Section 11. On the bursae mucosae of the tendons.
The bursae of the tendons, hurga muceota tendinum, are more complex than those of preceding classes; they are placed in all parts of the body where tendons are liable to friction; and according to their disposition, they are divided into two sets. The first species, called because of their figure, bursa mucosa tubularis, consist of rounded forms which are attached on one side to the tendon and on the other to the part, whatever it may be, on which the tendon glides; there are examples of these structures where the obturator internus lies between the gemellus, in the place where the tendon of the extensor carpi ulnaris lies against the lower extremity of the ulna, etc. Those of the second species are more complicated; they are called synovial sheaths or vaginiform processes, bursa mucosa vaginata. These structures resemble some of the more simple reflected serous membranes such as the pericardium; one part of the sheath surrounds the tendon and is closely adherent to it; the second, or reflected part, lines the canal which lodges the tendon; these two portions of the membrane are continuous with each other at their extremities; that is, where the loose portion is reflected. The vaginiform bursae are met with around many of the tendons belonging to the long muscles of the limbs; as on the flexors of the fingers, of the toes, etc.
The tendinous bursae constitute closed sacks and consequently each of them possesses a free and an adherent surface; the former is smooth and lubricated by the peculiar oily fluid which is secreted in the synovial system; the latter is closely attached to the tendon and to surrounding parts. These sheaths are provided in situations where tendons are exposed to friction; as, for example, where tendons cross over bones, especially in those places at which their course is altered by passing behind props, over pulleys, through grooves, etc.; it is evident from this statement that the greater number of the tendinous bursae must be disposed near the articulations of the limbs; as in the neighbourhood of the shoulder, elbow, and wrist; and of the hip, knee, and ankle.
In some of these bursae there are fringes which consist of folds of the membrane; they may be seen in several of the sheaths behind the inner malleoli. Frequently processes which have been incorrectly compared to excretory ducts, may also be observed in some of the vesiculated bursa. The synovial membranes of the tendons are of a whitish colour and semi-transparent; they are thin but firm in texture; the vesiculated bursae arc thicker than the vaginiform; both appear to be modifications of the common cellular tissue. They possess numerous small arteries, and some which also admit the coloured blood. No lymphatic vessels have yet been satisfactorily demonstrated, but it may be presumed that they exist. No nerves have been traced in these structures.
The use of the bursa is to facilitate the movements of the tendons by allowing them freely to play against the parts with which they are in contact; this is readily effected by means of the oily fluid which is secreted by the free surface.
Key Takeaways
- Bursae and synovial sheaths are crucial for reducing friction between tendons and surrounding tissues.
- These structures are found in areas where tendons cross bones or pass through tight spaces.
- Synovial fluid lubricates the bursa, allowing smooth tendon movement.
Practical Tips
- Understanding bursae can help identify potential sites for tendon injuries during physical activities.
- Maintaining joint health with proper nutrition and exercise can support synovial membrane function.
- Recognizing symptoms of bursitis early can prevent further damage to tendons and joints.
Warnings & Risks
- Ignoring signs of inflammation in bursae can lead to chronic conditions like bursitis.
- Overuse or repetitive strain on tendons without proper support from bursae can cause injury.
- Improper treatment of tendon injuries may result in long-term joint dysfunction.
Modern Application
While the anatomical descriptions provided here are foundational, modern medicine has advanced significantly. Understanding these structures is still crucial for recognizing and treating conditions like bursitis or tendinitis. However, contemporary medical practices such as anti-inflammatory medications, physical therapy, and surgical interventions offer more effective treatments than what was available in 1829.
Frequently Asked Questions
Q: What are the two main types of bursae mentioned in this chapter?
The chapter mentions two main types: tubular bursae (bursa mucosa tubularis) and vesiculated or vaginiform bursae (bursa mucosa vaginata).
Q: What is the primary function of synovial fluid in relation to tendons?
Synovial fluid lubricates the free surface of the bursae, allowing for smooth and frictionless movement of tendons against surrounding tissues.
Q: Where are bursae most commonly found within the body according to this chapter?
Bursae are typically located in areas where tendons cross over bones or pass through tight spaces such as near joints like the shoulder, elbow, wrist, hip, knee, and ankle.