The medical term for the inner diameter of a tube is "lumen."
The central hollow tube of an artery is known as the arterial lumen. Lumen is the general term for the hollow part of any tubular structure.
NG (nasal) generally have smaller lumen. An OG (oral) has a larger lumen size. They shouldn't be interchanged. Check the lumen sizes.
Suction lumen, Balloon, delivery lumen, airway suction port, gas delivery port
It is a two lumen tube that removes gastric contents. One lumen is a suction and the other is an air vent. The air vent never clamps or connects to the suction.
lumen - the central opening within a tube or hollow organ.
The lumen is the opening of the tube through which the "stuff" made by the gland exits. Some of that stuff (secretions) has hardened.
Ventricles & central canal of spinal cord
The empty space inside a tube is called the lumen. It is the hollow part through which fluid or air can flow.
Lumen
The eyepiece of a microscope is typically held in place by a tube called the eyepiece tube or the ocular tube, which is part of the microscope body. The eyepiece is inserted into the eyepiece tube and secured in place with set screws or a bayonet mount.
The 2002 Chevy Silverado dipstick tube is held in place with a retaining nut at the bottom of the dipstick tube. Loosen the retaining not in the dipstick tube will lift out.