[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Musculoskeletal system](https://durgical.com/en/clinical-exam/#a-musculoskeletal) › Compartment syndrome: the early signs [Clinical exam](https://durgical.com/en/clinical-exam/) · [Musculoskeletal system](https://durgical.com/en/clinical-exam/#a-musculoskeletal) # Compartment syndrome: the early signs - Syndrome When pressure rises inside a group of muscles wrapped in fascia, the pain is huge and gets worse when they are stretched: it is an emergency. Updated 2026-11-01 **See it in 3D:** [Crural fascia](https://durgical.com/en/anatomy/crural-fascia/) · [Tibialis anterior](https://durgical.com/en/anatomy/tibialis-anterior-muscle/) · [Anterior tibial artery](https://durgical.com/en/anatomy/anterior-tibial-artery/) · [Deep fibular nerve](https://durgical.com/en/anatomy/deep-fibular-nerve/) · [Antebrachial fascia](https://durgical.com/en/anatomy/antebrachial-fascia/) ## Key points - Earliest sign: pain out of proportion to the injury that does not ease with pain relief or elevation. - Pain on passive stretch of the compartment's muscles: the most useful exam sign. - A tense compartment on palpation and paresthesias in the territory of the nerve that crosses it. - Pallor, paralysis and pulselessness are late: a present pulse does not rule the syndrome out. - Classic cause: tibial fracture (anterior compartment of the leg); in children, supracondylar humerus fracture (forearm). - Nursing: serial neurovascular checks under casts and dressings, and immediate report of rising pain. ## What it is Acute compartment syndrome happens when the pressure inside a closed muscle compartment exceeds the pressure that lets capillary blood flow. Muscles and nerves lose their blood supply and can die within hours. The early signs are pain out of proportion and pain on passive stretch; a missing pulse is late. It is a surgical emergency that nurses and doctors must recognise at the bedside. ## Key findings - The classic '5 Ps': pain, paresthesia, pallor, paralysis and pulselessness; only the first two are early. - Stretch pain: in the anterior leg, passive plantar flexion of the toes and ankle; in the forearm flexors, passive finger extension. - Paresthesias between the first and second toes: deep fibular nerve involvement in the anterior compartment. - In sedated, intubated or nerve-blocked patients the exam is unreliable: compartment pressure is measured. - A difference between diastolic pressure and compartment pressure under about 30 mmHg supports the diagnosis. - Permanent nerve damage can follow a few hours of compression; muscle is damaged even sooner. ## Pathophysiology - Limb muscles sit in compartments wrapped in fascia that barely stretches (for example the crural and antebrachial fascia). - If the contents grow (swelling, bleeding) or the envelope tightens (a tight cast or dressing), the pressure rises. - When the pressure exceeds capillary and venous pressure, blood stops entering even though the main artery still pulses. - Ischemia causes more swelling and more pressure: a vicious circle that ends in muscle and nerve necrosis. - Muscle necrosis releases myoglobin and potassium: risk of kidney injury and arrhythmias. ## Common causes - Fractures, especially of the tibial shaft and forearm; in children, supracondylar humerus fracture. - Crush injury, severe contusion and circumferential burns. - A cast or dressing that is too tight. - Reperfusion after ischemia or vascular surgery, long positioning in theatre or prolonged unconsciousness. - Chronic exertional form: pain that appears while running and eases with rest, without the urgency of the acute form. ## Tests that confirm it - Intracompartmental pressure measured with a needle and transducer, especially when the exam is unreliable. - Creatine kinase and urine myoglobin to gauge muscle necrosis. - The diagnosis is above all clinical: do not wait for a test to raise the alarm. ## Memory aid If stretching hurts more than the fracture, the fascia is already squeezing: call before the pulse goes. ## Test yourself Think of the answer, then tap the question to see it. ## What is the earliest sign of acute compartment syndrome? Pain out of proportion to the injury, together with pain on passive stretch of the compartment's muscles. ## Does a present distal pulse rule out compartment syndrome? No. Pulselessness is a late sign; pressure can block capillary flow while the main artery still pulses. ## Which fracture is most often linked to compartment syndrome of the leg? Tibial shaft fracture, which mainly affects the anterior compartment. ## Which paresthesia suggests anterior compartment involvement in the leg? Paresthesia or numbness between the first and second toes, the territory of the deep fibular nerve. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-exam/compartment-syndrome-the-early-signs/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Crural fascia](https://durgical.com/en/anatomy/crural-fascia/) - [Tibialis anterior](https://durgical.com/en/anatomy/tibialis-anterior-muscle/) - [Anterior tibial artery](https://durgical.com/en/anatomy/anterior-tibial-artery/) - [Deep fibular nerve](https://durgical.com/en/anatomy/deep-fibular-nerve/) - [Antebrachial fascia](https://durgical.com/en/anatomy/antebrachial-fascia/) ## Related - [Peripheral pulses and the ankle–brachial index](https://durgical.com/en/clinical-exam/peripheral-pulses-and-the-ankle-brachial-index/) - [Pain assessment and pain scales](https://durgical.com/en/clinical-exam/pain-assessment-and-pain-scales/) - [Sensory examination: modalities and dermatomes](https://durgical.com/en/clinical-exam/sensory-examination-modalities-and-dermatomes/) - [Nursing assessment: head-to-toe and focused assessment](https://durgical.com/en/clinical-exam/nursing-assessment-head-to-toe-and-focused-assessment/) ## Related conditions - [Acute compartment syndrome](https://durgical.com/en/conditions/acute-compartment-syndrome/) - [Tibial shaft fracture](https://durgical.com/en/conditions/tibial-shaft-fracture/) - [Supracondylar humerus fracture](https://durgical.com/en/conditions/supracondylar-humerus-fracture/) [← All of the clinical exam](https://durgical.com/en/clinical-exam/) Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis. Sources: [Compartment syndrome: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001224.htm) (MedlinePlus, U.S. National Library of Medicine, 2026); [Musculo-Skeletal Exam – Practical Guide to Clinical Medicine](https://sites.ucsd.edu/clinicalmedguide/musculo-skeletal-exam/) (UC San Diego School of Medicine, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/clinical-exam/compartment-syndrome-the-early-signs/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/compartment-syndrome-the-early-signs/