Final answer:
The phenomenon where severe vessel rigidity leads to a falsely high blood pressure reading due to the inability of a blood pressure cuff to compress the calcified vessel wall is known as pseudohypertension.
Step-by-step explanation:
If severe vessel rigidity is present in the brachial artery, leading to a falsely high blood pressure reading when using a blood pressure cuff, this phenomenon is known as pseudohypertension.
Pseudohypertension occurs in the context of arteriosclerosis, where the compliance of the artery is significantly reduced due to the stiffening of the vessel walls.
The reduced compliance means that the artery is less capable of expanding to accommodate surges in blood flow, causing the cuff to be unable to compress the calcified vessel wall properly and thus indicating a higher than actual blood pressure.
Compliance is an important characteristic of healthy arteries, allowing them to expand and recoil as blood is pumped through them.
When arteries become less compliant, as in arteriosclerosis, blood flow resistance increases, and blood pressure rises to overcome this resistance, often leading to hypertension and increasing the workload of the heart.
This pathology is captured during blood pressure measurements with a cuff and stethoscope, but in cases of severe arteriosclerosis, these measurements may not be accurate due to the inability of the cuff to compress a rigid vessel, indicating the presence of pseudohypertension.