10 CLINICAL APPLIED ANATOMY. 



Submandibular Abscess. Abscess in the region beneath the 

 mandible is by no means rare, and is generally induced by septic 

 lymphadenitis of the submandibular glands caused by infection 

 from the mouth. 



Suppuration may be late, but extensive infiltration and oedema 

 is often early, and may induce dyspnoea by involving the loose 

 cellular tissue around the upper opening of the larynx. Incision 

 and free evacuation of the pus is necessary. 



SEPTIC^MIA AND PYAEMIA. 



Any focus of micro-organisms is a source from which bacteria 

 or their toxins may pass into the blood or lymph circulation. 



When pyogenic cocci enter the blood stream of the systemic 

 circulation it is generally into the capillaries and venous radicles 

 that they pass. If they are not rapidly killed or their toxins 

 neutralised, they are carried to the right side of the heart. Here 

 endocarditis may occasionally occur. The bacteria, however, 

 are usually swept into the lung capillaries, possibly to set 

 up pulmonic and pleural disease. If they traverse these 

 capillaries, which are large and allow ready passage, the left side 

 of the heart is next invaded, and again endocarditis may 

 supervene. 



Passing into the arterial system from the left ventricle, the 

 bacteria may travel to any part of the system, and may lodge in 

 any capillaries, but particularly those of the kidneys and the 

 synovial membranes of joints, in the former because the renal 

 organs are excretory, in the latter because there is always some 

 liability to slight degrees of trauma. 



If at the seat of infection thrombosis of small venules occurs, 

 there is a probability of infected emboli being detached and 

 carried in the blood to distant parts. These from their nature 

 are more apt to plug capillaries either of the pulmonary or 

 systemic circulation than are bacteria alone. 



When pyogenic bacteria enter the radicles of the portal circu- 

 lation, they are carried direct to the capillaries of the liver, there 

 to excite portal pyaemia or pylephlebitis. If they are not caught 



