Double-lumen follicle-biopsy cannula

Double-lumen biopsy cannula, especially for follicle biopsy as part of extracorporeal fertilisation, the biopsy cannula having a suction channel (4) with a larger lumen for aspirating the follicle contents, and a rinsing channel (3) with a smaller lumen for supplying rinsing liquid into the interior of the follicle, and the suction and rinsing channels terminating in a sharpened piercing tip. The biopsy cannula is designed as a double-walled tube comprising two coaxial tubes fitted tightly into one another: an outer tube (1) having an essentially circular cross-section and an inner tube (2) which is at a distance from the inner circumference (1.1) of the outer tube (1) with its wall, at least over a part-section of its circumference whose angle at circumference ( alpha ) is smaller than pi /2. The spacing (3) formed as a result between the inner tube and the outer tube having the radial width (a) and the middle chord length (b) is intended as a rinsing channel, whereas the remaining channel cross-section (4) of the inner tube (2) is intended as the suction channel.