Final answer:
The lumen is the part of a needle that allows the fluid (medication) to flow from the syringe into the patient's body, through the pressure created by the syringe plunger.
Step-by-step explanation:
The part of the needle that allows the medication to flow from the syringe to the needle is known as the lumen. The lumen is the hollow interior through which the medication travels. During an injection, the syringe plunger is depressed, creating pressure that forces the medication through the lumen and out through the needle tip into the patient's body.
The syringe itself consists of a barrel (where the medication is held before administration) and a plunger (which the healthcare provider pushes to administer the medication). The needle is attached to the barrel and has the critical lumen that enables fluid flow. A proper understanding of the syringe mechanism is essential for healthcare providers to administer injections safely and effectively. The lumen is the hollow central channel of the needle that runs from the base of the needle to its tip. It is through the lumen that the medication travels from the syringe and is delivered into the body.