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Background: Descriptions of the radiological appearance of the craniovertebral ligaments often lack detail. This study aimed to provide an accurate description of the morphology and radiological appearance of the alar and cruciform ligaments with confirmation of findings by fine dissection. Materials and Methods: Six embalmed human cadaveric specimens were reduced to an osseoligamentous arrangement spanning the C2/3 disc to the occiput. Specimens were imaged on a 4.6T Bruker magnetic resonance (MR) system using a 3D RARE multiple SE sequence with acquisition time 18 h 24 min. Acquired images were viewed in three planes, and detailed descriptions and morphometric measurement of the ligaments were obtained. Specimens were then examined and described using fine dissection. Direct comparison of the descriptions of each method was undertaken. Results: From imaging, detailed features of all alar ligaments could be identified in all specimens. Consistency in shape, orientation, and attachments is described. Attachment to the medial aspect of the atlantooccipital joints was evident in all specimens. Five of six alar ligament pairs contained fibers that traversed the dens without attachment. Ascending cruciform ligaments could be clearly identified in four of six specimens. No descending cruciform ligaments could be clearly delineated. Detailed features of the transverse ligaments could be identified and described in all planes. Dissection findings were mostly consistent with descriptions obtained from MR images. Conclusion: 4.6T MR images provide accurate detail of the structure, dimensions, and attachments of the craniovertebral ligaments. The morphology of the craniovertebral ligaments assessed radiologically was consistent with findings on gross dissection.

Background: Published descriptions of the tectorial membrane have been inconsistent. Descriptions vary from a simple ligamentous band extending between the axis and occiput to a more complex layered structure composed of bands of fibers. The purpose of this study was to examine and document the macrostructure of the tectorial membrane. Materials and Methods: The tectorial membrane was examined by fine dissection in 11 formalin-fixed human adult cadavers. Detailed descriptions of the macrostructure and attachments were recorded. Results: Each tectorial membrane examined consisted of two distinct layers. The superficial layer was composed variably of three or four bands. Its fibers extend caudally over multiple spinal levels, becoming continuous with the posterior longitudinal ligament. The deeper layer routinely consisted of three bands, each being firmly adherent to the posterior aspect of the body of the second cervical vertebra. Attachments of fibers from both layers extended beyond the foramen magnum to create a semicircular attachment onto the base of the skull. Conclusions: The tectorial membrane has a more complex structure than has been described to date in standard anatomical texts. The existence of a layered and banded composition may have implications for understanding its function and for the clinical assessment of this structure.

Abstract Background Up to 40% of individuals who sprain their ankle develop chronic ankle instability (CAI). One treatment option for this debilitating condition is joint mobilisation. There is preliminary evidence that Mulligan’s Mobilisation With Movement (MWM) is effective for treating patients with CAI, but the mechanisms by which it works are unclear, with Mulligan suggesting a repositioning of the fibula. This randomised controlled trial aims to determine the effects of MWM on anatomical and clinical characteristics of CAI. Methods Participants 18 years or over with CAI will be accepted into the study if they satisfy the inclusion and exclusion criteria endorsed by the International Ankle Consortium. They will be randomised into the experimental group (MWM) or the placebo group (detuned laser) and will receive the assigned intervention over 4 weeks. General joint hypermobility and the presence of mechanical instability of the ankle will be recorded during the first visit. Further, position of the fibula, self-reported function, ankle dorsiflexion range, pressure pain threshold, pain intensity, and static and dynamic balance will be assessed at baseline, and at the conclusion of course of intervention. Follow-up data will be collected at the twelfth week and at the twelfth month following intervention. Discussion Effectiveness of MWM on clinically relevant outcomes, including long term benefits will be evaluated. The capacity of MWM to reverse any positional fault of the fibula and the association of any positional fault with other clinically important outcomes for CAI will be explored. Proposed biomechanical mechanisms of fibular positional fault and other neurophysiological mechanisms that may explain the treatment effects of MWM will be further explored. The long term effectiveness of MWM in CAI will also be assessed. Trial registration Australian New Zealand Clinical Trials Registry; ACTRN12617001467325 (17/10/2017).