Morphometric and Immunohistochemical Characteristics of the Adult Human Soft Palate Muscles.

The soft palate is the only structure that reversibly separates the respiratory and gastrointestinal systems. Most species can eat and breathe at the same time. Humans cannot do this and malfunction of the soft palate may allow food to enter the lungs and cause fatal aspiration pneumonia. Speech is the most defining characteristic of humans and the soft palate, along with the larynx and tongue, plays the key roles. In addition, palatal muscles are involved in snoring and obstructive sleep apnea. Considering the significance of the soft palate, its function is insufficiently understood. The objectives of this study were to document morphometric and immunohistochemical characteristics of adult human soft palate muscles, including fiber size, the fiber type, and myosin heavy chain (MyHC) composition for better understanding muscle functions. In this study, 15 soft palates were obtained from human autopsies. The palatal muscles were separated, cryosectioned, and stained using histological and immunohistochemical techniques. The results showed that there was a fast type II predominance in the musculus uvulae and palatopharyngeus and a slow type I predominance in the levator veli palatine. Approximately equal proportions of type I and type II fibers existed in both the palatoglossus and tensor veli palatine. Soft palate muscles also contained hybrid fibers and some specialized myofibers expressing slow-tonic and embryonic MyHC isoforms. These findings would help better understand muscle functions.

Innervation of human soft palate muscles.

Our objective was to determine the branching and distribution of the motor nerves supplying the human soft palate muscles. Six adult specimens of the soft palate in continuity with the pharynx, larynx, and tongue were processed with Sihler's stain, a technique that can render large specimens transparent while counterstaining their nerves. The cranial nerves were identified and dissection followed their branches as they divided into smaller divisions toward their terminations in individual muscles. The results showed that both the glossopharyngeal (IX) and vagus (X) nerves have three distinct branches, superior, middle, and inferior. Only the middle branches of each nerve contributed to the pharyngeal plexus to which the facial nerve also contributed. The pharyngeal plexus was divided into two parts, a superior innervating the palatal and neighboring muscles and an inferior innervating pharyngeal constrictors. The superior branches of the IX and X nerves contributed innervation to the palatoglossus, whereas their middle branches innervated the palatopharyngeus. The palatoglossus and palatopharyngeus muscles appeared to be composed of at least two neuromuscular compartments. The lesser palatine nerve not only supplied the palatal mucosa and palatine glandular tissue but also innervated the musculus uvulae, palatopharyngeus, and levator veli palatine. The latter muscle also received its innervation from the superior branch of X nerve. The findings would be useful for better understanding the neural control of the soft palate and for developing novel neuromodulation therapies to treat certain upper airway disorders such as obstructive sleep apnea.

A Retrospective, Descriptive Analysis of Hospital-acquired Deep Tissue Injuries.

Preventing, identifying, and treating deep tissue injury (DTI) remains a challenge. PURPOSE: The purpose of the current research was to describe the characteristics of DTIs and patient/care variables that may affect their development and outcomes at the time of hospital discharge. METHODS: A retrospective, descriptive, single-site cohort study of electronic medical records was conducted between October 1, 2010, and September 30, 2012, to identify common demographic, intrinsic (eg, mobility status, medical comorbidities, and incontinence), extrinsic (ie, surgical and procedural events, medical devices, head-of-bed elevation), and care and treatment factors related to outcomes of hospital-acquired DTIs; additional data points related to DTI development or descriptive of the sample (Braden Scale scores and subscale scores, hospital length of stay [LOS], intensive care unit [ICU] LOS, days from admission to DTI, time in the operating room, serum albumin levels, support surfaces/specialty beds, and DTI locations) also were retrieved. DTI healing outcomes, grouped by resolved, partial-thickness/stable, and full-thickness/unstageable, and 30 main patient/treatment variables were analyzed using Kruskal-Wallis, chi-squared, and Fischer exact tests. RESULTS: One hundred, seventy-nine (179) DTIs occurred in 141 adult patients (132 in men, 47 in women; mean patient age 64 [range 19-94]). Of those patients, 110 had a history of peripheral vascular disease and 122 had hypertension. Sixty-nine (69) DTIs were documented in patients who died within 1 year of occurrence. Most common DTI sites were the coccyx (47 [26%]) and heel (42 [23%]); 41 (22%) were device-related. Median hospital LOS was 23 (range 4-258) days and median ICU LOS was 12 (range 1-173) days; 40 DTIs were identified before surgery and 120 after a diagnostic or therapeutic procedure. Data for DTI outcome groups at hospital discharge included 28 resolved, 131 partial-thickness/stable, and 20 full-thickness/unstageable; factors significantly different between outcome groups included mechanical ventilation (15/42/12; P = .01), use of a feeding tube (15/46/12; P = .02), anemia (14/30/9; P = .005), history of cerebrovascular accident (12/27/7; P = .03), hospital LOS (67/18/37.5; P <.001), ICU LOS (23/10/12; P = .03), time-to-event (13.5/8/9; P = .001), vasopressor use after DTI (13/31/11; P = .003), low-air-loss surface (10/9/3; P = .005), and device-related (14/24/4; P = .002). CONCLUSION: DTI risk factors mirrored those of other PUs, but progression to full-thickness injury was not inevitable. Early and frequent assessment and timely intervention may help prevent DTI progression.

Sensory Innervation of the Human Soft Palate.

The human soft palate plays an important role in respiration, swallowing, and speech. These motor activities depend on reflexes mediated by sensory nerve endings. To date, the details of human sensory innervation to the soft palate have not been demonstrated. In this study, eight adult human whole-mount (soft palate-tongue-pharynx-larynx-upper esophagus) specimens were obtained from autopsy. Each specimen was bisected in the midline, forming two equal and symmetrical halves. Eight hemi-specimens were processed with Sihler's stain, a whole-mount nerve staining technique. The remaining eight hemi-soft palates were used for immunohistochemical study. The soft palatal mucosa was dissected from the oral and nasal sides and prepared for neurofilament staining. Our results showed that the sensory nerve fibers formed a dense nerve plexus in the lamina propria of the soft palatal mucosa. There was a significant difference in the innervation density between both sides. Specifically, the oral side had higher density of sensory nerve fibers than the nasal side of the soft palate. The mean number and percent area of the sensory nerve fibers in the mucosa of the nasal side was 78% and 72% of those in the mucosa of the oral side, respectively (P < 0.0001). The data presented here could be helpful for further investigating the morphological and quantitative alterations in the sensory nerves in certain upper airway disorders involving the soft palate such as obstructive sleep apnea (OSA) and for designing effective therapeutic strategies to treat OSA. Anat Rec, 301:1861-1870, 2018. © 2018 Wiley Periodicals, Inc.