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Procedural Use of a Mini C-arm in the Emergency Department

C-arms are mobile, C-shaped X-ray units that allow dynamic imaging for a wide range of procedures in outpatient clinics, procedure suites, operating rooms, and even emergency departments. Their uses include: fracture reduction and fixation, hardware placement, joint injections, and other image-guided interventional procedures. They are available in a variety of sizes including a mini C-arm that is specifically designed for imaging smaller body parts such as the hands and wrists.

Mini C-arms in emergency departments (ED) are not commonplace but when available they are often in trauma centers and most commonly utilized by orthopedic surgeons. Literature on the use of mini C-arms in the ED has mostly been for distal forearm fractures, where they have been shown to facilitate safe and effective fracture reductions and reduce the need for repeat formal radiographs during reductions [1-4]. Although mini C-arms are not typically used by emergency medicine (EM) physicians, familiarity with this imaging modality may be a valuable skill, especially for trainees rotating on the orthopedics service.

This article reviews mini C-arm anatomy, fluoroscopic principles, radiation safety and equipment, and illustrates its application in a case of a distal radius fracture.

Mini C-arm structure

The C-arm’s name comes from the C-shape that connects the X-ray source on one side to the image detector on the other, allowing rotation around the patient (Figure 1).

Anatomy of a mini c-arm machine illustration

Figure 1. Anatomy of a mini c-arm machine

How it works

  1. The operator controls acquisition of images through a foot pedal (allowing single images or live imaging).
  2. X-rays are generated through a tube which diverge out in a cone-like projection and pass through structures such as bone, which absorb X-rays differently based on characteristics like density and tissue thickness.
  3. After passing through structures, X-rays are absorbed on the opposite side by an image detector.
  4. The image detector converts this radiation to light, which is then processed by a computer to create a digital image visible on the monitor.

The C-arm has a rotation mechanism and an adjustable arm with various joints that allow movements in multiple planes. It allows orbital rotation, vertical and lateral movements, tilt, or swivel (Figure 2).

Maneuverability of a mini c-arm illustration

Figure 2: Maneuverability of a mini c-arm

How to set up a mini C-arm

  1. Plug in the device to a power source
  2. Turn on the switch to power on the device
  3. Use the monitor and/or keyboard to set up a study (some monitors are touch screen)
  4. Enter patient information
    • Find and select the option to begin study
    • Adjust the C-arm to the desired position
  5. Position the body part of interest flat and center on the detector
  6. Place the foot pedal in an easy to reach position
  7. Ensure that everyone in the room has radioprotective equipment (see radiation safety and equipment below)
  8. Step on the foot pedal to obtain an image or activate live imaging (review individual devices manuals to determine function of pedals)
  9. Save desired images

How to interpret images on a mini C-arm

Interpreting an image with a mini C-arm requires familiarity with fundamental radiographic principles related to image projection.

Laterality:

Unlike formal radiographs which include left or right markers, orientation of fluoroscopic images on a mini C-arm will be displayed based on the orientation of the image detector.

To illustrate this, in Figure 3, the right hand is rested with the palm resting directly on the image detector. On the monitor, the image appears as if the operator were directly looking at the hand, with the thumb on the left-most side. Most C-arms allow inversion of images on the monitor if another orientation is preferred.

Note: The X-ray beam travels from dorsal (posterior) to palmar (anterior), corresponding to a posteroanterior (PA) view.

Illustrated mini C-arm image of hand in posteroanterior view.

Figure 3: Illustrated mini C-arm image of hand in posteroanterior view

Magnification and depth

The relative distance between the X-ray source, the object, and the image detector affects image magnification and apparent depth of structures. To put it simply: the closer an object is to an X-ray source, the more magnified it appears; the closer an object is to the image detector, the less magnified it appears. This is analogous to the size of a shadow formed when a finger is moved closer to a light source. This principle affects image interpretation and highlights the importance of standardized positioning when obtaining images [5].

To illustrate this effect, we can consider the lateral view of the hand. Starting from the position in Figure 3, the hand can be supinated so that the ulnar aspect rests on the detector producing a lateral view (Figure 4). In this orientation, the thumb and second metacarpal may appear slightly magnified because they are now closer to the X-ray source. This also applies to the relative appearance of the radius and ulna.

Illustrated mini C-arm image of hand in lateral view

Figure 4: Illustrated mini C-arm image of hand in lateral view

As an analogy, imagine using a mini C-arm to image a rubber duck. If the duck is placed flat on the detector, the part closest to the X-ray source—the head—will appear slightly magnified. If the duck has an abnormally long neck that brings the head closer to the X-ray source, this magnification increases further (Figure 5). This same concept explains the apparent difference in heart size between posteroanterior (PA) and anteroposterior (AP) chest radiographs.

llustrated mini C-arm image of rubber duck

Figure 5: Illustrated mini C-arm image of rubber duck

This concept is important when using the mini C-arm for fracture reduction. You often want to capture as much of the entire body part as possible in the X-ray image while decreasing magnification, which means you will position the extremity directly against the image detector as far away as possible from the X-ray source while performing a reduction.

Radiation safety and protection

C-arms, like standard X-rays, emit ionizing radiation. Although most of the radiation is directed at patients, interactions between X-rays and surrounding matter produce scatter radiation, which is the primary source of radiation exposure to personnel. Repeated exposure is associated with increased lifetime risk of cancer, cataracts, thyroid issues including cancer, and fertility issues [6].

Radiation dose is measured in various units, including millirem (mrem) [5]. For context:

  • Average background radiation exposure (due to cosmic rays, radioactive elements in earth’s crust, etc) to U.S. residents is on average 310 mrem/year or <1 mrem/day
  • A cross country flight from NY to LA is ~5 mrem
  • A chest x-ray is ~10 mrem
  • A CT abdomen/pelvis is ~1,000 mrem

A benefit of the mini C-arm is that it emits less radiation than a standard-sized C-arm [8, 9]. In pediatric studies of distal forearm reductions performed with mini C-arm fluoroscopy, the estimated radiation exposure per case ranged from approximately 30 to 80 mrem, with lower exposures observed when trainees had completed radiation safety training, likely reflecting behavioral changes including fewer image acquisitions and shorter fluoroscopy activation [10]. Thus image acquisition should be intentional to reduce unnecessary radiation to both patients and personnel.

Radiation exposure follows the inverse square law, where if you double your distance from the X-ray source, you reduce exposure by one-fourth the original intensity. When possible, standing further away (at least 1 meter) from the X-ray source is recommended to reduce exposure (Figure 6) [5].

Additionally, use of radiation protective equipment such as lead aprons, thyroid shields, and leaded glasses, can significantly attenuate scatter radiation [8]. See Figure 7.

Inverse square law of radiation

Figure 6: Inverse square law of radiation

Radiation protective equipment

Figure 7: Radiation protective equipment

Bottom line:

  • Image only when necessary
  • Stand at least 1 meter away from the X-ray source when feasible
  • Utilize appropriate radiation protective equipment
  • By adhering to these principles, radiation exposure can be minimized when using a mini C-arm

Case: Distal radius fracture reduction with mini C-arm fluoroscopy

You are rotating through orthopedics and holding the consult pager. A 30-year-old patient presents to the ED after falling on their right outstretched hand, resulting in a deformity to the right distal forearm.

On examination, the skin appears intact and distal neurovascular exam is normal. Formal three-view wrist radiographs show an impacted, dorsally angulated transverse distal radius fracture without intra-articular extension.

Your senior recommends a reduction under fluoroscopy with your assistance. You perform a hematoma block, apply finger traps, and suspend the extremity vertically under ~10 lbs of traction. While the arm remains in traction, you bring the mini C-arm into the room and apply lead shields.

Obtaining images:

  1. Position the C-arm so that the image detector is near the affected arm. For a reduction, you should obtain PA and lateral views (oblique views are excluded in this example for simplicity).
  2. To obtain a PA view, ensure the palmar side of the distal forearm is against the detector (Figure 8).
  3. To obtain a lateral view, place the ulnar aspect of the distal forearm against the detector (Figure 9).

Note: Since the forearm is suspended in traction, sometimes you will need to rotate the mini C-arm around the extremity to obtain the correct alignment, instead of manipulating the arm.

Illustrated mini C-arm image of a distal radius fracture in posteroanterior view

Figure 8: Illustrated mini C-arm image of a distal radius fracture in posteroanterior view

\Illustrated mini C-arm image of a distal radius fracture in lateral view

Figure 9: Illustrated mini C-arm image of a distal radius fracture in lateral view

Important radiographic measurements:

In these views, assess radiographic parameters such as radial height, radial inclination, ulnar variance, and volar versus dorsal angulation angles (Supplemental Figures 1 and 2).

Post-reduction imaging:

Once the fracture appears appropriately reduced, obtain repeat C-arm images prior to applying a splint (Figure 10). After splint placement, obtain another set of images to confirm the reduction was maintained. Finally, order a formal post-reduction three-view wrist radiograph.

Illustrated mini C-arm images of a post-reduction distal radius fracture

Figure 10: Illustrated mini C-arm images of a post-reduction distal radius fracture

Restrictions on the use of fluoroscopy

Before using a mini C-arm, clinicians should confirm that they are appropriately credentialed and permitted to operate the device under local or state regulations, as fluoroscopy use laws differ across states and countries. Alternatively, a fluoroscopy credentialed radiation technologist can operate the device while the clinician performs the reduction.

Conclusions

Mini C-arms are a useful imaging modality available in select emergency departments. With an understanding of proper device operation and radiographic concepts such as image projection and radiation safety, the mini C-arm can be an effective tool to facilitate procedures such as distal radius fracture reduction. Although ultrasound remains the primary imaging modality for many procedures in the emergency department, the mini C-arm may potentially be a useful adjunct in other ED procedures such as joint aspirations and could warrant future exploration.

Measurements of the distal radius in posteroanterior view

Supplemental Figure 1: Measurements of the distal radius in posteroanterior view

Measurements of the distal radius in lateral view

Supplemental Figure 2: Measurements of the distal radius in lateral view

References

  1. Lee SM, Orlinsky M, Chan LS. Safety and effectiveness of portable fluoroscopy in the emergency department for the management of distal extremity fractures. Ann Emerg Med. 1994;24(4):725-730. doi:10.1016/S0196-0644(94)70284-5. PMID: 7998561
  2. Lee MC, Stone NE 3rd, Ritting AW, et al. Mini-C-arm fluoroscopy for emergency-department reduction of pediatric forearm fractures. J Bone Joint Surg Am. 2011;93(15):1442-1447. doi:10.2106/JBJS.J.01052. PMID 21915550 
  3. Dailey SK, Miller AR, Kakazu R, Wyrick JD, Stern PJ. The effectiveness of mini-C-arm fluoroscopy for the closed reduction of distal radius fractures in adults: a randomized controlled trial. J Hand Surg Am. 2018;43(10):927-931. doi:10.1016/j.jhsa.2018.02.015. PMID: 29573894
  4. Sumko MJ, Hennrikus WL, Slough J, King S. Measurement of radiation exposure when using the mini C-arm in pediatric orthopaedics. J Pediatr Orthop. 2016;36(2):122-125. doi:10.1097/BPO.0000000000000418. PMID: 25730377
  5. Bushberg JT, Seibert JA, Leidholdt EM Jr, Boone JM. The essential physics of medical imaging. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012.
  6. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Ionizing Radiation. Atlanta, GA: US Department of Health and Human Services; 1999. Available from: https://www.ncbi.nlm.nih.gov/books/NBK597577/
  7. Centers for Disease Control and Prevention. Radiation Thermometer. Updated January 2, 2024. Accessed December 26, 2025. https://www.cdc.gov/radiation-emergencies/causes/radiation-thermometer.html
  8. Giordano BD, Ryder S, Baumhauer JF, DiGiovanni BF. Exposure to direct and scatter radiation with use of mini-C-arm fluoroscopy. J Bone Joint Surg Am. 2007;89(5):948-952. doi:10.2106/JBJS.F.00733. PMID: 17473130
  9. Giordano BD, Baumhauer JF, Morgan TL, Rechtine GR. Patient and surgeon radiation exposure: comparison of standard and mini-C-arm fluoroscopy. J Bone Joint Surg Am. 2009;91(2):297-304. doi:10.2106/JBJS.H.00407. PMID: 19181973
  10. Gendelberg D, Hennrikus W, Slough J, King S. A radiation safety training program results in reduced radiation exposure for orthopedic residents using the mini C-arm. J Pediatr Orthop. 2015;35(8):e123-e129. doi:10.1097/BPO.0000000000000345. PMID: 26566977
By |2025-12-30T18:08:43-08:00Dec 31, 2025|Orthopedic, Radiology|
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SAEM Clinical Images Series: Mind the Gap

scapholunate

A 25-year-old right-handed female with a longstanding history of right wrist pain presents with wrist pain. Her chronic pain had worsened over the past 2-3 weeks. She did not recall a specific recent injury, but did recall that she had a painful injury to the same wrist in the past when she fell on her outstretched hand. She was seen several weeks prior for the injury, but did not seek follow-up care after her initial evaluation. She had pain with any movement and complained of tenderness around the wrist, but denied any fever, redness, swelling, or any other complaints.

 

Vitals: All vital signs are normal.

General: No acute distress.

Musculoskeletal: Right upper extremity: Normal shoulder and elbow range of motion without tenderness. The right wrist is tender over the proximal carpal row and thenar eminence, with mild snuffbox tenderness. Radial and ulnar pulses are intact. Radial, median, and ulnar nerve motor and sensory function intact. The patient can fully flex and extend at the wrist, but has pain with motion. There is no obvious visual deformity and no ecchymosis. Capillary refill in all digits <2 seconds. Can flex and extend all digits without difficulty. There is no warmth or erythema over the joint.

Non-contributory

Terry Thomas sign (widening of the scapholunate space)

The scapholunate ligament is disrupted.

Scapholunate advanced collapse (SLAC)

A fall on an outstretched hand (FOOSH) injury can result in not only fractures, but also ligamentous disruptions. Scapholunate Advanced Collapse (SLAC) injury is a progressive form of degenerative osteoarthritis of the wrist, often resulting from untreated disruption of the scapholunate ligament (SLL). SLAC is the most common form of post-traumatic osteoarthritis of the wrist. Injury to the SLL may be identified by intra-articular space widening between the scaphoid and lunate bones of the proximal row of the carpal bones on radiographs. This classic x-ray finding is also known as the “Terry Thomas” sign, referring to the famous gap in the upper dental incisors of the late British comedian. The SLL is responsible for stabilizing the scapholunate joint, and this x-ray finding indicates disruption of the ligament. Patients with this degree of joint space widening will often require surgical repair to ensure best functional outcome, and in the short term the injury is managed with NSAIDS, splinting, and orthopedic hand referral.

Take-Home Points

  • Scapholunate ligament disruption can lead to long term arthritis and impaired wrist function. Early identification and treatment helps improve outcomes.

  • MRI may be needed to identify disruption of the scapholunate ligament. X-ray is approximately 63% sensitive in identifying the injury by demonstrating scapholunate space widening.

  • Kompoliti E, Prodromou M, Karantanas AH. SLAC and SNAC Wrist: The Top Five Things That General Radiologists Need to Know. Tomography. 2021 Sep 23;7(4):488-503. doi: 10.3390/tomography7040042. PMID: 34698283; PMCID: PMC8544666.
  • Wessel LE, Wolfe SW. Scapholunate Instability: Diagnosis and Management – Anatomy, Kinematics, and Clinical Assessment – Part I. J Hand Surg Am. 2023 Nov;48(11):1139-1149. doi: 10.1016/j.jhsa.2023.05.013. Epub 2023 Jul 14. PMID: 37452815.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2025 SAEM Annual Meeting | Copyrighted by SAEM 2025 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.



By |2025-11-17T01:47:19-08:00Nov 17, 2025|Orthopedic, SAEM Clinical Images|
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SAEM Clinical Images Series: A Case of Sudden Right Arm Pain and Deformity


popeye sign

A 73-year-old male presented to the Emergency Department with acute pain in his upper right arm. The pain began suddenly upon attempting to lift a 30-lb box that had been delivered to his house. He stated that as he began to lift the box, he felt a sudden pop coupled with the acute onset of pain. Since the injury, he had difficulty with flexion of his right upper extremity. He denied any other complaints.

Vitals: All vital signs are normal.

General: Alert and oriented, well appearing.

Chest: Heart and lung sounds are normal. Chest palpation is unremarkable.

Musculoskeletal: See provided images comparing right versus left upper arm appearance. The patient reports pain with right elbow range of motion. No bony tenderness is present. Flexion of the right upper extremity is limited on exam.

Neurologic: Sensation is intact throughout. The patient has weakness of right elbow flexion, but other tests of strength are preserved.

Non-contributory

The patient has a “Popeye sign” – a proximal biceps bulge at the anterior mid-arm level of his right arm.

The patient has a biceps tendon rupture of his right arm.

Patients with biceps tendon ruptures present with anterior upper arm pain, often after contraction against resistance. Ruptures of the proximal tendon are more common than distal ruptures. Risk factors include advanced age, male gender, chronic biceps tendinopathy, tobacco use, and obesity. Acute ecchymosis and swelling are common. Proximal ruptures such as in this case demonstrate a proximal muscular bulge at the anterior mid-arm level (known as the Popeye sign). Distal rupture can be examined with several maneuvers such as the hook test, supination pronation test,biceps squeeze test, and distal biceps provocation test, which overall have high sensitivity and specificity for diagnosing distal biceps tendon rupture. Proximal ruptures may be treated conservatively, though surgical repair options exist. For distal ruptures, definitive treatment is surgical intervention. Factors affecting recommendations for surgery include the location and severity of the tear (complete vs. partial), and the patient’s medical fitness. Though rare, rhabdomyolysis and compartment syndrome are possible complications.

Take-Home Points

  • Biceps tendon ruptures are usually due to forcible contraction against significant resistance.

  • Initial treatment can be conservative in the ED, though all biceps tendon ruptures require urgent outpatient orthopedic referral.

  • Kelly, Mick P., et al. “Distal Biceps Tendon Ruptures: An Epidemiological Analysis Using a Large Population Database.” The American Journal of Sports Medicine, vol. 43, no. 8, 2015, pp. 2012–17, https://doi.org/10.1177/0363546515587738.
  • Vishwanathan K, Soni K. Distal biceps rupture: Evaluation and management. J Clin Orthop Trauma. 2021 May 20;19:132-138. doi: 10.1016/j.jcot.2021.05.012. PMID: 34099972; PMCID: PMC8167284.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2025 SAEM Annual Meeting | Copyrighted by SAEM 2025 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2025-10-26T13:32:30-07:00Oct 27, 2025|Orthopedic, SAEM Clinical Images|
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SAEM Clinical Images Series: Pain and Swelling in a Roofer’s Right Wrist

A 27-year-old male with no significant past medical history presented to the ED due to right hand pain and swelling. The patient reported that he works as a roofer and felt severe, sharp pain in his right hand immediately after using a nail gun this morning. The pain was followed by gradual swelling of the right wrist and hand. There was no loss of sensation or bleeding from the injury site. He additionally denied any injury from the nail itself. The patient was in moderate pain but hemodynamically stable while in the ED.

 

lunate

Vitals: Temp 36.6 °C; BP 155/99; HR 71; RR 18; SpO2 99%

General: Alert, mild distress.

Musculoskeletal: No gross deformities to right hand, reduced right hand flexion/extension due to pain, normal ROM of right shoulder and elbow, pain with right forearm supination/pronation, swelling of right hand and fingers and diffusely tender carpal bones.

Non-contributory

Comminuted lunate fracture. Lunate fractures, especially comminuted lunate fractures, usually result from high-energy trauma, with an incidence ranging from only 0.5% to 6.5% of carpal fractures. Up to one-third of wrist fractures appear to be overlooked on traditional radiography. Further imaging should be warranted for patients who are clinically suspicious of wrist fractures in the ED. Multidetector Computed Tomography (MDCT) with multiplanar reformat capability is a useful method to identify occult wrist fractures.

The blood supply of the lunate bone comes from the palmar and medial arteries of the carpometacarpal branch of the radial artery. Damage to the artery may lead to avascular necrosis (Kienböck disease). Comminuted lunate fractures may result in severe intraosseous destruction of vasculature, increasing the risk of lunate bone necrosis. An at-risk nerve is the median nerve, which runs through the carpal tunnel. If the lunate is fractured or displaced, it may compress or damage the median nerve, resulting in pain, paresthesia, or sensory loss in the palmar surface of the thumb, index, and middle fingers and radial half of the ring finger.

Take-Home Points

  • Associated risk factors for a lunate fracture include occupations or sports involving repetitive pressure to the base of the hand with the wrist in extension (eg, roofer, gymnast, jack-hammer operator).

  • Due to complex carpal anatomy, traditional radiography may not be sufficient to detect lunate fractures.

  • At-risk structures that require evaluation in the case of lunate fracture include the palmar and medial branches of the radial artery and the median nerve.

  • Li, Jun, et al. “Comminuted lunate fracture combined with distal radius fracture and scaphoid fracture: A case report.” Medicine, vol. 102, no. 29, 2023, https://doi.org/10.1097/md.0000000000034393.

  • Balci, Ali, et al. “Wrist fractures: Sensitivity of radiography, prevalence, and patterns in MDCT.” Emergency Radiology, vol. 22, no. 3, 2014, pp. 251–256, https://doi.org/10.1007/s10140-014-1278-1.

  • Geissler, William B. “Carpal fractures in athletes.” Clinics in Sports Medicine, vol. 20, no. 1, 2001, pp. 167–188, https://doi.org/10.1016/s0278-5919(05)70254-4.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2025-04-28T14:39:34-07:00May 2, 2025|Orthopedic, SAEM Clinical Images|
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SAEM Clinical Images Series: Weird Flex

tenosynovitis

A 29-year-old female with a history of depression, anxiety, and tobacco use disorder presented with worsening right index finger pain, swelling, and redness for the previous three days. Additionally, she reported that she was unable to further flex or extend her finger. She denied fevers, chills, rashes, or recent illness. There was no history of trauma, aquatic or other environmental exposures, insect bites, or intravenous drug use. She did note that she uses a copper brillo pad to clean her dishes at home which often causes small abrasions to her fingers.

Vitals: BP 160/112; PR 73; Temp 36.4°C; RR 18; SpO2 100% on RA

General: Well-appearing, no acute distress.

Cardiovascular: Right index finger capillary refill <2 sec.

Skin: Right index finger uniformly edematous and erythematous with tenderness to palpation along the tendon sheath; small healed abrasions over distal palmar aspect of the digit; no focal area of fluctuance.

MSK: right index finger held in flexion, pain with passive extension.

WBC: 8.6

ESR: 129

CRP: 105.5

This patient has flexor tenosynovitis, an infection of the synovial sheath surrounding the flexor tendon of the hand. The condition is usually caused by local inoculation from penetrating trauma although can also result from hematogenous spread. Flexor tenosynovitis is considered a surgical emergency, as delayed intervention can lead to significant morbidity including tendon rupture, deep space infection, abscess development, soft tissue necrosis, amputation, and/or chronically compromised hand function. Diagnosis is usually clinical, based on history and physical exam findings; however, laboratory evaluation may reveal leukocytosis and/or elevated inflammatory markers. If there is a history of penetrating trauma, x-rays of the affected digit are recommended to rule out retained foreign body. Management in the ED includes prompt surgical consultation and broad-spectrum antibiotics against common cutaneous pathogens. Antibiotic coverage should be broadened in patients with a history of marine exposure or Pseudomonal risk factors including immunocompromised status.

Flexor tenosynovitis presents with four classic exam findings called “Kanavel Signs.” Kanavel Signs include (1) flexion of the involved digit, (2) tenderness to palpation over the tendon sheath, (3) pain with passive extension, and (4) uniform swelling of the finger. The presence of all four Signs has a sensitivity for flexor tenosynovitis as high as 97.1%, although early in the course of infection, pain with passive extension may be the only finding.

Take-Home Points

  • Flexor tenosynovitis is an infection of the flexor tendon sheath of the hand and a history of trauma or penetrating injury to the area should raise suspicion.

  • Flexor tenosynovitis is a “can’t miss” clinical diagnosis in the ED as there is a risk of significant complications with delayed antibiotics and surgical intervention.

  • Infection can reliably be identified by the presence of the four Kanavel Signs on physical exam.

  • Chan E, Robertson BF, Johnson SM. Kanavel signs of flexor sheath infection: a cautionary tale. Br J Gen Pract. 2019 Jun;69(683):315-316. doi: 10.3399/bjgp19X704081. PMID: 31147342; PMCID: PMC6532803.

  • Chapman T, Ilyas AM. Pyogenic Flexor Tenosynovitis: Evaluation and Treatment Strategies. J Hand Microsurg. 2019 Dec;11(3):121-126. doi: 10.1055/s-0039-1700370. Epub 2019 Nov 2. PMID: 31814662; PMCID: PMC6894957.

  • Hermena S, Tiwari V. Pyogenic Flexor Tenosynovitis. In: StatPearls. StatPearls Publishing; 2022.

  • Kennedy CD, Huang JI, Hanel DP. In Brief: Kanavel’s Signs and Pyogenic Flexor Tenosynovitis. Clin Orthop Relat Res. 2016 Jan;474(1):280-4. doi: 10.1007/s11999-015-4367-x. Epub 2015 May 29. PMID: 26022113; PMCID: PMC4686527.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2025-03-30T20:30:57-07:00Apr 7, 2025|Orthopedic, SAEM Clinical Images|
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SAEM Clinical Images Series: An Unusual Arm Conundrum

shoulder

A 58-year-old female with a past medical history significant for osteoporosis presented with right shoulder pain after a witnessed mechanical fall down two stairs. She sustained no headstrike or loss of consciousness. She endorses severe right shoulder pain without numbness/tingling over any part of her arm. Since the fall, she has been unable to move her arm, which remains abducted overhead.

 

dislocation

General: Right arm fixed, abducted position and elevated over her head.

Vascular: 2-second capillary refill in all nail beds, strong palpable radial pulse.

Neuro: Sensation intact to light touch on medial and lateral aspects of all distal digits, and throughout entire axillary, radial, ulnar and median nerve distribution.

Motor: Flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) intact in digits 2 through 5. Extensor digitorum communis (EDC) and extensor indicis proprius (EIP) intact. Normal finger abduction and adduction. Normal thumb opposition. Normal OK sign. Wrist flexors and extensors intact.

None

Luxatio erecta (inferior shoulder dislocation) is a rare type of shoulder dislocation. The majority of shoulder dislocations are anterior (over 95%), with a smaller number being posterior (2-4%). Inferior dislocations are the least common injury pattern (0.5%), but prompt identification and treatment are crucial due to the high risk of neurovascular damage.  Radiographs will typically demonstrate the humeral head lying inferior to the glenoid fossa, with the humeral shaft parallel to the spine of the scapula. Classically, the entire arm is held in abduction.

Inferior shoulder dislocation most commonly occurs either due to hyperabduction of the shoulder (such as when grasping at a tree branch above while falling) or through an axial load from above on a hyperabducted arm (as seen in falls or motor vehicle accidents). Patients presenting with inferior shoulder dislocation are at substantial risk for neurovascular compromise, particularly of the axillary nerve, leading to impaired upper extremity movement and sensation. Due to the substantial injury mechanism, patients with inferior shoulder dislocations are also at increased risk for rotator cuff pathology. Treatment of inferior shoulder dislocation is immediate closed reduction to reduce the risk of neurovascular complications. Once reduced, the arm should be placed in an immobilizer to prevent recurrent dislocation.

Take-Home Points

  • Patients with inferior shoulder dislocations often present holding their arm above their head. Often, patients cannot adduct their arm.

  • Axillary nerve injuries occur in about 60% of inferior dislocations. Compared to other dislocations, inferior dislocations have the highest incidence of axillary nerve injuries.

  • Patients with inferior dislocations often present with neurovascular compromise of the affected arm, so be sure to do a thorough exam after reduction.

  • Grate I Jr. Luxatio erecta: a rarely seen, but often missed shoulder dislocation. Am J Emerg Med. 2000 May;18(3):317-21. doi: 10.1016/s0735-6757(00)90127-x. PMID: 10830689.

  • Nambiar M, Owen D, Moore P, Carr A, Thomas M. Traumatic inferior shoulder dislocation: a review of management and outcome. Eur J Trauma Emerg Surg. 2018 Feb;44(1):45-51. doi: 10.1007/s00068-017-0854-y. Epub 2017 Oct 3. Erratum in: Eur J Trauma Emerg Surg. 2018 Feb;44(1):53. doi: 10.1007/s00068-017-0878-3. PMID: 28975397.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2025-03-09T21:48:15-07:00Mar 10, 2025|Orthopedic, SAEM Clinical Images|
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SAEM Clinical Images Series: Purple Finger

bruising

A 30-year-old female with a past medical history of Crohn’s Disease presented to the ED for evaluation of an acutely bruised right 4th finger. She stated she was typing on a computer keyboard approximately 10 minutes prior to presentation and she noticed a sudden popping sensation at the base of her right ring finger. After the popping sensation, she noticed a cool sensation of the finger and numbness to the entire finger. Shortly after that, the finger turned purple, so she came to the Emergency Department for evaluation. She denied pain in the hand and has had no problems moving the finger. She denied trauma to the hand or finger. No other complaints or issues. She noted that she has had this once in the past, which self-resolved on its own in 10 days a few months ago in the same situation.

General: No acute distress

Right hand: Right 4th finger with diffuse ecchymosis across the palmar surface of the finger with swelling, no tenderness, ecchymosis does not extend to the palmar surface of the hand. FROM of all 5 digits at both the DIP and PIP joints. Sensation to the right 4th finger is decreased to light touch.

Left hand: Normal

Extremities: Normal other than the right ring finger

Pulses: Radial pulses 2+ bilaterally

Remainder of the physical exam is normal.

Non-contributory

Achenbach Syndrome, also known as paroxysmal finger hematomas, is a self-limited condition. It typically afflicts middle-aged women and presents as spontaneous subcutaneous bleeding of the palmar surface of the middle and index fingers of the hand. Patients usually present with pain, swelling, tingling, numbness, and ecchymosis. Many report a burning sensation to the finger. Diagnosis is based on presentation and exam. Laboratory testing and imaging do not show pathologic findings in this disorder. There is no known treatment and symptoms usually resolve on their own in a few days, but can last up to months. It has been shown to be recurrent, but without a known cause. Given the dramatic presentation of Achenbach Syndrome, it is important to be aware of this benign process to prevent unnecessary testing and workup, as it is a self-limited process.

Take-Home Points

  • Achenbach Syndrome is a benign, self-limited condition that does not require treatment
  • Relapses may occur.
  • No testing is indicated, but if sent will be normal including laboratory studies and arterial dopplers of the extremity.

  • Ahmed Z, Elmallah A, Elnagar M, Dowdall J, Barry M, Sheehan SJ. Painful Blue Finger-Achenbach’s Syndrome: Two Case Reports. EJVES Short Rep. 2018 Jun 27;40:1-2. doi: 10.1016/j.ejvssr.2018.05.008. PMID: 30094355; PMCID: PMC6070693.
  • van Twist DJL, Hermans W, Mostard GJM. Paroxysmal finger hematoma. Cleve Clin J Med. 2020 Apr;87(4):194. doi: 10.3949/ccjm.87a.19122. PMID: 32238371.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.

By |2024-04-01T09:11:49-07:00Mar 18, 2024|Orthopedic, SAEM Clinical Images|
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