Final answer:
The FEV1/FVC ratio, assessed through spirometry, is used to diagnose obstructive and restrictive lung diseases. A lower ratio indicates obstructive lung disease, while a higher ratio suggests restrictive lung disease. Additionally, a motor exam can help in the detection of neuromuscular disorders by assessing muscle strength and tone.
Step-by-step explanation:
The ratio that can be used to identify obstructive and neuromuscular disorders is the FEV1/FVC ratio. FEV1, or forced expiratory volume in one second, is the amount of air that can be forcibly exhaled in one second after taking a deep breath. FVC, or forced vital capacity, is the total amount of air that can be forcibly exhaled. Spirometry is the technique used to measure these volumes and provide the ratio.
In someone with obstructive lung disease, such as chronic obstructive pulmonary disease (COPD), airway obstruction leads to slower exhalation speeds, meaning both FEV1 and FVC are reduced. However, the FEV1 is disproportionately reduced, leading to a lower FEV1/FVC ratio (less than 69 percent). Conversely, in restrictive lung disease, such as that caused by fibrosis, the FVC is reduced because the lung cannot fully inflate, but airways are generally not obstructed, which results in a higher FEV1/FVC ratio (88 to 90 percent).
Muscle strength and tone can be evaluated during a motor exam to detect neuromuscular disorders. This involves inspecting and palpating muscles for structural irregularities, assessing resting muscle tone, and testing muscle strength against resistance. A deficiency in muscle tone, known as hypotonicity, can signal issues with the lower motor neuron.