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Зміст2. Duration of studies
4. Basic knowledges, abilities, skills, that necessary for the study themes (interdisciplinary integration)
5. Advices to the student.
Muscles of the pharynx
Interior of the pharynx
Laryngeal Part of the Pharynx
Membranes and ligaments of the larynx
Inlet of the larynx
Muscles of the larynx
Voice Production in the Larynx
Movements of the Vocal Folds With Respiration
Nerve supply of the larynx
Blood supply and lymph drainage of the larynx
The Thyroid Gland
The Capsule of the Thyroid Gland
Arterial Supply of the Thyroid and Parathyroid Glands
Ministry of Health of Ukraine
Bukovinian State Medical University
on methodical meeting of the Department of Anatomy, Topographical anatomy and Operative Surgery
“………”…………………….2008 р. (Protocol №……….)
The chief of department
for the 3d-year foreign students of English-spoken groups of the Medical Faculty
(speciality “General medicine”)
for independent work during the preparation to practical studies
the Theme of studies
“Topographical anatomy and operative surgery
of the organs of the neck”
Topographical Anatomy and Operative Surgery
of the Head, Neck, Thorax and Abdomen
Topographical Anatomy and Operative Surgery of the Head and Neck
Chernivtsi – 2008
1. Actuality of theme:
The topographical anatomy and operative surgery of the neck are very importance, because without the knowledge about peculiarities and variants of structure, form, location and mutual location of their anatomical structures, their age-specific it is impossible to diagnose in a proper time and correctly and to prescribe a necessary treatment to the patient. Surgeons usually pay much attention to the topographo-anatomic basis of surgical operations on the neck.
^ 2 working hours.
3. Objectives (concrete purposes):
To know the definition of regions of the neck.
To know classification of surgical operations on the neck.
To know the topographical anatomy of the organs of the neck.
5.1. Table of contents of the theme:
The pharynx is situated behind the nasal cavities, the mouth, and the larynx. It is somewhat funnel shaped, with its upper, wide end lying under the skull and its lower, narrow end becoming continuous with the esophagus opposite the sixth cervical vertebra. The pharynx has a musculomembranous wall that is deficient anteriorly. Here, it is replaced by the posterior nasal apertures, the oropharyngeal isthmus (opening into the mouth), and the inlet of the larynx. The wall of the pharynx has three layers: mucous, fibrous, and muscular.
The muscles of the pharynx consist of the superior, middle, and inferior constrictor muscles, whose fibers run in a more or less circular direction, and the stylopharyngeus and salpingopharyngeus muscles, whose fibers run in a more or less longitudinal direction. The successive contraction of the constrictor muscles propels the bolus of food down into the esophagus. The lowest fibers of the inferior constrictor muscle, sometimes referred to as the cricopharyngeus muscle, are believed to exert a sphincteric effect on the lower end of the pharynx, preventing the entry of air into the esophagus between the acts of swallowing.
The longitudinal muscles elevate the pharynx and larynx during swallowing.
The pharynx is divided into three parts: nasal, oral, and laryngeal.
Nasal Part of the Pharynx
The nasal part of the pharynx lies behind the nasal cavities, above the soft palate. When the soft palate is raised and the posterior wall of the pharynx is drawn forward, as in swallowing, the nasal part of the pharynx is shut off from the oral part of the pharynx. It has a roof, a floor, an anterior wall, a posterior wall, and lateral walls.
The roof is supported by the body of the sphenoid and the basilar part of the occipital bone. A collection of lymphoid tissue, called the pharyngeal tonsil, is present in the submucosa of this region.
The floor is formed by the sloping upper surface of the soft palate. The pharyngeal isthmus is the opening in the floor between the free edges of the soft palate and the posterior pharyngeal wall. During swallowing, this communication between the nasal and oral parts of the pharynx is closed by the elevation of the soft palate and the pulling forward of the posterior wall of the pharynx.
The anterior wall is formed by the posterior nasal apertures, separated by the posterior edge of the nasal septum.
The posterior wall forms a continuous sloping surface with the roof. It is supported by the anterior arch of the atlas vertebra.
The lateral wall, on each side, has the pharyngeal opening of the auditory tube. The posterior margin of the tube forms an elevation called the tubal elevation.
The salpingopharyngeus muscle, which is attached to the lower margin of the tube, produces a vertical fold of mucous membrane called the salpingopharyngeal fold. The pharyngeal recess is a small depression in the lateral wall behind the tubal elevation. A collection of lymphoid tissue in the submucosa behind the opening of the auditory tube is called the tubal tonsil.
Oral Part of the Pharynx
The oral part of the pharynx lies behind the mouth cavity and extends from the soft palate to the upper border of the epiglottis. It has a roof, a floor, an anterior wall, a posterior wall, and lateral walls.
The roof is formed by the undersurface of the soft palate and the pharyngeal isthmus. Small collections of lymphoid tissue are present in the submucosa on the undersurface of the soft palate.
The floor is formed by the posterior one-third of the tongue (which is almost vertical) and the interval between the tongue and the anterior surface of the epiglottis. The mucous membrane covering the posterior third of the tongue is irregular in appearance because of the presence of the underlying lymphoid tissue, the lingual tonsil.
The mucous membrane is reflected from the tongue onto the epiglottis. In the midline is an elevation, called the median glossoepiglottic fold, and two lateral glossoepiglottic folds. The depression on each side of the median glossoepiglottic fold is called the vallecula.
The anterior wall opens into the mouth through the oropharyngeal isthmus. Below this opening is the pharyngeal part of the tongue.
The posterior wall is supported by the body of the second cervical vertebra and the upper part of the body of the third cervical vertebra.
The lateral walls on each side have the palatoglossal and the palatopharyngeal arches or folds and the palatine tonsils between them.
The palatoglossal arch is a fold of mucous membrane covering the underlying palatoglossus muscle.
The interval between the two palatoglossal arches marks the boundary between the mouth and the oral pharynx and is called the oropharyngeal isthmus.
The palatopharyngeal arch is a fold of mucous membrane on the lateral wall of the oral part of the pharynx behind the palatoglossal arch. It covers the underlying palatopharyngeus muscle.
The tonsillar sinus is a triangular recess on the lateral wall of the oral pharynx between the palatoglossal arch in front and the palatopharyngeal arch behind. It is occupied by the palatine tonsil.
The palatine tonsils are two masses of lymphoid tissue located in the lateral walls of the oral part of the pharynx in the tonsillar sinuses. Each tonsil is covered by mucous membrane, and its free medial surface projects into the cavity of the pharynx. The surface is pitted by numerous small openings, which lead into the tonsillar crypts. The tonsil is covered on its lateral surface by a layer of fibrous tissue called the capsule.
The tonsil reaches its maximum size during early childhood, but after puberty it diminishes considerably in size.
Relations of the Palatine Tonsil
- Anteriorly: The palatoglossal arch.
- Posteriorly: The palatopharyngeal arch.
- Superiorly: The soft palate. Here, the tonsil becomes
continuous with the lymphoid tissue on the undersurface of the soft palate.
- Inferiorly: The posterior third of the tongue. Here, the palatine tonsil becomes continuous with the lingual tonsil.
- Medially: The cavity of the oral part of the pharynx.
- Laterally: The capsule is separated from the superior constrictor muscle by loose areolar tissue.
The external palatine vein descends from the soft palate in this loose connective tissue to join the pharyngeal venous plexus. Lateral to the superior constrictor muscle lies the loop of the facial artery. The internal carotid artery lies 2.5 cm behind and lateral to the tonsil.
Blood Supply The arterial supply to the tonsil is the tonsillar artery, a branch of the facial artery.
The veins pierce the superior constrictor muscle and join the external palatine, the pharyngeal, or the facial veins.
Lymph Drainage The lymph vessels join the upper deep cervical lymph nodes. The most important node of this group is the jugulodigastric node, which lies below and behind the angle of the mandible.
The laryngeal part of the pharynx lies behind the opening into the larynx and the posterior surface of the larynx. It extends between the upper border of the epiglottis and the lower border of the cricoid cartilage. It has an anterior wall, a posterior wall, and lateral walls.
The anterior wall is formed by the inlet of the larynx and by the mucous membrane covering the posterior surface of the larynx.
The posterior wall is supported by the bodies of the third, fourth, fifth, and sixth cervical vertebrae.
The lateral wall is supported by the thyroid cartilage and the thyrohyoid membrane. A small but important groove in the mucous membrane, called the piriform fossa, is situated on each side of the laryngeal inlet. It leads obliquely downward and backward from the region of the back of the tongue to the esophagus. The piriform fossa is bounded medially by the aryepiglottic fold and laterally by the lamina of the thyroid cartilage and the thyrohyoid membrane.
Nerve supply of the pharynx
The nerve supply of the pharynx is from the pharyngeal plexus; the latter is formed from branches of the glossopharyngeal, vagus, and sympathetic nerves.
The motor nerve supply is derived from the cranial part of the accessory nerve, which, via the branch of the vagus to the pharyngeal plexus, supplies all the muscles of the pharynx except the stylopharyngeus, which is supplied by the glossopharyngeal nerve.
The sensory nerve supply of the mucous membrane of the nasal part of the pharynx is mainly from the maxillary nerve. The mucous membrane of the oral pharynx is mainly supplied by the glossopharyngeal nerve. The mucous membrane around the entrance into the larynx is supplied by the internal laryngeal branch of the vagus nerve.
Blood supply of the pharynx
The arterial supply of the pharynx is derived from branches of the ascending pharyngeal, the ascending palatine, the facial, the maxillary, and the lingual arteries.
The veins drain into the pharyngeal venous plexus, which in turn drains into the internal jugular vein.
Lymph drainage of the pharynx
The lymph vessels from the pharynx drain either directly into the deep cervical lymph nodes or indirectly via the retropharyngeal or paratracheal nodes.
Although we swallow without thinking, deglutition is a complex process whereby food is transferred from the mouth through the pharynx and esophagus into the stomach. The term bolus (L. bolos, lump or choice morsel) is used to describe the mass of food or quantity of liquid that is swallowed at one time. Solid food is masticated (chewed) and mixed with saliva to form a soft bolus during chewing. Deglutition is described in three stages: in the (1) mouth, (2) pharynx, and (3) esophagus.
The first stage of swallowing is voluntary, during which the bolus is pushed from the mouth into the oropharynx, mainly by movements of the tongue. The tongue is raised and pressed against the hard palate by the intrinsic muscles of the tongue.
The second stage of swallowing is involuntary and is usually rapid. It involves contraction of the walls of the pharynx. Breathing and chewing stop, and successive contractions of the three constrictor muscles move the food through the oral and laryngeal parts of the pharynx. The bolus of food is prevented from entering the nasopharynx by elevation of the soft palate. The tensor veli palatini and levator veli palatini muscles tense and elevate the soft palate against the posterior wall of the pharynx. These actions close the pharyngeal isthmus, thereby preventing food from entering the nasopharynx. Should a person happen to laugh during this stage, the muscles of the soft palate relax and may allow some food to enter the nasopharynx. In these cases the food, especially if it is liquid, is expelled through the nose.
As the bolus of food passes through the oropharynx, the walls of the pharynx are raised. The contraction of the pharyngeal muscles elevate the pharynx and larynx. Watch someone swallow, particularly a thin man, and observe that the laryngeal prominence rises. The palatopharyngeus and stylopharyngeus muscles elevate the larynx and pharynx in swallowing. Palpate your hyoid bone with your thumb and second digit as you swallow and verify that it also rises. The hyoid bone is raised and fixed during swallowing by contraction of the geniohyoid, mylohyoid, digastric, and stylohyoid muscles. Verify that elevation and anterior movement of the hyoid bone precedes elevation of the larynx.
During deglutition the vestibule of the larynx is closed, the epiglottis is bent posteriorly over the inlet of the larynx, and the aryepiglottic folds are approximated. These folds provide lateral food channels that guide the bolus of food from the sides of the epiglottis.
The food now passes over the oral surface of the epiglottis and the closed inlet of the larynx. All these actions are designed to prevent food from entering the larynx.
The third stage of swallowing squeezes the bolus from the laryngopharynx into the esophagus. This is produced by the inferior constrictor muscle of the pharynx.
Injury to the recurrent laryngeal nerves (e.g., during a thyroidectomy) results in paralysis of the muscles in the aryepiglottic folds. As a result, the inlet of the larynx does not close completely during swallowing and food may enter the larynx. Choking on food is a common cause of laryngeal obstruction, particularly in persons who have consumed excessive amounts of alcohol, or who have bulbar palsy (degeneration of motor neurons in the brain stem nuclei of CN IX and CN X that supply the muscles of deglutition).
Difficulty in swallowing is called dysphagia.
Young children swallow a variety of objects, most of which reach the stomach and pass through the gastrointestinal tract without difficulty, In some cases the foreign body stops at the inferior end of the laryngopharynx, its narrowest part , or in the esophagus just inferior to the cricopharyngeus muscle, part of the inferior constrictor. Foreign bodies in the pharynx are removed under direct vision through an pharyngoscope (an instrument for examining the interior of the pharynx). Radiographic examinations and magnetic resonance images (MRI) will also reveal the presence of a foreign body in the pharynx (e.g., a pin in the piriform recess).
The larynx (between the pharynx and trachea) is a specialized organ that provides a protective sphincter at the inlet of the air passages and is responsible for voice production. Above it opens into the laryngeal part of the pharynx and below it is continuous with the trachea.
The larynx is located in the anterior portion of the neck. In adult males it is about 5 cm in length and is related posteriorly to the bodies of C3 to C6 vertebrae. The larynx is shorter in women and children and is situated slightly more superiorly in the neck. This sex difference in the larynx normally develops at puberty in males, at which time all its cartilages enlarge.
The framework of the larynx is made up of cartilages, which are connected by membranes and ligaments and moved by muscles. It is lined by mucous membrane.
The thyroid cartilage consists of two laminae of hyaline cartilage meeting in the midline in the prominent V angle of the Adam's apple. The posterior border of each lamina is drawn upward into a superior cornu and downward into an inferior cornu. On the outer surface of each lamina is an oblique line for the attachment of the sternothyroid, the thyrohyoid, and the inferior constrictor muscles.
The cricoid cartilage is formed from a complete ring of hyaline cartilage . It is shaped like a signet ring and lies below the thyroid cartilage. It has a narrow anterior arch and a broad posterior lamina. On each side of the lateral surface is a circular facet for articulation with the inferior cornu of the thyroid cartilage. On each side of the upper border is an articular facet for articulation with the base of the arytenoid cartilage. All these joints are synovial joints.
The arytenoid cartilages are small, two in number, and pyramidal . They are situated at the back of the larynx, on the upper border of the lamina of the cricoid cartilage. Each cartilage has an apex above and a base below. The apex supports the corniculate cartilage. The base articulates with the cricoid cartilage. Two processes project from the base. The vocal process projects horizontally forward and gives attachment to the vocal ligament. The muscular process projects laterally and gives attachment to the posterior and lateral cricoarytenoid muscles.
The corniculate cartilages are two small nodules that articulate with the apices of the arytenoid cartilages and give attachment to the aryepiglottic folds. (See below.)
The cuneiform cartilages are two small, rod-shaped pieces of cartilage placed so that one is in each aryepiglottic fold. They serve as supports for the folds .
The epiglottis is a leaf-shaped elastic cartilage situated behind the root of the tongue . It is connected in front to the body of the hyoid bone, and by its stalk to the back of the thyroid cartilage. The sides of the epiglottis are connected to the arytenoid cartilages by the aryepiglottic folds. The upper edge of the epiglottis is free, and the covering of mucous membrane is reflected forward onto the posterior surface of the tongue. Here, a median glossoepiglottic fold and lateral pharyngoepiglottic folds are present. The valleculae are depressions of mucous membrane present on either side of the glossoepiglottic fold.
The thyrohyoid membrane connects the upper margin of the thyroid cartilage below to the posterior surface of the body and greater cornu of the hyoid bone above. In the midline the membrane is thickened to form the median thyrohyoid ligament; the posterior borders are thickened to form the lateral thyrohyoid ligaments. On each side the membrane is pierced by the superior laryngeal vessels and the internal laryngeal nerve.
The cricotracheal ligament connects the lower margin of the cricoid cartilage to the first ring of the trachea.
The fibroelastic membrane of the larynx lies beneath the mucous membrane lining the larynx. The upper portion of the membrane is called the quadrangular membrane, and it extends between the epiglottis and the arytenoid cartilages. Its lower margin forms the vestibular ligaments. The lower part of the fibroelastic membrane is called the cricothyroid ligament. The anterior part of the cricothyroid ligament is thick and connects the cricoid cartilage to the lower margin of the thyroid cartilage. The lateral part of the ligament is thin and is attached below to the upper margin of the cricoid cartilage. The superior margin of the ligament, instead of being attached to the lower margin of the thyroid cartilage, ascends within the thyroid cartilage on its medial surface. Its upper margin is thickened and forms the important vocal ligament on each side. The anterior end of each vocal ligament is attached to the deep surface of the thyroid cartilage. The posterior end is attached to the vocal process of the arytenoid cartilage.
The hyoepiglottic ligament attaches the epiglottis to the hyoid bone. The thyroepiglottic ligament attaches the epiglottis to the thyroid cartilage.
The inlet of the larynx looks backward and upward into the laryngeal part of the pharynx. The opening is bounded in front by the upper margin of the epiglottis; laterally by the aryepiglottic fold of mucous membrane, which connects the epiglottis to the arytenoid cartilage; and posteriorly and below by the mucous membrane stretching between the arytenoid cartilages. The corniculate cartilage on the apex of the arytenoid cartilage and the small bar, the cuneiform cartilage, produce a small elevation on the upper border of each aryepiglottic fold.