This general reduction in the size of the CC except for the rostrum was thought to be the result of cortical atrophy secondary to the disease. Concerning the preserved rostral part of the CC, it was thought that the fibers of the frontal lobe pass through different pathways than the tracts in the rostrum.
Background In the preauricular region, the frontotemporal branch of the facial nerve is vulnerable to injury, which can result in facial palsy and poor cosmesis, during various surgical interventions. Objectives The purpose of this study was to describe the variations in branching patterns of the frontotemporal branch and its relation to the surrounding anatomical landmarks. Based on our findings we propose a Danger Zone and Safe Zones for preauricular interventions to avoid frontal branch injury. Methods Twenty cadaveric half-heads, 10 freshly frozen and 10 embalmed, were dissected. The anatomy of the auriculotemporal nerve, facial nerve, and variations of its branching pattern in the preauricular region were investigated. Results The average number of frontotemporal branches crossing the zygomatic arch was 2.05 ± 0.6 (mean ± standard deviation). Beginning from the X point at the apex of the intertragal notch, frontal branches ran over the zygomatic arch at a distance extending from 10 to 31 mm anterior to the tragus, which can be defined as the “Danger Zone” for frontal branches. Safe Zones A and B are the triangular regions located behind and in front of the Danger Zone, respectively. Conclusions The mapping of the triangular Safety and Danger Zones is a reliable and simple approach in preauricular interventions to avoid frontal branch injury as the facial nerve typically has multiple frontal branches. This approach provides practical information to surgeons rather than estimating the trajectory of a single frontal branch by using Pitanguy’s line.
Background/aim: The localization of the standard posterior portal of shoulder arthroscopy and landmarks mentioned in the literature are unclear. The purpose of this prospective cadaveric study was to determine the localization of the standard posterior portal and its distance to the neural structures. Materials and methods:One fresh frozen and 10 formalin-fixed adult cadaveric shoulders were dissected. In the beach chair position, a 5-mm trocar was placed anteroposteriorly from the superior edge of the subscapularis muscle, superior to the tip of the coracoid process and tangent to the glenoid. The relevant distances of the posterior exit point were measured.Results: In all specimens, the exit point was a triangular fibrous area, between the posterior and lateral parts of the deltoid. Medial and inferior distances of the trocar to the posterolateral tip of the acromion were 1.88 ± 0.53 cm and 1.35 ± 0.34 cm and distances to the axillary and suprascapular nerves were 4.54 ± 1.08 cm and 2.54 ± 0.85 cm, respectively. Conclusion:The most important finding of this study was the superficial localization of the soft spot between the posterior and lateral parts of deltoid.
Background: Lateral pterygoid muscle activity is associated with the pathological mechanisms of some temporomandibular disorders. The authors aimed to define and demonstrate a novel, practical, and safe technique for botulinum toxin type A injection to the lateral pterygoid muscle based on their findings. Their secondary aims were to standardize the injection pattern according to the variations of the lateral pterygoid muscle and its surrounding anatomical structures, and to establish its advantages over intraoral injection. Methods: Twenty cadaver heads were dissected. The lateral pterygoid muscle and its surrounding structures were investigated for anatomical variations. Based on these findings, a standardized extraoral injection protocol was defined and compared with the intraoral technique for accuracy and safety. Results: The average depth of the lateral pterygoid plate from the skin surface was 49.9 ± 2.2 mm, and the mean width of the lateral pterygoid plate was 10.5 ± 3.9 mm. The extraoral injection approach based on the location of the maxillary tuberosity, tragus, and lateral pterygoid plate was consistent in all dissections for the accuracy of the intramuscular injection. In the intraoral approach, standardization of the entry point of the needle through the oral mucosa is difficult, which makes adjustment of the depth of the injection challenging while increasing the risk of neurovascular injury. Conclusions:The clinical significance of the lateral pterygoid muscle makes it worthwhile to implement minimally invasive treatments before considering more invasive options. The authors define a safe, accurate, and reliable approach with ease of administration in patients with temporomandibular disorders.
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