When MCC Stands for Motorcycle Crash and Most Common Cause - The Emergency Medical Minute

When MCC stands for motorcycle crash and most common cause

Chief Complaint:

Left Arm Pain


27 y/o RHD female presented via EMS. Patient was a helmeted passenger on a motorcycle that was hit by a car immediately prior to EMS arrival. Upon EMS arrival, the patient was lying in the supine position with an obvious deformity to her left upper extremity. Patient reports they were t-boned and she extended her left arm prior to the impact. She currently complains of severe, constant, diffuse left shoulder/arm pain that is made worse with movement by other people. She states that she is unable to feel her left hand and arm and can’t move it herself.

Pertinent Exam Findings:

Heart: Tachycardic, left hand is warm with cap refill < 2 sec. Biphasic doppler signals of radial and ulnar arteries on left with 2/4 palpable on right.

Lungs: CTAB

Msk: Left clavicular deformity with overlying hematoma and ecchymosis. Deformity of the left elbow with laceration overlying the joint. Multiple

deformities of left fingers 2-4
Neuro: Insensate from C4-T1 in the left upper extremity and had no motor function of the left arm.


Diagnostic Studies:

CXR: Showing clavicular dislocation.

CTA: Demonstrating disruption of the proximal left subclavian artery and extensive adjacent chest wall hemorrhage.

MRI: Demonstrating irregular tearing of the proximal brachial plexus.

Figure 1
CXR showing dislocation of left clavicle.

ED Course:

In the emergency department the patient was diagnosed with left extremity injuries including: brachial plexus injury, CSF leak at C7-T1, scapular fracture, subclavian artery dissection, open distal humerus fracture, and hand fractures. Neurosurgery, vascular surgery, trauma, and orthopedic surgery were consulted in the emergency department. The patient’s left elbow was irrigated and splinted in the ED. She was given ancef, tdap, pain medications and then admitted to the ICU.


Clavicular dislocations are rare, making up less than 1% of all joint dislocations and 3% of shoulder girdle injuries. Anterior SCJ dislocations are more common because anterior ligaments are weaker than posterior. This injury commonly occurs when a force is applied to the anterior lateral aspect of the shoulder resulting in force transmitted medially to the SCJ. Diagnostic modalities include CT, MRI, and xray, serendipity view is preferred. Anterior SCJ dislocations are usually treated conservatively without reduction by immobilizing the affected arm. While closed reduction can be attempted, recurrent dislocation rates range from 21% to 100%. Conversely, posterior dislocations are almost always managed operatively. Our patient’s anterior SCJ dislocation was treated conservatively without reduction.

Subclavian injuries in the setting of blunt trauma are reported in less than 1% of all arterial and chest related injuries. Subclavian artery dissections are often evaluated using CTA (Please see Figure 2 below). Doppler ultrasound can be used to assess the ipsilateral radial pulse to ensure sufficient collateral blood supply. In the past, subclavian artery injuries were approached with medial sternotomies and high lateral thoracotomies. However, newer and less invasive endovascular techniques have shown better outcomes. Treatments include balloon angioplasty, stenting, and bypass grafts. Anticoagulation therapy remains an area of variable practice, and may be of particular interest to the emergency medicine physician. Our patient’s vascular surgeon noted that she had excellent reconstitution of the axillary artery on CTA and biphasic doppler signals in the radial and ulnar arteries. She was not placed on anticoagulants and follow-up with vascular surgery 4-6 weeks post-discharge was recommended.

The incidence and severity of traumatic brachial plexus injuries (BPI) in the US population is unknown. However, one retrospective study at a Level I Trauma Center in the US had an incidence of 0.26% traumatic BPI from 2005 to 2016. Traumatic brachial plexus injuries are most commonly sustained during motor vehicle crashes or contact sports. The typical mechanism is rotation of the neck ipsilateral to the injury with traction contralateral to the injured extremity. BPI diagnoses are made with MRI (see figure 3 for our patient’s diagnostic imaging), CT myelogram, and/or electromyography (EMG). Apart from conservative management, surgical options include neurolysis, nerve repair, use of nerve grafts and nerve transfer. Surgery within the first 3 months is generally advised against as it could interfere with any possible spontaneous nerve recovery. Emergent operative intervention is usually indicated when there are open penetrating injuries. If after 3 months there are no clinical signs of functional restoration, surgical intervention is recommended. Our patient’s neurosurgeon noted that there was no significant neural compression caused by the CSF leak, and the patient did not require a cervical collar. An outpatient EMG was scheduled for 6 weeks post-discharge without any immediate surgical intervention.

Figure 2
Coronal oblique reformatted image from CTA demonstrating disruption of the proximal left subclavian artery (thin arrow) and extensive adjacent chest wall hemorrhage (thick arrows).

Figure 3
Axial STIR MR image demonstrating irregular tearing of the proximal brachial plexus (arrows).

High Yield Points:

  • Traumatic SCJ dislocation is an uncommon condition whose diagnosis is often missed as cxr can be subtle. Serendipity view on xray, a CT or a MRI should be considered. The importance in determining the direction of dislocation is emphasized by the dichotomy of management. Anterior dislocations are managed conservatively while posterior dislocations tend to be associated with mediastinal injuries and are managed surgically.

  • Subclavian artery injuries are rare and are associated with clavicular injuries. CTA imaging is commonly used in the ED for diagnosis. Fortunately, there is frequently significant collateralization of the vessels preventing limb ischemia. The emergency physician should consult with their vascular surgeon in regards to starting anticoagulation therapy in the ED.

  • Brachial plexus injuries are typically diagnosed with MRI imaging. Initially BPI are managed conservatively unless they are associated with penetrating trauma.


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Aaron Wolfe, DO, FACEP

Joshua Bridge, MSII

Sarah Rokhlin, MSI

Greg Czuczman, MD


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