Zuckerkandl's tubercle and its relationship to the recurrent laryngeal nerve: A cadaveric dissection and meta-analysis

OBJECTIVE

Zuckerkandl's tubercle (ZT), when present, is an anatomical landmark by which surrounding structures such as the recurrent laryngeal nerve (RLN) can be identified intraoperatively. This study aimed to investigate the prevalence and anatomical characteristics of Zuckerkandl's tubercle by combining cadaveric dissection with a meta-analysis.

METHODS

Through October 2016, an extensive search of PubMed, CNKI, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science was completed. Extracted data, along with the findings from our cadaveric dissections, were pooled into a meta-analysis to assess the prevalence and size of ZT and its relationship to the RLN.

RESULTS

The pooled prevalence estimate of a ZT was 70.2% in the general population, 65.0% of which were considered Grade 0 tubercles (<1.0cm) and 35.0% Grade 1 (≥1.0cm). The RLN ran posteromedially to the ZT in 82.7% of cases, laterally to it in 8.7%, and on top of it in 8.6% of hemilarynges.

CONCLUSION

RLN palsy is a common postoperative complication and cause for litigation following neck surgery. The ZT is a common component of the thyroid gland and with proper knowledge, surgeons can use it to reliably and quickly identify the RLN during operative procedures.

Ossification of the petrosphenoid ligament - a case study

The current study presents a case in which a human skull revealed a partially ossified petrosphenoid ligament. The ossified ligament appears as a hooked bony trabecula emerging below the right posterior clinoid process. Another bony trabecula arises from the petrous apex and runs towards the clivus. Both trabecula face each other but do not fuse, having a small gap between their tips. Their positions clearly indicate that they must have formed an overhang above the abducens nerve. Therefore, they should be considered a part of the walls of Dorello's canal, which is a conduit for the abducens nerve and associated vascular structures.

Micro-CT study of the dehiscences of the tympanic segment of the facial canal

PURPOSE

To depict the anatomy of the tympanic segment of the facial canal using a 3D visualization technique, to detect dehiscences, and to evaluate their frequency, location, shape, and size.

METHODS

Research included 36 human temporal bones (18 infant and 18 adult samples) which were scanned using a Nanotom 180N device. The final resolution of the reconstructed object was 18 µm. Obtained micro-CT data were subsequently processed by the volume rendering software.

RESULTS

The micro-CT study allowed for the 3D visualization of the tympanic segment of the facial canal and detects dehiscences in the studied material in both infants and adults. Most of the dehiscences (66.7 %) involved the inferior wall of the tympanic segment in infants as well as in adults, and were located above and backward to the oval window. The most frequent dehiscence shape was elliptic (66.7 % in infants; 50 % in adults). Furthermore, we observed dehiscences of fusiform and trapezoidal shape in infants. Length of the dehiscences in most cases ranged from 0.5 to 1.4 mm (50 % in infants; 75 % in adults).

CONCLUSIONS

Volumetric reconstructions demonstrated the course of the tympanic segment of the facial canal and its relationship with the tympanic cavity. Knowledge about the size and location of any dehiscence within the tympanic segment of the facial canal is necessary due to the surgical significance of this region. If a dehiscence occurs, there is an increased risk of injury to the facial nerve during the operations or spread of inflammation from the middle ear.

Morphology, topography and clinical signi cance of the jugular foramen

The paper describes morphological variants of the jugular foramen of the human skull and discusses the reasons for its frequent asymmetry. Bilateral disproportions between the anteroposterior and mediolateral diameters of the jugular foramina were analyzed. We established that the jugular foramen is extremely narrow when its anteroposterior diameter is less than 5.0 mm. When the mediolateral diameter exceeds 20.0 mm, then the foramen exhibits extreme widening.

Three-dimensional model of the skull and the cranial bones reconstructed from CT scans designed for rapid prototyping process

This paper presents the effects of building mesh models of the human skull and the cranial bones from a series of CT-scans. With the aid of computer so ware, 3D reconstructions of the whole skull and segmented cranial bones were performed and visualized by surface rendering techniques. The article briefly discusses clinical and educational applications of 3D cranial models created using stereolitographic reproduction.