Self locking surgical retractor

A medical retractor for holding open an incision in a body tissue comprising:

• a support shaft having threads on an outer surface thereof;
• a first retractor arm;
• a first retractor arm drive including
• a first housing having an opening sized and shaped to receive the first retractor arm,
• a first worm gear rotatably mounted within the first housing and having
• a bore having internal threads sized and shaped to receive and engage the threads on the support shaft, and
• worm gear teeth around the first worm gear;
• a first worm having threads and rotatably mounted in the first housing so that the threads on the first worm engage with the worm gear teeth on the first worm gear;
• a second retractor arm;
• a second retractor arm drive including
• a second housing having an opening sized and shaped to receive the second retractor arm, and
• a second worm gear rotatably mounted within the first housing and having
• a bore having internal threads sized and shaped to receive and engage the threads on the support shaft, and
• worm gear teeth around the worm gear;
• a second worm having threads and rotatably mounted in the first housing so that the threads on the worm engage with the worm gear teeth on the worm gear, whereby rotating the first and second worms turns the respective first and second worm gears, thereby moving the respective first and second retractor drives and associated first and second retractor arms in an axial direction along the support shaft.

A medical retractor for holding open an incision in body tissue comprising:

• a support shaft;
• first and second retractor arm drives mounted on the support shaft for longitudinal motion along the support shaft;
• first and second retractor arms mounted in the first and second retractor arm drives, respectively, to be generally parallel with each other and extend generally perpendicularly with respect to the support shaft, each of the retractor arms having a groove extending longitudinally and centrally on an upper surface of the respective retractor arm;
• first and second retractor blades, each of the retractor blades having a connector at an upper end slidingly mounted on a respective one of the retractor arms, each connector having a projection extending downward into a respective groove of one of the retractor arms, whereby the disposition of the projection into the grooves helps to retain the retractor blades on the respective retractor arms and further helps to guide motion of the retractor blades along the respective retractor arms.