Site and blood supply of the intertruncal glomera

Chronic carotid glomitis and the glomus pulmonale

A histological study was made of the carotid bodies and glomus pulmonale in 50 consecutive subjects over the age of 50 years who came to necropsy to determine if chronic glomitis is confined to the carotid bodies or whether it also occurs in other glomera. Lymphoid aggregates and plasma cell activity were found in the glomus pulmonale just as they were in the carotid bodies. Chronic pulmonary glomitis sometimes occurred in association with chronic carotid glomitis and sometimes independently of this. The mean age of the affected subjects was 76 years in isolated pulmonary glomitis and 79 years in chronic carotid glomitis. Chronic carotid glomitis affected seven (14%) subjects and predominated in women (six to one). In the seven cases of isolated pulmonary glomitis women predominated five to two. Chronic glomitis seems to be a disease process which may affect at least two members of the non-chromaffin paraganglionic system, but it is not clear why focal chronic inflammation affects the glomus pulmonale of one person but not of another.

Structure of the glomic arteries

The structure of the arteries which supply blood tp the carotid bodies was examined in five cases in which the weights of the cardiac ventricles were normal and in which hypoxaemia due to emphysema or systemic hypertension were absent. The right glomic arteries were studied by light microscopy, and the left by electron microscopy. A sixth case, also free from myocardial hypertrophy, was used solely for an examination of the common carotid artery, the carotid sinus and the internal carotid artery by light and electron microscopy. The glomic arteries resembled the carotid sinus in being highly elastic with a rich supply of non-myelinated nerve fibres and thus had a structure consistent with having a baroreceptor function.

Hyperplasia of the carotid body

The histopathology of hyperplasia of the carotid bodies was studied in 6 cases of hypoxaemia and right ventricular hypertrophy secondary to pan-acinar emphysema, and in five cases of systemic hypertension with left ventricular hypertrophy. The features of the hyperplasia were the same in the two groups. There was proliferation of sustentacular (type II) cells and compression of central cores of chief (type I) cells. It is speculated that the hyperplasia of sustentacular cells is associated in some way with the prevention of retention of sodium ions and water which characterises hypoxic cor pulmonale in "blue bloaters", systemic hypertension, and ascent to high altitude with the complications of acute mountain sickness, and pulmonary and cerebral oedema.