After evaluating this article, participants will be able to:
1. Develop strategies for the early recognition of compartment syndrome
2. Achieve competence with measuring forearm compartment pressures
3. Improve patient safety by avoiding delays in diagnosis awaiting consultation.
A 29-year-old African American male presents to the emergency department with a chief complaint of left arm pain. The patient states he was using a power drill with a quarter-inch drill bit several hours prior to arrival when it accidentally slipped and drilled into his left forearm. “I felt it bounce off my bone” he says. He explains he was able to successfully remove the bit from his arm and there’s been minimal bleeding since. An increasing amount of pain at the point of entry but is now migrating into his hands and fingers, to the point that he is unable to move his digits without excruciating pain. He also complains of a pins and needle sensation in his hand and fingers. The patient is right hand dominant and works as an auto mechanic.
Physical exam reveals a well-nourished, well-developed male of stated age in moderate pain. There is a puncture wound on his anterior-lateral mid left forearm around 2cm in diameter without any visible foreign body or active bleeding. Compared to the right forearm, the left is mildly swollen without visible color changes or ecchymosis. Capillary refill in the digits is less than two seconds and radial pulses are full and equal bilaterally. Sensation is intact to light touch and two point discrimination in the radial, ulnar and median distributions; however the patient reports subjective difference in the sensation when compared to his right hand. Despite IV analgesia, there is difficulty assessing the motor strength secondary to pain. Motor function in the anterior and posterior interossi as well as ulnar appear grossly intact, however with even passive extension of the digits he cries out in pain.
Why Compartment Syndrome?
Compartment syndrome is a condition in which the pressure in a given compartment of the body increases to a level that compromises the circulation and function of tissues in that compartment, including nerve function. Acutely, it usually occurs post-traumatically, although there are cases of acute compartment syndrome (ACS) from hereditary angioedema and even malignant infiltration of muscles. There is also a condition known as chronic compartment syndrome, although this is poorly understood.
Compartment syndrome can develop in numerous compartments throughout the body, although it is most commonly seen in the compartments of the leg and arm. Fractures of the tibial diaphysis and the distal radius are particularly high risk for development of compartment syndrome. ACS can, however, occur in the gluteal region as well as in the abdominal compartments. Fractures are the cause of ACS in approximately 75% of cases, with approximately 23% due to soft tissue injury only. Other causes include IV drug abuse, IV infiltration, burns, hemophilia, anticoagulant use, minor trauma and snake bites.
If the diagnosis is in question, it is imperative to obtain compartment pressures. The physical exam findings in ACS can be unreliable, and the classic “5 P’s of pain, pressure, pulselessness, paralysis, paresthesia and pallor” are more indicative of arterial injury or occlusion. “Pain out of proportion to exam” in addition to pain with passive stretching of the involved compartment are the most sensitive physical exam findings.
Interpretation of Results
Normal compartment pressures are less than 8mmHg. In addition to the clinical exam and index of suspicion, many surgeons use the delta pressure to help determine the need for fasciotomy. Delta pressure is obtained by subtracting the patient’s compartment pressure from their diastolic pressure. A delta pressure less than 20-30mmHg often requires fasciotomy. It is important to remember that a single reassuring compartment pressure does not rule out ACS – continuous or serial measurements are necessary when clinical suspicion is high.
ACS is a potentially devastating diagnosis with its tendency to damage nerves, muscles and vasculature. Fasciotomy is the only treatment option for ACS. Prompt emergency department diagnosis by measuring compartment pressures is essential to minimize patient morbidity and disability in this limb-threatening condition.
This patient had normal compartment pressures. His X-ray was negative for foreign body or fracture and his brachial-to-brachial arterial index was normal. He was observed in the emergency department for serial pressure measurements. His pain improved as well as his paresthesias which were thought to be secondary to muscle injury and swelling. Repeat pressures were normal and he was discharged. On follow-up the next day he was doing well.
There are several methods for measuring intra-compartmental pressures
including the simple manometer method, IV pump method and Whitesides
technique. The following pictorial will focus on the handheld manometer,
“Stryker” device technique.
The forearm contains four compartments; deep volar, superficial volar, dorsal and lateral (also referred to as mobile wad compartment). The volar compartments are at highest risk of compartment syndrome, usually secondary to distal radius fracture in adults or supracondylar fracture in children.
The Rule of Thirds: Between the wrist and the elbow divide the forearm into thirds. The junction of the proximal and middle third is where you want to check the pressures.
The Mobile Wad is made of 3 muscles which include the Brachioradialis, Extensor Carpi Radialis Brevis and the Extensor Carpi Radialus Longus. The Mobile Wad can be palpated by placing the forarm in fully supinated position and having the patient radially deviate the hand at the wrist while palpating at the junction of the proximal and middle thirds of the forarm. The mobile wad identifies the lateral compartment of the forearm.
The Dorsal Compartment is found with the forarm pronated with palm down. Identify the sharp edge of the Ulnar bone at the junction of the proximal and medial thirds of the forarm. Measure 1 cm towards the Radius and you have found the Dorsal Compartment. It contains 5 muscles including the Extensor Pollicus Longus, Extensor Carpi Ulnaris, Extensor Digiti Minimi, Extensor Digitorum and the Abductor Pollicus Longus.
With the forarm supinated find the tendon of the Palmaris Longus if the patient has one. Knowing the Palmaris Longus is proximally attached at the Medial Epicondyle of the Humerus the point of entry is just lateral to the trajectory of this muscle as it crosses the junction of the proximal and middle thirds of the forarm.
Finding the landmarks can be challenging. In a slender and muscular person some landmarks can be seen. In a heavyset individual with swelling and tenderness finding the landmarks can be very challenging, but every effort should be made to correctly identify the different compartments.
1. Obtain consent, observe universal precautions and prepare a sterile field
2. Mark entry site with sterile marking pen, using the landmarks in the illustration
3. Anesthetize the skin taking care to avoid injecting into deep tissue
4. Turn the Stryker device on by pressing the switch in upper left hand corner of the unit
5. Remove the needle and diaphragm unit from the sterile pouch
6. Assemble the Stryker device by first connecting a prefilled 3cc syringe to the diaphragm, then attach the needle to other end of diaphragm
7. Open the lid of the Stryker device by lifting the blue latch in the bottom left corner of the unit, place needle/syringe into the unit and gently secure the lid until it snaps closed
8. Point the needle upward and gently flick any air bubbles out of the syringe
9. Zero the device by holding the device perpendicular to the entry point and pressing the blue zero button. “00” will appear on LED screen
10. Remove the needle protective cover and while still holding the device perpendicular to the entry point, gently advance the needle approximately 1-3 cm into the skin, then insert 0.3cc of saline by gently pressing the hub of syringe
11. Hold the device steady and wait for pressures to equilibrate, the number on the LED screen will be the compartment’s pressure
12. Carefully remove the needle and device from forearm
13. Repeat steps 9-12 on the remaining compartments
- Kalyani BS, Fischer BE, Roberts CS, et al. Compartment Syndrome of the Forearm: A Systematic Review. J Hand Surg. 2011;36A:535–543
- Olson SA, Glasgow RR. Acute compartment syndrome in lower extremity musculoskeletal trauma. J Am AcadOrthopSurg 2005; 13:436.
- Shadgan B, Menon M, O’Brien PJ, Reid WD. Diagnostic techniques in acute compartment syndrome of the leg. J Orthop Trauma 2008; 22:581.
- Shaffer, R. Compartment Pressure Measurement. The Multimedia Procedure Manual. Retrieved February 1, 2012, from www.emprocedures.com.
- Perron AE, Brady WJ, Keats TE. Orthopedic Pitfalls in the ED: Acute Compartment Syndrome. American Journal of Emergency Medicine. 2001; 19:413.
- Uliasz A, Ishida JT, Fleming JK, Yamamoto LG. Comparing the Methods of Measuring Compartment Pressures in Acute Compartment Syndrome. American Journal of Emergency Medicine. 2003; 21:143.
Doctors Nicole Seleno and Brandy Drake are 3rd year emergency medicine residents at the Denver Health Emergency Medicine Residency Program.
Dr. Peter Pryor is a faculty member at Denver Health, an Assistant Professor of Emergency Medicine at the University of Colorado School of Medicine and has an academic focus in medical photography. Dr. Pryor can be reached at