An adult with a closed tibial fracture is receiving serial neurovascular checks. Click the earliest displayed assessment that should prompt immediate evaluation for acute compartment syndrome, without waiting for loss of the distal pulse.

B. The 09:00 assessment is the first cluster strongly concerning for acute compartment syndrome.

At 09:00, pain rises from 5 to 8 despite prescribed analgesia, passive toe extension produces marked pain, and the lower-leg compartment is tense. These findings require immediate escalation even though sensation and the dorsalis pedis pulse remain intact. Serial change and the combination of cues matter more than any single finding.

Acute compartment syndrome can develop after a tibial fracture. Early recognition should occur before pallor, paralysis, or pulselessness, which are late findings and may signal advanced ischemia.

Rising pain + passive-stretch pain + tense compartment: escalate before the pulse disappears.

Use serial trends and early symptom clusters; a present distal pulse does not rule out compartment syndrome.

A shows pain relief and a soft compartment. C is also concerning but occurs after B and adds paresthesia. D shows late progression with weakness and pulselessness; waiting for D would be unsafe.

• Acute compartment syndrome — Rising pressure within a closed fascial compartment can impair tissue perfusion and requires urgent evaluation.
• Pain with passive stretch — A concerning early assessment finding when paired with escalating pain and a tense compartment.
• Late pulse loss — Distal pulses can remain present after compartment syndrome has developed; pulselessness is a late finding.