Can Whitnall’s tubercle be localized using palpable landmarks around the orbit?

Abstract

Objectives: Whitnall’s tubercle (WT) is located deep in the lateral canthus and on the lateral orbital wall and has crucial structures attach to it. We aimed to define the location of WT using the palpable bone landmarks which can be used as reliable landmarks in eyelid and orbital surgery to prevent the damage of stuctures associated with WT. Methods: Forty-four adult skulls (22 right, 22 left) were included to the study. The skulls were divided into two groups according to the apparancy of the WT. The distances from WT to the frontozygomatic suture, the marginal tubercle, the anterior point of the zygomatic arch, and the lateral margin of the orbit were measured. The clock positions of WT according to the marginal tubercle and the anterior point of the zygomatic arc were determined. Results: The distances of the WT to the marginal tubercle, the anterior point of the zygomatic arch, the lateral margin of the orbit, and the frontozygomatic suture were 9.92±1.65 mm, 16.48±1.86 mm, 2.32±0.53 mm and 9.66±1.44 mm, respectively. WT was at 8 and 9 o’clock positions on the left, and at 4, 3, and 2 o’clock positions on the right according to the marginal tubercle. WT was at 10 o’clock position on the left, and 2 and 1 o’clock positions on the right according to the anterior point of the zygomatic arch. Conclusion: The marginal tubercle, the lateral margin of the orbit, and the anterior point of the zygomatic arch can be used as standart bony landmarks in eyelid and orbital surgery to prevent the soft tissue damage relevant to WT. The high kappa values of the interclass and intraclass correlations suggest that these parameters are reliable and repeatable for clinical use. Out of these parameters, the anterior point of the zygomatic arch is more beneficial to locate the WT because of the standard clock positions. The WT is typically located at 10 o’clock position on the left and 2 o’clock position on the right according to the anterior point of the zygomatic arch.

Frequency Morphologic and Morphometric Properties and Osseous Relationships of Whitnall’s Tubercle

“…Besides the fact that the WT is a crucial point for detecting the attachment of lateral retinaculum, the FZs is proved to be a reliable marker for identifying it. 23,24 In the absence of WT, to find the location of attachment of lateral retinaculum, in addition to FZs, we support the study of Korkmaz et al 13 declaring that MT, APoZA, and the closest point of the lateral margin of the orbital rim can also be used.…”

“…At the left zygomatic bones, according to the MT, WT were most frequently located at 9 o'clock in our study (70%), whereas Korkmaz and colleagues reported that 59% were located at 8 o'clock. According to the APoZA, WT of the right zygomatic bones were most frequently located at 1 o'clock in our study (92%), whereas Korkmaz et al 13 reported that 91% were located at 2 o'clock. At the left zygomatic bones, according to the APoZA, WT were most frequently located at 11 o'clock in our study (77%), whereas Korkmaz and colleagues reported that 100% were located at 11 o'clock.…”

“…Apart from this landmark, we also agree with Korkmaz and colleagues, that the APoZA can also be used in the detection of WT because of its superficial location. The last 2 parameters (ApoZA and MT) mentioned are included only in the research of Korkmaz et al 13 Their study was the first to report the position of WT according to the MT and APoZA. According to the MT, WT of the right zygomatic bones were most frequently located at 3 o'clock in our study (68%), whereas Korkmaz and colleagues reported that 68% of their right zygomatic bones were located at 4 o'clock.…”

“…After surgical reconstructive surgery of the soft tissues of the eye especially during lateral orbital approaches, not only the reorganization of the symmetry of the WT but also the preservation of the various structures adhering to this tubercle are significant. In the case that no WT exists, some other structures should be guided to find the attachment of the lateral retinaculum 2,13 Thus in our study we aimed not only to investigate the frequency, morphologic and morphometric properties of WT but also tried to collect data for other possible structures that will be aiding to identify the lateral canthal attachments.…”