title: Tendinous muscle insertions (scleromuscular junctions of the recti muscles) in patients with ocular alignment problems.
abstract: BACKGROUND
  The purpose of this study was to prove the hypothesis whether the scleromuscular junction of extraocular recti muscle is tendinous.
  
  
  METHODS
  Muscle samples of the 41 extraocular recti muscles of 33 patients and 4 muscle-/eye-matched samples from 2 postmortem eyes, were processed for light/electron microscopy and immunohistochemistry with antibodies against desmin, smooth-muscle actin and muscle regulating proteins like myf3 and myf4 (myogenin), tenascin C and for 8 samples against collagens I to IV.
  
  
  RESULTS
  Histological examination of the muscle samples confirmed a thick collagen-structured tissue, specific for muscle tendon; without appearance of muscle tissue. This was confirmed by immunohistochemistry with antibodies against desmin, smooth-muscle actin, myf3 and myf4 (myogenin) and for eight samples with collagens I to IV. Anti-tenascin C marker was only strongly positive in the connective tissue of the blood vessel walls. Electron microscopy demonstrated collagen bundles composed of parallel oriented fibrils with a moderate amount of ground substance.
  
  
  CONCLUSIONS
  The absence of contractile fibers at the sclerotendinous junction is an entirely normal finding in humans and cannot be related to ocular alignment pathogenesis.
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland (Chairman a. i.: Dr. sc. nat. Norbert Spirig).
authors.forename: M G
authors.initials: MG
authors.lastname: Todorova
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland (Chairman a. i.: Dr. sc. nat. Norbert Spirig).
authors.forename: A M
authors.initials: AM
authors.lastname: Palmowski-Wolfe
authors.affiliation: Department of Ophthalmology, University of Basel, Basel, Switzerland (Chairman a. i.: Dr. sc. nat. Norbert Spirig).
authors.forename: P
authors.initials: P
authors.lastname: Meyer
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000378:metabolism / Q000473:pathology*; D009801:Oculomotor Muscles / Q000378:metabolism / Q000648:ultrastructure*; D012590:Sclera / Q000378:metabolism / Q000648:ultrastructure*; D013710:Tendons / Q000378:metabolism / Q000648:ultrastructure*; D055815:Young Adult