Nerve fiber analysis of the lingual branch of the glossopharyngeal nerve in human adult subjects.

PURPOSE: Fibers of the glossopharyngeal part of the superior constrictor muscle are connected with fibers of the transverse lingual muscle, forming a ring of muscle at the base of the tongue. This group of muscles constrict the midpharyngeal cavity during retrusive movement of the tongue. The purpose of this study is to identify the contribution of the lingual branch of the glossopharyngeal nerve to the neuro-motor control of three muscles: the glossopharyngeal part of the superior pharyngeal constrictor muscle, the palatopharyngeal and the palatoglossus muscles. METHODS: Six en bloc samples (9 sides), including the tissue from the skull base to the hyoid bone were obtained from adult human cadavers. Nerve fiber of the lingual branch of the glossopharyngeal nerve (main root of the glossopharyngeal nerve) was examined by the use of a binocular stereomicroscope. RESULTS: We observed that, after branching to the stylopharyngeal muscle, the lingual branch of the glossopharyngeal nerve branched to the glossopharyngeal part of the superior pharyngeal constrictor muscle, the palatopharyngeal and the palatoglossus muscles before inserting into the space between the muscle layers of the superior and middle pharyngeal constrictors. CONCLUSION: These neuromuscular arrangements may suggest the presence of specialized constrictive movements of the midpharygeal cavity at the level of the base of the tongue with the retrusive movement of the tongue. The simultaneous contraction of the palatopharyngeal and palatoglossus muscles on the pharyngeal stage of deglutition may aid in the passage of bolus from the oral cavity to the midpharyngeal cavity by increasing pharyngeal pressure.

Anteriorly pedicled wide temporalis muscle flap with the minimum zygomatic osteotomy technique for post-discectomy temporomandibular joint arthroplasty.

An anteriorly pedicled temporalis muscle flap has been shown to be a suitable interpositional material for the treatment of ankylosis and post-discectomy arthroplasty. The passage of the wide flap beneath the zygomatic arch into the joint space can be difficult owing to its bulk, causing excessive trauma to the vascularized pedicle. We describe the use of minimum zygomatic osteotomy without fixation for the passage of an anteriorly pedicled wide temporalis muscle flap for post-discectomy arthroplasty.

Surgical improvement of speech disorder caused by amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive debilitating neurological disease. ALS disturbs the quality of life by affecting speech, swallowing and free mobility of the arms without affecting intellectual function. It is therefore of significance to improve intelligibility and quality of speech sounds, especially for ALS patients with slowly progressive courses. Currently, however, there is no effective or established approach to improve speech disorder caused by ALS. We investigated a surgical procedure to improve speech disorder for some patients with neuromuscular diseases with velopharyngeal closure incompetence. In this study, we performed the surgical procedure for two patients suffering from severe speech disorder caused by slowly progressing ALS. The patients suffered from speech disorder with hypernasality and imprecise and weak articulation during a 6-year course (patient 1) and a 3-year course (patient 2) of slowly progressing ALS. We narrowed bilateral lateral palatopharyngeal wall at velopharyngeal port, and performed this surgery under general anesthesia without muscle relaxant for the two patients. Postoperatively, intelligibility and quality of their speech sounds were greatly improved within one month without any speech therapy. The patients were also able to generate longer speech phrases after the surgery. Importantly, there was no serious complication during or after the surgery. In summary, we performed bilateral narrowing of lateral palatopharyngeal wall as a speech surgery for two patients suffering from severe speech disorder associated with ALS. With this technique, improved intelligibility and quality of speech can be maintained for longer duration for the patients with slowly progressing ALS.

Fiber arrangements of the vertical lingual muscle in human adult subjects

This study identified the anatomy of the vertical lingual muscle and functional relationships between the vertical lingual and the other lingual muscles in the human tongue. Three whole tongues were obtained from adult human cadavers and were used for histological study by the serial section method. At the tip of the tongue, the fibers of the vertical lingual muscle cross with the transverse lingual muscle, and extend inferiorly to the fibers of the inferior longitudinal lingual muscle. At the body of the tongue, the fibers of the vertical lingual muscle are located between the fibers of the superior longitudinal lingual and inferior longitudinal lingual muscle, crossing the fibers of the transverse lingual muscle, instead of crossing the fibers of the extrinsic lingual muscles. At the base of the tongue, the fibers of the vertical lingual muscle start by the fibers of the superior longitudinal lingual muscle, and connect with the fibers of the posterior muscle bundle of the styloglossus muscle. The average diameters of the vertical lingual muscle fibers increased gradually as they approached the base of the tongue. These findings suggest that posterosuperior movement of the tongue body may be accomplished with downward movement of the tip of the tongue by contractions of both the vertical lingual and the styloglossus muscle. The inferior longitudinal lingual muscle may also play a supporting role for the vertical lingual muscle at the tip of the tongue (AU)

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Nerve fiber analysis for the lingual nerve of the human adult subjects.

The neuro-motor control of the human tongue musculature had not been investigated in detail. This study identified first that the lingual nerve should play the neuro-motor control of some lingual muscles. Six en bloc samples (12 sides), including the tissues from the skull base to the hyoid bone, and three whole tongues were obtained from adult human cadavers. The former samples were used for the study of nerve fiber analysis of the lingual nerve with the aid of binocular stereomicroscope, and the latter samples were used for histological study by serial section method. On nerve fiber analysis of the lingual nerve from the trigeminal ganglion to the tongue musculature, we found that the motor- root of the trigeminal nerve gave off its supply to the lingual nerve and traveled into the lingual nerve, and branched to the superior and the inferior longitudinal muscles. On histological study, it was revealed that in the anterior part of the tongue the superior and the inferior longitudinal muscles surrounded the other lingual musculature and combined with the sub-mucosal connective tissues closely like the cutaneous muscle, for example, the facial muscles. The lingual nerve entered the inner side of the space between the genioglossus and the inferior longitudinal muscles with the lingual artery. These findings suggested that the superior and the inferior longitudinal muscles should be innervated by the motor fibers traveled into the lingual nerve from the motor root of the trigeminal nerve, and do not originate from the myotome originating in occipital somites but branchial muscles.

M-mode color Doppler ultrasonic imaging of vertical tongue movement during articulatory movement.

To observe and estimate the movement of the tongue, ultrasonic investigation is the most harmless real-time monitoring procedure for analyzing articulatory movements. Color Doppler ultrasonic imaging is special in that it can only sample a moving target, and it can indicate the velocity and direction of the target by color and brightness in real time. This study assessed and demonstrated the validity of M-mode color Doppler ultrasonic imaging to observe the movements of the tongue during syllable repetition tasks performed by normal subjects and dysarthric patients, those affected by amyotrophic lateral sclerosis, cerebellar ataxia, Parkinsonism, and polymyopathy. When the transducer was set below the jaw, upward movement was indicated by a blue signal and downward movement was indicated by a red one on the screen of the ultrasound machine. We also measured the velocity of the tongue by contrast scale classified by 15 degrees. Thus, we could observe vertical tongue movement by a color-coded pattern after quantitative analysis. The Doppler signal patterns of normal subjects were verified by simultaneous video x-ray fluorography recordings. The findings for dysarthric patients corresponded well with previously reported features analyzed by other methods. Therefore, color Doppler ultrasonic imaging of the tongue is a useful procedure to researchers for clinical speech and voice studies.

Morphological studies for retrusive movement of the human adult tongue.

This study identified the anatomical and close functional relationship between the transverse lingual and superior pharyngeal constrictor muscle. Two en bloc samples (including the tongue and mid-pharyngeal wall) and four whole tongues were obtained from adult human cadavers. We found that fibers of the superior pharyngeal constrictor muscle connected with fibers of the transverse lingual muscle, forming a ring of muscle at the base of the tongue. The average diameters of the transverse muscle fibers increased in size gradually as they approached the base of the tongue. Distribution of the muscle spindles in the transverse lingual muscle and the genioglossus muscle also increased as they reached posteriorly near the base of the tongue. These findings suggest that a ring of muscle formed by the postero-inferior portion of the transverse lingual muscle and the superior pharyngeal constrictor may be largely responsible for the retrusive movement of the tongue and the constrictive movement of the pharyngeal cavity as an antagonist of the genioglossus muscle.