Determination of slow-tonic MyHC immunoreactivity is an important step in the evaluation of muscle spindles in porcine extraocular muscles

Muscle spindles in the human bulbospongiosus and ischiocavernosus muscles

“…This finding may be due to a decrease in intrafusal fibers with aging. The existence of actual “incomplete” spindles lacking nuclear bag fibers and therefore the dynamic component should also be taken into account . The variability in fiber type composition of the single spindles may reflect diversity in physiologic and functional qualities .…”

Ultrastructural and Molecular Biologic Comparison of Classic Proprioceptors and Palisade Endings in Sheep Extraocular Muscles

“…In EOMs of even-toed ungulates muscle spindles are composed of a perineural capsule enclosing several intrafusal muscle fibers termed nuclear chain and nuclear bag fibers. In pig EOMs, Friedrich et al 31 show that intrafusal muscle fibers express spindle-special mysion heavy chain isoforms. Intrafusal muscle fibers are innervated by sensory nerve fibers twining around muscle fibers at the equatorial region and by motoneurons terminating on muscle fibers at the muscle spindles’ poles.…”