Extraocular muscle (EOM) paths during asymmetrical convergence were evaluated by tri-planar, contrast-enhanced magnetic resonance imaging of the orbits of eight young adults during binocular fixation of a target aligned to one eye at 800 and 15 cm distance. Cross sections and paths of EOMs were determined from area centroids. In convergence, the aligned eye rotated and translated negligibly, wh...

1. Single neurons in the abducens nucleus were recorded extracellularly in alert rhesus macaques trained to make a variety of eye movements. An abducens neurons was identified as a motoneuron (MN) if its action potentials triggered an averaged EMG potential in the lateral rectus muscle. Abducens internuclear neurons (INNs) that project to the oculomotor nucleus were identified by collision bloc...

Address for Correspondence: Edward Ridyard, 9 The Meadows, Rainhill, Prescot, L35 0PQ, UK. E-Mail: edward-ridyard@doctors.org.uk Foundation Year 2 doctor, Oxford University Hospitals, Prescot, UK. Background: The extraocular muscles (EOMs) bring about eye movement and studies exist which measure EOM length, cross-sectional diameter and volume. Knowledge of the normal values is crucial for deter...

The extraocular muscles are responsible for all eye movements required to track and fix objects. Superior rectus muscle is located in the superior level of orbital cavity, below musculus levator palpebrae superioris , tilted slightly lateral part orbit. In a routine dissection, we found left, unilateral variation with no other structures, such as nerves vessels. abnormal presented two parts - m...

To the Editors: Y splitting for the treatment of up or down shoots in Duane’s syndrome was first described by Jampolsky in 1980.1 Apart from Y splitting of the lateral rectus muscle, the other surgical options for patients with Duane’s retraction syndrome (DRS) with up and down shoots described previously include simple lateral rectus recession combined with medial and lateral rectus muscle rec...

Under general anaesthesia the eye position of esotropia generally moved divergently. When retrobulbar anaesthesia was added bilaterally, the eye position moved further in the same direction. In the electromyogram under general anaesthesia the 4 horizontal recti were silent in controls. In many cases of esotropia, however, both medial recti showed a considerable amount of discharge under general...

The anterior cutaneous branches of the thoracolumbar spinal nerves enter the rectus sheath at its lateral border and perforate the muscle after travelling a short distance in the ventral direction. In this anatomical case series, we show that dye injection at the medial margin did not lead to reliable impregnation of the target nerves. The local anesthetic should therefore be injected at the la...

S ynergistic divergence is a well-established clinical condition in which abduction arises on attempted adduction, leading to simultaneous abduction of both eyes on lateral gaze. Synergistic divergence can occur as an extreme form of Duane syndrome, where most if not all oculomotor nerve branch fibers originally directed to the medial rectus muscle innervate the lateral rectus muscle. Synergist...

It seems clear, both from pathological material in humans t°,15 and experiments in monkeysS, 34, that the median longitudinal fasciculus (MLF) carries a stimulus to the medial rectus subnucleus of the oculomotor complex to effect the adductive portion of lateral gaze. The importance of this pathway was emphasized by Shanzer et al. 34, who showed that section of the MLF of the monkey blocked add...