Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== Actions of Extraocular Muscles with Strabismus ====== ==== Ductions ==== Movement of a single eye in any direction * adduction- medial/nasal movement * abduction - lateral/temporal movement * sursumduction- elevation * infraduction- depression * incycloduction- superior limbus moves nasally * excycloduction- superior limbus moves temporally ==== Versions ==== Movement of both eyes in any direction. There are 9 cardinal positions of gaze including primary position. * Primary gaze- straight ahead * Right gaze * Left gaze * Upgaze * Downgaze * Up and Right gaze * Up and Left gaze * Down and Right gaze * Down and Left gaze ===Primary Movers for each gaze position=== Describes which muscles contract when the eyes are moved from primary position to one of the other 8 gaze positions. These are based on the primary action of each muscle. These are called Yoke muscles. * Right gaze- Right lateral rectus and Left medial rectus * Left gaze- Left lateral rectus and Right medial rectus * Elevation- Both superior rectus and Both inferior oblique * Depression- Both inferior rectus and Both superior oblique * Up and Right- Right superior rectus, Left inferior oblique * Up and Left- Left Superior recuts, Left inferior oblique * Down and Right- Right inferior rectus, Left superior oblique * Down and Left- Left inferior rectus, right superior oblique <WRAP round box> {{::versions_with_fields_of_action.jpg|}} From Clincal Strabismus Management. 1999 W.B. Saunders Company, A.L. Rosenbaum and A.P. Santigo Editors.p 16 </WRAP> <WRAP round box 60%> **Muscle responsible for the primary movement from primary position** {{::primary_eom_mover_from_primary_position.jpg|}} </WRAP> <WRAP round important 60%> See: [[action_extraocular_muscles_primary_position|Action of the Extraocular Muscles from Primary Position]] </WRAP> ==== Hering's Law ==== <WRAP round info 60%> **The Law of Equal Innervation** \\ When a voluntary eye movement is made, equal and simultaneous neural innervation is sent to the **yoke** muscles of both eyes. </WRAP> ==== Sherrington's Law ==== <WRAP round info 60%> **The Law of Reciprocal Innervation**\\ When a muscle contracts, its **antagonist** receives simultaneous inhibition, allowing smooth, efficient movement. </WRAP> ==== Synergist Muscles ==== ^ Action ^ Muscles ^ | Elevation | Superior Rectus and Inferior Oblique | | Depression | Inferior Rectus and Superior Oblique | | Adduction | Medial Rectus, Superior Rectus, Inferior Rectus | | Abduction | Lateral Rectus, Superior Oblique, Inferior Oblique | | Excyclotorsion | Inferior Oblique, Inferior Rectus | | Incyclotorsion | Superior Oblique, Superior Rectus | ==== Yoke Muscles ==== ^ Gaze (Versions) ^ Yoke Muscles ^ | Right | Right Lateral Rectus, Left Medial Rectus | |Left |Right Medial Rectus, Left Lateral Rectus | |Elevation|Both Superior Rectus and both Inferior Obliques| |Depression|Both Inferior Rectus and both Superior Obliques| |Up and Right|Right Superior Rectus, Left Inferior Oblique| |Down and Right| Right Inferior Rectus, Left Superior Oblique| |Up and Left | Left Superior Rectus, Right Inferior Oblique| |Down and Left|Left Inferior rRctus, Right Superior Oblique| ==== Grading of Eye Muscle Action during Versions ==== * overaction is graded +1 through +4 based on comparison to a standard photograph * underaction is graded -1 through -4 based on comparison to a standard photograph * Normal function is "0" ===Grading Medial Rectus Action on Versions=== {{::medial_rectus_grading.jpg|}} ===Grading Lateral Rectus Action on Versions=== {{::grading_lateral_rectus.jpg|}} ===Grading Inferior Oblique Action on Versions=== {{::grading_inferior_oblique.jpg|}} ===Grading Superior Oblique Action on Versions=== {{::grading_superior_oblique.jpg|}} ====Quantification of Eye Misalignment==== see: [[measuring_strabismus|How to Measure Strabismus]] {{tag>tutorial strabismus}} tutorial strabismus