Parks 3 step test

Right vs. left head tilt, the paretic muscle can be detected. Potential paretic muscle: LSO, left superior oblique; LIR, left inferior rectus; RSR, right superior rectus; RIO, right inferior oblique. Reprinted with permission from (22).It has been proposed to add a fourth step, namely, measuring the vertical deviation in upgaze and downgaze (14). For example, with a right fourth nerve palsy, given that the superior oblique depresses the eye, the right hypertropia will increase in downgaze and lessen in upgaze. There are 3 important caveats regarding the Parks–Bielschowsky 3-step test: spread on commitance, the test's sensitivity, and the test's specificity. With a longstanding fourth nerve palsy, the amount of vertical deviation may become similar in all fields of gaze (12). This usually occurs when the fourth nerve palsy affects the dominant eye. For example, in a patient with a right fourth nerve palsy, the right inferior oblique (antagonist of the right superior oblique) requires less innervation to move the eye into its field of action. Following the Hering law, the left superior rectus (yoke muscle of the antagonist of the paretic muscle) also receives less innervation and will seem paretic. This will, in turn, diminish the amount of vertical misalignment. This has been referred to as inhibitional palsy of the contralateral antagonist. An alternate explanation for the spread of comitance may be found in the study by Suh et al (15). Using high-resolution orbital MRI, these investigators demonstrated that displacements in the pulley systems of the rectus muscles can alter motility patterns in superior oblique palsy. The Parks–Bielschowsky 3-step test lacks both sensitivity and specificity. In a series of 7 patients, Kushner (16) suggested that a number of other entities might simulate a fourth nerve palsy with the Parks–Bielschowsky 3-step test including paresis of more than one vertical muscle, dissociated vertical deviation, myasthenia gravis, and previous vertical muscle surgery. Using superior oblique atrophy on MRI as evidence of a fourth nerve palsy, Manchandia and Demer (17) performed the Parks–Bielschowsky 3-step test on 50 patients. They found that the test was diagnostic in only 70% of cases. By reducing the test to 2 steps, the sensitivity increased to 76%–84% but diminished the specificity. Lee et al (18) measured the sensitivity of the 3-step test, depending on the presence or absence of the fourth nerve using high-resolution thin-section MRI. Testing sensitivity was 78% in patients with a fourth nerve and 72% in those without a fourth nerve. There was no statistically significant intergroup difference. Taken together, these reports demonstrate that the Parks–Bielschowsky 3-step test is insensitive in 22%–30% of patients with fourth nerve palsy: CYCLOTORSION Because the primary action of the superior oblique muscle is incyclotorsion, detection of a torsional component of diplopia is helpful in establishing the diagnosis of fourth nerve palsy. In obtaining the history, the clinician should not only elicit the vertical orientation of the diplopic images, but also inquire if one of the images seems “tilted” or “slanted.” For confirmation and quantitation of cyclotorsion, a valuable technique is

Toward the side of the palsied muscle, there was an increase in the vertical deviation, while tilting to the contralateral side caused either a decrease or resolution of the deviation. This became known as the Bielschowsky Head Tilt Test. Parks expanded on these observations and proposed a stepwise diagnostic schema in patients with vertical strabismus (13). As he pointed out, head tilt because of cyclovertical strabismus does not necessarily indicate binocular vision nor that the palsied muscle is an oblique. For example, head tilting may accompany a vertical rectus muscle palsy. In Parks' schema, the first step reduces the possibility from 8 to 4 cyclovertical muscles, the second step from 4 to 2, and the third step will determine which of the remaining 2 muscles is weak. Figures 4 and 5 illustrate the results of the Parks–Bielschowsky 3-step test for a right and left hypertropia, respectively. The first step determines that the paretic muscle is either one of 2 depressors in 1 eye or 1 of 2 elevators in the other. With the second step, one determines if the vertical deviation increases in right or left gaze. At this point, the 2 suspected muscles are in different eyes, both are always superior or inferior muscles and both are either incyclotorters or excyclotorters. In the third step, the paretic muscle is unable to perform its torsional and vertical actions. Yet, the muscle of the same eye that is able to perform the appropriate torsional movement will also move the eye vertically, thus increasing the vertical misalignment. For example, in a patient with a right fourth nerve palsy and the head tilted to the right, excyclotorsion will occur in the left eye because of contraction of both the left inferior oblique and left inferior rectus muscles. However, the paretic right superior oblique cannot balance the torsional and elevating activity of the right superior rectus, and the right eye will move upward leading to an increase in the vertical deviation (right hypertropia). With head tilt to the left, the paretic right superior oblique is not involved, and there will be either no increase in the vertical misalignment or it will diminish or no longer be detectable.FIG. 4.: Results of the Parks–Bielschowsky 3-step test are shown for a patient with a right hypertropia. In primary gaze, the vertical deviation may be due to paresis of 1 of 4 muscles. Increase in the deviation in right vs. left gaze reduces the possibility to 2 muscles and with measurement in right vs. left head tilt, the paretic muscle can be detected. Potential paretic muscle: LIO, left inferior oblique; LSR, left superior rectus; RIR, right inferior rectus; RSO, right superior oblique. Reprinted with permission from (22).FIG. 5.: Results of the Parks–Bielschowsky 3-step test are shown for a patient with a left hypertropia. In primary gaze, the vertical deviation may be due to paresis of 1 of 4 muscles. Increase in the deviation in right vs. left gaze reduces the possibility to 2 muscles and with measurement in

On the map that are shaded purple, identifying National Park lands, or use the search feature to look up a specific National Park. 3 Step 3: Choose An Adventure Look for an onX Backcountry Adventure, marked with a blue sign Waypoint, inside your park. Tap on the Waypoint to view guidebook-quality trail specs, a detailed write-up, photos, and weather forecast. 4 Step 4: Customize Your Adventure Use Custom Waypoints, Line Distance, Area Shape, and Notes tools to markup your map. 5 Step 5: Download Maps for Offline Use Many National Parks don’t have reliable cellular coverage. With onX Backcountry, that will be the last thing you’ll worry about. Download your Adventure with all your custom Markups to your mobile device for offline use. 6 Final Step: Go Explore! Use onX Backcountry as a reliable offline GPS tool and tracker while you’re exploring our National Parks’ most beautiful lands. Get The App Use onX Backcountry to find new adventures in national parks around the country. Plan your trips in the App, then share your Waypoints, Tracks, and other Markups with your friends. Asset 1apple Asset 2droidAsset 3droid

Adduction, the muscle acts as a depressor, whereas in abduction, its function is incyclotorsion. Although the superior oblique also has abduction activity in primary gaze, its abduction function is most apparent with superior oblique overaction, often seen in patients with an A-pattern strabismus. At the insertion of the superior oblique on the globe, the anterior fibers impart a primarily incyclotorsional force, whereas the posterior fibers impart depressing and abducting forces (8).FIG. 2.: Action of the superior oblique muscle is shown in primary gaze (A), adduction (B), and abduction (C).High-resolution MRI has provided anatomic details of the superior oblique muscle in vivo. These studies have been pioneered by Demer and Miller (9) in evaluating the muscle in both physiologic and pathologic settings. The normal superior oblique has its largest cross-sectional area in midorbit tapering both posteriorly to its origin and anteriorly as it transitions to a tendon. As shown in Figure 3, the superior oblique can be visualized in primary gaze and its anatomic alterations demonstrated in upgaze and downgaze.FIG. 3.: Quasicoronal MRI illustrates the appearance of the superior oblique (SO) in primary gaze and its increase in cross- section size from elevation to depression. IR, inferior rectus; MR, medial rectus; SR, superior rectus. Modified from (9).CLINICAL EXAMINATION Because the fourth nerve innervates a single muscle, the superior oblique, the terms fourth nerve palsy and superior oblique palsy will be used interchangeably. HEAD POSITION/FACIAL ASYMMETRY Patients often adopt a head tilt to the side opposite the fourth nerve palsy (ocular torticollis) with a chin-down position. This moves the eye out of the field of action of the palsied superior oblique and diminishes diplopia. Rarely, patients may tilt their heads to the same side as the fourth nerve palsy. It has been speculated that this increases the distance between the diplopic images, which allows the patient to more easily ignore the 2 images. In addition, individuals with congenital fourth nerve palsies may develop midfacial hemihypoplasia, also on the side opposite the palsy. There also may be deviation of the nose and mouth toward the hypoplastic side (10). However, in a study of 79 subjects, Velez et al (11) quantitated 3 morphometric facial features and found that facial asymmetry was not useful in distinguishing congenital from acquired superior oblique palsy. RANGE OF EYE MOVEMENTS In contrast to third and sixth nerve palsies where some limitation in ductions is usually evident, patients with fourth nerve palsy generally have grossly full ocular motility. On occasion, the clinician may detect some impairment of depression with the eye in adduction, but often this is subtle and easily overlooked. The technique to assist in the diagnosis of a fourth nerve palsy is the Parks–Bielschowsky 3-step test. PARKS–BIELSCHOWSKY 3-STEP TEST Over a century ago, Nagel and later Hofmann and Bielschowsky recognized the importance of the cycloduction function of the oblique muscles (12). This led Hofmann and Bielschowsky to investigate why many patients with superior oblique palsy habitually tilt their head to one shoulder. They found that with head tilt

Sound like we’re applying ‘heavy’ Rawlsian theory to the lighthearted topic of theme parks, but philosophy isn’t worth a damn if it can’t be applied to theme parks. 😉A lot of this might seem like an effort to absolve Disney of blame when it comes to refurbishments, but this is not the case. Disney has brought a lot of the guest unrest concerning refurbishments upon itself. The first issue is that Disney has numerous parks that have opened in the last two decades with incomplete slates of attractions, making it difficult to justify taking attractions offline for refurbishment. So step one, a wholly impractical step at this point, would be to open theme parks that are complete on day one.Failing that, Disney could avoid a lot of the guest backlash concerning refurbishments if they would schedule more 3-4 day refurbishments of attractions to proactively address problems with preventative maintenance. Although this would not totally negate the need for extended refurbishments, it would improve show quality across the board and help avoid a lot of situations where attractions have to abruptly close because they are in dire need of maintenance. Moreover, a 3-4 day refurbishment is shorter than the duration of most vacations, allowing tourists to effectively plan around the refurbishment.In this case, both parties planning ahead would prevent those “vacation ruined!” complaints. Don’t worry, Disney, we fans are resilient: we’ll still find something else to complain about. 😉Joking aside, I realize that’s a tough line to draw between an excusable refurbishment and a frustratingly irritating one. Even if you subscribe to the some degree of the ‘philosophy’ I’m advancing, there is no bright-line rule. It’s still going to amount to a value judgment about what should ‘trigger’ a need for refurbishment, how many attractions should be down simultaneously across Walt Disney World, and what times of year are ideal for which refurbishments.Planning a Walt Disney World trip? Learn about hotels on our Walt Disney World Hotels Reviews page. For where to eat, read our Walt Disney World Restaurant Reviews. To save money on tickets or determine which type to buy, read our Tips for Saving Money on Walt Disney World Tickets post. Our What to Pack for Disney Trips post takes a unique look at clever items to take. For what to do and when to do it, our Walt Disney World Ride Guides will help. For comprehensive advice, the best place to start is our Walt Disney World Trip Planning Guide for everything you need to know!Your ThoughtsAny questions about the current refurbishments at Walt Disney World? What do you think about refurbishments at the Disney Parks? Are you more concerned about an improved long-term experience, or do you think “not during my vacation!”? Where do you draw the line? Any other factors you think are worth considering? As mentioned, we think this is a conversation, so please share your ‘refurbishment philosophy’, or any other thoughts or questions you have, in the comments!

Films/Courtesy Everett Collection1945: After taking the required literacy test for a third time, Parks becomes a registered voter. Yet before she can cast a ballot, she must pay a retroactive poll tax of $1.50 for every year since she reached the voting age of 21.1948: Parks becomes the Alabama state secretary for the NAACP.1949: Parks steps back as NAACP secretary to take care of her mother.1952: Parks returns to the Montgomery NAACP and once more becomes a branch secretary.August 1955: Parks attends a two-week training session at the Highlander Folk School in Tennessee. Alongside other civil rights activists, both Black and white, she discusses how to integrate schools following the Supreme Court's Brown v. Board of Education decision of 1954.December 1, 1955: In Montgomery, Parks defies a bus driver's order to let a white man take her seatThe driver, who had treated Parks rudely and evicted her from his bus in 1943, contacts the police and she is arrested.Fingerprint card for Rosa Parks; Photo: Universal History Archive/Getty ImagesDecember 5, 1955: Though Parks was not the first Black woman arrested for defying segregation on city buses, news of her case spurs the Black community to begin a boycott of Montgomery buses.Parks' trial takes place. She is found guilty and fined $10, plus $4 in court costs. Her lawyers file an appeal.January 7, 1956: Parks is let go from her job as a tailor's assistant at the Montgomery Fair department store.January 1956: Raymond quits his barbershop job after discussion of his wife and the boycott is forbidden.February 21, 1956: Along with dozens of other civil rights leaders, including Martin Luther King Jr., Parks is indicted for violating a Montgomery law outlawing boycotts.February 22, 1956: Parks is among a group of indicted boycott leaders who present themselves for arrest. She is quickly released. The case against Parks is eventually dismissed.1956: During the boycott, Parks serves as a dispatcher to coordinate carpools. She also travels across the country to speak about the boycott.December 21, 1956: Following a Supreme Court ruling that segregated buses are unconstitutional, the 381-day boycott ends. Parks is photographed sitting at the front of a bus for Look magazine.Photo: Getty ImagesAugust 1957: Unable to find work in Montgomery and still facing threats for her role in the bus boycott, Parks and her family depart for DetroitOctober 1957: Parks becomes a hostess at the Holly Tree Inn, part of the Hampton Institute in Virginia, but leaves after the fall semester in 1958 to rejoin her husband and mother in Detroit.1959: Parks begins doing piecework for Detroit's Stockton Sewing Company, a job she holds through 1964.July 1960: A Jet magazine article reveals that Parks and her family have been struggling financially, due in