Ganglion cysts can be important when they are located around
the shoulder, especially when they are located in the suprascapular notch and
the spinoglenoid notch. The suprascapular nerve passes under the transverse
scapular ligament at the suprascapular notch. The transverse scapular artery
runs above the transverse scapular ligament. The artery and nerve joint and
then pass through the spinoglenoid notch under the inferior scapular ligament.
The suprascapular nerve gives branches to the supraspinatus muscle and branches
to the infraspinatus muscle.
Nerve compression from a ganglion cyst at the suprascapular
notch affects both the supraspinatus and infraspinatus muscles, causing a
decrease in abduction and loss of external rotation of the shoulder. Nerve
compression at the spinoglenoid notch affects only infraspinatus muscle,
causing loss of external rotation of the shoulder with the arm to the side.
Spinoglenoid notch compression is usually associated with cysts and ganglia. In
addition to compression of the suprascapular nerve, these patients may also
have associated posterior labral tears.
