Authors: Lewis, Steven L.
Title: Field Guide to the Neurologic Examination, 1st Edition
Copyright ©2004 Lippincott Williams & Wilkins
> Table of Contents > Section 2
– Neurologic Examination > Cerebellar Examination > Chapter 35 –
Testing of Lower Extremity Cerebellar Function
– Neurologic Examination > Cerebellar Examination > Chapter 35 –
Testing of Lower Extremity Cerebellar Function
Chapter 35
Testing of Lower Extremity Cerebellar Function
PURPOSE
The purpose of testing lower extremity cerebellar
function is to look for evidence of a lesion involving the cerebellar
hemispheres or the cerebellar pathways.
function is to look for evidence of a lesion involving the cerebellar
hemispheres or the cerebellar pathways.
WHEN TO TEST LOWER EXTREMITY CEREBELLAR FUNCTION
The heel-to-shin maneuver, a simple screening test of
lower extremity cerebellar function, should be performed on most
patients as part of a standard neurologic examination. When cerebellar
dysfunction is not suggested by the history or the preceding parts of
the examination, however, it’s reasonable to stop the examination of
cerebellar function after the (normal) finger-to-nose maneuver is
completed. When there is a clinical suspicion for cerebellar
dysfunction or to look for additional confirmation of cerebellar
dysfunction when an abnormality is suggested on the upper extremity
cerebellar examination (see Chapter 34, Testing of Upper Extremity Cerebellar Function), lower extremity cerebellar function should be tested.
lower extremity cerebellar function, should be performed on most
patients as part of a standard neurologic examination. When cerebellar
dysfunction is not suggested by the history or the preceding parts of
the examination, however, it’s reasonable to stop the examination of
cerebellar function after the (normal) finger-to-nose maneuver is
completed. When there is a clinical suspicion for cerebellar
dysfunction or to look for additional confirmation of cerebellar
dysfunction when an abnormality is suggested on the upper extremity
cerebellar examination (see Chapter 34, Testing of Upper Extremity Cerebellar Function), lower extremity cerebellar function should be tested.
Examination of gait, which should be a routine part of the neurologic examination, is discussed in Chapter 39, Examination of Gait.
NEUROANATOMY OF LOWER EXTREMITY CEREBELLAR FUNCTION
The basic relevant neuroanatomy of the cerebellum and its pathways is discussed in Chapter 33,
Approach to the Cerebellar Examination. The left cerebellar hemisphere
coordinates the left leg (and arm), and the right cerebellar hemisphere
coordinates the right leg (and arm). Table 33-1 summarizes the lesions within the cerebellum or its pathways that may cause incoordination on cerebellar testing.
Approach to the Cerebellar Examination. The left cerebellar hemisphere
coordinates the left leg (and arm), and the right cerebellar hemisphere
coordinates the right leg (and arm). Table 33-1 summarizes the lesions within the cerebellum or its pathways that may cause incoordination on cerebellar testing.
EQUIPMENT NEEDED TO TEST LOWER EXTREMITY CEREBELLAR FUNCTION
None.
HOW TO EXAMINE LOWER EXTREMITY CEREBELLAR FUNCTION
The main test of cerebellar function performed in the lower extremities is the heel-to-shin examination:
-
With the patient sitting in a chair or
lying in bed, ask the patient to place one of his or her heels up on
the knee of the opposite leg. The heel-to-shin maneuver needs to be
performed without the patient using his or her arms for assistance. -
Then ask the patient to smoothly move the
heel all the way (straight) down the other leg to the ankle, keeping
his or her heel on the anterior shin bone of the other leg throughout
the maneuver. -
Once the patient’s heel has gone down to
the ankle, ask the patient to move his or her heel back up the leg to
the knee, again keeping the heel on the shin of the other leg. -
Repeat the same maneuver with the other leg.
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NORMAL FINDINGS
Normally, the patient should be able to perform the
heel-to-shin maneuver smoothly and accurately with each leg, and there
should be no significant asymmetry between the two sides.
heel-to-shin maneuver smoothly and accurately with each leg, and there
should be no significant asymmetry between the two sides.
ABNORMAL FINDINGS
-
Clumsiness of a leg during the
heel-to-shin test is abnormal. Clumsiness due to cerebellar dysfunction
usually manifests as side-to-side wavering of the leg (including
movements at the hip) throughout its attempt to reach its target; this
is referred to as dysmetria or appendicular ataxia (or simply ataxia) (see Chapter 33, Approach to the Cerebellar Examination). -
Assuming the patient’s leg is strong
(cerebellar hemisphere lesions do not cause weakness), clumsiness
during the heel-to-shin maneuver on one side suggests cerebellar
hemisphere dysfunction ipsilateral to the side of the clumsy leg. -
As in the upper extremities, when
patients with mild weakness in the leg also have what appears to be
cerebellar dysmetria in the same leg (and the subtle weakness doesn’t
seem to be severe enough to explain the dysmetria), the lesion may be
in the contralateral posterior limb of the internal capsule or the
pons. This is called an ataxic-hemiparesis (see Table 33-1).
ADDITIONAL POINTS
Because of the mechanics of the test, the ability to
perform the heel-to-shin maneuver (even in the absence of cerebellar
dysfunction) is particularly affected by weakness (especially hip
flexion), body habitus, and hip problems, so keep this in mind when
performing and interpreting this examination element.
perform the heel-to-shin maneuver (even in the absence of cerebellar
dysfunction) is particularly affected by weakness (especially hip
flexion), body habitus, and hip problems, so keep this in mind when
performing and interpreting this examination element.