Page 177 - Clinical Anatomy

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162 The upper limb

Clinical features

1◊◊Developmental abnormalities are not uncommon. The nipple may fail
to evert and it is important to find out from the patient whether or not an
inverted nipple is a recent event or has been present since birth. Super-
numerary nipples or even breasts may occur along a vertical ‘milk line’—a
reminder of the line of mammary glands in more primitive mammals; on
the other hand, the breast on one or both sides may be small or even absent
(amazia).
2◊◊An abscess of the breast should be opened by a radial incision to avoid
cutting across a number of lactiferous ducts. Such an abscess may rupture
from one fascial compartment into its neighbours, and it is important at
operation to break down any loculi which thus form in order to provide
ample drainage.
3◊◊Dimpling of the skin over a carcinoma of the breast results from malig-
nant infiltration and fibrous contraction of Cooper’s ligaments — as these
pass from breast to skin, their shortening results in tethering of the skin to
the underlying tumour. This may also occur, however, in chronic infection,
after trauma and, very rarely, in fibroadenosis, so that skin fixation to a
breast lump is not necessarily diagnostic of malignancy.
4◊◊Retraction of the nipple, if of recent origin, is suggestive of involvement
of the milk ducts in the fibrous contraction of a scirrhous tumour.
5◊◊The excision of a breast carcinoma by radical mastectomy involves the
removal of a wide area of skin around the tumour, all the breast tissue, the
pectoralis major (through which lymphatics pass to the internal mammary
chain), the pectoralis minor (which lies as a gateway to the axilla), and the
whole axillary contents of fatty tissue and contained lymph nodes. This exci-
sion also removes the bulk of the lymphatics from the arm which pass along
the anterior and medial aspects of the axillary vein. A few lymph vessels
from the upper limb pass above the axillary vein and are therefore saved.
Most surgeons today perform less extensive surgery for breast cancer;
for example, a simple mastectomy, in which the breast alone is removed, or
an extended simple mastectomy, which combines this with clearance of the
axillary fat and its contained nodes.
Oedema of the arm after mastectomy usually only occurs if further
damage is done to this precarious lymph drainage by infection, malignant
infiltration or heavy irradiation, or if additional strain is put on the evacua-
tion of fluid from the limb by ligation or thrombosis of the axillary vein.

Surface anatomy and surface

markings of the upper limb

Much of the anatomy of the limbs can be revised on oneself; otherwise
choose a thin colleague.