Cerebrospinal fluid flows through a channel (the subarachnoid space) between the layers of tissue (meninges) that cover the brain and spinal cord. This fluid, which surrounds the brain and spinal cord, helps cushion them against sudden jarring and minor injury. Show
For a spinal tap (lumbar puncture), a sample of cerebrospinal fluid is withdrawn with a needle and sent to a laboratory for examination.
The cerebrospinal fluid is checked for evidence of infections, tumors, and bleeding in the brain and spinal cord. These disorders may change the content and appearance of the cerebrospinal fluid, which normally contains few red and white blood cells and is clear and colorless. For example, the following findings suggest certain disorders:
For a spinal tap, people typically lie on their side in a bed and draw their knees to their chest. A local anesthetic is used to numb the insertion site. Then, a needle is inserted between two vertebrae in the lower spine below the end of the spinal cord.
A spinal tap may be done for other reasons:
A spinal tap usually takes no more than 15 minutes.
The goals of the neurological examination are several:
The major areas of the exam, covering the most testable components of the neurological system, include:
Real and imagined problems with the neurological examination: The neurological examination is one of the least popular and (perhaps) most poorly performed aspects of the complete physical. I suspect that this situation exists for several reasons:
The above are not meant to lower expectations with regards to how well a physician should be expected to learn and perform the neurological examination. Rather, I mention these points to highlight some of the real and imagined obstacles to clinical performance. Like all other aspects of the physical exam, there is a wealth of information that can be obtained from the neurological examination, provided that it is done carefully and accurately.This is, of course, predicated on learning how to do it correctly. A few practical considerations/suggestions:
Like any other aspect of the exam, the neurological assessment has limits. Testing of one system is often predicated on the normal function of other organ systems. If, for example, a patient is visually impaired, they may not be able to perform finger to nose testing, a part of the assessment of cerebellar function (see below). Or, a patient's severe degenerative hip disease will prevent them from walking, making that aspect of the exam impossible to assess. The interpretation of "findings" must therefore take these things into account. Only in this way can you generate an accurate picture. Doing this, of course, takes practice and experience. Cranial Nerve (CN) Testing
Many practitioners incorporate cranial nerve testing with their complete examination of the head and neck (see the Head and Neck section of this web site for details). A detailed description of the CN assessment is provided below. As each half of the body has its own cranial nerve, both right and left sides must be checked independently. Cranial Nerve 1 (Olfactory): Formal assessment of ability to smell is generally omitted, unless there is a specific complaint. If it is to be tested:
Cranial Nerve 2 (Optic): This nerve carries visual impulses from the eye to the optical cortex of the brain by means of the optic tracts. Testing involves 3 phases (also covered in the section of this site dedicated to the Eye Exam):
For more information about visual field testing, see the following links: University of Arkansas, gross anatomy of visual pathway
Cranial nerves 3, 4 and 6 & extra ocular movements:Normally, the eyes move in concert (ie when left eye moves left, right eye moves in same direction to a similar degree). The brain takes the input from each eye and puts it together to form a single image. This coordinated movement depends on 6 extra ocular muscles that insert around the eye balls and allow them to move in all directions. Each muscle is innervated by one of 3 Cranial Nerves (CNs): CNs 3, 4 and 6. Movements are described as: elevation (pupil directed upwards), depression (pupil directed downwards), adbduction (pupil directed laterally), adduction (pupil directed medially), extorsion (top of eye rotating away from the nose), and intorsion (top of eye rotating towards the nose).
The 3 CNs responsible for eye movement and the muscles that they control are as follows: CN 4 (Trochlear): Controls the Superior Oblique muscle. CN 6 (Abducens): Controls the Lateral Rectus muscle. CN 3 (Oculomotor): Controls the remaining 4 muscles (inferior oblique, inferior rectus, superior rectus, and medial rectus). CN3 also raises the eyelid and mediates constriction of the pupil (discussed below). The mnemonic "S O 4, L R 6, All The Rest 3" may help remind you which CN does what (Superior Oblique CN 4, Lateral Rectus CN 6, All The Rest of the muscles innervated by CN 3). EOMs and their function: The medial and lateral rectus muscles are described first, as their functions are very straight forward: Lateral rectus: Abduction (ie lateral movement along the horizontal plane) Medial rectus: Adduction (ie. Medial movement along the horizontal plane) The remaining muscles each causes movement in more than one direction (e.g. some combination of elevation/depression, abduction/adduction, intorsion/extorsion). This is due to the fact that they insert on the eyeball at various angles, and in the case of the superior oblique, thru a pulley. Review of the origin and insertion of each muscle sheds light on its actions (see links @ the end of this section). The net impact of any one EOM is the result of the position of the eye and the sum of forces from all other contributing muscles. Specific actions of the remaining EOMs are described below. The action which the muscle primarily performs is listed first, followed by secondary and then tertiary actions. Inferior rectus: depression, extorsion and adduction. Superior rectus: elevation, intorsion and adduction Superior oblique: intorsion, depression and abduction Inferior oblique: extorsion, elevation and abduction
Practically speaking, cranial nerve testing is done such that the examiner can observe eye movements in all directions. The movements should be smooth and coordinated. To assess, proceed as follows:
Testing Extraocular Movements
Pathology: Isolated lesions of a cranial nerve or the muscle itself can adversely affect extraocular movement. Patients will report diplopia (double vision) when they look in a direction that's affected. This is because the brain can't put together the discordant images in a way that forms a single picture. In response, they will either assume a head tilt that attempts to correct for the abnormal eye positioning or close the abnormal eye. As an example, the patient shown below has a left cranial nerve 6 lesion, which means that his left lateral rectus no longer functions. When he looks right, his vision is normal. However, when he looks left, he experiences double vision as the left eye can't move laterally. This is referred to as horizontal diplopia.For Additional Information See: Digitial DDx: Double Vision
Left CN 6 Palsy It's worth mentioning that disorders of the extra ocular muscles themselves (and not the CN which innervate them) can also lead to impaired eye movement. For example, pictured below is a patient who has suffered a traumatic left orbital injury. The inferior rectus muscle has become entrapped within the resulting fracture, preventing the left eye from being able to look downward. The scleral blood and peri-orbital echymosis are secondary to the trauma as well. *For more on EOMs go to: Eyes -EOMs As mentioned above, CN 3 also innervates the muscle which raises the upper eye lid (Levator Palpebrae Superioris muscle). This can be assessed by simply looking at the patient. If there is CN 3 dysfunction, the eyelid on that side will cover more of the iris compared with the other eye. This is referred to as ptosis.
Right eye ptosis from CN 3 Palsy. In addition, the right eye is directed laterally, which is due to unopposed effects of CNs 4 & 6. The dilated right pupil is explained below. Assessing PupilsThe response of pupils to light is controlled by afferent (sensory) nerves that travel with CN 2 and efferent (motor) nerves that travel with CN 3. These innervate the ciliary muscle, which controls the size of the pupil. Testing is performed as follows:
Interpretation:
Right CN 3 Palsy - Note that the right pupil is dilated relative to the left, due to loss of efferent input. The ptosis and abnormal eye positioning are discussed above. For more information about pupillary response and CN 3, see the following links: More on Extraocular movements: http://www.tedmontgomery.com/the_eye/eom.html#top Dartmouth Neurosciences - Extraocular movements http://www.dartmouth.edu/~dons/part_1/chapter_4.html For Additional Information See: Digitial DDx: Pupil Abnormalities CN 4 (Trochlear): Seen under CN 3.CN 5 (Trigeminal): This nerve has both motor and sensory components.Assessment of CN 5 Sensory Function: The sensory limb has 3 major branches, each covering roughly 1/3 of the face. They are: the Ophthlamic, Maxillary, and Mandibular. Assessment is performed as follows:
The patient should be able to clearly identify when the sharp end touches their face. Of course, make sure that you do not push too hard as the face is normally quite sensitive. The Ophthalmic branch of CN 5 also receives sensory input from the surface of the eye. To assess this component:
Assessment of CN 5 Motor Function: The motor limb of CN 5 innervates the Temporalis and Masseter muscles, both important for closing the jaw. Assessment is performed as follows:
CN6 (Abducens): See under CN 3.CN7 (Facial): This nerve innervates many of the muscles of facial expression. Assessment is performed as follows:
Interpretation: CN 7 has a precise pattern of inervation, which has important clinical implications. The right and left upper motor neurons (UMNs) each innervate both the right and left lower motor neurons (LMNs) that allow the forehead to move up and down. However, the LMNs that control the muscles of the lower face are only innervated by the UMN from the opposite side of the face.
CN7 - Facial Nerve Thus, in the setting of CN 7 dysfunction, the pattern of weakness or paralysis observed will differ depending on whether the UMN or LMN is affected. Specifically:
Right central CN7 dysfunction: Note preserved abiltiy to wrinkle forehead. Left corner of mouth, however, is slightly lower than right. Left naso-labial fold is slightly less pronounced compared with right.
Left peripheral CN7 dysfunction: Note loss of forehead wrinkle, ability to close eye, ability to raise corner of mouth, and decreased naso-labial fold prominence on left. This clinical distinction is very important, as central vs peripheral dysfunction carry different prognostic and treatment implications. Bell's Palsy (peripheral CN 7 dysfunction)tends to happen in patient's over 50 and often responds to treatment with Acyclovir (an anti-viral agent) and Prednisone (a corticosteroid). Over the course of weeks or months there is usually improvement and often complete resolution of symptoms. Assessment of acute central (UMN) CN 7 dysfunction would require quite a different approach (e.g. neuroimaging to determine etiology). CN 7 is also responsible for carrying taste sensations from the anterior 2/3 of the tongue. However as this is rarely of clinical import, further discussion is not included. CN8 (Acoustic): CN 8 carries sound impulses from the cochlea to the brain. Prior to reaching the cochlea, the sound must first traverse the external canal and middle ear. Auditory acuity can be assessed very crudely on physical exam as follows:
These tests are rather crude. Precise quantification, generally necessary whenever there is a subjective decline in acuity, requires special equipment and training. The cause of subjective hearing loss can be assessed with bedside testing. Hearing is broken into 2 phases: conductive and sensorineural. The conductive phase refers to the passage of sound from the outside to the level of CN 8. This includes the transmission of sound through the external canal and middle ear. Sensorineural refers to the transmission of sound via CN 8 to the brain. Identification of conductive (a much more common problem in the general population) defects is determined as follows: Weber Test:
512 Hz Tuning Fork
Weber Test Rinne Test:
Rinne Test Interpretation:
Summary: Identifying conductive v sensorineural hearing deficits requires historical information as well as the results of Webber and Rinne testing. In summary, this data is interpreted as follows:
For Additional Information See: Digitial DDx: Hearing Loss CN9 (Glosopharyngeal) and CN 10 (Vagus): These nerves are responsible for raising the soft palate of the mouth and the gag reflex, a protective mechanism which prevents food or liquid from traveling into the lungs As both CNs contribute to these functions, they are tested together.Testing Elevation of the soft palate:
Normal Oropharynx Interpretation: If CN 9 on the right is not functioning (e.g. in the setting of a stroke), the uvula will be pulled to the left. The opposite occurs in the setting of left CN 9 dysfunction.
Left CN9 Dysfunction: Patient status post stroke affecting left CN9. Uvula therefore pulled over towards right. Be aware that other processes can cause deviation of the uvula.A peritonsilar abscess, for example, will push the uvula towards the opposite (i.e. normal) tonsil.
Left peritonsillar abscess: infection within left tonsil has pushed uvula towards the right. Testing the Gag Reflex:
Gag testing is rather noxious. Some people are particularly sensitive to even minimal stimulation. As such, I would suggest that you only perform this test when there is reasonable suspicion that pathology exists. This would include two major clinical situations:
CN 9 is also responsible for taste originating on the posterior 1/3 of the tongue. As this is rarely a clinically important problem, further discussion is not included. CN 10 also provides parasympathetic innervation to the heart, though this cannot be easily tested on physical examination. CN11 (Spinal Accessory): CN 11 innervates the muscles which permit shrugging of the shoulders (Trapezius) and turning the head laterally (Sternocleidomastoid).
CN12 (Hypoglossal): CN 12 is responsible for tongue movement. Each CN 12 innervates one-half of the tongue.Testing:
Interpretation: If the right CN 12 is dysfunctional, the tongue will deviate to the right. This is because the normally functioning left half will dominate as it no longer has opposition from the right. Similarly, the tongue would have limited or absent ability to resist against pressure applied from outside the left cheek.
Left CN 12 Dysfunction: Stroke has resulted in L CN 12 Palsy. Sensory and Motor Examinations - A Brief Review of Anatomy and Physiology:
Testing of motor and sensory function requires a basic understanding of normal anatomy and physiology. In brief:
For more information about spinal cord anatomy, see the following link: Review of Spinal Anatomy It may help to think of a nerve root as an electrical cable composed of many different colored wires, each wire representing an axon. As the cable moves away from the spinal cord, wires split off and head to different destinations. Prior to reaching their targets, they combine with wires originating from other cables. The group of wires that ultimately ends at a target muscle group may therefore have contributions from several different roots. For more information about radial nerve anatomy and function, see below. To view a dermatomal map, see the following link: Dermatome Map University of Scranton Understanding the above neruo-anatomic relationships and patterns of innervation has important clinical implications when trying to determine the precise site of neurological dysfunction. Injury at the spinal nerve root level, for example, will produce a characteristic loss of sensory and motor function. This will differ from that caused by a problem at the level of the peripheral nerve. An approach to localizing lesions on the basis of motor and sensory findings is described in the sections which follow. Realize that there is a fair amount of inter-individual variation with regards to the specifics of innervation. Also, recognize that often only parts of nerves may become dysfunctional, leading to partial motor or sensory deficits. As such, the patterns of loss are rarely as "pure" as might be suggested by the precise descriptions of nerves and their innervations. Sensory TestingSensory testing of the face is discussed in the section on Cranial Nerves. Testing of the extremities focuses on the two main afferent pathways: Spinothalamics and Dorsal Columns.
A screening evaluation of these pathways can be performed as follows: Spinothalamics
Dorsal Columns Proprioception: This refers to the body's ability to know where it is in space. As such, it contributes to balance. Similar to the Spinothalamic tracts, disorders which affect this system tend to first occur at the most distal aspects of the body. Thus, proprioception is checked first in the feet and then, if abnormal, more proximally (e.g. the hands). Technique:
Testing Proprioception Similar testing can be done on the fingers. This is usually reserved for those settings when patients have distal findings and/or symptoms in the upper extremities. Vibratory Sensation: Vibratory sensation travels to the brain via the dorsal columns. Thus, the findings generated from testing this system should corroborate those of proprioception (see above). Technique:
128 Hz tuning fork
Testing vibratory sensation Repeat testing on the other foot. Additional/Special Testing for Dorsal Column Dysfunction Testing Two Point Discrimination: Patients should normally be able to distinguish simultaneous touch with 2 objects which are separated by at least 5mm. These stimuli are carried via the Dorsal Columns. While not checked routinely, it is useful test if a discrete peripheral neruropathy is suspected (e.g. injury to the radial nerve). Technique:
Special Testing for Early Diabetic Neuropathy: A careful foot examination should be performed on all patients with symptoms suggestive of sensory neuropathy or at particular risk for this disorder (e.g. anyone with Diabetes). Loss of sensation in this area can be particularly problematic as the feet are a difficult area for the patient to evaluate on their own. Small wounds can become large and infected, unbeknownst to the insensate patient. Sensory testing as described above can detect this type of problem. Disposable monofilaments (known as the Semmes-Weinstein Aethesiometer) are specially designed for a screening evaluation. These small nylon fibers are designed such that the normal patient should be able to feel the ends when they are gently pressed against the soles of their feet.
Monofiliment Technique:
Monofiliment testing: Patients with normal sensation should be able to detect the monofiliment when it is lightly applied (picture on left). If the force required to provoke a sensory response is strong enough to bend the monofiliment Interpretation: If the examiner has to supply enough pressure such that the filament bends prior to the patient being able to detect it, they likely suffer from sensory neuropathy. Testing should be done in multiple spots to verify the results. Patient's with distal sensory neuropathy should carefully examine their feet and wear good fitting shoes to assure that skin breakdown and infections don't develop. Efforts should also be made to closely control their diabetes so that the neuropathy does not progress.
Neuropathic Ulcer: Large ulcer has developed in this patient with severe diabetic neuropathy. Interpreting Results of Sensory Testing For Additional Information See: Digital DDx: Numbness Patterns of Impairment for the Spinothalamic Tracts:
For more information about peripheral nerve injuries, see the following link: Peripheral nerves and their territories of innervation For more information about nerve root compression, see the following links: University of Wisconsin, Anatomy and pathophysiology of nerve root compression Image of Herniated Disk For more information about peripheral nerves and their territories of innervation, see the following link: Peripheral nerves and their territories of innervation Patterns of Impairment for Dorsal Column Dysfunction: Proprioception: Patients should be able to correctly identify the motion and direction of the toe. In the setting of Dorsal Column dysfunction (a common complication of diabetes, for example), distal testing will be abnormal. This is similar to the pattern of injury which affects the Spinothalamic tracts described above. Vibratory Sensation:
Motor TestingThe muscle is the unit of action that causes movement. Normal motor function depends on intact upper and lower motor neurons, sensory pathways and input from a number of other neurological systems. Disorders of movement can be caused by problems at any point within this interconnected system. For Additional Information See: Digital DDx: Weakness Muscle Bulk and Appearance: This assessment is somewhat subjective and quite dependent on the age, sex and the activity/fitness level of the individual. A frail elderly person, for example, will have less muscle bulk then a 25 year old body builder. With experience, you will get a sense of the normal range for given age groups, factoring in their particular activity levels and overall states of health. Things to look for:
Muscle Asymmetry
A number of more common (and relatively benign) conditions can also cause fasciulations, including: post exercise, meds, stimulants, and assorted metabolic processes. For more information about Parkinson's Disease, see the following link: NIH Sponsored Site About Parkinson's Disease For Additional Information See: Digital DDx: Tremor
Diffuse Muscle Wasting: Note loss muscle bulk in left hand due to peripheral denervation.In particular, compare left and right thenar eminences. Tone: When a muscle group is relaxed, the examiner should be able to easily manipulate the joint through its normal range of motion. This movement should feel fluid. A number of disease states may alter this sensation. For the screening examination, it is reasonable to limit this assessment to only the major joints, including: wrist, elbow, shoulder, hips and knees. Technique:
Things to look for:
Strength: As with muscle bulk (described above), strength testing must take into account the age, sex and fitness level of the patient. For example, a frail, elderly, bed bound patient may have muscle weakness due to severe deconditioning and not to intrinsic neurological disease. Interpretation must also consider the expected strength of the muscle group being tested. The quadriceps group, for example, should be much more powerful then the Biceps. There is a 0 to 5 rating scale for muscle strength:
'+' and '-' can be added to allow for more nuanced scoring of 4/5 strength (e.g., 4+ or 4- but not 5-, 3+ or 3-, etc.) Thus, a patient who can overcome "moderate but not full resistance" might be graded 4+. This is quite subjective, with a fair amount of variability amongst clinicians. Ultimately, it's most important that you develop your own sense of what these gradations mean, allowing for internal consistency and interpretability of serial measurements. Specifics of Strength Testing - Major Muscle Groups: In the screening examination, it is reasonable to check only the major muscles/muscle groups. More detailed testing can be performed in the setting of discrete/unexplained weakness. The names of the major muscles/muscle groups along with the spinal roots and peripheral nerves that provide their innervation are provided below. Nerve roots providing the greatest contribution are printed in bold. More extensive descriptions of individual muscles and their functions, along with their precise innervations can be found in a Neurology reference text.
It is generally quite helpful to directly compare right v left sided strength, as they should more or less be equivalent (taking into account the handedness of the patient). If there is weakness, try to identify a pattern, which might provide a clue as to the etiology of the observed decrease in strength. In particular, make note of differences between:
Special Testing for subtle weakness: Subtle weakness can be hard to detect. Pay attention to how the patient walks, uses and holds their arms and hands as they enter the room, get up and down from a seated position, move onto the examination table, etc. Pronator drift is a test for slight weakness of the upper extremities. The patient should sit with both arms extended, palms directed upward. Subtle weakness in either arm will cause slight downward drift and pronation of that limb (i.e. the arm will rotate slightly inward and down). Common peripheral nerves, territories of innervation, and clinical correlates.
This table provides information about usual patterns of innervations. There is occasionally interindividual variation. In the setting of peripheral nerve dysfunction, the level of the lesion will determine the extent of the deficit. That is, proximal insults will cause the entire nerve distribution to be affected while more distal lesions will only impact function beyond the site of the injury. More on carpal tunnel syndrome...
Carpal Tunnel Induced Atrophy: Chronic, severe compression of the median nerve within the carpal tunnel has led to atrophy of the Thenar muscles (hand on right). A normal appearing Thenar Eminence is demonstrated on left.Reflex TestingReflex testing incorporates an assessment of the function and interplay of both sensory and motor pathways. It is simple yet informative and can give important insights into the integrity of the nervous system at many different levels. Physiology of Reflexes Assessment of reflexes is based on a clear understanding of the following principles and relationships:
TechniqueThe Reflex Hammer You will need to use a reflex hammer when performing this aspect of the exam. A number of the most commonly used models are pictured below. Regardless of the hammer type, proper technique is critical. The larger hammers have weighted heads, such that if you raise them approximately 10 cm from the target and then release, they will swing into the tendon with adequate force. The smaller hammers should be swung loosely between thumb and forefinger.
Small Hammers
Large Hammer,
Large Hammer, Technique:
This grading system is rather subjective. Additional levels of response can be included by omitting the '+' or adding a '-' to any of the numbers. As you gain more experience, you'll have a greater sense of how to arrange your own scale. Specifics of Reflex Testing - The peripheral nerves and contributing spinal nerve roots that form each reflex arc are listed in parentheses: Achilles (S1, S2 - Sciatic Nerve):
Achilles Tendon:Tendon is outlined in pen on left, grasped by forceps (gross dissection) on right.
Positions for Checking Achilles Reflex Patellar (L3, L4 -Femoral Nerve):
Patellar Tendon: Outlined in pen on left, grasped by forceps (gross dissection) on right.
Patellar Reflex Testing, seated patient
Patellar Reflex, supine patient Biceps (C5, C6 - Musculocutaneous Nerve):
Biceps Tendon:Tendon is outlined in pen on left, grasped by forceps (gross dissection) on right.
Biceps Reflex Testing
Biceps Reflex Testing,arm supported Brachioradialis (C5, C6 - Radial Nerve):
Brachioradialis Tendon: Tendon is outlined in pen on left, grasped by forceps (gross dissection) on right.
Brachioradialis Reflex Triceps (C7, C8 - Radial Nerve):
Triceps Tendon:Tendon is outlined in pen on left, grasped by forceps (gross dissection) on right. Making Clinical Sense of Reflexes:Normal reflexes require that every aspect of the system function normally. Breakdowns cause specific patterns of dysfunction. These are interpreted as follows:
Trouble Shooting
Babinski Response The Babinski response is a test used to assess upper motor neuron dysfunction and is performed as follows:
Interpretation: In the normal patient, the first movement of the great toe should be downwards (i.e. plantar flexion). If there is an upper motor neuron injury (e.g. spinal cord injury, stroke), then the great toe will dorsiflex and the remainder of the other toes will fan out. A few additional things to remember:
Babinski Response Present
CoordinationThe cerebellum fine tunes motor activity and assists with balance. Dysfunction results in a loss of coordination and problems with gait. The left cerebellar hemisphere controls the left side of the body and vice versa. Specifics of Testing: There are several ways of testing cerebellar function. For the screening exam, using one modality will suffice. If an abnormality is suspected or identified, multiple tests should be done to determine whether the finding is durable. That is, if the abnormality on one test is truly due to cerebellar dysfunction, other tests should identify the same problem. Gait testing, an important part of the cerebellar exam, is discussed separately (see next section).
Interpretation: The patient should be able to do this at a reasonable rate of speed, trace a straight path, and hit the end points accurately. Missing the mark, known as dysmetria, may be indicative of disease.
Interpretation: The movement should be fluid and accurate. Inability to do this, known as dysdiadokinesia, may be indicative of cerebellar disease.
Interpretation: The movement should be performed with speed and accuracy. Inability to do this, known as dysdiadokinesia, may be indicative of cerebellar disease.
Intepretation: The movement should trace a straight line along the top of the shin and be done with reasonable speed. If the movement is accurate and smooth but slow, the likely problem is weakness. Realize that other organ system problems can affect performance of any of these tests. If, for example, the patient is visually impaired, they may not be able to see the target during finger to nose pointing. Alternatively, weakness due to a primary muscle disorder might limit the patient's ability to move a limb in the fashion required for some of the above testing. Thus, other medical and neurological conditions must be taken into account when interpreting cerebellar test results. Gait TestingAbility to stand and walk normally is dependent on input from several systems, including: visual, vestibular, cerebellar, motor, and sensory. The precise cause(s) of the dysfunction can be determined by identifying which aspect of gait is abnormal and incorporating this information with that obtained during the rest of the exam. Difficulty getting out a chair and initiating movement, for example, would be consistent with Parkinson's Disease. On the other hand, lack of balance and a wide based gait would suggest a cerebellar disorder. In each case, finding elsewhere in the exam should help point you in the right direction. For Additional Information See: Gait Disorders A lot of information about neurological (and other) disorders can be gained from simply watching a patient stand and then walk. For the screening exam, simply observing while the patient walks into your office and gets up and down from the exam table will provide all of the relevant information. If there is suspicion of neurological disease (based on history, other exam findings, observation of gait) then more detailed testing should be performed. Proceed as follows:
To see a video showing the gait of a patient status post stroke, click on the movie icon. Making Sense of Neurological FindingsWhile compiling information generated from the motor and sensory examinations, the clinician tries to identify patterns of dysfunction that will allow him/her to determine the location of the lesion(s). What follows is one way of making clinical sense of neurological findings.
Information from the sensory, motor and reflex examinations should correlate with one another, painting the best picture of where the level of dysfunction is likely to exist. A few examples of injuries resulting in characteristic patterns of motor and sensory loss are described below: Example 1 In the setting of a suspected acute spinal cord injury at the T 10 vertebral level, for example, the following might be identified on detailed neurological examination:
Example 2 Partial Cord Transection - The Brown-Sequard Lesion: A knife injury, for example, might damage only the right half of the cord at the T 10 level. This would result in the following findings on detailed exam:
Several additional examples of specific patterns of nerve injury/dysfunction can be found via the following links: University of Wisconsin, Anatomy and pathophysiology of spinal cord copression syndromes University of Wisconsin, Anatomy and pathophysiology of motor weakness University of Wisconsin, Examples of various radiculopathies A few final comments about diagnosing neurologic disorders: It is also important to note that the pace at which a particular disorder develops will have a dramatic effect on symptoms and exam findings. Acute dysfunction (as might occur with a stroke) generally causes obvious symptoms as the loss of function is abrupt, allowing the patient no time to develop compensatory mechanisms. Patient presentation will also be affected by the size and location of the lesion. Larger lesions or those affecting critical areas of function tend to generate more overt problems. Additionally, patients with pre-existing medical or neurological dysfunction may well tolerate new lesions poorly. In contrast, disorders which occur more slowly tend to cause relatively subtle symptoms. For example, toxin induced damage to the cerebellum can result in profound atrophy of this region of the brain. While imaging may reveal significant volumetric loss, exam findings can remain relatively minimal. These same principles apply to most other aspects of the physical examination. |