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- 1. Anatomía y fisiología de músculos extraoculares y movimientos oculares Dra. Ana Teresa Ferrer Mac Gregor Armenta I R1 Oftalmología Hospital Regional Manuel Cárdenas de la Vega ISSSTE
- 2. Músculos del globo ocular Pueden ser divididos en 2 grupos: ● Involuntarios Intraoculares ● Voluntarios Extraoculares 2
- 3. Anatomía microscópica de los músculos estriados 1
- 4. 4 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier.
- 5. 5 Sarcolemma Túbulos T Sarcoplasm Miofibrillas Sarcómero Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier.
- 6. 6 Miofibrillas Gruesas Subunidades de miosina Delgadas Doble helice de actina Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier.
- 7. 7 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier.
- 8. 8 Sliding Ratchet Model of muscle contraction Liberación Acetilcolina Despolarización sarcolema Túbulos T Ca2+ RS Se une a T y TM Parte activa actina se une a cabeza de miosina (ATP lo permite) Cabeza miosina se alinea y mueva filamento de actina ATP se une de nuevo. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier.
- 9. 9 Diferencias con músculo estriado no craneal: • Riqueza en irrigación sanguínea • Riqueza en sustancia elástica • Riqueza en inervación [1:1 (OS) 1:1.8 (RL) 1: 2.7 (RM)] Fibras de los músculos extraoculares
- 10. 10 • Manejo de calcio: Más eficiente lo que lo hace resistente a elevaciones patológicas. • Resistente a estrés oxidativo Tiene niveles más altos de superóxido dismutasas. • Pueden utilizar lactato como energía ante una actividad contráctil aumentada Explica porque pueden tener un metabolismo oxidativo alto mientras mantienen resistencia a la fatiga. Levin, L. A., Nilsson, S. F., Hoeve, J. V., Wu, S. M., & Kauffman, A. A. (2003). ADLER´S PHYSIOLOGY OF THE EYE. Elsevier. Metabolismo de los músculos extraoculares
- 11. Anatomía macroscópica de músculos extraoculares 2
- 12. 12 Origen de los músculos rectos • Los 4 músculos tienen su origen en el anillo tendinoso común de Zinn. • Anillo es continuo con la periorbita, en el ápex, anteiror al forámen óptico y medial a FOS • Área rodeada por el anillo tendinoso es conocida como foramen oculomotor. • 2 engrosamientos (loockwood y Zinn) Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology.
- 13. 13 Origen de los músculos rectos • Vasos y nervios que entran por canal óptico o FOS pasan por el foramen oculomotor Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology.
- 14. 14 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology.
- 15. 15 Inserción de los músculos rectos: Espiral de Tillaux Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology. .
- 16. 16 Recto medial Origen Parte superior e inferior del anillo de Zinn + Vaina del NO Inserción 5.5 mm del limbo Tendón 3.7 mm Relaciones Superior con MOS, art. oftálmica, n. nasociliar. Inervación División inferior del NCIII, entra por cara ocular Extras Más grande de todos los EOM. Más cercano al limbo. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 17. 17 Recto lateral Origen Parte superior e inferior del anillo de Zinn + prominencia en ala mayor esfenoides (espina rects lateral) Inserción 6.9 mm del limbo Tendón 8.8 mm Relaciones Superior con art y nervio lagrimal, medial con art. Oftálmica y ganglio ciliar, NCVI. Inervación NCVI, entra por cara ocular Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 18. 18 Recto superior Origen Parte superior del anillo de Zinn + vaina del nervio óptico Inserción 7.7 mm del limbo (nasal > cerca que temporal) Tendón 5.8 mm Relaciones Superior nervio frontal, inferior n. nasociliar, art. Oftálmica, tendón MOS. Inervación División superior del NCIII, entra en cara ocular Extras 23º con el eje sagital Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 19. 19 Recto inferior Origen Parte inferior del anillo de Zinn Inserción 6.5 mm del limbo (nasal > cerca que temporal) Tendón 5.5 mm Relaciones Arriba con la división inferior del NCIII, Inferior con piso de la órbita, anteriormente MOI Inervación División inferior del NCIII, entra en cara superior. Extras 23º con el eje sagital Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 20. 20 Músculo oblicuo superior Origen Ala menor del esfenoides, medial al canal óptico, cercaa de la sutura frontoetmoidal. Trcolea Placa orbitaria del hueso frontal “origen fisiológico o efectivo” Inserción Superoposterior lateral Tendón 2.5 cm Relaciones Superior el RS, abajo arteria oftálmica y n. nsociliar RM Inervación NCIV, entra en el cara orbitaria. Extras Más largo y delgado Ángulo de 51-55º con eje sagital. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 21. 21 Músculo oblicuo inferior Origen Hueso maxilar, piso anteromedial Inserción Parte posteroinferior temporal, poco lateral a la mácula. Tendón Relaciones Arriba con el RI, abajo el piso de la órbita. Inervación División inferior del NCIII, entra en la superficie superior Extras Eje de 51 grados con el eje sagital. Único con origen fuera del apex. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 22. 22 Músculo oblicuo inferior Origen Hueso maxilar, piso anteromedial Inserción Parte posteroinferior temporal, poco lateral a la mácula. Tendón Relaciones Arriba con el RI, abajo el piso de la órbita. Inervación División inferior del NCIII, entra en la superficie superior Extras Eje de 51 grados con el eje sagital. Único con origen fuera del apex. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology. .
- 23. 23 Irrigación músculos extraoculares Arteria oftálmica Superior (lateral) Recto superior Recto Lateral Inferior (medial) Recto inferior Oblicuo inferior Recto medial Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 24. 24 Irrigación músculos extraoculares Arteria oftálmica Superior (lateral) Recto superior Recto Lateral Inferior (medial) Recto inferior Oblicuo inferior Recto medial American Academy of Ophtalmology. (2020-2021). Fundamentals and Principles of ophtalmology. .
- 26. 26 Geometría de la órbita Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 27. 27 Ejes de Fick • Los movimientos oculares se pueden describir como rotaciones alrededor de 1 o más ejes. • Se asume que el ojo rota alrededor del punto de encuentro de esos ejes, 13.5 mm posterior a la córnea. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 28. 28 Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 29. 29 Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 30. 30 Posiciones de la mirada Primaria Terciaria Secundaria Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 31. 31 DUCCIONES • Monoculares • Aducción, abducción elevación, depresión, extorsión, intorsión TERMINOLOGÍA Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 32. 32 Versiones • Binoculares, simultáneas, conjugados • Dextroversión y levoversión, elevación, depresión • Dextroelevación, dextrodepresión y Levo. TERMINOLOGÍA Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 33. 33 Vergencias • Binoculares, simultáneas, NO conjugados • Convergencia • Divergencia TERMINOLOGÍA Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 34. 34 Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 35. 35 Posiciones de la mirada Cardinales (6) • Dextroversión • Levoversión • Dextroelevación • Levoelevación • Dextrodepresión • Levodepresión Diagnósticas (9) • Se agregan: • Posición primaria • Depresión • Elevación Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 36. 36 Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 37. 37 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 39. 39 Modelo agonista aislado • Descrito por Duane. • De los primeros descritos, utilizado en evaluación clínica, para evaluar contracción de cada músculo. • Recordar que todos los EOM están en algún estado de contracción, relajación. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 40. 40 Movimientos desde la posición primaria de mirada
- 41. 41 Músculos rectos horizontales Paralelo al eje Y y perpendicular al Z. Por eso solo tiene una acción que rodea eje vertical. • RECTO MEDIAL Aducción nasal • RECTO LATERAL Abducción temporal
- 42. 42 Músculos rectos horizontales Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 43. 43 Músculos rectos verticales Acciones mucho más complejas. Recto superior: • Inserción arriba de origen--> Elevación #1 • Inserción lateral a origen Aducción #2 • Inserción oblicua Intorsión #2 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 44. 44 Músculos rectos verticales Recto inferior: • Inserción abajo de origen--> Depresión #1 • Inserción lateral a origen Aducción #2 • Inserción oblicua Extorsión #2 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 45. 45 Músculos rectos verticales Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 46. 46 Músculos rectos verticales Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 47. 47 Músculos oblicuos OBLICUO SUPERIOR • Inserción en porción posterosuperior lateral Intorsión #1 (rota al eje Y). • Inserción posterior e inferior al origen (fisiológico) Depresión #2. • Inserción posterior y lateral a origen Abducción #2. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 48. 48 Músculos oblicuos OBLICUO INFERIOR • Inserción es superior y lateral Extorsión #1 (rota al eje Y). • Inserción posterior y superior al origen (fisiológico) Elevación #2. • Inserción posterior y lateral al origen Abducción #2. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 49. 49 Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 50. 50
- 51. 51
- 52. 52
- 53. 53
- 54. 54
- 55. 55 Movimientos desde la posición secundaria de mirada
- 56. 56 Músculos verticales rectos Si se abduce 23º desde la posición primaria, los rectos verticales se vuelven paralelos con el eje Y y perpendiculares con el X Solo movimiento vertical puro . • MRS Sólo elevación • MRI Solo depresión Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 57. 57 Músculos verticales rectos Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 58. 58 Músculos verticales rectos Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 59. 59 Músculos oblicuos Ojo en aducción de 51-55º Músculos paralelos a sagital y perpendicular a eje X. MOS Depresión. MOI Elevación. . Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 60. 60 Músculos oblicuos Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 61. 61 Músculos oblicuos Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier
- 63. 63 Agonistas-antagonistas Músculos trabajan juntos como agonistas, antagonistas o sinergistas. Ejemplo Cuando el RS y OI se contraen simultáneamente: o Acción aductora y de intorsión del RS y abductora y de extorsión de OI se contraponen Sinergia en elevación. o OS y OI son antagonistas en movimientos verticales y torsionales pero sinergistas en horizontales. . Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 64. 64 Agonistas-antagonistas Ley de Sherrington de inervación recíproca: • Contracción de músculo va acompañado de relajación de su antagonista. Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
- 66. 66 Músculos de Yoke Músculos de ambos ojos que actuan juntos creando visión binocular Ley de inervación de Hering´s: La innervación de ambos músculos de Yoke es simétrica. Ejemplo Ojo en levoversión RMD y RLI reciben mismo estímulo Remington, L. A. (2012). Clinical Anatomy and Physiology of the Visual System. Elsevier Salmon, J. F. (2020). Kanski´s Clinical Ophtalmology, a Systematic Approach. Elsevier.
Notas del editor
- Intraoculares: Músculo ciliar, esfínter y dialtador del iris. Extrínsecos: 6 músculos extraoculares
- Epimysium: Vaina de tejido conectivo que rodea el músculo Perimysium: Continuo a epimysium se va infiltrando la capa y formando paquetes o fascículos. Endomysium: Rodea cada fibra muscular dentro del fascículo.
- The plasma cell membrane surrounding each muscle fiber, the sarco- lemma, forms a series of invaginations into the cell, the transverse tubules (T tubules), which allow ions to spread quickly through the cell in response to an action poten- tial. The cell cytoplasm, sarcoplasm, contains normal cel- lular structures and special muscle fibers, the myofibrils.
- Subunidades de miosina: long, slender filament with two globular heads attached by arms at one end. These fila- ments lie next to each other and form the “backbone” of the myofibril, with the heads projecting outward in a spi- ral Doble hélice elicoidal de actina: double-helical filament, with a molecular complex of troponin and tropomyosin lying within the grooves of the double helix
- The light band is the I (isotropic) band, and the dark band is the A (anisotropic) band. These names describe the birefrin- gence to polarized light exhibited by the two areas.1 The I band contains two sets of actin filaments con- nected to each other at the Z line, a dark stripe bisecting the I band. Only actin myofibrils are found in the I band. The A band contains both myosin and actin; the central lighter zone of the A band—the H zone—contains only myosin. Overlapping actin and myosin filaments form the outer darker edges of the A band (Figure 10-3). The M line bisects the H zone and contains proteins that interconnect the myosin fibrils. A sarcomere extends from Z line to Z line and is the contractile unit of striated muscle. With muscle contrac- tion, a change in configuration occurs A sarcomere extends from Z line to Z line and is the contractile unit of striated muscle. With muscle contrac- tion, a change in configuration occurs; the H zone width decreases as the actin filaments slide past the myosin fil- aments. The sarcomere is shortened; as this occurs along the muscle, muscle length is decreased. The length of the actin and myosin filaments remain constant as does the A band, the I band, and the H zone shorten.
- The process of muscle contraction and sarcomere shortening is explained by the sliding ratchet model2-4 (Figure 10-4). The initiation of a muscle contraction occurs when a nerve impulse causes the release of ace- tylcholine into the neuromuscular junction. The sar- colemma depolarizes and an action potential passes along the surface and is carried into the muscle fiber through the system of T-tubules. Ionic channels are opened and calcium ions are released from the sarco- plasmic reticulum into sarcoplasm. Ca2+ binds to the troponin-tropomyosin complex, resulting in a config- urational change, allowing an active site on the actin protein to be available for binding with a myosin head. Coincidentally, adenosine triphosphate (ATP) attached to the myosin head is broken down and released, allowing a cross-bridge to bind with the active actin site. Once this bond is formed, the head tilts toward the shaft of the myosin filament, pulling the actin fila- ment along with it. The junction between the actin and myosin is broken by the attachment of a new ATP molecule to the myosin head. The head then rights itself, and the cross-bridge is ready to bind with the next actin site along the chain.
- Riqueza elástica se debe a proteína conocida como Titina, permite ahorro de energía, por la energía pasiva que utiliza al regresar a su forma. Relación nervio/fibra 1:100 en músculo esquelético, en ojo puede ser de 1:1 (OS) 1:1.8 (RL) 1: 2.7 (RM)
- ADLERS
- The upper and lower areas are thickened bands and sometimes are referred to as the upper and lower tendons or limbs. The medial rectus and the superior rectus also attach to the dural sheath of the optic nerve. The optic foramen is found within the lesser wing of the sphenoid bone at the orbital apex, through which runs the optic nerve (cranial nerve II, CNII) and ophthalmic artery. Between the greater and lesser wings of the sphenoid is the superior orbital fissure. The structures entering the orbit through this fissure are divided by the tendinous annulus (formerly the annulus of Zinn). Structures that enter the orbit superior to the annulus are the lacrimal and frontal nerves, both sensory branches of the ophthalmic division of the trigeminal nerve (CNV); the trochlear nerve (CNIV), motor nerve to the superior oblique muscle; and the supe- rior ophthalmic veins (Fig. 7.5). Once through the annulus, structures enter what is referred to as the muscle cone, and are surrounded by the EOM and their connective tissue ensheathments. Within the annulus, the superior orbital fissure admits the superior and inferior divisions of the ocu- lomotor nerve (CNIII) the motor nerve to the inferior rectus, inferior oblique, medial rectus, superior rectus and levator palpebrae superioris muscles; the nasociliary nerve which is a sensory branch of the ophthalmic division of the trigemi- nal nerve (CNV), and the abducens nerve (CNVI), the motor nerve to the lateral rectus muscle.3 On the floor of the orbit is the inferior orbital fissure, which admits the zygomatic nerve, a sensory nerve innervating the lateral mid-face; com- munications of the inferior ophthalmic vein with the ptery- goid plexus of veins inferiorly; and the lacrimal rami, carrying parasympathetic innervation from the facial nerve (CNVII) to the lacrimal gland.
- The optic nerve and ophthalmic artery enter the oculomotor foramen from the optic canal; the superior and inferior divisions of the oculomotor nerve, the abducens nerve, and the nasociliary nerve enter the oculomotor foramen from the superior orbital fissure (see Figure 10-8). These structures lie within the muscle cone, the area enclosed by the four rectus muscles and the connective tissue joining them. Thus the motor nerve to each rectus mus- cle can enter the surface of the muscle that lies within the muscle cone. The lacrimal and frontal nerves and the superior oph- thalmic vein lie above the common ring tendon, and the inferior ophthalmic vein lies below. They are outside the muscle cone
- The four rectus muscles insert into the globe anterior to the equator. A line connecting the rectus muscle insertions forms a spiral, as described by Tillaux. This spiral starts at the medial rectus, the insertion that is closest to the limbus, and proceeds to the inferior rectus, the lateral rectus, and finally the superior rectus, the inser- tion farthest from the limbus. In a recent study, variations were found from person to person in specific measurements, but the spiral of Tillaux was always observed.33 The tendons of insertion pierce Tenon’s capsule and merge with scleral fibers.
- Neuritis óptica dolor al voltear arriba y adentro.
- Expansión de la fascia del músculo se adhiere a la pared lateral y forma el lateral check ligament.
- Expansión de la fascia del músculo se adhiere a la pared lateral y forma el lateral check ligament. The superior rectus muscle paral- lels the roof of the orbit until it passes through a con- nective tissue pulley just posterior to the equator of the globe Neuritis óptica dolor al voltear arriba y adentro.
- The sheaths of these two inferior muscles unite to con- tribute to the suspensory ligament of Lockwood (see Figure 8-17). The capsulopalpebral fascia, an anterior extension from the sheath of the inferior rectus muscle and the suspensory ligament, inserts into the inferior edge of the tarsal plate, allowing coordination of eye movements with eyelid position and ensuring lower- ing of the lid on downward gaze.
- The sheaths of these two inferior muscles unite to con- tribute to the suspensory ligament of Lockwood (see Figure 8-17). The capsulopalpebral fascia, an anterior extension from the sheath of the inferior rectus muscle and the suspensory ligament, inserts into the inferior edge of the tarsal plate, allowing coordination of eye movements with eyelid position and ensuring lower- ing of the lid on downward gaze. The trochlea is considered the physiologic or effec- tive origin of the superior oblique muscle in deter- mining muscle action because it acts as a pulley and changes the direction of muscle pull. In considering the action of the superior oblique, a line is drawn from the trochlea to the insertion rather than from the ana- tomic origin to the insertion.
- Inferiores arteria infraorbitaria. Lateral Lagrimal Arterias musculares irrigan al músculo y lo atraviesa o rodean para irrigar el SA, Qx de estos músculos podría comprometer irrigación de SA. Todos 2 arterias, excepto lateral.
- Inferiores arteria infraorbitaria. Lateral Lagrimal
- The lateral and medial orbital walls are at an angle of 45° with each other. The orbital axis therefore forms an angle of 22.5° with both lateral and medial walls, though for the sake of simplicity this angle is usually regarded as being 23° (Fig. 18.2A). When the eye is looking straight ahead at a fixed point on the horizon with the head erect (primary position of gaze), the visual axis forms an angle of 23° with the orbital axis
- The x-axis is the horizontal or trans- verse axis and runs from nasal to temporal. The y-axis is the sagittal axis running from the anterior pole to the posterior pole. The z-axis is the vertical axis and runs from superior to inferior The anterior pole of the globe is the reference point used in the description of any eye movement. Eye move- ments are described and based on the movement of the muscle insertion towards its origin. The globe rotates left and right on the vertical Z axis. ○ The globe moves up and down on the horizontal X axis. ○ Torsional movements (wheel rotations) occur on the Y (sagittal) axis which traverses the globe from front to back (similar to the anatomical axis of the eye). ○ Intorsion occurs when the superior limbus rotates nasally and extorsion on temporal rotation.
- The x-axis is the horizontal or trans- verse axis and runs from nasal to temporal. The y-axis is the sagittal axis running from the anterior pole to the posterior pole. The z-axis is the vertical axis and runs from superior to inferior The anterior pole of the globe is the reference point used in the description of any eye movement. Eye movements are described and based on the movement of the muscle insertion towards its origin.
- The visual axis passes from the fovea, through the nodal point of the eye, to the point of fixation. In normal binocular single vision (BSV) the visual axes of the two eyes intersect at the point of fixation, the images being aligned by the fusion reflex and combined by binocular responsive cells in the visual cortex to give BSV. The anatomical axis is a line passing from the posterior pole through the centre of the cornea. Because the fovea is usually slightly temporal to the anatomical centre of the posterior pole of the eye, the visual axis does not usually correspond to the anatomical axis of the eye. Angle kappa is the angle, usually about 5°, subtended by the visual and anatomical axes The angle is positive (normal) when the fovea is temporal to the centre of the posterior pole resulting in a nasal displacement of the corneal reflex and negative when the converse applies. ○ A large angle kappa may give the appearance of a squint when none is present (pseudosquint) and is seen most commonly as a pseudoexotropia following displacement of the macula in retinopathy of prematurity, where the angle may significantly exceed +5°.
- The primary position of gaze is defined as the position of the eye with the head erect, the eye located at the intersection of the sagittal plane of the head and the horizontal plane passing through the centers of rotation of both eyes, and the eye focused for infinity. Secondary positions of gaze are rotations around either the vertical axis or the horizontal axis Tertiary positions are rota- tions around both the vertical and the horizontal axes. The actions of the extraocular muscles depend on the position of the globe at the time of muscle contraction
- They are tested by occluding the fellow eye and asking the patient to follow a target in each direction of gaze.
- Convergence is simultaneous adduction (inward turning) and divergence is outwards movement from a convergent position. Tonic convergence, which implies inherent innervational tone to the medial recti. Proximal convergence is induced by psychological awareness of a near object. Fusional convergence is an optomotor reflex that maintains BSV by ensuring that similar images are projected onto corre- sponding retinal areas of each eye. It is initiated by bitemporal retinal image disparity. Accommodative convergence is induced by the act of accom- modation as part of the synkinetic-near reflex.
- Tonic convergence, which implies inherent innervational tone to the medial recti. Proximal convergence is induced by psychological awareness of a near object. Fusional convergence is an optomotor reflex that maintains BSV by ensuring that similar images are projected onto corre- sponding retinal areas of each eye. It is initiated by bitemporal retinal image disparity. Accommodative convergence is induced by the act of accommodation as part of the synkinetic-near reflex.
- The visual axis passes from the fovea, through the nodal point of the eye, to the point of fixation. In normal binocular single vision (BSV) the visual axes of the two eyes intersect at the point of fixation, the images being aligned by the fusion reflex and combined by binocular responsive cells in the visual cortex to give BSV. The anatomical axis is a line passing from the posterior pole through the centre of the cornea. Because the fovea is usually slightly temporal to the anatomical centre of the posterior pole of the eye, the visual axis does not usually correspond to the anatomical axis of the eye. Angle kappa is the angle, usually about 5°, subtended by the visual and anatomical axes The angle is positive (normal) when the fovea is temporal to the centre of the posterior pole resulting in a nasal displacement of the corneal reflex and negative when the converse applies. ○ A large angle kappa may give the appearance of a squint when none is present (pseudosquint) and is seen most commonly as a pseudoexotropia following displacement of the macula in retinopathy of prematurity, where the angle may significantly exceed +5°.
- It is strictly hypothetical to discuss the movement of the eye as if only one muscle contracts. In each of these descriptions the eye begins in primary position.
- Intorsión y extorsión depende de que polo te estés llevando a medial, como aquí llevas a medial el inferior el superior va temporal (es el que manda en nomenclatura), por eso es extorsión.
- As the position of the globe changes, the relationship between the muscle origin and insertion changes rela- tive to the axes, and contraction of a muscle has a differ- ent effect than when the eye is in primary position.
- As the position of the globe changes, the relationship between the muscle origin and insertion changes rela- tive to the axes, and contraction of a muscle has a differ- ent effect than when the eye is in primary position.
- As the position of the globe changes, the relationship between the muscle origin and insertion changes rela- tive to the axes, and contraction of a muscle has a differ- ent effect than when the eye is in primary position.
- As the eye adducts 51 to 55 degrees, the plane of the oblique muscles becomes parallel to the sagittal axis and perpendicular to the horizontal axis. In this position the superior oblique will cause only depression, and the inferior oblique will cause only elevation. When the eye is abducted 35 to 39 degrees, the plane of the oblique muscles makes a right angle with the sagittal axis and parallels the horizontal axis, and the obliques cannot cause vertical movement
- As the eye adducts 51 to 55 degrees, the plane of the oblique muscles becomes parallel to the sagittal axis and perpendicular to the horizontal axis. In this position the superior oblique will cause only depression, and the inferior oblique will cause only elevation. When the eye is abducted 35 to 39 degrees, the plane of the oblique muscles makes a right angle with the sagittal axis and parallels the horizontal axis, and the obliques cannot cause vertical movement
- As the eye adducts 51 to 55 degrees, the plane of the oblique muscles becomes parallel to the sagittal axis and perpendicular to the horizontal axis. In this position the superior oblique will cause only depression, and the inferior oblique will cause only elevation. When the eye is abducted 35 to 39 degrees, the plane of the oblique muscles makes a right angle with the sagittal axis and parallels the horizontal axis, and the obliques cannot cause vertical movement
- The sheaths of these two inferior muscles unite to con- tribute to the suspensory ligament of Lockwood (see Figure 8-17). The capsulopalpebral fascia, an anterior extension from the sheath of the inferior rectus muscle and the suspensory ligament, inserts into the inferior edge of the tarsal plate, allowing coordination of eye movements with eyelid position and ensuring lower- ing of the lid on downward gaze. The trochlea is considered the physiologic or effec- tive origin of the superior oblique muscle in deter- mining muscle action because it acts as a pulley and changes the direction of muscle pull. In considering the action of the superior oblique, a line is drawn from the trochlea to the insertion rather than from the ana- tomic origin to the insertion.
- As the eye adducts 51 to 55 degrees, the plane of the oblique muscles becomes parallel to the sagittal axis and perpendicular to the horizontal axis. In this position the superior oblique will cause only depression, and the inferior oblique will cause only elevation. When the eye is abducted 35 to 39 degrees, the plane of the oblique muscles makes a right angle with the sagittal axis and parallels the horizontal axis, and the obliques cannot cause vertical movement
- Todos los músculos están en cierto estado de contracción o relajación. Músculos trabajan juntos como agonistas, antagonistas o sinergistas.
- Todos los músculos están en cierto estado de contracción o relajación. Músculos trabajan juntos como agonistas, antagonistas o sinergistas.