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[ Home ](https://mdster.com) 2. [ Blog ](https://mdster.com/blog) 3. [ Medical Education ](https://mdster.com/blog?category=medical-education) 4. Lacerations and Tendon Injuries: ED Hand Exam Pearls [ Medical Education ](https://mdster.com/blog?category=medical-education) Lacerations and Tendon Injuries: ED Hand Exam Pearls ====================================================== How to recognize extensor and flexor tendon injuries, avoid common misses, and immobilize correctly before hand surgery follow-up. [ MDster Editorial Team ](https://mdster.com/about) · Jun 11, 2026 · 6 min read · 554 [ Reviewed by Dr. Ali Ragab, MBBCH, MSc, MCAI ](https://mdster.com/medical-reviewers/dr-ali-ragab) [Editorial Policy](https://mdster.com/editorial-policy) | [Corrections Policy](https://mdster.com/corrections) [ Emergency Medicine ](https://mdster.com/blog?tag=emergency-medicine) [ Trauma ](https://mdster.com/blog?tag=trauma) [ Orthopedics ](https://mdster.com/blog?tag=orthopedics) [ Hand Injuries ](https://mdster.com/blog?tag=hand-injuries) [ Laceration Repair ](https://mdster.com/blog?tag=laceration-repair) ![Lacerations and Tendon Injuries: ED Hand Exam Pearls](https://mdster.com/storage/blog/images/lacerations-and-tendon-injuries-ed-hand-exam-pearls.jpg) Share this article Share this post On this page 1. [ Start With the Exam You Can Defend ](#start-with-the-exam-you-can-defend) 2. [ Extensor Tendon Injuries: The Dorsal Hand Trap ](#extensor-tendon-injuries-the-dorsal-hand-trap) 3. [ Flexor Tendon Injury Recognition: Volar Wounds Are Never “Just Skin” ](#flexor-tendon-injury-recognition-volar-wounds-are-never-just-skin) 4. [ Referral and Immobilization: Protect the Repair You Haven’t Done ](#referral-and-immobilization-protect-the-repair-you-havent-done) 5. [ Clinical Correlations: What Actually Hurts Patients ](#clinical-correlations-what-actually-hurts-patients) 6. [ Key Takeaways ](#key-takeaways) 7. [ Conclusion ](#conclusion) 8. [ Frequently Asked Questions ](#blog-faqs) 9. [ References ](#references-heading) On this page 1. [ Start With the Exam You Can Defend ](#start-with-the-exam-you-can-defend) 2. [ Extensor Tendon Injuries: The Dorsal Hand Trap ](#extensor-tendon-injuries-the-dorsal-hand-trap) 3. [ Flexor Tendon Injury Recognition: Volar Wounds Are Never “Just Skin” ](#flexor-tendon-injury-recognition-volar-wounds-are-never-just-skin) 4. [ Referral and Immobilization: Protect the Repair You Haven’t Done ](#referral-and-immobilization-protect-the-repair-you-havent-done) 5. [ Clinical Correlations: What Actually Hurts Patients ](#clinical-correlations-what-actually-hurts-patients) 6. [ Key Takeaways ](#key-takeaways) 7. [ Conclusion ](#conclusion) 8. [ Frequently Asked Questions ](#blog-faqs) 9. [ References ](#references-heading) A tiny hand laceration can look like a discharge-before-lunch case until the patient returns unable to extend a finger or make a fist. In the ED, your job is not to definitively repair every tendon. Your job is to recognize the injury, protect the hand, reduce infection risk, and get the patient to the right surgeon without delay. As of June 2026, the core principles remain simple: examine before anesthesia, test each tendon independently, assume bites over joints are dangerous, and immobilize in a position that unloads the injured structure. Start With the Exam You Can Defend ---------------------------------- Do the tendon and neurovascular exam before local anesthetic, procedural sedation, or copious irrigation distorts the wound. Document hand dominance, occupation, mechanism, time of injury, contamination, bite exposure, tetanus status, and baseline function. Always inspect the hand at rest. The normal digital cascade is not decoration; it is your first tendon screen. High-yield ED sequence: 1. Check capillary refill, pulse oximetry if needed, and two-point discrimination. 2. Observe resting posture and tenodesis effect. 3. Test active ROM against resistance, joint by joint. 4. Explore the wound through the relevant range of motion after anesthesia and irrigation. 5. Obtain radiographs when fracture, foreign body, glass, tooth fragment, or open joint is plausible. > **Clinical Pearl:** A patient who can move the finger may still have a partial tendon laceration. Painful motion, weakness against resistance, triggering, or a wound directly over a tendon should make you splint and refer. Extensor Tendon Injuries: The Dorsal Hand Trap ---------------------------------------------- Extensor tendons are superficial, so dorsal lacerations are tendon injuries until proven otherwise. The trap is that extension can appear preserved because of juncturae tendinum, especially over the dorsum of the hand. Test extension against resistance at the joint distal to the wound. Do not simply ask, “Can you straighten your finger?” Stabilize the hand, isolate the joint, and compare with the other side. Key extensor checks: - DIP extension: terminal extensor tendon; loss suggests mallet-type injury. - PIP extension: central slip; use the Elson test when the wound or tenderness is over the dorsal PIP. - MCP extension: common extensor mechanism and sagittal band region. - Thumb extension: test EPL with thumb IP extension and retropulsion off the table. For the Elson test, flex the PIP to 90 degrees over a table edge and ask the patient to extend against resistance. Weak PIP extension with a rigidly extended DIP supports central slip disruption. LocationSuspectED immobilizationDorsal DIPTerminal extensorDIP in full extension, PIP freeDorsal PIPCentral slipPIP in full extensionDorsal MCP/handExtensor tendon or fight biteWrist/MCP extension splint; urgent hand review Board exams love the clenched-fist injury. A small laceration over the MCP after punching teeth is an open joint or extensor tendon injury until proven otherwise. Irrigate, give appropriate antibiotics, assess tetanus and bloodborne exposure risk, and involve hand surgery early. Flexor Tendon Injury Recognition: Volar Wounds Are Never “Just Skin” -------------------------------------------------------------------- Flexor tendon injuries are easier to miss and harder to fix. The digital nerves and arteries run nearby, so numbness after a sharp volar laceration is a nerve transection until proven otherwise. Start with resting posture. A finger that lies more extended than its neighbors suggests loss of flexor tone. Then use tenodesis: passive wrist extension should cause finger flexion. Failure of one digit to flex with tenodesis is a major warning sign. Isolate the flexors deliberately: - FDP: hold the PIP extended and ask for active DIP flexion. - FDS: hold the other fingers extended and ask the injured finger to flex at the PIP. - FPL: stabilize the thumb MCP and ask for IP flexion. Partial flexor lacerations may produce pain, weakness, or catching rather than complete loss of flexion. Do not reassure yourself with “some movement.” If the wound trajectory crosses the tendon sheath, treat the exam as high risk. Referral and Immobilization: Protect the Repair You Haven’t Done ---------------------------------------------------------------- Most flexor tendon lacerations need hand surgery evaluation and operative planning. Clean extensor injuries may sometimes be managed in the ED by clinicians with appropriate training, but uncertain depth, contamination, joint involvement, or functional deficit should push you toward consultation. Call hand surgery urgently for: - Dysvascular digit or uncontrolled bleeding. - Suspected flexor tendon laceration. - Open joint, open fracture, or tooth contamination. - Associated digital nerve injury. - Gross contamination, crush injury, infection, or immunocompromise. - Pediatric injuries or unreliable follow-up. Immobilize to reduce tendon tension. Flexor injuries generally need a dorsal blocking splint with the wrist and MCPs flexed enough to prevent extension stress. Extensor injuries are splinted with the injured joint in extension, tailored to the zone. Do not bury a contaminated tendon injury under a tight primary closure. For bite wounds to the hand, irrigate aggressively, avoid tight closure, update tetanus, and use preemptive antibiotics when the wound is high risk. Amoxicillin-clavulanate is the usual oral choice for mammalian bites when not contraindicated. Clinical Correlations: What Actually Hurts Patients --------------------------------------------------- The dangerous miss is not the dramatic open tendon you can see from the doorway. It is the small glass laceration, the “minor” kitchen knife wound, or the intoxicated patient with a fight bite. Common ED pitfalls: - Testing only gross ROM instead of isolated tendon function. - Performing the exam after anesthesia without baseline documentation. - Forgetting that extensor function may persist despite complete laceration. - Closing a clenched-fist wound and sending routine follow-up. - Splinting in a position that places tension across the injured tendon. Key Takeaways ------------- - Examine and document tendon, nerve, and vascular function before anesthesia. - Test FDP, FDS, FPL, and extensor function independently. - Painful motion or weakness against resistance can signal partial tendon injury. - Hand bites, especially over the MCP, require aggressive infection-risk management. - Flexor tendon injuries need urgent hand referral and dorsal blocking immobilization. - Extensor splinting depends on zone, but the injured joint generally needs extension protection. Conclusion ---------- Treat hand lacerations with respect. A normal-looking wound can hide a career-changing tendon injury, and your ED exam determines whether that injury gets recognized in time. Be systematic, document clearly, splint intelligently, and refer early when function, contamination, or anatomy makes the wound high risk. Frequently Asked Questions ---------------------------- ### Can a patient still move the finger with a complete extensor tendon laceration? Yes. Juncturae tendinum can preserve apparent extension, especially over the dorsum of the hand. Always test extension against resistance. ### What is the best ED test for FDP injury? Hold the PIP joint extended and ask the patient to flex the DIP. Inability to flex the DIP suggests FDP disruption. ### Should flexor tendon lacerations be repaired in the ED? Usually no. They require hand surgery evaluation, careful operative repair, and therapy planning. The ED should irrigate, close skin selectively, splint, and arrange urgent follow-up. ### How should suspected flexor tendon injuries be splinted? Use a dorsal blocking splint that prevents wrist and finger extension stress across the injured flexor tendons. ### Why are fight bites over the MCP high risk? They may penetrate the extensor tendon, joint capsule, or metacarpal head and are contaminated with oral flora, so they need irrigation, antibiotics, and early specialist involvement. References (5) ------------------ 1. 1. [ StatPearls: Flexor Tendon Lacerations, NCBI Bookshelf ](https://www.ncbi.nlm.nih.gov/books/NBK493223/) 2. 2. [ StatPearls: Hand Extensor Tendon Lacerations, NCBI Bookshelf ](https://www.ncbi.nlm.nih.gov/books/NBK554431/) 3. 3. [ AAOS OrthoInfo: Flexor Tendon Injuries ](https://orthoinfo.aaos.org/en/diseases--conditions/flexor-tendon-injuries) 4. 4. [ IDSA Practice Guidelines for Skin and Soft Tissue Infections ](https://www.idsociety.org/practice-guideline/skin-and-soft-tissue-infections/) 5. 5. 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