Page 95 Guide to Pain Management in Low-Resource Settings

Physical Examination: Neurology 83

in muscle mass can further be evaluated by palpating Fast (posterior column, lemniscal, or discrimi-
as the muscle contracts and/or by measuring the girth natory) sensations that include light touch (tested with
of the limbs. Localized atrophy may be due to disuse a wisp of cotton wool), joint position sense, two point
because of chronic pain and should be kept in mind as discrimination, and vibration.
a non-neurological cause of changes in muscle mass. Slow (spinal thalamic) sensations that tradition-
Ensure the patient is calm and comfortable before test- ally are represented by pain (pinprick) and temperature
ing tone and limb mobility. Decreased tone is usually sensations.
a feature of lower motor neuron pathology, whereas Th e patient is normally requested to close his/
increased tone (spasticity, rigidity) is a feature of up- her eyes during the tests. Th e stimulus is applied on
per motor neuron pathology. Limb mobility at joints one side initially and then on two sides simultaneously
should be tested in all directions allowed by the joint in corresponding parts of the body. Th e latter tests for
and any restrictions noted. One should be aware that sensory extinction where the patient may fail to regis-
there may be some modifi cations of tone and limb mo- ter stimulation of one side (the left usually) in lesions of
bility by pain. the nondominant hemisphere. If any abnormalities are
Muscle power is then tested in muscle groups detected, attempts should then follow to accurately map
around the joints and in the axial musculature. A good the area of the defi cit and establish the anatomical site
knowledge of segmental and peripheral nerve innerva- of the lesion or the structure involved.
tion of the various muscles or muscle groups is essen- Pain and temperature tests yield information on
tial in evaluating the etiopathology of any weakness. If the same systems, and therefore it may not be necessary
nerve-related weakness is noted, then it is imperative to test for both in the routine patient without neuro-
that it be graded according to an established scaling pathic pain. However, a positive increase or pathologi-
system such as the Medical Research Council (MRC) cal increase in sensation (like dysesthesia) that may have
scale. Also, establish whether it is upper motor neuron partly been picked up during history taking will need to
or lower motor neuron and whether it is segmental, be elucidated further. Regions of hyperesthesia and al-
diff use, distal, or peripheral in distribution. Myopathic lodynia need to be mapped out accurately, noting that
weakness does not respect peripheral nerve or segmen- skin hypersensitivity to various stimuli (touch, cold, and
tal demarcations and is usually more marked proximal- warmth) may be diff erent and therefore should be test-
ly. Neuropathic weakness needs to be delineated and ed separately.
assessed for the anatomical site of the pathology (spinal Light touch, joint position, and vibration should
cord, roots, specifi c peripheral nerve, or diff use neu- be tested even though they are physiologically related in
ropathy). Subtle weakness in the lower limbs may occa- that they are all fast sensations, because they may be af-
sionally be picked up by requesting patients to rise from fected diff erentially in certain clinical situations.
a squatting position, walk on their tiptoes or on their Higher sensory functions such as two point dis-
heels, while in the upper limbs one may look for prona- crimination, graphesthesia (recognition of numbers or
tor drift. letters drawn on the skin), and stereognosis (ability to
Other tests may be done to elicit specifi c defi - recognize familiar objects placed in the hand) are not
ciencies such as the straight leg raise to identify lumbar normally part of a routine neurological examination but
disk protrusion or the femoral stretch if higher disk pa- can be performed where a cerebral lesion is suspected.
thology is suspected. Th ere are numerous maneuvers in
clinical practice aimed at eliciting specifi c joint or struc- What does examination
ture pathology, and these can be obtained from books of the refl exes tell us?
on neurology and orthopedic surgery if they are needed.
Th e deep tendon refl exes are normally tested after the
How do I examine the sensory examination of the sensory systems. Th e jaw jerk, the su-
system? pinator, the biceps, the triceps jerks in the upper limbs
and the knee and the ankle jerks in the lower limbs are
The sensory system is examined guided by func- routinely tested. Others like fi nger fl exion and adductor
tion and anatomy. There are two types of sensations refl exes in the upper and lower limbs respectively are not
physiologically: routine. Th eir responses are usually graded in a simple