2034 HUMAN ANATOMY. 



exists towards the bottom of which the ducts of the mamma converge. In such 

 cases the depression persists ; in others the areola is present, but the nipple absent. 

 In both, while lactation may be normal, the suckling of children is impossible. The 

 nipple may be absent or defective as a result of trauma or of disease — wounds, burns, 

 ulcers, abscesses — during infancy. 



The normal nipples of virgins or nulliparae may be almost on a level with the 

 areola, while those of multiparae are often greatly elongated from the traction 

 upon them. Temporary elongation or erection of the nipple may be caused by 

 reflex stimulation of the unstriped muscular tissue of the skin of the nipple and 

 areola. 



Infection of the nipple is common, because, on the one hand, of the many folds 

 of its delicate cutaneous covering, containing a number of sebaceous glands and 

 closely connected to the underlying structures ; and, on the other, of its frequent 

 exposure during suckling to irritation from unhealthy discharges from the child's 

 mouth, leading to epidermic maceration and to painful erosions, fissures, and ulcers. 



Atrophy of the mammary glandular elements is of normal occurrence after the 

 menopause, the fibrous and fatty structure being also affected in many instances of 

 noticeable withering of the breasts. In early life this condition may result from 

 disease, or from removal of the ovaries, and become a true deformity. 



Hypertrophy of the breast consists in an overgrowth of both the glandular and 

 the fibrous elements, the latter predominating, and occurs usually between 14 and 

 30 years of age — the period of greatest sexual activity. Amenorrhoea and pregnancy 

 are frequently associated with it. 



Infection of the breast is usually carried through either the lymphatics or the 

 milk ducts, most commonly during the early period of lactation ; more rarely it 

 appears during the other notable periods of mammary physiological excitement — 

 i.e.y in the newly born — the "witch-milk" period {vide supra) — and at puberty. 

 In the nursing woman the presence of fissures or abrasions of the nipple predisposes 

 to lymphatic infection. Lack of cleanliness, with fermentation or decomposition of 

 milk and of cutaneous secretions in the folds or crevices of the nipple, favors infec- 

 tion in the ampullae of the ducts. 



If the superficial lymphatics are the channels of infection, suppuration in the 

 cellulo-fatty tissue superficial to the breast may result (supramammary abscess) 

 and, owing to the lack of tension, pointing will occur early, the course of the case 

 will be rapid, and the constitutional symptoms relatively slight. If the deeper lym- 

 phatics or milk ducts convey the infection, suppuration occurs within the lobules 

 (intraniammary abscess) and spreads slowly from one to another through the inter- 

 lobular connective tissue. As the pus is surrounded by the unyielding breast tissue 

 and confined by the capsule of subcutaneous fascia and its septa, pain, tenderness, 

 fever, and other constitutional symptoms are marked and the progress of the disease 

 is slow. Occasionally, by extension from an intramammary focus, the connective 

 tissue lying between the breast and the pectoral sheath is involved (retro, infra, or 

 submammary abscess), but suppuration in this region is more apt to be consecutive 

 to caries of a rib (usually tuberculous). The constitutional symptoms are less 

 marked. The whole breast is pushed forward and made more prominent. Point- 

 ing —by reason of the efTect of gravity — is apt to occur somewhere at the circum- 

 ference of the breast, usually towards the inframaxillary region. Sometimes these 

 abscesses ulcerate directly through the breast tissue to the subcutaneous area, making 

 two cavities, one infra, the other supramammary, connected by a narrow channel, 

 a form of Velpeau's " abces de bouton en chemise." As the breast is thinnest 

 along a lin^ drawn from the sterno-clavicular joint to the nipple, it is in that region 

 that such perforation of the gland usually occurs. As the breast — glandular and 

 other structures, including the skin covering it — is supplied chiefly by the lateral cuta- 

 neous branches of the second to sixth intercostal nerves, pain in inflammatory or sup- 

 purative affections, or in the case of new growth, may be felt down the arm (intercosto- 

 humeral) ; over the shoulder-blade (posterior branches of the thoracic nerves) ; 

 down the side or along the posterior parietes of the thorax (intercostals) ; or up the 

 neck (supraclavicular from the cervical plexus anastomosing with the second inter- 

 costal). Incisions for the evacuation of pus should be made on lines radiating out- 



