Which of the following muscles rotates the eye upward and away from the midline?

The lateral rectus muscle is a muscle on the lateral side of the eye in the orbit. It is one of six extraocular muscles that control the movements of the eye. The lateral rectus muscle is responsible for lateral movement of the eyeball, specifically abduction. Abduction describes the movement of the eye away from the midline (i.a. nose), allowing the eyeball to move horizontally in the lateral direction, bringing the pupil away from the midline of the body.[1]

Structure[edit]

The lateral rectus muscle originates at the lateral part of the common tendinous ring, also known as the annular tendon. The common tendinous ring is a tendinous ring that surrounds the optic nerve and serves as the origin for five of the seven extraocular muscles, excluding the inferior oblique muscle.[2]

The lateral rectus muscle inserts into the temporal side of the eyeball.[3] This insertion is around 7 mm from the corneal limbus.[3] It has a width of around 10 mm.[3]

Nerve supply[edit]

The lateral rectus is the only muscle supplied by the abducens nerve (CN VI). The neuron cell bodies are located in the abducens nucleus in the pons. These neurons project axons as the abducens nerve which exit from the pontomedullary junction of the brainstem, travels through the cavernous sinus and enter the orbit through the superior orbital fissure. It then enters the medial surface of the lateral rectus to innervate it.

Relations[edit]

The insertion of the lateral rectus muscle is around 8 mm from the insertion of the inferior rectus muscle, around 7 mm from the insertion of the superior rectus muscle, and around 10 mm from the corneal limbus.[3]

Function[edit]

The lateral rectus muscle abducts the eye, turning the eye laterally in the orbit.

Clinical significance[edit]

A sixth nerve palsy, also known as abducens nerve palsy, is a neurological defect that results from a damaged or impaired abducens nerve. This damage can stem from stroke, trauma, tumor, inflammation, and infection. Damage to the abducens nerve by trauma can be caused by any type of trauma that causes elevated intracranial pressure; including hydrocephalus, traumatic brain injury with intracranial bleeding, tumors, and lesions along the nerve at any point between the pons and lateral rectus muscle in orbit. This defect can result in horizontal double vision and reduced lateral movement. The lateral rectus muscle will be denervated and paralyzed and the patient will be unable to abduct the eye. For example, if the left abducens nerve is damaged, the left eye will not abduct fully. While attempting to look straight ahead, the left eye will be deviated medially towards the nose due to the unopposed action of the medial rectus of the eye.[4] Proper function of the lateral rectus is tested clinically by asking the patient to look laterally. Depending on the underlying cause of the lateral rectus palsy, some improvement may occur naturally over time. While the prognosis for a lateral rectus palsy onset by a viral illness is generally positive, the prognosis for an onset of trauma or tumor is quite poor. Ultimately, nerves are not very good at regenerating or healing themselves, so if the damage is severe there will be permanent damage.[5]

In addition, another disorder associated with the lateral rectus muscle is Duane Syndrome. This syndrome occurs when the sixth cranial nerve which controls the lateral rectus muscle does not develop properly. It is believed that Duane Syndrome is a result of a disturbance of normal embryonic development due to a genetic or an environmental factor.[6]

Additional images[edit]

• Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.

  Superior and inferior rectus muscle bridle sutures of 4-0 silk (or locking forceps) are placed to stabilize and facilitate repositioning of the eye for GSL.

  An initial paracentesis is made opposite to the planned operative site. This incision should be made longer than wide and should leak only with depression of its posterior lip. This paracentesis allows for egress of aqueous from the anterior and posterior chambers. A rounded muscle hook can be used to depress the limbus and facilitate movement of aqueous from the posterior chamber into the AC. By releasing aqueous completely from the AC and posterior chamber, the AC is more easily deepened with viscoelastic to an exaggerated depth of six to eight corneal thicknesses, causing the iris to be stretched and bowed posteriorly (Fig. 11.1).

  Using a sterile gonioscopy lens (e.g. Koeppe lens, gonioprism, mirrored lens), the angle is reexamined to confirm the extent and location of synechial angle closure on the trabeculum. Synechialysis is next performed using an operating gonioscopy lens for direct visualization of the procedure. When a loupe is used, a headlight must be employed for illumination and viewing of the angle. If an operating microscope is used, the patient's head and the operating microscope are positioned as for goniotomy surgery (see Figs 9.4–9.6Fig 9.4Fig 9.5Fig 9.6).

  Synechialysis is performed by entering a spatula, needle, or goniotomy knife into the AC through the paracentesis that is opposite to the PAS (Fig. 11.2). The passage through the cornea must be short enough to allow rotation of the knife in the plane of the iris, but long enough to discourage leakage and shallowing of the AC. The entered instrument is passed across the AC (Fig. 11.3A) and brought into contact with the iris at its abnormal insertion to the trabeculum (Fig. 11.3B). Repetitive posterior depression movements of the instrument are combined with circumferential rotation of the knife to successfully disinsert the iris from the trabeculum without causing a cyclodialysis.

  The instrument is then withdrawn from the AC, and more viscoelastic may be added to discourage bleeding into the AC. The procedure may be repeated in adjacent areas using other paracentesis tracks if needed. Following these synechialysis steps, a 30 gauge blunt needle or cannula is entered into the AC to irrigate out the viscoelastic with balanced salt solution (Fig. 11.4). An intraocular miotic may be infused to keep the iris on stretch.

  Alternatively, GSL can be performed with an indirect gonioscopy lens. After the area to be operated on is visualized with the gonioscopy lens, the gonioscopy lens is removed and the knife is inserted through the paracentesis. The iris is then gently pushed posteriorly away from the angle. The indirect gonioscopy lens is then replaced onto the eye for reexamination of the angle to ascertain the effect. This can be done repetitively until the angle is free from PAS.

  As another alternative, this procedure can employ the use of AC iris microforceps. These can be used to repetitively and carefully pull the iris centripetally, followed by reexamination of the angle for effect.

  Ultrasound biomicroscopy demonstrates the angle before and after GSL (Fig. 11.5).

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  Extraocular Muscles

  Lee Ann Remington OD, MS, FAAO, in Clinical Anatomy and Physiology of the Visual System (Third Edition), 2012

  Superior Rectus Muscle

  The superior rectus muscle has its origin on the superior part of the common tendinous ring and the sheath of the optic nerve.30 The muscle passes forward beneath the levator muscle; the sheaths enclosing these two muscles are connected to each other, allowing coordination of eye movement with eyelid position and resulting in elevation of the eyelid with upward gaze. An additional band of this tissue connects to the superior conjunctival fornix. The superior rectus muscle parallels the roof of the orbit until it passes through a connective tissue pulley just posterior to the equator of the globe; at this point it follows the curve of the globe to its insertion.34,35

  The insertion of the superior rectus is approximately 7.7 mm from the limbus5 and is curved slightly, with the convex side forward. The line of the insertion is oblique, with the nasal side closer to the limbus than the temporal side (see Figure 10-10, B). The tendon length is approximately 5.8 mm.5 A line drawn from the origin to the insertion along the muscle will form an angle of approximately 23 degrees with the sagittal axis.

  The frontal nerve runs above the superior rectus and levator muscles, and the nasociliary nerve and the ophthalmic artery lie below. The tendon of insertion for the superior oblique muscle runs below the anterior part of the superior rectus muscle (see Figure 10-7).

  The superior rectus is innervated by the superior division of the oculomotor nerve, which enters the muscle on its inferior face. Branches pass either through the muscle or around it to innervate the levator.

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  INFERIOR RECTUS MUSCLE PALSY 378.81

  Richard A. Saunders MD, Richard L. Golub MD, in Roy and Fraunfelder's Current Ocular Therapy (Sixth Edition), 2008

  Differential diagnosis

  Other ocular pathology may present a clinical picture similar to inferior rectus palsy.

  For instance, superior rectus muscle restriction (e.g. Graves disease or myositis) may cause a hypertropia with down gaze limitation. The orbital floor adherence syndrome may also present with hypertropia, most pronounced or exclusively present in down gaze. It is most often seen after orbital floor fracture and represents a pseudoparesis of the inferior rectus muscle. The reduced infraduction is caused by mechanical limitation of the muscle excursion posteriorly along the orbital floor, simulating muscle ‘weakness.’ Patients with chronic hypertropia (e.g. longstanding superior oblique muscle palsy or skew deviation) may have limited infraduction on version testing. This problem is distinguished from inferior rectus muscle palsy by the clinical context. Duction testing can differentiate an inferior rectus paresis from a contralateral superior oblique muscle over action; ductions will shows a difference in the ability to depress the involved eye when the fellow eye is covered. Saccadic velocity elicited by optokinetic testing also can be helpful, showing a slowed saccade with inferior rectus paresis, but a normal saccade with skew deviation.

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  General Eye Examination

  MARIA AARON, ... GEOFFREY BROOCKER, in Primary Care Ophthalmology (Second Edition), 2005

  Motility, Position, and Extraocular Muscles

  The six ocular muscles—superior, inferior, medial, and lateral recti and superior and inferior obliques—are responsible for movements of the globe (Fig. 1-7). Cranial nerve VI innervates the lateral rectus, which abducts (turns out) the eye. Cranial nerve IV innervates the superior oblique, which abducts, depresses, and intorts (rotates in) the eye. Cranial nerve III innervates the medial rectus, inferior rectus, superior rectus, and inferior oblique muscles. The medial rectus adducts (turns in) the eye, the inferior rectus depresses the eye, the superior rectus elevates the eye, and the inferior oblique abducts, elevates, and extorts (rotates out) the eye. Cranial nerve III also innervates the levator muscle, which is responsible for lid elevation. (The cardinal movements of the eye are shown in Fig. 1-8.)

  The examiner must carefully note the position of the eyes and their excursions relative to each other in patients with complaints of diplopia, those with strabismus (misalignment of the eyes), and those with suspected neurologic or orbital disease. The extraocular movements involve complex coordination of frontomesencephalic and cerebellomesencephalic interactions by the third, fourth, and sixth cranial nerves. Any disturbance in intracranial processing, midbrain or cranial nerve function, or intraorbital muscle pathology may result in an ocular position imbalance. Abnormalities may be seen in the primary gaze (straight ahead) or congruity of gaze in the six cardinal positions: left, right, up and right, up and left, down and right, and down and left. The examiner can identify instances of esodeviation (as in cross-eye) or exodeviation (as in walleye) by position of the light reflex temporal to the central cornea (Fig. 1-9) or nasal to the central cornea (Fig. 1-10), respectively. A cover-uncover test can help document the presence of esodeviation, exodeviation, and hyperdeviation. In this test, the patient's gaze remains fixed on a distant object while the examiner covers and uncovers each eye. The deviated eye straightens when the normal eye is covered (opposite the direction of the original deviation). In esotropia (cross-eye), the eye moves temporally to pick up fixation when the straight, fixating eye is covered. In exotropia (walleye), the eye moves nasally when the straight, fixating contralateral eye is covered. The examiner also can identify vertical deviations using this method, with the higher eye labeled as hypertropic. Determining the origin of the motility disturbance may be challenging because the condition may be inherited, acquired, neural, muscular, or a combination of these factors.

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  DISSOCIATED VERTICAL DEVIATION 378.9 (Dissociated Strabismus Complex, Alternating Sursumduction, Dissociated Vertical Divergence, Double-Dissociated Hypertropia, Occlusion Hypertropia, Dissociated Torsional Deviation, Dissociated Horizontal Deviation)

  Richard J. Olson MD, Ronald V. Keech MD, in Roy and Fraunfelder's Current Ocular Therapy (Sixth Edition), 2008

  Surgical

  •

  The most commonly used procedure for DVD is a superior rectus muscle recession of 5 to 16 mm from the insertion.

  •

  Recession and anterior displacement of the inferior oblique muscle near the temporal pole of inferior rectus muscle is another common procedure for DVD. Some surgeons recommend this surgery for isolated DVD, however, most experts prefer this approach when the DVD is associated with concomitant inferior oblique muscle overaction.

  Residual DVD after large superior rectus recession may benefit from a small (5 mm or less) resection of the inferior rectus muscle. Recently, nasal myectomy of the inferior oblique muscle has been advocated if the inferior oblique muscle has previously been recessed and anteriorized.

  Other surgical approaches reported in the literature include posterior fixation of the superior rectus muscle with or without recession, botulinum toxin type A injection into the superior rectus muscle, weakening of both the superior rectus and inferior oblique muscles, graded resection with anteriorization of the inferior oblique and weakening of all four oblique muscles

  •

  DHD may be treated with lateral rectus muscle recession of 3 to 8 mm on the affected side (or ipsilateral side).

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  Strabismus surgery

  Scott R. Lambert, Amy K. Hutchinson, in Ophthalmic Surgery: Principles and Practice (Fourth Edition), 2012

  Gross anatomy of the extraocular muscles

  There are six extraocular muscles – the medial, lateral, superior and inferior rectus muscles, and the superior and inferior oblique muscles. The rectus muscles all have insertions that are 10–11 mm in width. The four rectus muscles all arise from the apex of the orbit at the annulus of Zinn and then insert at varying distances from the limbus. The medial rectus muscle inserts closest to the limbus and the superior rectus muscle furthest from the limbus. The outward spiraling of the insertions of the rectus muscles, beginning with the medial rectus muscle and ending with the superior rectus muscle, is referred to as the spiral of Tillaux (Fig. 57.1). The inferior and superior rectus muscle insertions are slanted nasally whereas the medial and lateral rectus muscles are not usually slanted. The rectus muscles have varying arcs of contact with the globe – the longest being 10 mm for the lateral rectus muscle. Certain disorders can be associated with ectopia of the rectus muscles. For example, patients with craniosynostosis often have medial rectus muscles which are abnormally high and lateral rectus muscles which are abnormally low, which can result in a V-pattern mimicking overaction of the inferior oblique muscles.

  The superior oblique muscle also arises in the apex of the orbit, but it has a long tendon that is redirected temporally after it traverses the trochlea, which is located just superior to the medial canthal tendon. Brown syndrome is associated with dysfunction of the trochlea–superior oblique tendon complex. The superior oblique tendon fans out and then inserts beneath the superior rectus muscle. It is attached to the superior rectus muscle by a frenulum, which is an important anatomical structure when performing large recessions of the superior rectus muscle or disinserting the superior oblique tendon. The insertion of the superior oblique tendon is more variable than that of the other extraocular muscles. The inferior oblique muscle arises near the lacrimal fossa and traverses the floor of the orbit to insert near the inferior border of the lateral rectus muscle overlying the macula.

  There are two distinct layers to the rectus muscles – the global and orbital layers. The orbital layer inserts directly into the muscle pulleys while the global layer inserts into the globe3 (Fig. 57.2).

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  Oculomotor nerve

  Jean-Pierre Barral, Alain Croibier, in Manual Therapy for the Cranial Nerves, 2009

  12.3.2 Technique for the eyeball

  The muscles innervated by the oculomotor nerve are shown in Figure 12.7.

  The superior rectus muscle of the eye

  The superior division of the oculomotor nerve goes principally to the superior rectus muscle of the eye. This nerve may be stretched by mobilizing the superior aspect of the eyeball in an essentially caudad direction, during the cranial expansion phase. This technique is not specific to the muscle; it can also produce an effect on the frontal nerve, ciliary nerve, ciliary ganglion and ophthalmic artery, to mention just a few.

  Medial rectus muscle

  The nerve of the medial rectus muscle comes from the caudal branch (inferior division) of the oculomotor nerve. To effect a stretch, draw the eyeball laterally during the expansion phase.

  Inferior rectus muscle

  The nerve to the inferior rectus muscle also stems from the caudad branch of the oculomotor nerve. To effect a stretch, draw the eyeball cephalad during the cranial expansion phase.

  Inferior oblique muscle

  The inferior oblique muscle originates in the medial part of the caudad border of the orbit and directs the eyeball laterally. Its innervation also derives from the inferior division of the oculomotor nerve. To effect a stretch, draw the eyeball lateral and cephalad during the cranial expansion phase (Fig. 12.8).

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  Anatomy of the eye

  In The Ophthalmic Assistant (Ninth Edition), 2013

  Ocular muscles

  Six ocular muscles move the globe: the medial, lateral, superior, and inferior rectus muscles and the superior and inferior oblique muscles (Fig. 1-14). The medial rectus muscle moves the eye toward the nose or adducts the eye. The lateral rectus muscle moves the eye horizontally to the outer side or abducts the eye. The superior rectus muscle elevates the eye primarily, whereas the inferior rectus muscle depresses the eye. The rectus muscles are inserted very close to the limbus, the medial rectus lying approximately 5.5 mm and the lateral rectus approximately 7 mm from the limbus. The rectus muscles are not normally visible as they are covered with conjunctiva and subconjunctival tissue. Because they lie on the surface of the globe, they are readily accessible for muscle surgery.

  The superior oblique muscle functions primarily as an intorter by rotating the vertical and horizontal axis of the eye toward the nose; it also functions to depress the eye. The inferior oblique muscle acts to extort and elevate the eye. The oblique muscles are inserted behind the equator of the globe.

  In the lid the levator palpebrae superioris muscle serves to elevate the lid, whereas the orbicularis oculi muscle closes the eye during winking, blinking, or forced lid closure. If the levator muscle is weak or absent, the lid droops and ptosis results.

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  Cranial Nerves and Autonomic Innervation in the Orbit

  B.C. Anderson, L.K. McLoon, in Encyclopedia of the Eye, 2010

  The Oculomotor Nerve or Cranial Nerve III

  The oculomotor nerve provides motor innervation to the levator palpebrae superioris, the superior, medial and inferior rectus muscles, and the inferior oblique muscle. All these muscles insert directly onto the globe and move the eye within the orbit. In addition, as discussed in the section on autonomic innervation, the oculomotor nerve carries the parasympathetic preganglionic axons that synapses in the ciliary ganglion, and whose postganglionic axons innervate the pupillary sphincter and ciliary muscles of the eye.

  The oculomotor neurons within the brainstem that give rise to the oculomotor nerve have a complex organization. The oculomotor nucleus is found at the level of the mesencephalon, ventral to the cerebral aqueduct. It extends from the posterior floor of the fourth ventricle to the trochlear nucleus. Generally, the oculomotor nucleus contains a midline dorsal nucleus and two lateral nuclei. Using a variety of tract-tracing techniques, it has been shown that the oculomotor nucleus is organized in a muscle-specific manner, with specific groups of neurons innervating single extraocular muscles. In addition, the muscles can receive ipsilateral, contralateral, or bilateral innervation. Each superior rectus muscle is innervated by contralateral oculomotor neurons located medially within the paired lateral nuclei. Each medial rectus is innervated by ipsilateral oculomotor neurons found in the inferior-most part of the paired lateral nuclei. Each inferior rectus muscle is innervated by ipsilateral oculomotor neurons located in the superior-most part of each of the paired lateral nuclei. The inferior oblique is innervated ipsilaterally by neurons located in the middle and lateral portion of the paired lateral nuclei. Only the levator palpebrae superioris muscle receives bilateral innervation from the single dorsal caudal nucleus located in the midline. All the nerve fibers from these various topographically organized nuclei join together within the brainstem, and after running through the red nucleus and cerebral peduncle, exit the brainstem on its ventral surface in the interpeduncular fossa. In their cisternal location, they pass between the posterior cerebral and superior cerebellar arteries, and course anteriorly, deep to the posterior communicating artery. The intracranial course is on average 25 mm long before the nerves enter into the dural border of the lateral cavernous sinus at the level of the posterior clinoid process (Figure 10). The oculomotor nerve enters the orbit through the superior orbital fissure, where it divides into a superior and an inferior division and enters the tendinous annulus (Figure 3). The diameter of the oculomotor nerve, as it enters the superior orbital fissure, is on average 2.1 mm, while the superior and the inferior divisions are 1.6 and 1.9 mm in diameter, respectively. The superior division innervates the superior rectus and levator palpebrae superioris muscles; the nerve enters the conal surface of the superior rectus muscle (Figure 11), and nerve fibers continue to the levator by either piercing through the superior rectus muscle or passing on its lateral border. The inferior division innervates the medial rectus, the inferior rectus, and the inferior oblique muscles. To reach these muscles, the inferior division of the oculomotor nerve runs medially and inferiorly, dividing into three branches (Figure 12). One branch enters the medial rectus muscle and the second branch enters the inferior rectus muscle, both on their conal surfaces; a third branch courses anteriorly along the lateral border of the inferior rectus muscle and pierces the inferior oblique at the point where it crosses the inferior rectus muscle. All the oculomotor nerve branches enter the muscles between the middle and posterior 1/3 of each muscle. In the majority of cases, the branch to the inferior oblique gives rise to nerves that carry parasympathetic axons to the ciliary ganglion. This is discussed in the section on autonomic nervous system.

  

  Figure 10. Superior view of the floor of the cranium. The orbital contents can be seen anteriorly. Four of the five cranial nerves can be seen. On the medial wall of the middle cranial fossa, the three divisions of the trigeminal nerve can be seen coursing from the anterior border of the trigeminal ganglion. The ophthalmic division can be seen coursing in the direction of the orbit. The oculomotor nerve can be seen crossing superior to the sella turcica of the sphenoid bone (which houses the pituitary gland in the hypophyseal fossa). The abducens nerve can be seen diving through the dura and coursing on the medial side of the trigeminal ganglion. The large foramen seen at the bottom of the photograph is the foramen magnum, where the spinal cord joins the medulla oblongata of the brain. The optic nerve can also be seen as it enters the optic canal.

  

  Figure 11. A deep dissection of the orbit from the superior view of the orbit. The optic nerve can be seen exiting the globe. The two divisions of the oculomotor nerve are dissected. The superior division is seen entering the superior rectus/levator palpebrae superioris muscles. The inferior division dives deep to the optic nerve on its way to innervate the medial and inferior rectus, and inferior oblique muscles. (Forceps is holding the cut proximal end of the oculomotor nerve.)

  

  Figure 12. Superior view of a deep dissection of the human orbit. The globe has been retracted so we can see its inferior surface. This allows visualization of the lateral, the inferior, and the medial rectus muscles. The inferior division of the oculomotor nerve can be seen coursing directly into the posterior 1/3 of the inferior and medial rectus muscles. (Forceps is holding the cut proximal end of the oculomotor nerve. The lacrimal gland is covering the anterior portion of the lateral rectus muscle.)

  The course of the oculomotor nerve is easily seen using standard magnetic resonance imaging (MRI) techniques, both intracerebrally and intraorbitally.

  Which muscle rotates the eye upward and away from the midline?

  Medial Rectus The medial rectus is the largest extraocular movement muscle. It's responsible for the up-and-down and the side-to-side movement of the eye.

  Which muscle moves the eye upward?

  The superior rectus and inferior oblique muscles primarily move the eye upward. The inferior rectus and superior oblique muscles primarily move the eye downward. The lateral rectus moves the eye horizontally laterally (abduction).

  Which eye muscle is responsible for upward and outward movement?

  EXTRAOCULAR MUSCLES: These muscles originate in the eye socket (orbit) and work to move the eye up, down, side to side, and rotate the eye. The superior rectus is an extraocular muscle that attaches to the top of the eye. It moves the eye upward.

  What muscle laterally rotates the eye and moves it up and away from the nose?

  The lateral rectus is a flat-shaped muscle, and it is wider in its anterior part. The lateral rectus muscle is an abductor and moves the eye laterally, and side to side along with the medial rectus, which is an adductor.