2. Which statement concerning the rectus extraocular muscle pulleys is correct? a. The rectus pulleys are composed of rings of cartilage. b. The rectus pulleys are rigidly attached to the walls of the orbit. c. Each rectus pulley receives an insertion from the global layer fibers of its rectus extraocular muscle. d. The global layer fibers of the extraocular muscles do not insert on the pulleys...

It has long been known that the striated muscle fibres of which the extraocular muscles are composed differ in many respects from skeletal muscle in general. Their relatively small size, rich innervation, their small motor units and the presence of a proportion of fibres with multiple endplates are special characteristics which are recounted in most modern texts of ophthalmology. There are thre...

PURPOSE Our goal was to determine whether the extraocular muscles in patients with chronic progressive external ophthalmoplegia (CPEO) could be distinguished from those of age-matched control subjects by MR imaging. METHODS Nine patients with CPEO and eight age-matched healthy control subjects were studied. The extraocular muscles of eight of the patients (16 eyes) and all the control subject...

The paradigm that an "underacting" extraocular muscle is always atrophic or hypoplastic and that an overacting extraocular muscle should always be enlarged leads to inconsistencies with clinical observations. These include findings of "overacting" inferior oblique muscles, superior rectus muscle overaction or contracture syndrome, and normal extraocular muscle diameters in patients with apparen...

Purpose: To introduce an advanced muscle hook to decrease risks and create more feasible extraocular muscle surgeries for physicians. Case Report: Tight extraocular muscles during strabismus surgery could be extremely challenging even in experienced hands due to restricted globe rotation, limited view, and lack of muscle elasticity. Although a variety of surgical instruments have been introduce...

The extraocular muscles of dystrophic mouse strain Re-129 dy/dy were studied in combined phase and electron microscopy. Changes in fiber morphology were found which are similar to those described in dystrophic human and mouse peripheral musculature, i.e., changes in fiber diameter, alteratiotxs in the cellular organelles, including mitochondria, sarcoplasmic reticulum, nuclei, sarcolemma, and l...

Extraocular sebaceous carcinoma is a relatively rare skin appendage carcinoma [1]. Although ocular sebaceous carcinoma is thought to arise from the Meibomian glands and glands of Zeis, there is no evidence that extraocular sebaceous carcinoma arises from pre-existing sebaceous glands [2]. Most sebaceous carcinomas are invasive [1], however, only a few cases of sebaceous carcinoma associated wit...

Extraocular muscle pulleys, now well known to be kinematically significant extraocular structures, have been noted in passing and described in fragments several times over the past two centuries. They were late to be fully appreciated because biomechanical modeling of the orbit was not available to derive their kinematic consequences, and because pulleys are distributed condensations of collage...