Ossification of the suprascapular ligament: A risk factor for suprascapular nerve compression?

Abstract

Entrapment of the suprascapular nerve at the suprascapular notch may be due to an ossified suprascapular ligament. The present study was conducted in order to investigate the incidence of this anomaly and to analyze the resultant bony foramen (foramen scapula) for gross nerve compression.
We evaluated 104 human scapulae from 52 adult skeletons for the presence of complete ossification of the suprascapular ligament. When an ossified suprascapular ligament was identified, the diameter of the resultant foramen was measured. Also, the suprascapular regions of 50 adult cadavers (100 sides) were dissected. When an ossified suprascapular ligament was identified, the spinati musculature was evaluated for gross atrophy and the diameters of the resultant foramen scapulae and the suprascapular nerve were measured. Immunohistochemical analysis of the nerve was also performed.
For dry scapular specimens, 5.7% were found to have an ossified suprascapular ligament. The mean diameter of these resultant foramina was 2.6 mm. For cadavers, an ossified suprascapular ligament was identified in 5% of sides. Sections of the suprascapular nerve at the foramen scapulae ranged from 2 to 2.8 mm in diameter. In all cadaveric samples, the suprascapular nerve was grossly compressed (~10-20%) at this site. All nerves demonstrated histologic signs of neural degeneration distal to the site of compression. The presence of these foramina in male cadavers and on right sides was statistically significant.
Based on our study, even in the absence of symptoms, gross compression of the suprascapular nerve exists in cases of an ossified suprascapular ligament. Asymptomatic patients with an ossified suprascapular ligament may warrant additional testing such as electromyography.

Full text

Editors Joe F. de Beer and Deepak N. Bhatia. Printed and published by Medknow Publications and Media Pvt. Ltd. on behalf of Cape Shoulder Institute, Cape Town, South Africa and Printed at
Dhote Offset Technokrafts Pvt. Ltd., Jogeshwari, Mumbai, India and published at B5-12, Kanara Business Centre, Ghatkopar, Mumbai, India.
Volume 7 Issue 1
Jan-Mar 2013
}Coracoid bone graft osteolysis after Latarjet procedure: A comparison study
between two screws standard technique vs mini-plate fixation
}A biomechanical assessment of superior shoulder translation after reconstruction
of anterior glenoid bone defects: The Latarjet procedure versus allograft
reconstruction
}Beyond the peak of the anterior glenoid rim: A cadaveric study
}Ossification of the suprascapular ligament: A risk factor for suprascapular nerve
compression?
}Digital photography for assessment of shoulder range of motion: A novel clinical
and research tool
}Supraspinatus and infraspinatus compartment syndrome following scapular
fracture
}Arthroscopic autograft reconstruction of the inferior glenohumeral ligament:
Exploration of technical feasibility in cadaveric shoulder specimens
}Metal markers for radiographic visualization of rotator cuff margins: A new
technique for radiographic assessment of cuff repair integrity
C o n t e n t s

19 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 
Original Article

     

R. Shane Tubbs
1
, Carl Nechtman
1
, Anthony V. D’Antoni
2
, Mohammadali M. Shoja
1
,
Martin M. Mortazavi
1
, Marios Loukas
3
, Curtis J. Rozzelle
1
, Robert J. Spinner
4
ABSTRACT
Introduction: Entrapment of the suprascapular nerve at the suprascapular notch may be due

the incidence of this anomaly and to analyze the resultant bony foramen (foramen scapula) for

Materials and Methods: We evaluated 104 human scapulae from 52 adult skeletons for the

           
            



Results:            






Conclusions: 


Key words:

INTRODUCTION
        
        

       
      
       






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       


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

Alabama,
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

Medicine, New York, USA,
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Department


4

Clinic, Rochester, MN, USA

Dr. R. Shane Tubbs,



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www.internationalshoulderjournal.org
DOI:
10.4103/0973-6042.109882
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Tubbs, et al.
 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 20
     
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  



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
        
    

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

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


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




     


      

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

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


MATERIALS AND METHODS
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




       


       




 





     

 Pt

RESULTS




    



           









  
Figure 2: Schematic drawing illustrating compression of the left
suprascapular nerve within the foramen scapulae as found in all of
our cadaveric specimens with such a foramen. Note that this is a
posterior view
Figure 1:        
ligament (L) resulting in the foramen scapulae (seen above the L).
For reference, note the spine (S), coracoid process (C) and acromion
(A) of the scapula

Tubbs, et al.
21 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 
      







    P   


DISCUSSION
         




    





       
       
      

  

    

  et al

 
et al





       
  



 
        
    
       




       
      





          



        
       

The
     

 
       
   





  

 
           


CONCLUSIONS





REFERENCES
           




 

 
     

 
     
    

          
Figure 3: Histologic specimen noting signs of suprascapular nerve

          
ligament and notes vascular hyalinization and thickening of the epi
and perineuria (Trichrome ×44)

Tubbs, et al.
 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 22


           


  



 

 
          



 
      
       

 

  


       

  


 



 


 


 


        

 
et al


              
      
Source of Support: Nil,  None declared.