Cannula, obturator, stylet and needle hub connectors for lumbar disc puncture

A cannula has a hub formed with a hollow upward projection on its top which communicates with a lumen having a bore in the hub and the cannula itself. On one side of the hub is a vane having converging sides and a rounded end. The vane has a horizontal opening extending inward and the portion above the opening is cut away so that it is about half the thickness of the portion below the opening. A stylet or an obturator fits through the hollow projection, bore and cannula, extending to the tip of the cannula. A hub on the stylet or obturator has a socket to receive the cannula hub projection and a vane formed with a cutout to receive the portion above the opening of the cannula hub, the portion of the stylet or obturator vane below the cutout locking in the opening in the cannula hub. A hollow needle also fits through the hollow projection, bore and cannula and has a hub formed with a socket to receive the hollow projection and a fitting for attachment to a syringe. The end of the needle is bevelled and frequently curved. A vane on the needle hub orients the end of the needle by the alignment of the needle vane with the bevel.