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Sensory organs
Published in Aida Lai, Essential Concepts in Anatomy and Pathology for Undergraduate Revision, 2018
Attachments of med. rectus– origin: lat. part of common tendinous ring– insertion: med. ant. part of pupil– nerve SS: CNIII (inf. branch)– function: adduction of pupil
Intramuscular Nerve Distribution of the Inferior Oblique Muscle
Published in Current Eye Research, 2020
Hyun Jin Shin, Shin-Hyo Lee, Tae-Jun Ha, Wu-Chul Song, Ki-Seok Koh
The intramuscular nerve distribution of the IO appears to differ from those of the other EOMs, for which segregated motor nerve innervation have been reported.4,16,17 Sihler’s staining in the present study revealed that compartmentalization is less clear for the IO, which has a nerve trunk that directly arborizes into multiple smaller branches without forming distinct subdivisions (Figure 4). This might be related to the unique anatomic features of the IO that distinguish it from other EOMs. The IO is the shortest eye muscle, being only 30 mm long, and it is the only EOM that arises from the anterior margin of the orbital floor, rather than the common tendinous ring. Unlike the other EOMs that have both muscular and tendinous components, the IO is almost wholly muscular. This feature also implies that in contrast to the superior oblique muscle, which is a homologous muscle that is compartmentally innervated by the trochlear nerve,17 selective surgical procedures applied to anterior or posterior muscle fibers might not be applicable to the IO.
Clinical Features of Crowded Orbital Syndrome on Magnetic Resonance Imaging
Published in Neuro-Ophthalmology, 2021
Mayumi Iwasa, Masato Wakakura, Hiromi Kohmoto, Sonoko Tatsui, Hitoshi Ishikawa
The distance from the common tendinous ring to the eyeball on axial MR images was set as the globe-axis (GA) distance. The length of the line segment connecting the leading edge of the zygomatic bone on the outer orbital surface and that of the maxilla on the inner orbital surface was measured and set as the transverse diameter of the anterior part of the orbit (x). A straight line parallel to x that touched the posterior part of the eyeball was drawn, and the length of this straight line segment bisected by the outer and inner surfaces of the orbit was set as y. A perpendicular line was drawn between x and y, denoted as z, which represented the distance between the two segments x and y (Figure 2).