1366 



CLINICAL AND TOPOGRAPHICAL ANATOMY 



upper part of the first thoracic vertebra, the following structures are met with : 

 — (1) In the middle line. Sterno-hj^oid and sterno-thyreoid muscles, with their 

 sheaths of deep cervical fascia, cellular tissue in which are the remains of the 

 thymus gland, the inferior thyreoid veins, the trachea and tracheal fascia, the 

 oesophagus, and longus colli muscles. Between the trachea and oesophagus are 

 the recurrent nerves. (2) On each side. The apex of the lung, covered by pleura, 

 deep cer\'ical fascia, and membranous cervical diaphragms ("Sibson's fascia") 

 derived from the scalenes, rises about 3.7 cm. (1| in.) above the first rib. Between 

 it and the trachea and oesophagus lie the following : the internal mammary artery, 

 the phrenic nerve; on the right side, the innominate vein and artery, with the 

 vagus between the two, the cardiac nerves, and the right lymphatic duct. On 

 the left side are the common carotid and subclavian arteries, with the left vagus 

 between them, the cardiac nerves and the thoracic duct. Farthest back and 

 on each side are the trunk of the sympathetic, the superior intercostal artery, and 

 the first thoracic nerve. 



The mamma. — This lies chiefly on the pectoralis major and slightly on the 

 rectus abdominis and serratus anterior. It is usually described as reaching from 

 the second to the sixth rib, and from the sternum to the anterior border of the 

 axilla. It is most important to remember that the breast is often a much more 

 extensive structure than would be included in the above very limited description. 

 Thus — (1) the gland is not encapsuled at its periphery, its tissue branching and 

 breaking up here to become continuous with the superficial fascia. (Stiles.) (2) 



Fig. 1106. — Section op the Sixth Left Intercostal Space, at the Junction of the 

 Anterior and Posterior Thirds. (Tillaux.) 



Intercostal vein 

 Intercostal artery 

 Intercostal nerve 



Serra tus anterior--J; rpjW«lfc,J|l||S^^. — Aponeurosis covering the internal 

 Serratus aponeurosis TO'jBMI'^fii^'--- intercostal muscle 



Aponeurosis covering external inter- -_|l#MH^^l!;!BWB^^fe Internal intercostal muscle 



costal muscle H ] IMSKSI^imml^^^^ Pleura 



External intercostal muscle- 



The retinacula cutis contain lymphatics and, sometimes, mammary tissue. (3) 

 There is a lymphatic plexus, and, often, minute lobules of gland tissue, in the 

 pectoral fascia. (Heidenhain.) Fully one-third of the whole mamma lies 

 posterior and lateral to the axillary border of the pectoralis major so that it 

 reaches almost to the mid-axillary line. That part of the upper and lateral 

 quadrant known as the axillary lobe is of especial importance from its reach- 

 ing into close vicinity with the anterior pectoral group of axillary nodes (p. 719). 

 In the male the nipple is usually placed in the fourth space, nearly 2.5 cm. (1 in.) 

 lateral to the cartilages of the fourth and fifth ribs. On the nipple itself open the 

 fifteen or twenty ducts which dilate beneath it, and then. diverge and break up 

 for the supply of the lobules. The skin over the areola is very adherent, pig- 

 mented, and fatless. Here also are groups of little swellings corresponding to 

 large sebaceous follicles and areolar glands. The skin over the breast is freely 

 movable, and united to the fascia which encases the organ, and thus to the inter- 

 lobular connective tissue, by bands of the same structure — the retinacula cutis. 

 Under the breast, and giving it its mobility, is a cellulo-fatty layer, the seat of 

 .submammary abscess. 



Tho nerves whic^h supply the breast are the anterior cutaneous branches of the second, 

 third, fourth, and fifth intercostal nerves, and the lateral branches of the last three. The 

 connection of those trunks serves to explain the difTusion of the pain often observed in painful 

 afTections of the breast. Thus pain may Ix; nifc^rred to the side of the chest and back (along the 

 above intcTcostal trunks), ov(t the scapuhi, along the inediMl side of tlie arm (along the inter- 

 costo-brachial nerve), or up into tlu; ncuik. Tho gland is su|)plio(l by the following arteries: tho 

 aortic intorcostals of tlie ,so(;ond, third, fourth, and fiftli spaces, sinular intercostal branches 

 from the internal mammary, which runs outward, two small l)ranches to each sjiace, perforating 

 branches from the sanu; vessel, one or two given olT opposite to each space, the long thoracic and 

 external mammary (when ])rosent) from the axillary. 



