Suprascapular Nerve Injury After Coracoid Fracture: MRI Findings of Muscle Denervation

Case Summary

A 70-year-old male presented with shoulder pain after a fall. Initial computed tomography (CT) demonstrated a linear, nondisplaced fracture extending from the glenoid to the coracoid process.

The patient was treated conservatively with shoulder immobilization.

Three weeks later, persistent pain and restricted shoulder motion prompted further evaluation with MRI.

Imaging Findings

MRI demonstrated an unhealed mildly displaced fracture line extending from the superior glenoid to the coracoid process (white arrow) with surrounding bone marrow edema.

At the level of the fracture line, interruption of the suprascapular nerve continuity was suspected, and the distal segment of the nerve could not be visualized (red arrows).

Proton density–weighted sequences showed diffuse hyperintensity within the supraspinatus and infraspinatus muscles, compatible with subacute denervation changes.

Additionally, signal alterations consistent with a partial tear of the coracoclavicular ligament were present (blue arrows).

Taken together, the findings suggested post-traumatic suprascapular nerve injury with secondary muscle denervation.

Teaching Pearls

???? Suprascapular nerve anatomy matters
The suprascapular nerve arises from the upper trunk of the brachial plexus (C5–C6) and innervates the supraspinatus and infraspinatus muscles.

???? Typical denervation pattern on MRI
Subacute denervation manifests as T2/PD hyperintensity due to muscle edema, while chronic stages demonstrate fatty atrophy.

???? Localization of nerve injury
Injury at the suprascapular notch results in denervation of both supraspinatus and infraspinatus, whereas injury at the spinoglenoid notch affects the infraspinatus only.

???? Most cases are due to compression
Suprascapular neuropathy most commonly results from paralabral cysts or ganglion cysts, but trauma or scapular fractures are rare causes.

???? MRI is key for diagnosis
MRI can demonstrate both the cause of nerve injury and the secondary muscle denervation pattern, making it the most informative imaging modality.

Key Takeaway

Persistent shoulder pain after scapular or coracoid fractures should raise suspicion for suprascapular nerve injury, especially when MRI shows edema of the supraspinatus and infraspinatus muscles.