Swallowing , also called deglutition or inglutition in scientific contexts, is the process in the body of a human that allows for a substance to pass from the mouth , to the pharynx , and into the esophagus , while shutting the epiglottis . Swallowing is an important part of eating and drinking . If the process fails and the material (such as food, drink, or medicine) goes through the trachea , then choking or pulmonary aspiration can occur. In the human body the automatic temporary closing of the epiglottis is controlled by the swallowing reflex .
47-508: The portion of food, drink, or other material that will move through the neck in one swallow is called a bolus . In colloquial English , the term "swallowing" is also used to describe the action of taking in a large mouthful of food without any biting . Swallowing comes so easily to most people that the process rarely prompts much thought. However, from the viewpoints of physiology , of speech–language pathology , and of health care for people with difficulty in swallowing (dysphagia) , it
94-523: A 26% increased risk for each centimeter increase in neck circumference. Moreover, hospitalized COVID-19 patients with a "large neck phenotype" on admission had a more than double risk of death. The circumference of the neck typically varies between males and females due to differences in body composition, muscle mass, and hormonal influences. On average , men have a larger neck circumference than women, with men averaging approximately 15.2 inches (38.7 cm) and women around 13.1 inches (33.3 cm). This difference
141-455: A bolus which is moved from one side of the oral cavity to the other by the tongue. Buccinator (VII) helps to contain the food against the occlusal surfaces of the teeth. The bolus is ready for swallowing when it is held together by saliva (largely mucus), sensed by the lingual nerve of the tongue (VII—chorda tympani and IX—lesser petrosal) (V 3 ). Any food that is too dry to form a bolus will not be swallowed. 3) Trough formation A trough
188-443: A failure of the reflex to swallow leads to a build-up of mucus or saliva in the throat and airways, producing a noise known as a death rattle (not to be confused with agonal respiration , which is an abnormal pattern of breathing due to cerebral ischemia or hypoxia). Abnormalities of the pharynx and/or oral cavity may lead to oropharyngeal dysphagia . Abnormalities of the esophagus may lead to esophageal dysphagia . The failure of
235-455: A line drawn from a point midway between the angle of the jaw and the mastoid process to the middle of the posterior border of the sterno-mastoid muscle and thence across the posterior triangle to the deep surface of the trapezius. The external jugular vein can usually be seen through the skin; it runs in a line drawn from the angle of the jaw to the middle of the clavicle, and close to it are some small lymphatic glands. The anterior jugular vein
282-470: A speech pathologist to evaluate dysphagia include Fiberoptic Endoscopic Evaluation of Swallowing and Modified Barium Swallow Study. Occupational Therapists may also offer swallowing rehabilitation services as well as prescribing modified feeding techniques and utensils. Consultation with a dietician is essential, in order to ensure that the individual with dysphagia is able to consume sufficient calories and nutrients to maintain health. In terminally ill patients,
329-421: Is IX and efferent limb is the pharyngeal plexus- IX and X). They are scattered over the base of the tongue, the palatoglossal and palatopharyngeal arches, the tonsillar fossa, uvula and posterior pharyngeal wall. Stimuli from the receptors of this phase then provoke the pharyngeal phase. In fact, it has been shown that the swallowing reflex can be initiated entirely by peripheral stimulation of the internal branch of
376-444: Is an interesting topic with extensive scientific literature . Eating and swallowing are complex neuromuscular activities consisting essentially of three phases, an oral , pharyngeal and esophageal phase. Each phase is controlled by a different neurological mechanism. The oral phase, which is entirely voluntary, is mainly controlled by the medial temporal lobes and limbic system of the cerebral cortex with contributions from
423-400: Is bordered by the posterior border of the sternocleidomastoid muscle, anterior border of the trapezius muscle and the superior edge of the middle third of the clavicle. This triangle contains the sternocleidomastoid, trapezius, splenius capitis , levator scapulae , omohyoid, anterior, middle and posterior scalene muscles . Sensation to the front areas of the neck comes from the roots of
470-744: Is largely attributed to body composition , as men generally have more muscle mass and a higher body mass index (BMI) than women. Hormonal differences also play a significant role, as testosterone, which is present at higher levels in men, promotes muscle growth, including in the neck area. In addition to these biological factors, neck circumference can serve as an important health indicator . Larger neck sizes in both men and women have been associated with an increased risk of conditions such as cardiovascular diseases and sleep apnea. While these differences are generally consistent across populations, individual variations may occur based on factors like overall body weight and fitness levels. The neck appears in some of
517-531: Is notable, as many have life stations similar to a terrestrial or tetrapod counterpart or could otherwise make use of the added flexibility. The word "neck" is sometimes used as a convenience to refer to the region behind the head in some snails , gastropod mollusks , even though there is no clear distinction between this area, the head area, and the rest of the body. Palatoglossal arch The palatoglossal arch ( glossopalatine arch , anterior pillar of fauces ) on either side runs downward, lateral (to
SECTION 10
#1732801095103564-445: Is similar to the techniques used by sword swallowers. In many birds, the esophagus is largely a mere gravity chute , and in such events as a seagull swallowing a fish or a stork swallowing a frog , swallowing consists largely of the bird lifting its head with its beak pointing up and guiding the prey with tongue and jaws so that the prey slides inside and down. In fish , the tongue is largely bony and much less mobile and getting
611-464: Is smaller and runs down about half an inch from the middle line of the neck. The clavicle or collarbone forms the lower limit of the neck, and laterally the outward slope of the neck to the shoulder is caused by the trapezius muscle. Disorders of the neck are a common source of pain. The neck has a great deal of functionality but is also subject to a lot of stress. Common sources of neck pain (and related pain syndromes, such as pain that radiates down
658-482: Is then formed at the back of the tongue by the intrinsic muscles (XII). The trough obliterates against the hard palate from front to back, forcing the bolus to the back of the tongue. The intrinsic muscles of the tongue (XII) contract to make a trough (a longitudinal concave fold) at the back of the tongue. The tongue is then elevated to the roof of the mouth (by the mylohyoid (mylohyoid nerve—V 3 ), genioglossus , styloglossus and hyoglossus (the rest XII)) such that
705-415: The auditory tube The actions of the levator palatini (pharyngeal plexus—IX, X), tensor palatini (Vc) and salpingopharyngeus (pharyngeal plexus—IX, X) in the closure of the nasopharynx and elevation of the pharynx opens the auditory tube, which equalises the pressure between the nasopharynx and the middle ear. This does not contribute to swallowing, but happens as a consequence of it. 8) Closure of
752-418: The oropharynx The oropharynx is kept closed by palatoglossus (pharyngeal plexus—IX, X), the intrinsic muscles of tongue (XII) and styloglossus (XII). 9) Laryngeal closure The primary laryngopharyngeal protective mechanism to prevent aspiration during swallowing is via the closure of the true vocal folds. The adduction of the vocal cords is affected by the contraction of the lateral cricoarytenoids and
799-422: The piriform fossa . Additionally, the larynx is pulled up with the pharynx under the tongue by stylopharyngeus (IX), salpingopharyngeus (pharyngeal plexus—IX, X), palatopharyngeus (pharyngeal plexus—IX, X) and inferior constrictor (pharyngeal plexus—IX, X). This phase is passively controlled reflexively and involves cranial nerves V, X (vagus) , XI (accessory) and XII (hypoglossal) . The respiratory center of
846-420: The spinal cord , upper parts of the respiratory and digestive tracts , endocrine glands , nerves , arteries and veins . Muscles of the neck are described separately from the compartments. They bound the neck triangles. In anatomy , the neck is also called by its Latin names, cervix or collum , although when used alone, in context, the word cervix more often refers to the uterine cervix ,
893-467: The spinal nerves C2-C4, and at the back of the neck from the roots of C4-C5. In addition to nerves coming from and within the human spine, the accessory nerve and vagus nerve travel down the neck. The head and neck get the majority of its blood supply through the carotid and vertebral arteries. Arteries which supply the neck are common carotid arteries , which bifurcate into the internal and external carotid arteries . The thyroid cartilage of
940-448: The superior laryngeal nerve . This phase is voluntary and involves important cranial nerves : V (trigeminal) , VII (facial) and XII (hypoglossal) . For the pharyngeal phase to work properly all other egress from the pharynx must be occluded—this includes the nasopharynx and the larynx . When the pharyngeal phase begins, other activities such as chewing, breathing, coughing and vomiting are concomitantly inhibited. 5) Closure of
987-402: The suprahyoid and infrahyoid muscles depending on if they are located superiorly or inferiorly to the hyoid bone. The suprahyoid muscles (stylohyoid, digastric, mylohyoid, geniohyoid) elevate the hyoid bone, while the infrahyoid muscles (omohyoid, sternohyoid, thyrohyoid, sternothyroid) depress it. Acting synchronously, both groups facilitate speech and swallowing . Posterior triangle
SECTION 20
#17328010951031034-460: The arm) include (and are strictly limited to): Higher neck circumference has been associated with cardiometabolic risk. Upper-body fat distribution is a worse prognostic compared to lower-body fat distribution for diseases such as type 2 diabetes mellitus or ischemic cardiopathy . Neck circumference has been associated with the risk of being mechanically ventilated in COVID-19 patients, with
1081-415: The arytenoids to appose each other (closes the laryngeal aditus by bringing the aryepiglottic folds together), and draws the epiglottis down to bring its lower half into contact with arytenoids, thus closing the aditus. Retroversion of the epiglottis, while not the primary mechanism of protecting the airway from laryngeal penetration and aspiration, acts to anatomically direct the food bolus laterally towards
1128-435: The bolus The pharynx is pulled upwards and forwards by the suprahyoid and longitudinal pharyngeal muscles – stylopharyngeus (IX), salpingopharyngeus (pharyngeal plexus—IX, X) and palatopharyngeus (pharyngeal plexus—IX, X) to receive the bolus. The palatopharyngeal folds on each side of the pharynx are brought close together through the superior constrictor muscles, so that only a small bolus can pass. 7) Opening of
1175-399: The deglutition process is started, it is quite hard to stop it. Swallowing becomes a great concern for the elderly since strokes and Alzheimer's disease can interfere with the autonomic nervous system . Speech pathologists commonly diagnose and treat this condition since the speech process uses the same neuromuscular structures as swallowing. Diagnostic procedures commonly performed by
1222-442: The earliest of tetrapod fossils, and the functionality provided has led to its being retained in all land vertebrates as well as marine-adapted tetrapods such as turtles, seals, and penguins. Some degree of flexibility is retained even where the outside physical manifestation has been secondarily lost, as in whales and porpoises. A morphologically functioning neck also appears among insects. Its absence in fish and aquatic arthropods
1269-459: The esophagus by pharyngeal peristalsis which takes place by sequential contraction of the superior, middle and inferior pharyngeal constrictor muscles (pharyngeal plexus—IX, X). The lower part of the inferior constrictor ( cricopharyngeus ) is normally closed and only opens for the advancing bolus. Gravity plays only a small part in the upright position—in fact, it is possible to swallow solid food even when standing on one's head. The velocity through
1316-400: The esophagus into the stomach. 13) Relaxation phase Finally the larynx and pharynx move down with the hyoid mostly by elastic recoil. Then the larynx and pharynx move down from the hyoid to their relaxed positions by elastic recoil. Swallowing therefore depends on coordinated interplay between many various muscles, and although the initial part of swallowing is under voluntary control, once
1363-418: The food to the back of the pharynx is helped by pumping water in its mouth and out of its gills . In snakes , the work of swallowing is done by raking with the lower jaw until the prey is far enough back to be helped down by body undulations. Neck The neck is the part of the body on many vertebrates that connects the head with the torso . The neck supports the weight of the head and protects
1410-511: The larynx forms a bulge in the midline of the neck called the Adam's apple . The Adam's apple is usually more prominent in men. Inferior to the Adam's apple is the cricoid cartilage . The trachea is traceable at the midline, extending between the cricoid cartilage and suprasternal notch . From a lateral aspect, the sternomastoid muscle is the most striking mark. It separates the anterior triangle of
1457-443: The lips to form a tight seal of the oral cavity. Next, the superior longitudinal muscle elevates the apex of the tongue to make contact with the hard palate and the bolus is propelled to the posterior portion of the oral cavity. Once the bolus reaches the palatoglossal arch of the oropharynx, the pharyngeal phase, which is reflex and involuntary, then begins. Receptors initiating this reflex are proprioceptive (afferent limb of reflex
Swallowing - Misplaced Pages Continue
1504-416: The lower esophagus sphincter to respond properly to swallowing is called achalasia . M-Type Swallowing With practice, people can learn to swallow fluidly without closing the mouth by merely manipulating the tongue and jaw to drive fluids or foods down the esophagus. With a continuous motion, an individual forges breathing and priorities the swallowed matter. This intermediate level of muscle manipulation
1551-482: The medulla is directly inhibited by the swallowing center for the very brief time that it takes to swallow. This means that it is briefly impossible to breathe during this phase of swallowing and the moment where breathing is prevented is known as deglutition apnea . 10) Hyoid elevation The hyoid is elevated by digastric (V & VII) and stylohyoid (VII), lifting the pharynx and larynx up even further. 11) Bolus transits pharynx The bolus moves down towards
1598-467: The motor cortex and other cortical areas. The pharyngeal swallow is started by the oral phase and subsequently is coordinated by the swallowing center on the medulla oblongata and pons . The reflex is initiated by touch receptors in the pharynx as a bolus of food is pushed to the back of the mouth by the tongue, or by stimulation of the palate (palatal reflex). Swallowing is a complex mechanism using both skeletal muscle ( tongue ) and smooth muscles of
1645-468: The nasopharynx The soft palate is tensed by tensor palatini (Vc), and then elevated by levator palatini (pharyngeal plexus—IX, X) to close the nasopharynx. There is also the simultaneous approximation of the walls of the pharynx to the posterior free border of the soft palate, which is carried out by the palatopharyngeus (pharyngeal plexus—IX, X) and the upper part of the superior constrictor (pharyngeal plexus—IX, X). 6) The pharynx prepares to receive
1692-467: The neck attach to the skull , hyoid bone , clavicles and the sternum . They bound the two major neck triangles; anterior and posterior. Anterior triangle is defined by the anterior border of the sternocleidomastoid muscle , inferior edge of the mandible and the midline of the neck. It contains the stylohyoid , digastric , mylohyoid , geniohyoid , omohyoid , sternohyoid , thyrohyoid and sternothyroid muscles . These muscles are grouped as
1739-529: The neck from the posterior. The upper part of the anterior triangle contains the submandibular glands , which lie just below the posterior half of the mandible. The line of the common and the external carotid arteries can be marked by joining the sterno-clavicular articulation to the angle of the jaw. Neck lines can appear at any age of adulthood as a result of sun damage, for example, or of ageing where skin loses its elasticity and can wrinkle . The eleventh cranial nerve or spinal accessory nerve corresponds to
1786-406: The neck of the uterus . Thus the adjective cervical may refer either to the neck (as in cervical vertebrae or cervical lymph nodes ) or to the uterine cervix (as in cervical cap or cervical cancer ). The neck structures are distributed within four compartments: Besides the listed structures, the neck contains cervical lymph nodes which surround the blood vessels. Muscles of
1833-418: The nerves that carry sensory and motor information from the brain down to the rest of the body. In addition, the neck is highly flexible and allows the head to turn and flex in all directions. The structures of the human neck are anatomically grouped into four compartments: vertebral, visceral and two vascular compartments. Within these compartments, the neck houses the cervical vertebrae and cervical part of
1880-415: The normal and necessary actions to form the bolus, which is defined as the state of the food in which it is ready to be swallowed. 1) Moistening Food is moistened by saliva from the salivary glands ( parasympathetic ). 2) Mastication Food is mechanically broken down by the action of the teeth controlled by the muscles of mastication (V 3 ) acting on the temporomandibular joint . This results in
1927-413: The oblique and transverse arytenoids (all recurrent laryngeal nerve of vagus). Since the true vocal folds adduct during the swallow, a finite period of apnea (swallowing apnea) must necessarily take place with each swallow. When relating swallowing to respiration, it has been demonstrated that swallowing occurs most often during expiration, even at full expiration a fine air jet is expired probably to clear
Swallowing - Misplaced Pages Continue
1974-434: The pharynx and esophagus . The autonomic nervous system (ANS) coordinates this process in the pharyngeal and esophageal phases. Prior to the following stages of the oral phase, the mandible depresses and the lips abduct to allow food or liquid to enter the oral cavity. Upon entering the oral cavity, the mandible elevates and the lips adduct to assist in oral containment of the food and liquid. The following stages describe
2021-406: The pharynx depends on a number of factors such as viscosity and volume of the bolus. In one study, bolus velocity in healthy adults was measured to be approximately 30–40 cm/s. 12) Esophageal peristalsis Like the pharyngeal phase of swallowing, the esophageal phase of swallowing is under involuntary neuromuscular control. However, propagation of the food bolus is significantly slower than in
2068-417: The pharynx. The bolus enters the esophagus and is propelled downwards first by striated muscle (recurrent laryngeal, X) then by the smooth muscle (X) at a rate of 3–5 cm/s. The upper esophageal sphincter relaxes to let food pass, after which various striated constrictor muscles of the pharynx as well as peristalsis and relaxation of the lower esophageal sphincter sequentially push the bolus of food through
2115-522: The side), and forward to the side of the base of the tongue , and is formed by the projection of the glossopalatine muscle with its covering mucous membrane . It is the anterior border of the isthmus of the fauces and marks the border between the mouth and the palatopharyngeal arch . The latter marks the beginning of the pharynx . [REDACTED] This article incorporates text in the public domain from page 1137 of the 20th edition of Gray's Anatomy (1918) This anatomy article
2162-446: The tongue slopes downwards posteriorly. The contraction of the genioglossus and styloglossus (both XII) also contributes to the formation of the central trough. 4) Movement of the bolus posteriorly At the end of the oral preparatory phase, the food bolus has been formed and is ready to be propelled posteriorly into the pharynx. In order for anterior to posterior transit of the bolus to occur, orbicularis oris contracts and adducts
2209-432: The upper larynx from food remnants or liquid. The clinical significance of this finding is that patients with a baseline of compromised lung function will, over a period of time, develop respiratory distress as a meal progresses. Subsequently, false vocal fold adduction, adduction of the aryepiglottic folds and retroversion of the epiglottis take place. The aryepiglotticus (recurrent laryngeal nerve of vagus) contracts, causing
#102897