ANU'RA (Gk. di', an, priv. oOpd, oura, tail), or SALIENTIA (Lat., from salire, to hop, jump). An order of Amphibia including those that hare no tail when adult. It is subdivided by Cope into three sub-orders: .1 glossa, African and tropical American (Pipa ) toads, and fossil forms; Firm is t ernia, frogs; Areifcra, toads.
A'NUS (Lat.). The external termination of the rectum. The anus is kept firmly closed by the external and internal sphincter muscles, the former of which contracts the integument around the opening, and, by its attachment to the coccyx behind and to a tendinous cen tre in front, helps the lerator ani muscle in supporting the aperture during the expulsive efforts that are made in the passage of the farces or intestinal evacuations; while the latter, or internal sphincter, is an aggregation of the circular muscular fibres of the lowest part of the rectum, and acts in contracting the extremity of the tube. The main function of the /crator-ani muscle is expressed in its name. It supports the rectum and pelvic structures, and during the act of defecation lifts the lower end of the gut up from the mass of extruded farces. The integ,u meat around the anus lies in radiating folds, which allow of its stretching without pain dur ing the passage of the farces; and the margin is provided with a number of sebaceous glands, which, in some of the lower animals, secrete strongly odorous matters. (See SCENT GLANDS.) Infants are occasionally born with an imperfo rate anus, or congenital closure of the rectum. In the simplest form of this affection, the anus is merely closed by thin skin, which soon becomes distended with the meconium (q.v.). :More com plicated eases are those (1) in which the gut ter minates some distance above the seat of the anus in a blind sac or pouch, (2) where the rectum terminates in the bladder, etc. Fortunately, the closure by a layer of skin is far the most com mon form of imperforate anus, and the condition is readily relieved by a simple surgical opera tion. The complicated eases require opening of the abdominal cavity and the insertion of an artificial anus through the lower part of the ab dominal wall. if the condition of imperforate anus is neglected, the child dies in a few days as a result of intestinal obstruction.
Spasm of the sphincter ani, is by no means a rare affection; it is characterized by violent pain of the anus, with difficulty in passing the faeces. On attempting an examination, the muscle feels hard. and resists the introduction of the finger. It usually oceurs in sudden paroxysms, which soon subside, but sometimes it is of a more per sistent character. Spasm of the sphincter may be regarded as a symptom of fissure, ulcer, or some other form of anal or rectal irritation. Suppositories containing opium or belladonna, introduced during the period of relaxation, are sometimes of use. and if there arc ulcers or fis su•es they must be specially treated. Ulceration occurring as a breach of surface at one or more points around the anus, but not extending within the orifice, is by no means uncommon in persons who are not attentive to cleanliness, and espe cially in women with vaginal discharges. The
treatment consists in strict attention to cleanli ness, and perhaps one or two applications of the silver nitrate stick or of pure carbolic acid. If the ulcer is seated partly without the anus and partly within the rectum, the distress is much more severe, and the treatment often requires excision, where local applications have failed to give relief. Fissure of the anus is a term. applied to an affection consisting in one or more cracks, excoriations, or superficial ulcerations, situated between the folds of the skin and mucous mem brane at the verge of the anus, and only slightly involving the rectum.' They give rise to intense pain during the passage of the evacuations, and for sonic hours afterward to great discomfort, smarting, and itching. The treatment to be adopted is to endeavor to procure regular and somewhat soft evacuations, and to sponge with warm water immediately afterward, the parts being dried with a soft cloth. One or two appli cations of solid nitrate of silver will sometimes cure the disease, and an ointment of oxide of zinc, or one containing cocaine, will sometimes serve to allay the irritation and heal the parts. if these measures do not afford relief, the sphine ter muscle must be dilated, the base of the fis sure incised, and its surface scraped with a sharp spoon. Pruritus ani, which simply means intense itching and irritation of this part, is to be regarded as a symptom of certain morbid changes rather than as a special disorder; but as it is a very common affection, and is productive of much suffering, it must not be passed over. It is often associated with an unhealthy state of the intestinal secretions, or with simple eonsti pation ; with a congested state of the mucous membrane; with uterine and ovarian diseases; kidney disease; diabeteA; neurasthenia; tea, al cohol, tobacco, and opium habits: the presence of thread-worms in the rectum; eczema, etc.; and it is peculiarly common in persons whose occupa tions are sedentary. The affection is often much aggravated by the patient's being unable to re frain from scratching the parts, which tends to exeoriations, ulcerations, thickening of the skin, etc. The symptoms are usually most severe when the sufferer begins to get warm in bed. The treatment in every case mnst aim to remove the cause, whether general or local. If the affection arise from worms, or a loaded state of the large intestines, enemata and purgatives will give im mediate relief. if tmhealthy excretions exist, attention must be paid to the diet, the bowels must be kept freely open, and strict local cleanli ness observed. If there are any cracks or ulcers, nitrate of silver must be applied until they heal. In all cases of pruritic which have persisted for any length of time, the skin is found thickened and the redundant layers of epidermis must be removed and kept from reaccumulating by the repeated applications of ointments containing such substances as carbolic acid. calomel, and corrosive sublimate. The other principal affec tions of the anus are fistula, piles, and prolapsus, which arc discussed in special articles.