Brainstem Organization of Swallowing and Its Interaction With Respiration
Alan D. Miller, Armand L. Bianchi, Beverly P. Bishop in Neural Control of the Respiratory Muscles, 2019
Single swallowing motor events are characterized by a typical and complete motor sequence including a complex oropharyngeal stage and a simpler esophageal stage, also called primary peristalsis14,21 (Figure 1 A). This sequence begins with the contraction of the mylohyoid muscle and, at nearly the same time, the coordinated contraction of several muscles in the mouth and upper pharynx, forming the so-called “leading complex” of swallowing identified by Doty and Bosma.15 This primary event is followed by the activity of muscles in the larynx and by those of the middle and inferior constrictors of the pharynx, and later on by the different segments of the esophagus. In parallel with the beginning of the motor sequence, both the upper and lower esophageal sphincters relax until they are reached by the wave of contraction, indicating the beginning of the primary peristalsis and the end of the whole swallowing sequence, respectively.14,21 The periesophageal region of the diaphragm also relaxes during swallowing. In the case of rhythmic swallowing, successive oropharyngeal sequences occur at a rhythm of 1 to 2 Hz with a concomitant inhibition of esophageal peristalsis. Only the last oropharyngeal sequence of the series is followed by the complete esophageal stage 21,36 (Figure 1B).
Head and Neck
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno in Understanding Human Anatomy and Pathology, 2018
The anterior digastric muscle attaches anteriorly onto the digastric fossa of the mandible and is innervated by the mylohyoid nerve (Plate 3.25a and 3.29). This muscle is attached posteriorly by the intermediate digastric tendon to the posterior digastric muscle, which is a 2nd arch muscle innervated by the facial (CN VII) nerve, so the entire muscle complex is called the “digastric,” or two-bellied muscle. The digastric muscle complex elevates the hyoid bone and depresses the mandible (opens the jaw), the posterior digastric being mainly related to the former movement, and the anterior digastric to the latter movement. This is logical, because the posterior digastric is derived from the 2nd arch, and thus originally associated with movements of the hyoid apparatus; in humans it maintains a connection with the hyoid bone via a fibrous sling that holds the intermediate digastric tendon to the body of the hyoid. The mylohyoid muscle is also innervated by the mylohyoid nerve and mainly connects the two sides of the mandible— reflecting its developmental derivation from the 1st arch—although it also attaches on to the hyoid bone. In humans the demi-mandibles are fused. Therefore, the mylohyoid has lost its main original function, which was to connect and bring together the two demi-mandibles (as illustrated by the name of the muscle complex that gave rise to this muscle in evolution—the intermandibularis muscle complex). In our species, the mylohyoid is mainly involved in depression of the mandible, raising the floor of the mouth during the first stage of swallowing, and elevation of the hyoid bone.
Cysts of the jaws, face and neck
John Dudley Langdon, Mohan Francis Patel, Robert Andrew Ord, Peter Brennan in Operative Oral and Maxillofacial Surgery, 2017
The treatment for dermoid cysts is complete surgical excision. Recurrence does not occur if the cyst and associated tract are completely excised. For submental cysts arising above the mylohyoid muscle, a transoral incision may be used. For cysts arising below the mylohyoid muscle, a transcutaneous incision is recommended to permit better surgical access. Subcutaneous dermoid cysts may have deep tracts that can be adherent to underlying periosteum and other bony structures. Meticulous surgical technique must be used during removal because of the cyst’s adherence to adjacent tissue that may lead to inadequate excision. Malignant transformation has been reported but is rare.31
Cell culture models of oral mucosal barriers: A review with a focus on applications, culture conditions and barrier properties
Published in Tissue Barriers, 2018
Lisa Bierbaumer, Uwe Yacine Schwarze, Reinhard Gruber, Winfried Neuhaus
The parotid, submandibular and sublingual glands are the three major paired salivary glands. Numerous other minor salivary glands open into the mouth and are scattered throughout the oral cavity. The parotid gland, the largest of the saliva glands, is situated in front of the external ear and is almost entirely serous. The palpable parotid duct runs superficial of the buccinator muscle and through the cheek to drain into the mouth opposite of the second permanent maxillary molar. The submandibular gland is the size of a walnut and irregular in shape but generally spheroid and is located at the posterior and lower part of the mylohyoid muscle and mostly serous. The sublingual gland is the smallest of the three major paired salivary glands; it is flat and shaped like an almond. The location is cranial of the mylohyoid muscle and beneath the mouth floor mucosa. The sublingual gland is seromucous but most cells are mucous.11
Does the mandibular lingual release approach impact post-operative swallowing in patients with oral cavity and/or oropharyngeal squamous cell carcinomas: a scoping review
Published in Speech, Language and Hearing, 2023
N. M. Hardingham, E. C. Ward, N. A. Clayton, R. A. Gallagher
The MLRA is appropriate for large or inaccessible OC/OPSCC and is referred to in the literature as the ‘mandibular lingual release approach’ (Song et al., 2013; Stanley, 1984; Stringer et al., 1992) and in conjunction with the term ‘visor flap’ (Cilento, Izzard, Weymuller, & Futran, 2007). Where clinically indicated, the technique is preceded by a unilateral or bilateral neck dissection. This is then followed by an incision from the mastoid to mastoid, with an apron flap raised to the level of the mandible. The mandibular periosteum is then incised at the lower border. The alveolar mucosa is also incised around the lingual surface at the teeth from angle to angle, if teeth are absent, the incision is continued along the apex of the alveolus. The anterior belly of digastric is detached from the mentum. The geniohyoid and genioglossus muscles are detached from the genial tubercle. The periosteum is then elevated to the insertion of the mylohyoid muscle. This then allows delivery of the tongue and floor of mouth (FOM) into the neck. Following appropriate resection, closure of site can be done locally or via a free flap.
Design and application of submental island flap to reconstruct non-circumferential defect after hypopharyngeal carcinoma resection: a prospective study of 27 cases
Published in Acta Oto-Laryngologica, 2020
Wenting Pang, Aobo Zhang, Cheng Lu, Jun Tian, Wan-xin Li, Zhenxiao Wang, Yanbo Dong, Shuoqing Yuan, Zihao Niu, Yiyuan Zhu, M. Shahed Quraishi, Liangfa Liu
Total or partial laryngopharyngectomy was performed according to the extent of tumor invasion. After completion of tumor ablation and neck dissection, flap was harvested from the contralateral side in a subplatysmal fashion. In the midline, surgical incision extended down to the mylohyoid muscle in order to allow dissection of the anterior belly of the digastric muscle and mylohyoid muscle from the mandible and the hyoid bone [17]. The submandibular gland was then identified and dissected superiorly and posteriorly with the gland left in position. The marginal mandibular branch of the facial nerve was also identified and protected. During cervical lymphadenectomy we ensured that the facial vessels and the internal jugular vein were protected and preserved. The harvested flap was then transposed downward to close the hypopharyngeal defects with continuous mattress sutures using 3–0 Vicryl and 3–0 silk thread was interrupted sutured subcutaneously and submucosally for strengthening (Figure 1).
Related Knowledge Centers
- Digastric Muscle
- Hyoid Bone
- Mandible
- Mouth
- Muscle
- Pharyngeal Arch
- Tongue
- Molar
- Submental Triangle
- Swallowing