Proprioception of extra-ocular muscles in the human: on the morphology of muscle spindles

Klinische Monatsblätter für Augenheilkunde
J R LukasR Mayr

Abstract

Increasing importance is attributed to the proprioceptive innervation of extraocular muscles for the development of binocular vision. In the literature, data on proprioceptors in human extraocular muscles are rare and inconsistent. Therefore a detailed morphological analysis of spindles in human extraocular muscles appeared indicated. Complete serial sections of all extraocular muscles of 3 human individuals, 67, 72, and 83 years of age, were alternately impregnated with silver, stained following Mowry and immunohistochemically stained for S100 or PGP 9.5. Distal parts of extraocular muscles from multiorgan donors, 2, 17, and 34 years of age, were prepared for electron microscopy. Spindles contained 1 to 18 intrafusal muscle fibers, 55% of which were nuclear chain fibers, 2% nuclear bag fibers, and 43% fibers exhibiting the same morphological features as extrafusal fibers. The latter had been previously described as "anomalous fibers" (Ruskell). This intrafusal type exclusively occurs in human extraocular muscle spindles. Ultrastructural analysis revealed morphologically normal sensory terminals on all 3 types of intrafusal fibers. Findings in a two-year-old individual were similar to those in aged individuals. Spindles in huma...Continue Reading

Citations

Apr 7, 1999·Progress in Retinal and Eye Research·G L Ruskell
Jun 3, 2000·Annals of Anatomy = Anatomischer Anzeiger : Official Organ of the Anatomische Gesellschaft·A Maier
Jun 9, 2006·Strabismus·Roland BlumerJulius-Robert Lukas
Oct 11, 2017·Journal of Pediatric Ophthalmology and Strabismus·Ala Paduca, Jan Richard Bruenech

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