Suprascapular Nerve
Lennard Funk
‣ Motor innervation: ‣ Supraspinatus & infraspinatus muscles
‣Sensory branches to: ‣ Coracohumeral & coracoacromial ligaments ‣ Subacromial bursa ‣ AC & GH joints
‣Cutaneous innervation: ‣ ? Proximal-lateral one-third of the arm.
Amjani. J Anat. 1994 Horiguchi. J Anat. 1980
Causes
• Idiopathic • Paralabral Cyst / Ganglion • Trauma
Suprascapular Notch
Spinoglenoid Notch
Sites
Natural History
No Cyst Mostly recover in 1yrCyst Less likely to recover
Cummins. JBJS. 2000.
Suprascapular Nerve Palsy• Supraspinatus +/- Infraspinatus
• Wasting • Weakness
Clinical
• Supraspinatus +/- Infraspinatus • Wasting • Weakness
Investigations
• MRI Scan: • Ganglion Cyst / Mass lesion
Suprascapular Spinoglenoid
Electro-diagnostic• EMG + Nerve Conduction Velocities:
• Proximal - Suprascapular Notch • Distal - Spinoglenoid Notch
Nerve Conduction Velocity
‣ From Erb’s point: ‣ Supraspinatus = 2.7 ± 0.5ms ‣ Infraspinatus = 3.3 ± 0.5ms
Kraft. Arch Phys Med and Rehab. 1972
EMG
‣ Increased in denervated muscles: ‣ Spontaneous activity ‣ Fibrillations ‣ Positive sharp waves
‣ Also: ‣ Polyphasic activity ‣ Reduced amplitude of evoked potentials.
Kraft. Arch Phys Med and Rehab. 1972
Note...
‣ After 3 weeks of onset
‣ Operator dependent
‣ Other Periscapular Muscles must be assessed
‣ Repeat studies should be same operator
‣ Discuss!
Treatment
‣ No Cyst - Early decompression appears to show better results (Level 4 studies)
‣Cyst
‣ Aspiration
‣ Open decompression (doesn’t deal with associated pathology)
‣ Arthroscopic Decompression
Aspiration UltrasoundCourtesy of Prof Waqar Bhatti
Arthroscopic Decompression‣ Suprascapular Notch
Position
Portals
1
3
2
4
1 = standard posterior portal
2 = standard anterior portal
3 = anterolateral portal
4 = Nevasier portal
5
5 = Lateral portal
Identify CAL
Identify Coracoid & CCL
Follow Coracoid Base medial to CCL into Scapula Notch
Create Superior (Nevasier) Portal & retract Supraspinatus with probe
Identify Artery & STSL (Superior Transverse Scapular Ligament)
6wks Postop
Spinoglenoid Cyst
Chronic Posterior Shoulder Pain in the Overhead Athlete
‣ Chronic Posterior Pain
‣ Normal EMG & MRI
‣ Exclusion
‣ High index of suspicion
Kevin Plancher
Spinioglenoid Ligament
Summary:
‣ Spinoglenoid / Suprascapular Notch
‣Always get: EMG & MRI
‣ No cyst = Non-operative initially
‣ Cyst = Surgery
‣ Surgery - train on cadaver
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