PURPOSE Clinical data indicate that extraocular muscles have different susceptibilities for some orbital immune disorders depending on their anatomic location. The resident immunocompetent cells may be important mediators in the local pathogenesis of such disorders so the distribution of these cells was studied in extraocular muscles obtained from normal human donors. For comparison skeletal mu...

To the Editors: Ocular motility problems related to congenital abnormalities of the extraocular muscles are rare. Such congenital abnormalities may present in a spectrum from accessory additional rectus muscles to the absence of extraocular muscles.1-5 Absence of one or more extraocular muscles is a rare condition usually seen in association with craniofacial syndromes. We present a case of bil...

Morphopathological changes induced in the extraocular muscles by the local anesthetic agent bupivacaine hydrochloride were studied in the monkey using light and electron microscopy. Retrobulbar anesthetic blocks, using 0.75% bupivacaine hydrochloride, were performed in five adult cynomolgus monkeys. Morphological alterations in extraocular muscle fiber types were examined following survival per...

Primary abnormalities in the dystrophin gene underlie x-linked muscular dystrophy. However, the absence of the dystrophin isoform Dp427 does not necessarily result in a severe dystrophic phenotype in all muscle groups. Distal mdx muscles, namely extraocular and toe fibres, appear to represent a protected phenotype in muscular dystrophy. Thus, a comparative analysis of affected versus naturally ...

Sarcoidosis is a chronic granulomatous disease that can affect multiple organs. The lungs, eyes, and skin are known to be highly affected organs in sarcoidosis. There have been reports based on random muscle biopsy that 32-80% of systemic sarcoidosis comprises noncaseating granulomas; however, muscle involvement in sarcoidosis is generally asymptomatic and has an unknown frequency. We describe ...

INTRODUCTION Extraocular muscle tenotomy has been reported to damp congenital nystagmus in an achiasmatic sheepdog. We performed extraocular muscle tenotomy to evaluate its effects on congenital nystagmus in primates. METHODS Magnetic search coil eye movement recordings were used to document the presence of horizontal congenital nystagmus in 2 adult macaque monkeys that also had naturally occ...

PURPOSE Strabismus affects as many as 60% to 70% of patients with Crouzon syndrome. V-pattern strabismus is common and is thought to be secondary to severe oblique muscle dysfunction. The complex motility disorders produced by abnormal extraocular muscles in this syndrome can be difficult to manage. Few studies have reported findings regarding the extraocular muscles or how to plan and adapt th...

Introduction Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advances in technology have afforded clinicians the ability to assess otolith function through vestibular ...

Genetic regulatory networks governing skeletal myogenesis in the body are well understood, yet their hierarchical relationships in the head remain unresolved. We show that either Myf5 or Mrf4 is necessary for initiating extraocular myogenesis. Whereas Mrf4 is dispensable for pharyngeal muscle progenitor fate, Tbx1 and Myf5 act synergistically for governing myogenesis in this location. As in the...

PURPOSE Fibroelastic pulleys function like the trochlea to fix the position and pulling direction of the recti extraocular muscles within the orbit. This study characterized the fine structure of the human medial rectus muscle pulley. METHODS Human medial rectus muscle pulley tissue was dissected at autopsy, immersed in aldehyde fixative solution, and processed for and examined with light and...