Syringe device with protective cap

A syringe device comprising:

• a syringe body having a distal end fitted with an injection needle;
• at least one sheath inside which the syringe body is positioned;
• a protective cap having:
• (i) a protection position, wherein the cap is retained relative to the syringe body such that a distal end of the cap is located at a shortest distance, as measured along a longitudinal axis of the needle, from a distal end of the needle so as to cover the needle, movement of the distal end of the cap with respect to the distal end of the needle from the protection position being limited to a distal direction along the longitudinal axis, and
• (ii) a free state, wherein the cap is separated from the syringe body to release the needle;
• and
• an elastic lip joined to the sheath and which forms a closed ring having a free end, the lip being elastically constrained wherein the free end defines a first diameter when the cap is in the protection position and defines a second diameter in the free state, the second diameter being smaller than the first diameter to oppose refitting of the cap in the protection position once the needle has been released, wherein in both the protection position and the free state, the free end of the elastic lip is located distally of the joint of the elastic lip with the sheath.