Answer:
Suprascapular Nerve Entrapment Syndrome caused by a ganglion cyst in spinoglenoid notch
Findings: Images demonstrate a large cystic lesion occupying the suprascapular incisura and spinoglenoid notch consistent with a ganglion cyst. Abnormal hyperintensity consistent with denervation edema involving the infraspinatus muscle is noted.
Discussion:
The suprascapular nerve originates from the upper trunk of the brachial plexus.The suprascapular nerve contains motor fibers that innervate the supraspinatus and infraspinatus muscles as well as sensory fibers that carry sensation from both the glenohumeral and acromioclavicular joints. The nerve traverses the supraclavicular fossa with the suprascapular vein and artery. It then enters the suprascapular notch, making a sharp turn around the scapular spine. Patients with suprascapular nerve entrapment present with pain and muscle atrophy. Compression may result from trauma, thickening of the scapular ligaments, or soft tissue masses. Nerve compression may be due to soft tissue masses, paralabral cysts, or dilated veins . Paralabral cysts may be synovial, ganglion cysts, or pseudocysts. Given its peculiar branching pattern, proximal entrapment of the suprascapular nerve at the scapular incisura results in a supraspinatus and infraspinatus muscle denervation syndrome. Distal entrapment at the spinoglenoid notch may be manifested as isolated compromise of the infraspinatus muscle.
References:
1. MRI of the musculoskeletal system – Thomas Berquist.
2. Magnetic Resonance Imaging in Orthopaedics and Sports Medicine by Stoller David W., 3rd Edition
Contributed By: Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India
Suprascapular Nerve Entrapment Syndrome caused by a ganglion cyst in spinoglenoid notch
Findings: Images demonstrate a large cystic lesion occupying the suprascapular incisura and spinoglenoid notch consistent with a ganglion cyst. Abnormal hyperintensity consistent with denervation edema involving the infraspinatus muscle is noted.
Discussion:
The suprascapular nerve originates from the upper trunk of the brachial plexus.The suprascapular nerve contains motor fibers that innervate the supraspinatus and infraspinatus muscles as well as sensory fibers that carry sensation from both the glenohumeral and acromioclavicular joints. The nerve traverses the supraclavicular fossa with the suprascapular vein and artery. It then enters the suprascapular notch, making a sharp turn around the scapular spine. Patients with suprascapular nerve entrapment present with pain and muscle atrophy. Compression may result from trauma, thickening of the scapular ligaments, or soft tissue masses. Nerve compression may be due to soft tissue masses, paralabral cysts, or dilated veins . Paralabral cysts may be synovial, ganglion cysts, or pseudocysts. Given its peculiar branching pattern, proximal entrapment of the suprascapular nerve at the scapular incisura results in a supraspinatus and infraspinatus muscle denervation syndrome. Distal entrapment at the spinoglenoid notch may be manifested as isolated compromise of the infraspinatus muscle.
References:
1. MRI of the musculoskeletal system – Thomas Berquist.
2. Magnetic Resonance Imaging in Orthopaedics and Sports Medicine by Stoller David W., 3rd Edition
Contributed By: Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India