title: Tears at the myotendinous junction of the infraspinatus: ultrasound findings.
abstract: OBJECTIVE
  Tears involving the myotendinous junction (MTJ) of the infraspinatus (IS) have been recently described on MRI. These occur centrally in the muscle belly, and are not associated with full thickness tears of the distal infraspinatus tendon. They also induce a rapidly progressive fatty infiltration of the muscles and amyotrophy. The purpose of this study is to assess the accuracy of ultrasonography in diagnosing MTJ tears of the infraspinatus and to describe the usual ultrasonographic appearance compared with MRI.
  
  
  METHODS
  Retrospective study of 2403 US examinations of the shoulder (over 5 years). Fifteen patients with a reported suspicion of infraspinatus MTJ tears were included. MRI examination was available in all cases, CT arthrography in 13 cases, and one patient underwent surgical confirmation.
  
  
  RESULTS
  All patients were sent for an ultrasound for suspect lesion of the tendons of the rotator cuff, with posterior pain in the infraspinatus fossa. All cases seen on ultrasonography were confirmed on MRI. CT arthrography confirmed the absence of tear of the IS tendon in all cases and did not reveal the MTJ tears. Two signs appeared to us as being of special interest: the "tadpole sign" on longitudinal views, and the "black eye sign" on sagittal views. The proximal retraction of the tendon at the MTJ is the anatomical explanation of both signs.
  
  
  CONCLUSIONS
  Tears at the myotendinous junction of the infraspinatus are rare but can be diagnosed on US examination, provided that the sonographer pays attention to the infraspinatus fossa especially in cases of normality of the distal tendinous cuff.
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France. Electronic address: henri.guerini@gmail.com.
authors: H
authors: H
authors: Guerini
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: E
authors: E
authors: Pluot
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: E
authors: E
authors: Pessis
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: F
authors: F
authors: Thevenin
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: R
authors: R
authors: Campagna
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: A
authors: A
authors: Feydy
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: P
authors: P
authors: Gaudin
authors: Service de radiologie B, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, 75014 Paris, France.
authors: J L
authors: JL
authors: Drapé
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000000981:diagnostic imaging* / Q000473:pathology; D000070636:Rotator Cuff Injuries; D014463:Ultrasonography
keywords: Infraspinatus lesion; MRI; Tear; US