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.
Tingling, tingly, pins and needles feelings can be caused by a number of factors including: 1  Remaining in the same position (seated or standing) for a long time.  Injury or pressure on a nerve (for example, a back injury can cause numbness in the legs or feet, and a neck injury can cause numbness in the arms and hands).