plantar reflex.pptx

plantar reflex.pptx

• 1.
  PLANTAR REFLEX
• 2.
  ◦ In normalindividual-stimulation of the skin of the plantar surface of the foot is followed by plantar flexion of the toes ◦ the response is usually fairly rapid, the small toes flex more than the great toe, and the reaction is more marked when the stimulus is along the medial plantar surface.
• 3.
  THE BABINSKI SIGN ◦In disease of the corticospinal system, there may be instead extension (dorsiflexion) of the toes, especially the great toe, with variable separation or fanning of the lateral four toes: the Babinski sign or extensor plantar response
• 5.
  ◦ Dorsiflexion ofgreat toe and small toes ◦ Fanning of toes ◦ Dorsiflexion of ankle ◦ Flexion of knee joint ◦ Flexion of hip joint ◦ Contraction of tensor fascia lata
• 6.
  ◦ Positioning patient– supine , knees extended , heels should rest in the bed ◦ Prerequisites – rule out ankylosis of great toe ◦ Stimulating agent -a blunt point, such as an applicator stick, handle of a reflex hammer, a broken tongue blade, the thumbnail, or the tip of a key. ◦ Strength of stimulus - should be firm enough to elicit a consistent response, but as light as will suffice. ◦ If no response is obtained, progressively sharper objects and firmer applications are necessary
• 7.
  ◦ Site ofstimulus- Plantar stimulation must be carried out far laterally, in the S1 root/sural nerve sensory distribution ◦ The stimulus should begin near the heel and be carried up the side of the foot at a deliberate pace, not too quickly, usually stopping at the metatarsophalangeal joints. ◦ The response has usually occurred by the time the stimulus reaches the midportion of the foot. If the response is difficult to obtain, the stimulus should continue along the metatarsal pad from the little toe medially but stopping short of the base of the great toe. ◦ The most common mistakes are insufficiently firm stimulation, placement of the stimulus too medially, and moving the stimulus too quickly so that the response does not have time to develop.
• 8.
  ◦ Reinforcement ofplantar reflex- reinforced by rotating the patient’s head to the opposite side. ◦ Puusepp’s sign is tonic, slow abduction of the little toe on plantar stimulation and may be present when great toe extension is absent.
• 9.
  ◦ The Babinskisign is a part of the primitive flexion reflex. The central nervous system is organized according to movement patterns, and one of the most basic patterns is avoidance or withdrawal from a noxious stimulus. ◦ In higher vertebrates, the flexion response includes flexion of the hip and knee, and dorsiflexion of the ankle and toes, all serving to remove the threatened part from danger ◦ In human infants, the primitive flexion response persists, and an extensor plantar response is normal in infancy
• 10.
  ◦ Maturation ofthe descending motor systems suppresses the primitive flexion response. This may be necessary for normal ambulation, or else our legs and feet might be whipping into flexion unexpectedly, just from stepping on a pebble. ◦ The corticospinal tract is myelinated by about the end of the first year of life, about the time babies begin to walk. ◦ When there is disease involving the corticospinal tract, the primitive flexion response may reappear, and the first clinical evidence of this is the Babinski sign.
• 11.
  Triple flexion response ◦With more severe and extensive disease, the entire flexion response emerges, so that stimulation of the sole causes dorsiflexion not only of the toe, but also the ankle, as well as flexion of the hip and knee (which for some perplexing reason has four parts) ◦ In addition, there is often contraction of the tensor fascia lata causing slight internal rotation at the hip and more rarely abduction of the hip (Brissaud’s reflex) ◦ These movements are all part of a spinal defense reflex mechanism, also known as the reflex of spinal automatism (Marie), the pathologic shortening reflex, reflex flexor synergy, the withdrawal reflex, mass flexion reflex, and the réflexe or phénomène des raccourcisseurs. ◦ The response may be bilateral and is then called the crossed flexor reflex.
• 14.
  Problems in Interpretingthe Plantar Response ◦ The most common problem is distinguishing an upgoing toe from voluntary withdrawal, especially when the plantar surface of the foot is unusually sensitive ◦ If the patient is ticklish, it may help to simply hold the ankle firmly. Some believe withdrawal is less if the patient performs the plantar stimulation himself (an auto-Babinski) ◦ Some patients have no elicitable plantar response, in which case the plantars are said to be mute or silent.
• 15.
  ◦ Toe extensionmay occasionally fail to occur because of disruption of the lower motor neuron innervation to the EHL (e.g., radiculopathy, peroneal nerve palsy, peripheral neuropathy, amyotrophic lateral sclerosis [ALS]), in which case the toe is paralyzed for voluntary contraction as well. ◦ Frontal lobe lesions may cause a hyperactive plantar grasp reflex , driving the toes downward.
• 16.
  ◦ With extensivedisease involving both the basal ganglia and the corticospinal tract, there may be no extensor response. ◦ Intact extrapyramidal pathways are essential to its production. ◦ The extensor plantar response does not occur in lesions of the basal ganglia alone; its presence in some extrapyramidal disorders, such as Parkinson’s disease,suggests associated corticospinal tract involvement. ◦ Paralysis of the toe flexors may cause a false-positive extensor plantar response.
• 17.
  ◦ An extensorplantar response does not always signify structural disease ◦ it may occur as a transient manifestation of physiologic dysfunction of the corticospinal pathways. ◦ A Babinski sign may sometimes be found in ◦ deep anesthesia and narcosis, in drug and alcohol intoxication, in metabolic coma such as hypoglycemia, in deep sleep, postictally. ◦ During Cheyne-Stokes respirations, an upgoing toe may appear during the apneic phase anddisappear during the phase of active respiration.
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