THE FUNNEL CHEST A round or oval depression in the median line of the anterior wall of the thorax is known as funnel chest. The depression may be only a small cavity, but it may also attain to such a size as to receive easily the fist of a man.
The depression begins in the upper region of the sternum at the point of its articulation with the second rib (Ludwig's angle). The greatest depth of the cavity is located generally several centimetres below the inter-mammillary line. Further below, the wall of the funnel rises again to end somewhere between the xyphoid process and the navel. The of the funnel laterally varies likewise. In pronounced cases the cavity may extend to the nipples.
From the description of the location of the funnel it may he easily inferred that the deformity is caused by an abnormal condition of the sternum, which presents an arched curvature with the convexity inward. The condition has also been termed loyphosis of the sternum.
The anterior ends of the ribs a-re bent in the opposite direction, the convexity facing to the front along the border of the funnel.
It is manifest that, owing to the deformity, the sagitt al diameter of the chest is more or less diminished. In marked cases it is not more than 3 to 4 cm.
As a rulo the transverse diameter of the chest is increased.
Funnel chest may exert an influence upon the location of organs within. Some authors have observed displacements of the heart to the left as far as the anterior axillary line and a lowering of the inferior pulmonary border, clue entirely to the funnel-shaped condition of the sternum. The functions of the thorax and abdominal organs are, as a rule, not impaired.
Etiology.—Opinions as to the cause of funnel chest differ widely. Recent observations seen to substantiate the hypothesis that funnel chest is caused by abnormal intrauterine pressure. In some cases the chin, in others the elbow or a foot has been accused of producing the detrimental pressure. The theory is further supported by the fact that
in quite a number of patients with funnel chest other deformities are evident, for example, congenital dislocation of the hip, club-foot, and congenital deficiency of the pectoral muscle, all well known as intra uterine disturbances due to overpressure and weight.
Other authors consider funnel chest to be a result of faulty develop ment, a congenital defect.
To aid this hypothesis, reports of different cases of funnel chest in the same family are published, claiming that heredity plays an impor tant role in a number of them.
Ebstein assumed that, owing to its slow growth, as compared with the other parts of the chest, the sternum does not attain to a full develop ment. Exception must be taken to the correctness of his opinion, inas much as in all reported cases the sternum itself was not thrust back in toto, but, as Byrston pointed out, presented only a kyphotic curvature.
The treatment of funnel chest is confined to a few measures. It has been attempted by means of forced expirations, as in blowing a horn, to thrust the depressed parts forward by exerting pressure from within upon the sternum and the anterior ends of the ribs.
Improvements after prolonged deep breathing exercises have also been reported. However, complete recovery has not been observed up to the present time.
Adhesive plaster bandages applied for the purpose of raising the sternum from the outside are, in our opinion, entirely ineffective.
Thus far the application of a vacuum has produced the best results. We placed a bell-glass over the depressed part and established a vacuum with a pneumatic pump; elevation of the funnel wasimmediately observed.
The technic of the method is rather complicated, because of the difficulty in adapting the sides of the bell-glass to the uneven surface of the anterior chest wall. This is accomplished by introducing a thick ring of Unna's zinc paste between the glass and the thorax.