Antrum Health Dictionary

Antrum: From 2 Different Sources


Antrum means a natural hollow or cavity. The maxillary antrum is now known as the maxillary SINUS. The mastoid antrum is situated in the mastoid process, the mass of bone felt behind the ear. It may become the seat of an ABSCESS in cases of suppuration of the middle ear (see EAR, DISEASES OF). The pyloric antrum is the part of the stomach immediately preceding the PYLORUS.
Health Source: Medical Dictionary
Author: Health Dictionary
n. 1. a cavity, especially a cavity in a bone. The mastoid (or tympanic) antrum is the space connecting the air cells of the *mastoid process with the chamber of the inner ear. 2. (gastric antrum) the distal third of the *stomach. —antral adj.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Antrostomy

Antrostomy is the operation in which an opening is made through the nose into the maxillary ANTRUM.... antrostomy

Duodenal Ulcer

This disorder is related to gastric ulcer (see STOMACH, DISEASES OF), both being a form of chronic peptic ulcer. Although becoming less frequent in western communities, peptic ulcers still affect around 10 per cent of the UK population at some time. Duodenal ulcers are 10–15 times more common than gastric ulcers, and occur in people aged from 20 years onwards. The male to female ratio for duodenal ulcer varies between 4:1 and 2:1 in di?erent communities. Social class and blood groups are also in?uential, with duodenal ulcer being more common among the upper social classes, and those of blood group O.

Causes It is likely that there is some abrasion, or break, in the lining membrane (or mucosa) of the stomach and/or duodenum, and that it is gradually eroded and deepened by the acidic gastric juice. The bacterium helicobacter pylori is present in the antrum of the stomach of people with peptic ulcers; 15 per cent of people infected with the bacterium develop an ulcer, and the ulcers heal if H. pylori is eradicated. Thus, this organism has an important role in creating ulcers. Mental stress may possibly be a provocative factor. Smoking seems to accentuate, if not cause, duodenal ulcer, and the drinking of alcohol is probably harmful. The apparent association with a given blood group, and the fact that relatives of a patient with a peptic ulcer are unduly likely to develop such an ulcer, suggest that there is some constitutional factor.

Symptoms and signs Peptic ulcers may present in di?erent ways, but chronic, episodic pain lasting several months or years is most common. Occasionally, however, there may be an acute episode of bleeding or perforation, or obstruction of the gastric outlet, with little previous history. Most commonly there is pain of varying intensity in the middle or upper right part of the abdomen. It tends to occur 2–3 hours after a meal, most commonly at night, and is relieved by some food such as a glass of milk; untreated it may last up to an hour. Vomiting is unusual, but there is often tenderness and sti?ness (‘guarding’) of the abdominal muscles. Con?rmation of the diagnosis is made by radiological examination (‘barium meal’), the ulcer appearing as a niche on the ?lm, or by looking at the ulcer directly with an endoscope (see FIBREOPTIC ENDOSCOPY). Chief complications are perforation of the ulcer, leading to the vomiting of blood, or HAEMATEMESIS; or less severe bleeding from the ulcer, the blood passing down the gut, resulting in dark, tarry stools (see MELAENA).

Treatment of a perforation involves initial management of any complications, such as shock, haemorrhage, perforation, or gastric outlet obstruction, usually involving surgery and blood replacement. Medical treatment of a chronic ulcer should include regular meals, and the avoidance of fatty foods, strong tea or co?ee and alcohol. Patients should also stop smoking and try to reduce the stress in their lives. ANTACIDS may provide symptomatic relief. However, the mainstay of treatment involves four- to six-week courses with drugs such as CIMETIDINE and RANITIDINE. These are H2 RECEPTOR ANTAGONISTS which heal peptic ulcers by reducing gastric-acid output. Of those relapsing after stopping this treatment, 60–95 per cent have infection with H. pylori. A combination of BISMUTH chelate, amoxycillin (see PENICILLIN; ANTIBIOTICS) and METRONIDAZOLE – ‘triple regime’ – should eliminate the infection: most physicians advise the triple regime as ?rst-choice treatment because it is more likely to eradicate Helicobacter and this, in turn, enhances healing of the ulcer or prevents recurrence. Surgery may be necessary if medical measures fail, but its use is much rarer than before e?ective medical treatments were developed.... duodenal ulcer

Mastoid Process

The large process of the temporal bone of the SKULL which can be felt immediately behind the ear. It contains numerous cavities, one of which – the mastoid antrum – communicates with the middle ear, and is liable to suppurate when the middle ear is diseased. (See under EAR, DISEASES OF.)... mastoid process

Mastoiditis

Inflammation of the mastoid bone in the skull. The disease is caused by infection spreading from the middle ear (see otitis media) to the air cells in the mastoid bone through a cavity called the mastoid antrum.

Mastoiditis causes earache and severe pain, swelling, and tenderness behind the ear. There is usually also fever, a creamy discharge from the ear, progressive hearing loss, and displacement of the outer ear. If the infection spreads, it may lead to meningitis, a brain abscess, blood clotting in veins within the brain, or facial palsy.

Treatment is with antibiotic drugs.

If the infection persists, an operation known as a mastoidectomy may be carried out to remove the infected air cells.... mastoiditis

Duodenum

This is the beginning of the small intestines, and it empties the stomach. It is 9 or 10 inches long, holds about the same amount of food as the digestive antrum or bottom of the stomach, and, through a papilla or sphincter, squirts a mixture of bile and pancreatic juices onto the previous stomach contents. These juices neutralize the acidic chyme; the pancreatic alkali and bile acids form soap to emulsify and aid fat digestion; and the duodenum walls secrete additional fluids and enzymes to admix with the pancreatic enzymes to initiate the final upper digestive investment. The duodenal wall secretes blood hormones to excite the brain, and gallbladder and pancreas secretions, and, if overwhelmed, can inhibit the stomach from sending anything else down for a while, until they can catch all their collective breath.... duodenum

Antral Irrigation

Irrigation of the maxillary antrum, one of the nasal sinuses.

More commonly known as sinus washout, this procedure is used to diagnose and treat persistent sinusitis.

Antral irrigation is performed less often since the introduction of nasal endoscopy.... antral irrigation

Mastoid Bone

The lower part of the temporal bone in the skull. It has a projection, known as the mastoid process, which can be felt behind the ear. The mastoid bone is honeycombed with air cells. These are connected to a cavity called the mastoid antrum, which leads into the middle ear. Infections of the middle ear (see otitis media) occasionally spread through the mastoid bone to cause acute mastoiditis.... mastoid bone

Antrectomy

n. 1. surgical removal of the bony walls of an *antrum. See antrostomy. 2. (distal gastrectomy) a surgical operation in which the gastric antrum is removed. Indications for antrectomy include peptic ulcer disease resistant to medical treatment, tumours, perforation, and gastric outlet obstruction.... antrectomy

G-cell

n. any of the gastrin-secreting cells of the stomach lining located predominantly in the gastric *antrum. Gastrin stimulates the production of gastric acid by parietal cells in the stomach. Increased G-cell activity is associated with the formation of duodenal ulcers and the *Zollinger-Ellison syndrome.... g-cell

Ear

The ear is concerned with two functions. The more evident is that of the sense of hearing; the other is the sense of equilibration and of motion. The organ is divided into three parts:

(1) the external ear, consisting of the auricle on the surface of the head, and the tube which leads inwards to the drum; (2) the middle ear, separated from the former by the tympanic membrane or drum, and from the internal ear by two other membranes, but communicating with the throat by the Eustachian tube; and (3) the internal ear, comprising the complicated labyrinth from which runs the vestibulocochlear nerve into the brain.

External ear The auricle or pinna consists of a framework of elastic cartilage covered by skin, the lobule at the lower end being a small mass of fat. From the bottom of the concha the external auditory (or acoustic) meatus runs inwards for 25 mm (1 inch), to end blindly at the drum. The outer half of the passage is surrounded by cartilage, lined by skin, on which are placed ?ne hairs pointing outwards, and glands secreting a small amount of wax. In the inner half, the skin is smooth and lies directly upon the temporal bone, in the substance of which the whole hearing apparatus is enclosed.

Middle ear The tympanic membrane, forming the drum, is stretched completely across the end of the passage. It is about 8 mm (one-third of an inch) across, very thin, and white or pale pink in colour, so that it is partly transparent and some of the contents of the middle ear shine through it. The cavity of the middle ear is about 8 mm (one-third of an inch) wide and 4 mm (one-sixth of an inch) in depth from the tympanic membrane to the inner wall of bone. Its important contents are three small bones – the malleus (hammer), incus (anvil) and stapes (stirrup) – collectively known as the auditory ossicles, with two minute muscles which regulate their movements, and the chorda tympani nerve which runs across the cavity. These three bones form a chain across the middle ear, connecting the drum with the internal ear. Their function is to convert the air-waves, which strike upon the drum, into mechanical movements which can affect the ?uid in the inner ear.

The middle ear has two connections which are of great importance as regards disease (see EAR, DISEASES OF). In front, it communicates by a passage 37 mm (1.5 inches) long – the Eustachian (or auditory) tube – with the upper part of the throat, behind the nose; behind and above, it opens into a cavity known as the mastoid antrum. The Eustachian tube admits air from the throat, and so keeps the pressure on both sides of the drum fairly equal.

Internal ear This consists of a complex system of hollows in the substance of the temporal bone enclosing a membranous duplicate. Between the membrane and the bone is a ?uid known as perilymph, while the membrane is distended by another collection of ?uid known as endolymph. This membranous labyrinth, as it is called, consists of two parts. The hinder part, comprising a sac (the utricle) and three short semicircular canals opening at each end into it, is the part concerned with the balancing sense; the forward part consists of another small bag (the saccule), and of a still more important part, the cochlear duct, and is the part concerned with hearing. In the cochlear duct is placed the spiral organ of Corti, on which sound-waves are ?nally received and by which the sounds are communicated to the cochlear nerve, a branch of the vestibulocochlear nerve, which ends in ?laments to this organ of Corti. The essential parts in the organ of Corti are a double row of rods and several rows of cells furnished with ?ne hairs of varying length which respond to di?ering sound frequencies.

The act of hearing When sound-waves in the air reach the ear, the drum is alternately pressed in and pulled out, in consequence of which a to-and-fro movement is communicated to the chain of ossicles. The foot of the stapes communicates these movements to the perilymph. Finally these motions reach the delicate ?laments placed in the organ of Corti, and so affect the auditory nerve, which conveys impressions to the centre in the brain.... ear

Maxillary Sinus

(maxillary antrum) see paranasal sinuses.... maxillary sinus

Oroantral Fistula

a connection between the mouth and the maxillary sinus (antrum), usually as a sequel to tooth extraction. It may resolve or require surgical closure.... oroantral fistula

Gave

(gastric antral vascular ectasia) a condition characterized by the presence of dilated capillaries or veins in the lining of the distal stomach (the gastric *antrum), which may extend to involve the whole of the stomach. It may be diffuse or it may adopt a more linear appearance like the stripes of a watermelon (watermelon stomach). Certain medical conditions (e.g. *cirrhosis, *systemic sclerosis, and chronic renal failure) are associated with this condition. It is often asymptomatic but can lead to transfusion-dependent anaemia. Treatment focuses on management of the underlying condition and endoscopic treatment of bleeding areas using *argon plasma coagulation or laser thermocoagulation.... gave



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