POD4PAM (Articles/Merriman's Book)

Key Concepts:

Terms in this set (59)

• Muscle power
Muscle power can be graded according to the Medical Research Council scale (Fuller 1993, p 107) as follows:
5 = normal power
4 + = submaximal movement against resistance
4 = moderate movement against resistance
4 − = slight movement against resistance
3 = moves against gravity, but not resistance
2 = moves with gravity eliminated
1 = flicker
0 = no movement
A reduced strength of contraction suggests paresis or paralysis
• Fatigability If the site of the lesion is the neuromuscular junction, the muscle will show a sliding decrease in response or fatigability, as seen in myasthenia gravis. The acetylcholine receptors are destroyed in an autoimmune attack and, although the first quanta of neurotransmitter can diffuse to remaining receptors, subsequent release of neurotransmitter is less likely to make contact, so that the response fades. The muscle cells are able to replace the receptors, but the autoimmune attack will invariably strike again, in the same or different muscles.
• Muscle tone In the skeletal muscles of a healthy person, there will always be some motor units firing, which means that the muscle will feel firm. This is referred to as the 'tone' of the muscle. In LMN or muscle damage, the muscle will feel flabby, due to lack of tone.
• Patellar and Achilles tendon reflexes
Reflexes will be weak or absent, because of interruption of the final common pathway. A single reduced or absent reflex suggests mononeuropathy or radiculopathy. A reduction or absence of all lower limb reflexes suggests polyradiculopathy, cauda equina lesions, peripheral polyneuropathy or a myopathy. In the latter, there will be no sensory deficit. Values of below 1 suggest LMN lesions, peripheral sensory nerve or muscle damage.