Inspection of the Lower Limbs
After positioning the patient on the bed and ensuring adequate exposure, the lower limbs should be inspected as follow:
The examiner should stand at the end of the bed and inspect for any obvious leg length discrepancy, asymmetry, wasting or abnormal posturing. One should then stand on the right hand side of the patient and inspect the lower limbs in greater detail, focusing on whether there is any muscle wasting (proximal and / or distal muscles), fasciculations, scars, tremor, pes cavus and clawing of toes.
Eliciting Fasciculations of the Lower Limbs
If there are no fasciculations visible on inspection, one can tap onto the muscle bulk gently, which may help bring out the fasciculations if an underlying lower motor neuron lesion is present. However, one common pitfall of medical students is that they often rush through the tapping of the muscle bulk, but do not observe long enough for the fasciculations to appear.
Determining the Tone of the Lower Limbs
The tone of the lower limbs could be determined first of all by gently rolling the lower limb on the bed as if it was a log. In patients with hypertonia, there would be increased resistance with this manoeuvre. The normal swinging motion of the foot will also be reduced. This should be followed by gently lifting up the thigh of the lower limb and releasing it back onto the bed. In patients with hypertonia, the heel of the foot would often elevate from the surface of the bed. The tone of the lower limb is classified as normal, hypertonic or hypotonic.
Determining the Power of the Lower Limbs
The power of the lower limbs could be determined as shown in the video. One should examine the flexion, extension, adduction and abduction of the hip muscles, followed by extension and flexion of the knee muscles. Finally, foot dorsiflexion, dorsiflexion of the big toe, foot plantar flexion, foot inversion and eversion should be examined.
Again, the power of the muscles should then be graded according to the Medical Research Council (MRC) scale for muscle strength as follow:
- Grade 5: Muscle contracts normally against full resistance
- Grade 4: Muscle strength is reduced but muscle contraction can still move joint against resistance
- Grade 3: Muscle strength is further reduced such that the joint can be moved only against gravity
- Grade 2: Muscle can move only if the resistance of gravity is removed
- Grade 1: Only a trace or flicker of movement is seen or felt in the muscle, or fasciculations observed in the muscle
- Grade 0: No movement is observed
One should then compare the muscle power between the right leg and left leg, as well as between proximal and distal leg muscles.
Eliciting the Lower Limb Reflexes
The reflexes of the lower limbs including the knee jerk, Achilles tendon reflexes and plantar reflexes can be examined as shown in the video.
Testing Coordination of the Lower Limbs
The heel-shin test is performed as demonstrated in the video shown here.