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The human tongue has a critical role in speech, swallowing, and respiration, however, its motor control is poorly understood. Fundamental gaps include detailed information on the course of the hypoglossal (XII) nerve within the tongue, the branches of the XII nerve within each tongue muscle, and the type and arrangement of motor endplates (MEP) within each muscle. In this study, five adult human tongues were processed with Sihler’s stain, a whole-mount nerve staining technique, to map out the entire intra-lingual course of the XII nerve and its branches. An additional five specimens were microdissected into individual muscles and stained with acetylcholinesterase and silver staining to study their MEP morphology and banding patterns. Using these techniques the course of the entire XII nerve was mapped from the main nerve to the smallest intramuscular branches. It was found that the human tongue innervation is extremely dense and complex. Although the basic mammalian pattern of XII is conserved in humans, there are notable differences. In addition, many muscle fibers contained multiple en grappe MEP, suggesting that they are some variant of the highly specialized slow tonic muscle fiber type. The transverse muscle group that comprises the core of the tongue appears to have the most complex innervation and has the highest percentage of en grappe MEP. In summary, the innervation of the human tongue has specializations not reported in other mammalian tongues, including non-human primates. These specializations appear to allow for fine motor control of tongue shape.

The human tongue is one of the most important yet least understood structures of the body. One reason for the relative lack of research on the human tongue is its complex anatomy. This is a real barrier to investigators as there are few anatomical resources in the literature that show this complex anatomy clearly. As a result, the diagnosis and treatment of tongue disorders lags behind that for other structures of the head and neck. This report intended to fill this gap by displaying the tongue’s anatomy in multiple ways. The primary material used in this study was serial axial images of the male and female human tongue from the Visible Human (VH) Project of the National Library of Medicine. In addition, thick serial coronal sections of three human tongues were rendered translucent. The VH axial images were computer reconstructed into serial coronal sections and each tongue muscle was outlined. These outlines were used to construct a 3-dimensional computer model of the tongue that allows each muscle to be seen in its in vivo anatomical position. The thick coronal sections supplement the 3-D model by showing details of the complex interweaving of tongue muscles throughout the tongue. The graphics are perhaps the clearest guide to date to aid clinical or basic science investigators in identifying each tongue muscle in any part of the human tongue.

A retrospective review of 400 Chinese children who had inhaled foreign bodies was undertaken. There has been a yearly increase in the total number of cases of airway foreign bodies removed in our hospital. Fifty-eight percent of the children presenting were from the countryside; 42% were townspeople. Approximately 90% of the patients were under 3 years of age, with the peak incidence of foreign body inhalation occurring between 1 and 2 years of age (57.8%). The male-female ratio was about 1.2:1. About 95% of the removed foreign bodies were organic in origin. The majority of the foreign bodies were found most often in the right bronchial tree (46%). A positive history of foreign body inhalation was obtained in 98% of the cases. Twenty-eight percent of the children presented at the hospital within 24 hours, 71% within 1 week, and 29% more than 1 week after inhaling the foreign body. The most common presenting symptoms of laryngotracheal foreign bodies were cough, wheezing, dyspnea, and hoarseness; those of bronchial foreign bodies were cough, wheezing, decreased air entry, and rhonchi. More than two-thirds of the children with larygotracheal foreign bodies had normal x-ray findings. The most common fluoroscopic findings in those children with bronchial foreign bodies were mediastinal shift (36.8%), obstructive emphysema (35.7%), and normal findings (35%). A total of 348 (87%) bronchial foreign bodies were removed by rigid bronchoscopy (81%), rod-lens bronchoscopy (5%), and spontaneous expulsion (1%); 52 (13%) laryngeal and tracheal foreign bodies were removed by direct laryngoscopy (12%) and tracheotomy (1%). A single endoscopic procedure successfully removed 92.5% of 400 foreign bodies detected in the airways. One child died during bronchoscopy, for a mortality rate of 0.25%.

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