BATES VISUAL GUIDE TO PHYSICAL EXAMINATION. Vol. 18: Nervous System: Sensory System and Reflexes

Size: px

Start display at page:

Download "BATES VISUAL GUIDE TO PHYSICAL EXAMINATION. Vol. 18: Nervous System: Sensory System and Reflexes"

Roland Holt
6 years ago
Views:

1 BATES VISUAL GUIDE TO PHYSICAL EXAMINATION Vol. 18: Nervous System: Sensory System and Reflexes Your learning objectives for mastering the examination of the sensory system and reflexes are: to assess pain, temperature, light touch, and vibratory sensations, as well as position sense and discriminative sensation. And to correctly elicit the deep tendon reflexes of the biceps, triceps, brachioradialis, knee (or patellar tendon), and ankle (or Achilles tendon), as well as to properly test the plantar response (or Babinski s sign). Sensory impulses participate in reflex activity and give rise to conscious sensation, calibrate body position in space, and help regulate autonomic functions such as blood pressure, heart rate, and respiration. Anatomy Review Sensory System A complex system of sensory receptors relays impulses from skin, mucous membranes, muscles, tendons, and viscera that travel through peripheral projections into the posterior root ganglia and are eventually directed to the spinal cord and into the brain. When testing sensation, use a symmetric pattern on both sides of the body. Comparison helps you to better identify where sensory losses occur. By identifying the distribution of sensory abnormalities and the kinds of sensations affected, you can infer the location of causative lesions. To help localize neurologic lesions, the body is commonly mapped into dermatomes, which are skin bands innervated by the sensory root of a single spinal nerve. It is helpful to familiarize yourself first with the dermatomes shaded in green, for example, T4 at the nipple line, T10 at the umbilicus, and L5 at the anterior ankle and foot. Examining the Sensory System With the patient s health history in mind, and after good hand hygiene, you are ready for the physical examination. Begin the sensory examination by assessing pain sensation in arms, legs, and trunk. To do this, first warn the patient, then use the sharp end of a broken cotton swab stick, a previously unused safety pin, or some other suitable tool. Ask the patient to close his eyes, then, starting with the arms, test scattered areas in a symmetric pattern on both sides of the body, occasionally substituting the blunt end for comparison between sharp and dull. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 1

2 Discard the broken swab after using it. Temperature testing is performed when pain sensation is abnormal. Use two test tubes filled with hot and cold water. We ve got two test tubes here. That one is cold and that one is hot. Now you close your eyes and tell me which it is. Cold hot hot cold hot cold. Next, assess light touch with a cotton wisp. In diabetics, watch for the stocking glove pattern of sensory peripheral neuropathy. Now I m going to touch you with this cotton wisp. Whenever you feel it, you say, now. Okay. Close your eyes. Now...now... Next, assess vibratory sensation using a lightly vibrating, low pitched tuning fork. Have the patient close his eyes. Tap the tuning fork on the heel of your hand and place it against the soft distal tissue of the finger and large toe and ask the patient to tell you what he feels. Ask the patient to tell you when the sensation stops. What do you feel? The same thing. Okay, tell me when it stops. Then move the tuning fork closer to the trunk to see if it is perceived. Even in normal patients, some slight distal to proximal gradient may be found. Vibratory sense is often impaired in alcoholic peripheral neuropathy. To test position sense, or proprioception, hold the sides of the patient s big toe with your thumb and index finger. Avoid touching the other toes. Next, ask the patient to close his eyes and identify the direction of motion. Repeat several times on each side in an irregular sequence. Then compare with the big toe on the other foot. Up. Again with the patient s eyes closed, test position sense in the upper extremities beginning with a finger on each of the patient s hands and moving more proximally to the metacarpophalangeal joints and beyond if indicated. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 2

3 Here it comes. Up down. Finally, test discriminative sensations, beginning with stereognosis the ability to identify an object by feeling it. Ask the patient to close his eyes, then place a familiar object in the palm and ask the patient to identify it. A small coin. Repeat the procedure on the other hand using a different sized coin or a different object. A bigger coin? Not the same as the other hand? No, it s bigger. Okay. To test graphesthesia (or number identification), ask the patient to close his eyes and use a blunt object to draw a large number on the palm. What was that? Five. Using two ends of an opened paper clip or the ends of two pins, repeatedly touch the patient s finger pad with the two points at the same time and with one point occasionally. Be careful not to cause pain. Ask the patient to identify if he s being touched with one or two points. One. Then, reduce the distance between the points, so that you can determine the minimum distance at which the patient can identify two points. On the finger pad, the distance should be less than 5 millimeters. Two. Good. To test point localization, ask the patient to keep the eyes closed. Then touch a point on the patient s skin. Ask him to open his eyes and point to the place touched. Alright, close your eyes. Here comes the first one. This test is especially helpful for locating sensory loss on the trunk and legs. To test double extinction, use your fingertips to provide stimulus in either one area of the patient s body or in two areas simultaneously. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 3

4 Normally, the patient should be able to identify whether your stimulus was on one side or on both sides. Both. Anatomy Review Reflexes Before we assess the deep tendon reflexes, let's see how and where they occur. Deep tendon reflexes are involuntary monosynaptic cord reflexes arising from the stimulation of partially stretched muscle fibers. This sudden additional stretching sends impulses along afferent sensory nerve fibers to synapses in the spinal cord. Then efferent nerve fibers carry the impulses back to the muscle fibers, causing them to contract. Interruption of these monosynaptic arcs anywhere along their paths will cause loss of the reflex. Each deep tendon reflex corresponds to a specific spinal segment. The ankle reflex primarily relates to S1 and L5, the knee reflex to L2, L3, and L4...the brachioradialis to C5 and C6...the biceps reflex also to C5 and C6...and the triceps reflex to C6 and C7. Note the ascending order of the numerical sequence from ankle to triceps, a tip for helping you remember the reflex innervations. Assessment of Reflexes When assessing deep tendon reflexes, grade them on a scale from 0 to 4+. A grade of 0 reflects no response. 1+ indicates a somewhat diminished reflex. A 2+ reflex shows greater movement than 1+ and is the average, normal response. A 3+ reflex is brisker than average but is still normal. A 4+ reflex is a very brisk hyperactive response. By definition it must be accompanied by clonus, a rhythmic oscillation between flexion and extension. Begin assessing deep tendon reflexes by testing the biceps reflex. The patient's arm must be relaxed, partially flexed at the elbow, and positioned with the palm down. Depress the biceps tendon with your thumb or index finger. Strike your thumb or finger briskly with the reflex hammer. You should feel the biceps muscle contract and see flexion of the forearm. To assess the triceps reflex, flex the patient's arm at the elbow with the palm toward the body and pull the arm slightly across the chest. Strike the triceps tendon above the elbow. Watch for contraction of the triceps muscle and extension at the elbow. To elicit the supinator or brachioradialis reflex, the patient's forearms should rest on the abdomen or lap with the forearm partly pronated. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 4

5 When the patient is ready, strike the radius 1 to 2 inches above the wrist. Observe for flexion and supination of the forearm. To test the knee reflex, locate the patellar tendon with the patient's knee flexed. Briskly tap the tendon just below the patella. Note contraction of the quadriceps and look for quick extension of the knee. A hand on the anterior thigh lets you feel this reflex. Supporting both knees at once allows you to assess small differences between the reflexes of each knee. Test the ankle reflex. If the patient is sitting, dorsiflex the foot at the ankle. Ask the patient to relax and strike the Achilles tendon. Watch for the plantar flexion at the ankle and note the speed of relaxation after the muscular contraction. If the patient is lying down, flex one leg at both hip and knee and rotate it externally so that the lower leg rests across the opposite shin. Then, dorsiflex the foot at the ankle and strike the Achilles tendon. Repeat this test on the opposite side. If the knee and ankle reflexes seem hyperactive, test for ankle clonus. Support the knee in a slightly flexed position. With your other hand, dorsiflex and plantar flex the foot a few times, and then sharply dorsiflex the foot and maintain it in dorsiflexion. Look and feel for sustained rhythmic oscillations between dorsiflexion and plantar flexion. In most normal people, the ankle does not show clonus. A few clonic beats may be seen and felt, especially when the patient is tense or has exercised. Now turn to the cutaneous stimulation reflexes. To test these reflexes, lightly but briskly stroke each side of the abdomen from above (T8 10) and below (T10 12) the umbilicus. You should see contraction of the abdominal muscles and sometimes deviation of the umbilicus toward the stimulus. To test for plantar response, use an object such as the wooden end of an applicator stick or the handle of your reflex hammer to stroke the lateral aspect of the sole of the foot from the heel to the ball, curving medially across the ball. Warn the patient that this stimulus may feel uncomfortable. Use the lightest stimulus that will provoke a response. Note this patient s normal response: plantar flexion (or downgoing ) of the big toe. Some patients withdraw from the stimulus by flexing the hip and the knee. Hold the ankle if necessary to complete your observation. It is sometimes difficult to distinguish withdrawal from a Babinski response. Dorsiflexion of the big toe, or a positive Babinski s sign, is a pathological response, which, as simulated here, manifests itself in dorsiflexion (or upgoing ) of the big toe in conjunction with fanning of the other toes. A positive test indicates a corticospinal tract lesion, seen in stroke. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 5

6 If you suspect meningeal inflammation, test for meningeal signs. First, make sure there is no injury to the cervical vertebrae or cervical cord. With the patient lying down, place your hands behind the patient's head and flex the neck forward until the chin touches the chest if possible. There should be no resistance or pain. As you flex the patient's neck, watch his hips and knees. Normally they should remain relaxed and motionless. Hip and knee flexion with this maneuver is a positive Brudzinski sign. Flex one of the patient's legs at the hip and knee and then straighten the knee. This action normally produces discomfort behind the knee during extension but should not cause pain. Pain and resistance to knee extension is a positive Kernig s sign. For low back pain with nerve pain that radiates down the leg, commonly called sciatica, in the S1 distribution, test straight leg raising for lumbosacral radiculopathy. Raise the supine patient s relaxed and straightened leg, flexing the leg at the hip, then dorsiflex the foot at an angle of about 60 degrees. Radicular pain into the leg constitutes a positive test. Do not mistake normal tightness or discomfort in the buttocks or hamstring muscles as a positive test. Recording Your Findings A clear, well organized clinical record employing language that is neutral, professional, and succinct is one of the most important adjuncts to patient care [TYPING] Sensory: Pinprick, light touch, position, and vibration intact. Reflexes: 2+ and symmetric, with plantar reflexes downgoing. After practice and further review of this video, make sure you have mastered the important learning objectives for examining the patient s neuro sensory system. Copyright 2014 Wolters Kluwer Health, Inc. All rights reserved. Page 6

Neurological Assessment. Lecture 8

Neurological Assessment. Lecture 8 Neurological Assessment Lecture 8 Nervous System Central Nervous System Brain Spinal cord Peripheral Nervous System Cranial nerves Spinal nerves Central Nervous System-Brain Central Nervous System-Spinal