PART VI. 



CHAPTER 41. 

 BCKSAL ENLARGEMENTS. 



637. Nature of Bursal Enlargements. 638. Synovial Membranes. 639. 

 Causes of Bur sal Enlargements. 640. Bog Spavin. 641. Thorough-pins. 

 642. Of Thorough-pins arising from irritation of the true Hock-joint. 643. 

 Of thorough-pins arising from irritation of the Flexor pedis tendon. 644. 

 Windfalls. 645. Treatment of Bursal Enlargements. 645a. Dry pressure 

 bandages. 6455. Further treatment. 646. Decrease of Bursal Enlarge- 

 ments in old age. 647. Dealers. 648. Blood Spavin. 



637. Nature of Bursal Enlargements. 



Thorough-pins, Bog Spavins, Windfalls, and such like affections, in 

 whatever part appearing, may all be conveniently classed under the com- 

 mon head of Bursal Enlargements. 



Such enlargements, though proceeding from various causes, are in 

 themselves simply distensions of the bursse or sheaths, which enclose all 

 true joints and certain parts of all tendons and of some ligaments. The 

 enlargement in recent cases arises wholly from an increased secretion of 

 Synovia, otherwise called joint oil ; but in cases of long standing it is 

 often much increased by thickening of the synovial fringes, and some- 

 times also by the products of inflammatory action in the bursa. 



638. Synovial Membranes. 



Nature has endued these bursie and sheaths with a lining membrane, 

 which secretes Synovia, a fluid resembling oil, for the due lubrication of 

 the parts. 



It is not necessary here to enter into the physical structure of Synovial 

 membranes. It may be sufficient to say that the outer coat of the mem- 

 brane is thick, tough, and but slightly sensitive ; whilst its inner lining 

 is highly vascular and sensitive. From this inner lining is secreted the 

 clear, bright, glistening, pale straw-coloured sero-albuminous fluid, known 

 as Synovia or joint oil. 



