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Suprascapular Neuropathy


KEY FACTS

Terminology

  • Suprascapular nerve impingement with muscle denervation

Imaging

  • Suprascapular nerve impingement may occur at either spinoglenoid or suprascapular notch

  • Spinoglenoid notch: Between neck and blade of scapula, roofed by spinoglenoid ligament

    • Entrapment affects infraspinatus muscles only

  • Suprascapular notch: At superior border of scapula, roofed by superior transverse ligament

    • Entrapment affects both supraspinatus and infraspinatus muscles

  • Denervation edema is 1st sign on MR

    • Uniformly increased signal intensity of muscle

  • Fatty atrophy occurs later

Top Differential Diagnoses

  • Cervical radiculopathy

  • Parsonage-Turner syndrome (brachial neuritis)

  • Rotator cuff tear

  • Traction neuropathy

  • Neural tumor

Pathology

  • Paralabral cyst due to tear of posterosuperior glenoid labrum

  • Mass or venous varicosities compressing nerve

  • Posttraumatic scar or heterotopic ossification

Clinical Issues

  • Young or middle-aged patients, M > F

  • Overhead athletes

Diagnostic Checklist

  • Denervation edema best seen on sagittal fluid-sensitive sequences

Coronal graphic shows suprascapular nerve coursing through suprascapular notch
, after which it gives rise to motor branch to supraspinatus muscle
. Nerve then passes through the spinoglenoid notch
and innervates the infraspinatus muscle
.

Coronal T2WI FS MR shows an elongated, multilocular cyst
extending from a posterosuperior glenoid labral tear
through the spinoglenoid notch. Infraspinatus muscle
shows a mild, homogeneous increase in signal intensity.

Axial PD FSE FS MR in the same patient shows the cyst
at the level of the spinoglenoid notch
. Denervation edema is less visible on this sequence than on T2 FS or STIR.

Sagittal T2WI FS MR in the same patient shows the cyst
at the spinoglenoid notch. The sagittal image most readily shows the abnormal signal intensity of the infraspinatus
relative to the supraspinatus
muscle.

TERMINOLOGY

Definitions

  • Suprascapular nerve impingement with muscle denervation

IMAGING

General Features

  • Location

    • Suprascapular nerve: Motor nerve to supraspinatus and infraspinatus muscles (mm)

      • –

        Arises from C5 + C6 nerve roots

    • Impingement may occur at either spinoglenoid or suprascapular notch

      • –

        Spinoglenoid notch: Between neck and blade of scapula, roofed by spinoglenoid ligament

        • □

          Entrapment affects infraspinatus mm only

      • –

        Suprascapular notch: At superior border of scapula, roofed by superior transverse ligament

        • □

          Entrapment affects both supraspinatus and infraspinatus mm

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