The Influence of Pulleys on the Quantitative Characteristics of Medial Rectus Muscle Recessions: The Torque Vector Model

Bilateral combined resection-recession of the same rectus muscle versus Fadenoperation for treatment of purely tonic esotropias

“…First, it decreases the torque vector rotational force of the eyeball by decreasing the effective length of the lever arm and the muscle arc of contact. 13,32 Then, it reduces muscle contractile force by inactivation of the sarcomeres between the scleral insertion of the muscle and the strapping. And finally, it produces a mechanical restriction related to the fixation of the pulley against the sclera that tightens the orbital check ligament of the pulley.…”

Bilateral combined resection-recession of the same rectus muscle versus Fadenoperation for treatment of purely tonic esotropias

“…First, it decreases the torque vector rotational force of the eyeball by decreasing the effective length of the lever arm and the muscle arc of contact. 13,32 Then, it reduces muscle contractile force by inactivation of the sarcomeres between the scleral insertion of the muscle and the strapping. And finally, it produces a mechanical restriction related to the fixation of the pulley against the sclera that tightens the orbital check ligament of the pulley.…”

Magnetic Resonance Imaging of the Globe-Tendon Interface for Extraocular Muscles: Is There an “Arc of Contact”?

“…2, 3 Given the current practicality and widespread availability of noninvasive high-resolution orbital imaging, this data strongly suggests that the “arc of contact” be abandoned and replaced in biomechanical modeling by the experimentally measured angles at tendon insertion. Conclusions that rely exclusively on line-drawn biomechanics 1–4, 8 should require in vivo confirmation prior to widespread acceptance to ensure that the actual EOM tendon anatomy matches the schematic anatomy.…”

Posterior Inflection of Weakened Lateral Rectus Path: Connective Tissue Factors Reduce Response to Lateral Rectus Recession

“…Earlier studies have considered anatomic changes resulting from surgical recession of rectus muscles, but these studies typically employed simplistic line drawings and speculation on post-operative anatomy without actually imaging and measuring the relationships within the orbit10, 24, 25. The in vivo behavior of the LR after surgery is much more complex.…”

Bilateral combined resection-recession of the same rectus muscle versus Fadenoperation for treatment of purely tonic esotropias

“…First, it decreases the torque vector rotational force of the eyeball by decreasing the effective length of the lever arm and the muscle arc of contact. 13,32 Then, it reduces muscle contractile force by inactivation of the sarcomeres between the scleral insertion of the muscle and the strapping. And finally, it produces a mechanical restriction related to the fixation of the pulley against the sclera that tightens the orbital check ligament of the pulley.…”

Magnetic Resonance Imaging of the Globe-Tendon Interface for Extraocular Muscles: Is There an “Arc of Contact”?

“…2, 3 Given the current practicality and widespread availability of noninvasive high-resolution orbital imaging, this data strongly suggests that the “arc of contact” be abandoned and replaced in biomechanical modeling by the experimentally measured angles at tendon insertion. Conclusions that rely exclusively on line-drawn biomechanics 1–4, 8 should require in vivo confirmation prior to widespread acceptance to ensure that the actual EOM tendon anatomy matches the schematic anatomy.…”

Posterior Inflection of Weakened Lateral Rectus Path: Connective Tissue Factors Reduce Response to Lateral Rectus Recession

“…Earlier studies have considered anatomic changes resulting from surgical recession of rectus muscles, but these studies typically employed simplistic line drawings and speculation on post-operative anatomy without actually imaging and measuring the relationships within the orbit10, 24, 25. The in vivo behavior of the LR after surgery is much more complex.…”

Bilateral combined resection-recession of the same rectus muscle versus Fadenoperation for treatment of purely tonic esotropias

“…First, it decreases the torque vector rotational force of the eyeball by decreasing the effective length of the lever arm and the muscle arc of contact. 13,32 Then, it reduces muscle contractile force by inactivation of the sarcomeres between the scleral insertion of the muscle and the strapping. And finally, it produces a mechanical restriction related to the fixation of the pulley against the sclera that tightens the orbital check ligament of the pulley.…”

Magnetic Resonance Imaging of the Globe-Tendon Interface for Extraocular Muscles: Is There an “Arc of Contact”?

“…2, 3 Given the current practicality and widespread availability of noninvasive high-resolution orbital imaging, this data strongly suggests that the “arc of contact” be abandoned and replaced in biomechanical modeling by the experimentally measured angles at tendon insertion. Conclusions that rely exclusively on line-drawn biomechanics 1–4, 8 should require in vivo confirmation prior to widespread acceptance to ensure that the actual EOM tendon anatomy matches the schematic anatomy.…”

Posterior Inflection of Weakened Lateral Rectus Path: Connective Tissue Factors Reduce Response to Lateral Rectus Recession

“…Earlier studies have considered anatomic changes resulting from surgical recession of rectus muscles, but these studies typically employed simplistic line drawings and speculation on post-operative anatomy without actually imaging and measuring the relationships within the orbit10, 24, 25. The in vivo behavior of the LR after surgery is much more complex.…”