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Head and Neck Anatomy Dr. Motaz Shieban 1 Muscles of tongue • each half of the tongue contain two type of muscles i.e. four intrinsic and four extrinsic extrinsic muscles : • genioglossus M. styloglossus M. Paltoglossus M. Hyloglossus M. intrinsic muscles : superior longitudinal M. inferior longitudinal M. transverse M. vertical M. Dr. Motaz Shieban 2 Dr. Motaz Shieban 3 Dr. Motaz Shieban 4 Dr. Motaz Shieban 5 Dr. Motaz Shieban 6 Dr. Motaz Shieban 7 Dr. Motaz Shieban 8 Dr. Motaz Shieban 9 Dr. Motaz Shieban 10 Soft palate Muscles The five muscles of the soft palate, play important roles in swallowing and breathing. The muscles are: • Tensor veli palatini, which is involved in swalloing. • Palatoglossus, involved in swallowing • Palatopharyngeus, involved in breathing • Levator veli palatini, involved in swallowing • Musculus uvulae, which moves the uvula These muscles are innervated by the pharyngeal plexus via the vagus nerve, with the exception of the tensor veli palatini. The tensor veli palatini is innervated by cranial nerve 5 branch V3 (which is the mandibular division of the trigeminal cranial nerve). Dr. Motaz Shieban 11 Palatoglossal Muscle If you open the mouth and look at the tonsils on the side of the throat wall, you will see that there is a vertical fold of tissue in front of and behind each tonsil. These are called the anterior and posterior faucial pillars, or the palatoglossal and palatopharyngeal folds, respectively. Beneath the palatoglossal fold is the palatoglossal muscle. It originates from the posterior end of the hard palate and the anterior end of the soft palate. The fibers run downward, laterally, and forward to insert into the posterior and lateral part of the tongue. When the palatoglossal muscle contracts, it pulls the sides of the tongue up and back, pulls the soft palate down on the lateral edges, and narrows the space between the left and right anterior faucial pillars. The nerve that supplies this muscle is a part of the eleventh (XI) cranial nerve running with branches of the tenth (X) cranial nerve • Palatopharyngeal Muscl The posterior faucial pillar is formed by the palatopharyngeal muscle. It originates from the posterolateral part of the soft palate and runs downward and laterally to insert into the pharyngeal constrictor muscle and the thyroid cartilage of the larynx. When it contracts, it narrows the posterior faucial pillar and elevates the pharynx and larynx. The nerve supply is also the 10th and 11th cranial nerves Dr. Motaz Shieban 12 View of the lateral throat wall looking from the midline. Mucosa has been removed and various muscles can be seen. Palatoglossal and palatopharyngeal muscles form anterior and posterior pillars, respectively; the palatine tonsil would lie between them View of the lateral throat wall similar to above but with mucosa in place. Anterior and posterior pillars can be seen, as can the opening of the auditory tube in the nasal pharynx; the fold caused by the salpingopharyngeal muscle runs down from it. Dr. Motaz Shieban 13 • Muscles of Uvula The uvula is the small fold of tissue that hangs down in the throat from the posterior part of the soft palate. It is formed by two small bands of muscle that originate from the posterior end of the hard palate and run back and down in the soft palate to form that structure. When the muscle of the uvula contracts, it shortens and broadens the uvula and changes the contour of the posterior end of the soft palate so that it adapts to the posterior throat wall when it is moved up against it. This muscle is also innervated by the eleventh and tenth cranial nerves Dr. Motaz Shieban 14 Pharynx The pharynx is a muscular tube that connects the nasal cavities to the larynx and oesophagus. It is common to both the alimentary and the respiratory tract. The tube begins at the base of the skull and ends inferior to the cricoid cartilage (C6). It is comprised of three parts; the nasopharynx, oropharynx and laryngopharynx (from superior to inferior). When analysed cross-sectionally, it is comprised of pharyngeal mucosa, an incomplete ring of lymphoid tissue, a longitudinal muscle layer, a circular muscle layer and buccopharyngeal fascia (from medial to lateral). Muscles There are two types of muscles that form the walls of the pharynx – longitudinal and circular. Both types are innervated by the vagus nerve, except for the stylopharyngeus, which is innervated by the glossopharyngeal nerve Circular Muscles The circular muscles contract sequentially from superior to inferior to constrict the lumen and propel the bolus of food inferiorly into the oesophagus. They are stacked like glasses and are an incomplete muscular circle, anteriorly attaching to structures in the neck. They are all innervated by the vagus nerve (CN X): Superior pharyngeal constrictor is found in the oropharynx. Middle pharyngeal constrictor is found in the laryngopharynx. Inferior pharyngeal constrictor is found in the laryngopharynx and has two components. The superior component (thyropharyngeus) has oblique fibres that attach to the thyroid cartilage and the inferior component (cricopharyngeus) has horizontal fibres that attach to the cricoid cartilage. Dr. Motaz Shieban Lateral view of the deep structures of the pharynx. Visible are the circular muscles of the pharynx, and the stylopharyngeus. 16 Longitudinal Muscles The longitudinal muscles shorten and widen the pharynx, and elevate the larynx during swallowing. • Stylopharyngeus: from the styloid process of the temporal bone to the pharynx, innervated by the glossopharyngeal nerve (CN IX) • Palatopharyngeus: from hard palate of the oral cavity to the pharynx, innervated by the vagus nerve (CN X) • Salpingopharyngeus: from the Eustachian tube to the pharynx, innervated by the vagus nerve (CN X). In addition to contributing to swallowing, it also opens the Eustachian tube to equalize the pressure in the middle ear with the atmosphere Posterior view of the pharynx. The pharynx has been split down the midline and opened, to show the longitundinal muscles Dr. Motaz Shieban 17 Divisions Divisions Lower Limit of Nasopharynx Lower border of soft palate or Junction b/w hard & soft palate Oropharynx Tip of epiglottis or Body of hyoid bone or Base of vallecula Hypopharynx Lower border of cricoid or Lower border of C6 vertebra Muscles Dr. Motaz Shieban 22 Structures Passing Between Skull Base & Superior Constrictor (Sinus of Morgagni) Eustachian tube + Levator palatini + Tensor palatini + Ascending palatine artery Between Superior & Middle Constrictors Glossopharyngeal nerve & Stylopharyngeus muscle Between Middle & Inferior Constrictors Internal Laryngeal nerve & Superior Laryngeal artery Below Inferior Constrictor Recurrent Laryngeal nerve & Inferior Laryngeal artery Innervation Blood Supply Innervation of the majority of the pharynx is achieved by the pharyngeal plexus, which comprises of: Branches of the glossopharyngeal nerve (CN IX) Branches of the vagus nerve (CN X) Sympathetic fibres of the superior cervical ganglion. Sensory: Each of the three sections of the pharynx have a different innervation: The nasopharynx is innervated by the maxillary nerve (CN V2). The oropharynx by the glossopharyngeal nerve (CN IX). The laryngopharynx by the vagus nerve (CN X). Motor: All the muscles of the pharynx are innervated by the vagus nerve (CN X), except for the stylopharyngeus, which is innervated by the glossopharyngeal nerve (CN IX). Arterial supply is via branches of the external carotid artery: ascending pharyngeal, lingual, facial and maxillary arteries. Venous drainage is achieved by the pharyngeal venous plexus, which drains into the internal jugular vein. Dr. Motaz Shieban 24 Nerve Supply Nasopharynx: pterygo-palatine ganglion (V2) Oropharynx: glossopharyngeal & vagus nv Hypopharynx: Superior & recurrent laryngeal nv All muscles by pharyngeal nerve plexus (vagus nv carrying cranial part of accessory nv) except stylopharyngeus (glossopharyngeal nv) & cricopharyngeus (also by recurrent laryngeal) Arterial Supply 1) Facial artery 2) Lingual artery 3) Ascending pharyngeal artery 4) Ascending palatine artery 5) Greater palatine artery 6) Artery of pterygoid canal 7) Superior laryngeal artery Venous Drainage Upper pharynx: • Pharyngeal venous plexus situated on middle constrictor pterygoid venous plexus & internal jugular vein Lower pharynx: • Inferior thyroid veins Lymphatic Drainage Nasopharynx: upper deep cervical + retropharyngeal + parapharyngeal + posterior triangle Oropharynx: upper deep cervical + retropharyngeal + parapharyngeal Hypopharynx: deep cervical + parapharyngeal + paratracheal + supraclavicular ANTERIOR NECK Dr. Motaz Shieban 29 ANTERIOR NECK Dr. Motaz Shieban 30 ANTERIOR NECK Dr. Motaz Shieban 31 POSTERIOR NECK Dr. Motaz Shieban 32 POSTERIOR NECK , Clinical View Dr. Motaz Shieban 33 POSTERIOR NECK , Clinical View Dr. Motaz Shieban 34 Dr. Motaz Shieban 35 What did you learn ? Dr. Motaz Shieban 36