A nurse is assessing a client who has impaired mobility. The nurse should monitor the client for a pressure injury due to which of the following factors?

Rationale: A. Decreased serum calcium affects bone health and may lead to osteoporosis or muscle weakness, but it is not a direct factor in the development of pressure injuries. While poor calcium levels may indirectly affect mobility, pressure injuries are primarily caused by localized tissue ischemia rather than systemic calcium deficiencies. B. Increased muscle mass actually provides more padding over bony prominences, which helps protect against pressure injury. Clients with well-developed musculature are generally at lower risk compared with those who have muscle wasting or atrophy. C. Decreased circulation is a primary risk factor for pressure injury development. Impaired blood flow reduces oxygen and nutrient delivery to tissues, making skin and subcutaneous tissue more susceptible to ischemia and necrosis when exposed to prolonged pressure, friction, or shear. Clients with impaired mobility are especially vulnerable because they cannot shift positions effectively to relieve pressure. D. Increased collagen strengthens connective tissue and promotes skin integrity. While insufficient or abnormal collagen can contribute to skin breakdown, increased collagen alone does not predispose a client to pressure injuries and is generally protective rather than harmful.