A nurse is reviewing the chest x-ray of an older adult client. Which of the following findings is a normal age-related change in the thorax?

The correct answer is A.

Increased anteroposterior diameter.

This is a normal age-related change in the thorax that results from changes in the bones and muscles of the chest and spine.The ribcage becomes less flexible and more rounded, which increases the front-to-back dimension of the chest.

This can affect the lung function and breathing capacity of older adults.

Choice B is wrong because decreased kyphosis means reduced curvature of the spine, which is not a normal age-related change.In fact, kyphosis tends to increase with aging due to osteoporosis and vertebral compression fractures.

Choice C is wrong because increased lung expansion means greater ability to fill the lungs with air, which is not a normal age-related change.In fact, lung expansion tends to decrease with aging due to loss of elasticity and shape of the air sacs (alveoli) and weakening of the respiratory muscles.

Choice D is wrong because decreased calcification means reduced deposition of calcium in the tissues, which is not a normal age-related change.In fact, calcification tends to increase with aging, especially in the costal cartilages that connect the ribs to the sternum.

This can make the chest wall more rigid and less compliant.

Normal ranges for anteroposterior diameter vary depending on age, sex, height and weight, but generally it should be less than the transverse diameter (the side-to-side dimension of the chest).

A ratio of anteroposterior to transverse diameter greater than 0.9 is considered abnormal and may indicate chronic obstructive pulmonary disease (COPD).

The correct answer is B. Decreased stroke volume.

Stroke volume is the amount of blood pumped by the left ventricle of the heart in one contraction.

The contractile strength of the myocardium determines how much blood is ejected with each beat.As people age, the myocardium becomes less elastic and less responsive to catecholamines, which can reduce the contractile force and lower the stroke volume.

Choice A is wrong because increased heart rate is not related to the decreased contractile strength of the myocardium, but rather to the decreased responsiveness of the baroreceptors, which regulate blood pressure.Older adults may have higher resting heart rates and lower maximum heart rates than younger adults.

Choice C is wrong because increased cardiac output is not related to the decreased contractile strength of the myocardium, but rather to the increased blood volume and cardiac workload that may occur with aging.Cardiac output is the product of stroke volume and heart rate, so a lower stroke volume would tend to decrease cardiac output.

Choice D is wrong because decreased peripheral resistance is not related to the decreased contractile strength of the myocardium, but rather to the decreased elasticity and increased stiffness of the arterial walls that may occur with aging.

Peripheral resistance is the opposition to blood flow caused by friction between the blood and the vessel walls.A higher peripheral resistance would increase the afterload on the heart and reduce the stroke volume.

Normal ranges for stroke volume are 60 to 100 mL/beat for men and 50 to 90 mL/beat for women.

Normal ranges for heart rate are 60 to 100 beats per minute for adults.

Normal ranges for cardiac output are 4 to 8 L/min for adults.

Normal ranges for peripheral resistance are 800 to 1200 dynes/sec/cm-for adults.