Surgical and radiologic anatomy : SRA
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Nerve injury is a common complication during anterior shoulder surgery. The purpose of the study was to evaluate the musculocutaneous nerve (MN) anatomically and to clarify the relationship of the MN to the glenoid labrum and coracoid process in different arm positions. The study was carried out on 40 shoulders of 20 adult cadavers fixed in 10% formaldehyde. ⋯ The results of this study might be of use in avoiding the MN especially during Bristlow operations and certain rotator cuff procedures. Transferring the coracoid process during Bristow operations or placing arthroscopic portals when the arm is abducted to 45 degrees appears to be the safest position in terms of MN injury. Based on our results, when the arm needs to be abducted to 90 degrees during operation, externally rotating it may decrease the tension on the brachial plexus thus increasing the distance between the MN and the portals or retractors.
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The discomallear ligament (DML) runs through a narrow space of bony petrotympanic fissure, which joins the articular disc of the temporomandibular joint (TMJ) and the malleus in the tympanic cavity. Previous report suggest that an anatomical feature gives rise to TMJ pain and dysfunction. Recently, the movement of the malleus caused by hypertension on the discomallear ligament is important to the function of the TMJ. ⋯ It is revealed that a wide tunnel-like structure was found on CBCT images in the middle region of the petrotympanic fissure to the malleus in the tympanic cavity consisting of mainly three types: a wide tunnel-shaped structure (29.2%, 7/24, type 1), a tunnel-shaped structure widely open in the entrance of the petrotympanic fissure to the mandibular fossa and gradually thinning out in the tympanic cavity (20.8%, 5/24, type 2), and a tunnel-shaped structure widely open in the entrance of the mandibular fossa, middle region with flat-shaped tunnel structure and narrow exit in the tympanic cavity (41.7%, 10/24, type 3). These structures between the entrance of the petrotympanic fissure and the exit at the tympanic cavity are important to define the limited movement of the malleus. Therefore, morphological feature of the ligaments in malleus may relate to TMJ pain, dysfunction and hearing function.