The trachea bifurcates, or divides, into two branches at its most distal portion and forms the bronchi. The bifurcation is reinforced by a cartilaginous plate called the carina. Like the trachea, each bronchus is made up of cartilaginous rings to keep the lumen open as it goes into the lung. As the branches get smaller, they are called secondary bronchi and segmental (or tertiary) bronchi.
Pins and Needles - Paraesthesia. The most common cause of pins and needles is a moderately pinched nerve. Pins and needles is referred to as paraesthesia in the medical community. Did you know that feeling pins and needles can actually be a worse sign than having pain in your arm or leg.
1. Femoral nerve. There is a strong association between what you are feeling in the lower limb and what's happening in the lumbar spine, pelvis and hips; very painful radiating nerve pain emanating from the lumbar spine or the pelvis may cause pain, numbness, weakness and tingling in the feet and legs.