Lower Limb Anatomy, Human Anatomy, USMLE Step 1 - Full Vignette with Extended Explanations скачать в хорошем качестве

Lower Limb Anatomy, Human Anatomy, USMLE Step 1 - Full Vignette with Extended Explanations

A 32-year-old woman is brought to the emergency department after a high-speed car crash, suffering direct knee impact with ensuing hypotension, bradycardia, and symptoms of foot weakness and sensory changes. Her knee appears unstable with ecchymosis and neurological deficits on exam. What clinical features and diagnostic priorities should guide your assessment of peripheral nerve injury in this traumatic knee presentation? Which physical findings are key in this acute setting? VIDEO INFO Category: Lower Limb Anatomy, Human Anatomy, USMLE Step 1 Difficulty: Moderate - Intermediate level - Requires solid foundational knowledge Question Type: Epidemiology Case Type: Emergency - Emergency scenario requiring urgent decision-making Explore more ways to learn on this and other topics by going to https://endlessmedical.academy/auth?h... QUESTION A 32-year-old woman is brought to the ED after a high-speed collision with dashboard knee impact and transient loss of consciousness. She arrives hypotensive with pulse 40/min (bradycardic during resuscitation), respirations 10/min, BP 84/16 mm Hg initially (manual reading repeated at 94/54 mm Hg after fluids), O2 saturation 91% on room air, temperature 36.6 degreesC. She reports tingling on the dorsum of the right foot and struggles to dorsiflex the ankle.... OPTIONS A. Common fibular (peroneal) nerve, especially at the fibular neck and with knee dislocation. B. Tibial nerve, particularly around the tarsal tunnel beneath the flexor retinaculum after hindfoot trauma or space-occupying lesions. C. Saphenous nerve, the terminal sensory branch of the femoral nerve along the medial leg. D. Sural nerve, a sensory branch vulnerable at the lateral malleolus. CORRECT ANSWER A. Common fibular (peroneal) nerve, especially at the fibular neck and with knee dislocation. EXPLANATION The best choice is "Common fibular (peroneal) nerve, especially at the fibular neck and with knee dislocation." The patient has knee dislocation features with a small fibular head avulsion, lateral ecchymosis, foot drop (weak dorsiflexion), first web space numbness, and eversion weakness, all consistent with injury to the common fibular nerve at the fibular neck and/or within the posterolateral corner. Across trauma series, this is the most frequently injured lower-extremity peripheral nerve and a leading cause of foot drop after knee dislocation. Vascular status may be initially intact, but concomitant popliteal injury must be assessed in knee dislocations. The tibial nerve is less commonly injured in these patterns and would cause plantar sensory changes and plantarflexion weakness. The saphenous nerve is purely sensory to the medial leg and cannot cause foot drop. The sural nerve is purely sensory to the lateral foot and also cannot produce dorsiflexion or eversion weakness. The distribution of motor and sensory deficits in this case is classic for common fibular neuropathy. Further reading: Links to sources are provided for optional further reading only. The questions and explanations are independently authored and do not reproduce or adapt any specific third-party text or content. --------------------------------------------------- Our cases and questions come from the https://EndlessMedical.Academy quiz engine - multi-model platform. Each question and explanation is forged by consensus between multiple top AI models (i.e. Open AI GPT, Claude, Grok, etc.), with automated web searches for the latest research and verified references. Calculations (e.g. eGFR, dosages) are checked via code execution to eliminate errors, and all references are reviewed by several AIs to minimize hallucinations. Important note: This material is entirely AI-generated and has not been verified by human experts; despite stringent consensus checks, perfect accuracy cannot be guaranteed. Exercise caution - always corroborate the content with trusted references or qualified professionals, and never apply information from this content to patient care or clinical decisions without independent verification. Clinicians already rely on AI and online tools - myself included - so treat this content as an additional focused aid, not a replacement for proper medical education. Visit https://endlessmedical.academy for more AI-supported resources and cases. This material can not be treated as medical advice. May contain errors. ---------------------------------------------------