally fully inhibited by upper motor neurons. The pathway producing the plantar response is more complicated, and is not monosynaptic.

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. * Bing sign – multiple pinpricks on the dorsum of the foot * Cornell sign – scratching along the inner side of the extensor hallucis longus tendon * Chaddock sign – stroking the lateral malleolus * Doug's sign – electrically stimulating peripheral nerves during a

Nerve conduction study A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical specia ...

* Gonda sign – flexing and suddenly releasing the 4th toe * Gordon sign – squeezing the calf muscle *

Moniz sign Moniz 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.It is named after Port ...

– forceful passive

plantar flexion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...

of the ankle * Oppenheim sign – applying pressure to the medial side of the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

* Schaeffer sign – squeezing the

Achilles tendon The Achilles tendon or heel cord, also known as the calcaneal tendon, is a tendon at the back of the lower leg, and is the thickest in the human body. It serves to attach the plantaris, gastrocnemius (calf) and soleus muscles to the calcaneus (h ...

* Silva sign – pinching the

rectus femoris muscle The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius (deep to the rectus femoris), and the vastus lateralis. All four parts of the quadriceps muscle attach t ...

* Stransky sign – vigorously abducting and suddenly releasing the

little toe Toes are the digits (fingers) 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 ''plant ...

* Strümpell sign – patient attempts to flex the knee against resistance * Throckmorton reflex – percussion over the

metatarsophalangeal joint The metatarsophalangeal joints (MTP joints), also informally known as toe knuckles, are the joints between the metatarsal bones of the foot and the proximal bones (proximal phalanges) of the toes. They are condyloid joints, meaning that an ellipt ...

of the big toe

Abnormal reflexes seen as flexion of toes

* Bekhterev-Mendel reflex – flexion of the 2nd to 5th toes on percussion of the dorsum of the foot * Rossolimo sign – exaggerated flexion of the toes induced by rapid percussion on the tips of the toes

References

{{DEFAULTSORT:Plantar Reflex Reflexes