The external layrngeal nerve (ELN) may be at risk during thyroidectomy. Because the relationship between the ELN and superior thyroid artery (STA) can be variable, we aimed to investigate their relationship in detail. In human cadavers, 81 ELN and STA and their branches were carefully dissected. The position of the nerve was classified as medial (Group I, on 76.5% sides), lateral (Group II, on 20.9% sides), or posterior (Group III, on 2.4% sides) to the origin of the STA. In Group Ia, the nerve did not cross the artery while it did cross the artery in Group Ib. In Group II, the nerve was located lateral to the origin of the artery and crossed it. In Group III, the nerve coursed downward posterior to the artery. In conclusion, the topography of the ELN showed much more variability in its relationship to the STA than is described in the literature. Such variations should be kept in mind during surgery of the anterior neck. It is our hope that such data will decrease surgical morbidity following surgery of the anterior neck.
The external branch of the superior laryngeal nerve gives off many branches above the upper pole of the thyroid gland. Differentiating the branch innervating the cricothyroid muscle from the others may be important during surgery. Therefore, we aimed to demonstrate the branching pattern of this nerve in detail. In 34 human cadavers (59 sides), branches of the nerve were exposed and measurements related to them and neighboring structures were made. A cricothyroidal branch was present on all sides. This branch pierced the inferior pharyngeal constrictor muscle 3.9-17.6 mm above, 3.1-9.9 mm below, or at the level of the upper pole of the thyroid gland. On all sides, the nerve provided one or two thyroidal branches. The thyroidal branch was generally thinner than the cricothyroidal branch. But they were equal in size on three (5%) sides. The external laryngeal nerve provided two or three pharyngeal branches on all sides. These branches arose from the nerve 3.5-12.7 mm from the upper pole of the thyroid gland. Although the branch was generally thinner than the cricothyroidal branch, both branches were equal on four (6.7%) sides. Two cardiac branches were observed on two (3.3%) left sides. In conclusion, the cricothyroidal branch was generally thicker than the other branches. But on seven (11.8%) sides, thyroidal or pharyngeal branches and the cricothyroidal branch were equal in size. These data may be important during surgery as the surgeon may confuse the cricothyroidal branch with other branches of the external laryngeal nerve.
A variant nerve branch via the ulnar nerve can innervate the medial head of the triceps brachii at the distal third of the brachium. This variant nerve branch will be under risk of iatrogenic injury during elbow surgery and it seems to be an option for nerve grafts.
The production of androgens (mostly testosterone) during the early fetal stage is essential for the differentiation of the male brain. Some authors have suggested a relationship between androgen exposure during the prenatal period and schizophrenia. These two separate relationships suggest that digit length ratios are associated with schizophrenia in males. The study was performed in a university hospital between October 2012 and May 2013. One hundred and three male patients diagnosed with schizophrenia according to DSM-IV using SCID-I, and 100 matched healthy males, were admitted to the study. Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms (SANS) and Brief Psychiatric Rating Scale (BPRS) were used to assess schizophrenia symptoms. The second digit (2D) and fourth digit (4D) asymmetry index (AI), and the right- and left-hand 2D:4D ratios were calculated. All parametric data in the groups were compared using an independent t-test. The predictive power of the AI was estimated by receiver operating characteristics analysis. The 2D:4D AI was statistically significantly lower in the patient group than the healthy control comparison group. There were significant differences between the schizophrenia and the control groups in respect of left 2D:4D and right 2D:4D. There was no correlation between AI, left, or right 2D:4D, BPRS, or SAPS in the schizophrenia group. However, there was a negative correlation between left 2nd digit (L2D):4D and the SANS score. Our findings support the view that the 2D:4D AI can be used as a moderate indicator of schizophrenia. Even more simply, the right or left 2D:4D can be used as an indicator. L2D:4D could indicate the severity of negative symptoms.
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