Head and Neck Muscles
Eve K. Boyle, Vondel S. E. Mahon, Rui Diogo in Handbook of Muscle Variations and Anomalies in Humans, 2022
Myloglossus originates from the inner surface of the angle of the mandible and inserts into the lateral aspect of the tongue (Wood 1867b; Macalister 1875; Knott 1883a; Valenti 1926; Bergman et al. 1988; Nakajima and Nakamura 2008; Patel and Loukas 2016; Buffoli et al. 2017). Knott (1883a) attributes its name to Rolfincius but other authors (e.g., Valenti 1926; Bergman et al. 1988) credit Wood. It may present as a slip or second head of styloglossus instead of a distinct muscle (Macalister 1875; Patel and Loukas 2016). In these cases, it often joins with styloglossus before reaching the tongue (Buffoli et al. 2017). Myloglossus may be associated with a rudimentary styloglossus or replace styloglossus when it is absent (Macalister 1875; Nakajima and Nakamura 2008; Patel and Loukas 2016; Buffoli et al. 2017).
Extracranial carotid aneurysm resection
Sachinder Singh Hans, Alexander D Shepard, Mitchell R Weaver, Paul G Bove, Graham W Long in Endovascular and Open Vascular Reconstruction, 2017
The goal of surgical treatment is to remove the aneurysm and restore vessel continuity. Aneurysm resection can be challenging depending on size, inflammation, and location. In addition, the contents are vulnerable to embolization and must be removed completely. There are several operative techniques, all of which involve the standard oblique surgical incision and can extend from the sternal notch to the mastoid process. The internal jugular vein (IJV) and its branches are mobilized. Identification and protection of the vagus, hypoglossal, and glossopharyngeal nerves are necessary. Division of the posterior belly of the digastric muscle can assist in mobilization of the ICA near the skull base. The fragile branches of the IJV anterior to the ICA must be ligated for additional exposure. Other maneuvers to assist in dissection of the distal ICA include mandibular subluxation. Nasotracheal intubation is essential for this technique. Further exposure and control can be obtained by dividing the stylohyoid ligament and removing the styloid process. This higher mobilization requires dividing the styloglossus, stylopharyngeus, and stylohyoid muscles and avoiding injuring the glossopharyngeal nerve. Manipulation of the ICA at this level should be limited to prevent nerve injury.
Oral cavity
Paul Ong, Rachel Skittrall in Gastrointestinal Nursing, 2017
The tongue forms the base of the oral cavity. It is covered by oral mucosa and is divided into the root or pharyngeal portion and the body or oral portion. It is a large striated, skeletal muscle which is attached at its base to the hyoid bone. It is also tethered to the floor of the oral cavity by the centrally placed lingual frenulum. The skeletal muscle tissue which forms the bulk of the tongue is made up of two muscle groups: The intrinsic muscles have their origin and insertion within the tongue. They are responsible for changes in shape and size of the tongue and are essential to assist in manipulation of food during chewing. There are four groups of muscles: inferior longitudinal muscle, superior longitudinal muscle, transverse muscle and vertical muscle. Each group represents a different orientation of muscle fibres. Together they create up and down movements, flattening, narrowing and lengthening of the tongue. They are innervated by the hypoglossal nerve (cranial nerve XII).The extrinsic muscles arise outside of the tongue. They include four muscles: genioglossus, styloglossus, palatoglossus and hyoglossus muscles. They provide movement for retraction and protrusion of the tongue. They are also important to raise the bolus toward the pharynx in preparation for swallowing. They are innervated by the hypoglossal nerve (cranial nerve XII).
Bilateral elongated styloid process (Eagle’s syndrome) - a case report and short review
Published in Acta Oto-Laryngologica Case Reports, 2022
Arun Panwar, Vaishali Keluskar, Shivayogi Charantimath, Lokesh Kumar S, Sridhar M, Jayapriya T
At the prenatal stage, the stylohyoid complex has four segments (superior portion of the hyoid corpus, SP, lesser cornua of the hyoid, and stylohyoid ligament). These are all derivatives of Reichert's cartilage (2nd branchial arch), which can be further divided into four parts based on the consequent development of the stylohyoid complex. Tympanohyal, being the first and most proximal segment, gives origin to the tympanic (proximal) segment of the SP, as well as the stapes. The second segment is called the stylohyal segment and gives rise to the distal portion of the SP. The third segment is ceratohyal and degenerates in utero, forming the stylohyoid ligament. The fourth and most distal segment is called the hypohyal segment and forms the lesser cornua of the hyoid. The stylohyoid process arises from the temporal bone immediately medial and anterior to the stylomastoid foramen, extends anteromedially, rarely shows any anatomical variations in its course, and is encircled on both sides by the internal carotid artery (ICA) and external carotid artery (ECA). The stylopharyngeus, styloglossus, and stylohyoid along with the two ligaments being stylohyoid ligament and stylomandibular ligament originate from the SP (6,7).
Analysis of fiber strain in the human tongue during speech
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Arnold D. Gomez, Maureen L. Stone, Jonghye Woo, Fangxu Xing, Jerry L. Prince
As in the heart (also a hydrostat), any given reference configuration is not purely strain-free due to the effect of biological processes such as residual tone and stresses, which make obtaining initial stretch information intractable (Costa et al. 1997). For this reason, and based on previous studies on motion analysis in the tongue and the heart (Pan et al. 2005; Parthasarathy et al. 2007), strain was measured with respect to the initial time frame in the time sequence, when the tongue was in a relatively relaxed configuration while the mandible opened as the/ ə /sound was initiated. All the analysis in this study leveraged SLAF approximations averaged across a volume associated with particular muscles. This averaging strategy enables us to see if structures that have been grouped together via gross dissection, do indeed correspond to mechanical groups that act together over time. The genioglossus was subdivided into anterior (GGA) and posterior (GGP) parts. The other muscle representations consist of the following muscles: superior longitudinal (SL), inferior longitudinal (IL), geniohyoid (GH), hyoglossus (HG), transverse (T), vertical (V), and styloglossus (SG) (Figure 3). The mean SLAF approximations enabled a visual semiquantitative analysis of consistency, and a quantitative correlation-based assessment of whether two muscles acted together determining mechanical cooperation. As a reference, the spatially distributed SLAF evaluated at discrete locations can be seen in Figure 4.
An interactive surgical simulation tool to assess the consequences of a partial glossectomy on a biomechanical model of the tongue
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
K.D.R. Kappert, M.J.A. van Alphen, S. van Dijk, L.E. Smeele, A.J.M. Balm, F. van der Heijden
The musculature was modeled using ArtiSynth’s "muscle material" which effect is applied in addition to the regular material for an element. When excitation is applied to a muscle material, it generates an externally applied stress in the direction associated with the muscle (Lloyd et al. 2012). For the simulation of the muscle stress-strain function, we used ArtiSynth’s implementation of the method described by Blemker et al. (2005). In this method, stress and strain are influenced by muscle activation based on the direction of the particular muscle. In order to compare our model to the Buchaillard et al. (2009) model, muscle divisions and muscle directions were converted and incorporated in our model. Using the Inverse Distance Weighted (IDW) interpolation, the string-based muscles of Buchaillard et al. (2009) were converted into dense vector fields defining muscle directions and locations. The vector closest to the centroid of a particular element will determine the direction of its contraction upon activation. A typical distribution of element-muscles in an unedited model is demonstrated in Figure 2. This muscle representation also enables us to easily use other muscle configurations for future (personalized) models. Because of the long and compact trajectory of the styloglossus muscle towards the styloid process, we were unable to create a stable (automatically generated) element-based muscle for it. The styloglossus was, therefore, the only muscle simulated using string-based muscles.
Related Knowledge Centers
- External Carotid Artery
- Hyoglossus
- Hypoglossal Nerve
- Internal Carotid Artery
- Temporal Styloid Process
- Stylomandibular Ligament
- Superior Pharyngeal Constrictor Muscle
- Middle Pharyngeal Constrictor Muscle
- Inferior Longitudinal Muscle of Tongue
- Palatoglossus Muscle