Outline:  
Thecal cyst is a cystic mass occurring around joint or inside tendon sheath. Within the cyst there is colorless and transparent or whitish or yellowish thick mucous liquid. The disease is often caused by strain, or induced by trauma. It is related to the retrograde degeneration of connective tissues resulting from malnutrition within the articular capsule, ligament and sheath. The cysts are not always communicated with articular cavity or thecal synovial cavity. The cystic wall is composed of dense and tough fibroid connective tissue, and inside it there is mucus.

Major points for diagnosis  
1. The disease occurs mostly in youth or the middle-aged people, and the female incidence is higher. The most affected part is dorsal side of wrist, occasionally it occurs in the palmar side of wrist, anterior part of ankle or dorsum of foot.
 
2. The onset is rapid, but the progress is slow. The big cyst manifests itself as a hemispherical eminence, with a smooth surface, no color change of the skin, no connection with the skin and normal local temperature.
 
3. The base of the cyst is fixed or movable when being pushed, of rubber-like hardness or cystic sensation. There is slight or no tenderness.

Treatment  
Tendon-smoothing manipulation:
For the case with a thin wall of cyst, finger-pressure method may be applied to make the cyst broken. If the cyst is in the wrist, the wrist should be flexed toward palm as much as possible so that the cyst is prominent and fixed. The operator uses his two thumbs to do counter pressure on the cyst forcefully to break it off. Then he applies massage manipulation for resolving swelling and promoting blood flow. Finally, local bandaging is done for one or two days.
 
For the case with thick cystic wall and low tension inside the cyst and that the cyst can not be broken by pressure, a three-edged needle is used to prick the cyst. After withdrawing the needle, press around the cyst to make its content spread over subcutaneously, then pressure bandaging with sterile dressing is applied for one or two days.

Herbal therapy:
For the case whose cystic wall has been broken with small cyst and localized hypertrophy, Huixiang wine may be externally applied, or Wanying Plaster is externally applied in order to promote resolving the mass.

Hydro-acupuncture therapy:
Some cases of thecal cyst are polycystic. Under routine disinfecting and local anesthesia, a big syringe needle is used to draw up the fluids in the cyst as much as possible. Then, fix the needle, change the syringe for another one, inject 2 to 4 ml of 1% procaine plus 12.5 or 25 mg prednisolone. Finally, cover with sterile dressing and bandage it forcefully.