Introduction
The suprascapular nerve is a mixed nerve in the upper limb. Suprascapular nerve injuries are increasing in clinical significance due to their role in shoulder pain and upper extremity weakness.[1]
Anatomy
The suprascapular nerve and its nerves
The superficial nerve arises from the upper trunk of the brachial plexus. Its nerve roots are C5 and C6. Sometimes it may also have roots from C4. From the posterior triangle of the neck, the muscles run to the upper part of the scapula then down and parallel to it laterally omohyoid muscle belly. It then passes under the suprascapular ligament through the suprascapular notch and enters the supraspinous fossa where it innervates the supraspinatus muscle. Through here, it twists around the spine of the scapula through the spinoglenoid notch and then goes away infraspinous fossa where it innervates the infraspinatus muscle.[1]The suprascapular muscle also provides sensory input to the glenohumeral and acromioclavicular joints.[2]
Etiology
Common sites of suprascapular nerve compression
Compression neuropathy resulting from nerve entrapment is the most common cause of suprascapular nerve palsy. The most common sites through the nerve are the suprascapular notch and the spinoglenoid notch.[3]
Shoulder injuries resulting from fractures of the scapula clavicle and proximal humerus can cause extensive damage to the suprascapular nerve.[4][5]
Postoperative complications after open or athroscopic shoulder surgery can lead to facial nerve damage.[6]
Scapula dyskinesia can lead to suprascapular nerve palsy.[7]
Tumors cysts and other space-occupying lesions around the shoulder can compress the suprascapular nerve.[8]
In rare cases, systemic conditions such as systemic lupus erthymatosus and arthritis can cause suprascapular nerve palsy.[9]
Clinical presentation
Often, patients will present with dull aching pain over the upper or dorsal region of the shoulder. Pain may go down over the upper limb or into the neck. Cross-body adduction and internal rotation can increase pain. If the nerve injury is distal to spinoglenoid, there will be no pain notch. Nearly 40% of cases present with shoulder-related trauma. This is common in athletes who participate in repetitive altitude activities. Patients with a history of trauma may also report feelings of shoulder instability.[7]
The most common clinical symptom of suprascapular nerve palsy is paralysis of the supraspinatus and/or infraspinatus muscles. It is seen in 80% of cases. Because the muscle body is continuous if the injury is close to the spinoglenoid notch, both muscles will be atrophied and if the injury is atrophied distal to the spinoglenoid notch, the supraspinatus is spared and only the infraspinatus will show atrophy.[7]
The suprascapular nerve stretch test is useful to determine suprascapular nerve involvement during physical examination. Here, the patient is asked to rotate the head sideways away from the affected shoulder and pull the neck. If the pain in the shoulder worsens in this way, take it the study is positive.[10]
Diagnosis
Conduction studies and electromyography are considered the gold standard for the diagnosis of suprascapular nerve palsy. Longer latency of decreased amplitude fibrillation potential and positive sharp waves in the nerve conduction test suggest suprascapular nerve compression and denervation. X-rays can help rule out trauma to the surrounding bones. CT MRI and diagnostic ultrasound can help locate the lesion. Pain immediately following cosmetic insertion into the suprascapular or supraglenoid notch may aid in the diagnosis.[7]
Management
Medical
Nonsteroidal anti-inflammatory drugs and local anesthetics (muscle blockers) are used to manage the pain conservatively.[7]
Surgical
Surgery is considered only in cases showing no improvement after 6-12 months of conservative management. Surgical excision of the suprascapular nerve is performed along with repair of the underlying shoulder pathology (if present).[7]
Physiotherapy
Specific sport-activity modifications are suggested for participating athletes to prevent frequent concussions. All motion should be maintained at the shoulder to prevent adhesive capsulitis. The posterior shoulder capsule that stretches and strengthens the rotator cuff and shoulder muscles is recommended. There is no program of physical therapy for suprascapular nerve palsy.[7] Research should focus on addressing this area of clinical importance.
For a more detailed description of muscle injury rehabilitation in general, visit this page on Physiopedia.
References
- ↑ Jump up to:1.0 1.1 Kostretzis L, Theodoroudis I, Boutsiadis A, Papadakis N, Papadopoulos P. Suprascapular Nerve Pathology: A Review of the Literature. Open Orthop J. 2017 Feb 28;11:140-53.
- ↑ Avery BW, Pilon FM, Barclay JK. Anterior coracoscapular ligament and suprascapular nerve entrapment. Clin Anat. 2002 Nov;15(6):383-6.
- ↑ Gosk J, Urban M, Rutowski R. Entrapment of the suprascapular nerve: anatomy, etiology, diagnosis, treatment. Ortop Traumatol Rehabil. 2007 Jan-Feb;9(1):68-74.
- ↑ Zoltan JD. Injury to the suprascapular nerve associated with anterior dislocation of the shoulder: case report and review of the literature. J Trauma. 1979 Mar;19(3):203-6.
- ↑ Solheim LF, Roaas A. Compression of the suprascapular nerve after fracture of the scapular notch. Acta Orthop Scand. 1978 Aug;49(4):338-40.
- ↑ Mallon WJ, Bronec PR, Spinner RJ, Levin LS. Suprascapular neuropathy after distal clavicle excision. Clin Orthop Relat Res. 1996 Aug;(329):207-11
- ↑ Jump up to:7.0 7.1 7.2 7.3 7.4 7.5 7.6 Reece CL, Varacallo M, Susmarski A. Suprascapular Nerve Injury. [Updated 2021 Jul 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559151/
- ↑ Sjödén GO, Movin T, Güntner P, Ingelman-Sundberg H. Spinoglenoid bone cyst causing suprascapular nerve compression. J Shoulder Elbow Surg. 1996 Mar-Apr;5(2 Pt 1):147-9.
- ↑ Zehetgruber H, Noske H, Lang T, Wurnig C. Suprascapular nerve entrapment. A meta-analysis. Int Orthop. 2002;26(6):339-43.
- ↑ Lafosse L, Piper K, Lanz U. Arthroscopic suprascapular nerve release: indications and technique. J Shoulder Elbow Surg. 2011 Mar;20(2 Suppl):S9-13.
