Comparing the left and right Whitnall’s tubercles and their relation to the frontozygomatic suture: Application to symmetry following lateral orbital surgery

Abstract

We compare, on left and right side of human skulls, the length of Whitnall's tubercle as a relevant landmark and anchor point for the lateral retinaculum. Twenty human skulls were used in this study. A caliper was used to measure the length of Whitnall's tubercle, the distance from Whitnall's tubercle to the frontozygomatic suture and the height of the orbit. An overall mean for these three parameters was calculated using the data obtained. There were no significant differences between left and the right sides. The combined mean length of Whitnall's tubercle was 4.9 mm ± 23%. The combined mean distance from the frontozygomatic suture was 7.8 mm ± 25%. The orbital height was found to be the measurement with the highest congruence between the two sides having a combined mean of 32.3 mm ± 7%. Although 6 out of 20 skulls were found to have no tubercle, five out of twenty skulls had a tubercle only on one side. Even though human skulls develop from bilateral symmetric osteogenesis, surgeons should always be aware of possible asymmetry and possible absence of Whitnall's tubercle between sides or among individuals. The frontozygomatic suture was found to be a useful landmark in identifying the position of Whitnall's tubercle in the majority of specimens. Such information will be useful in realigning the lateral retinaculum following surgery.

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

“…[4,14,23] Moreover, Whitnall [1] tubercle to be approximately 11 mm below the frontozygomatic suture. This distance was 7.4±2 mm on the right and 8.3±1.9 mm on the left in the study by Fries et al [8] In our study, the distance between the WT and the frontozygomatic suture was 9.41±1.46 mm on the right and 9.91±1.39 mm on the left. In the present study and the study by Fries et al, [8] the distance on the left was longer than the right ones.…”

“…This tubercle was noticed at a rate of 95% by Whitnall, [1] 63% by Buschkowitsch, [13] 80.1% by Kangas, [12] 80% by Ono, [11] 49.15% by Tomita, [21] 96.3% by Didio, [9] and 70% by Fries at al. [8] The most crucial reason why it is seen at different rates is the differences between populations. Another important reason is how the existence of tubercle is decided in these studies.…”

“…He indicated that this tubercle was about 11 mm below the frontozygomatic suture and a few millimeters deep to the lateral margin of orbit. [1] Other terms used for WT are; lateral orbital tubercle, [2][3][4][5][6][7] lateral palpebral tubercle, [8] orbital eminence, [8,9] and orbital tubercle.…”

Tenonplasty for closing defects during sclerocorneal surgery—A brief review of its anatomy and clinical applications

“…Well-founded knowledge of the orbit's anatomical structures is mandatory not only for every ophthalmic surgeon but also for conservative clinicians to provide science-based clinical care (Fries et al, 2016;Tubbs, 2016Tubbs, , 2017. In their anatomical study, Kakizaki et al describe the morphological essentials of Tenon's capsule in detail, as follows:…”

Mirroring Procedures for the Assessment of Asymmetry of Different Anatomical Structures of the Cranium: A Protocol Based on 3D-3D Superimposition

“…Therefore possible methods for assessing morphological and metrical characteristics of anatomical asymmetry represent an interesting field of research, not only from a theoretical point of view, but especially for practical reasons. With time several methods for evaluating the characteristics of anatomical asymmetry in different districts have been developed, being the most commonly used the measurements and comparison of linear parameters between the right and the left side [2][3][4][5]. Measurements can be taken directly on dry bones through a caliper, or on CT-scans.…”