Final answer:
The question appears to be confused between anatomical terminology for the human nose and parts of a military aircraft, the P-8 Poseidon. The external nose includes the root, bridge, dorsum nasi, apex, alae, nares, and philtrum. No accurate location for BRU 3 and BRU 4 on a P-8 can be provided based on this terminology.
Step-by-step explanation:
The query about BRU 3 and BRU 4 locations on a P-8 seems to be a mix-up with terminology, as BRU refers to Bomb Rack Units found on military aircraft such as the P-8 Poseidon, not anatomical terms related to the human nose. Due to this confusion, it is important to clarify that the answer provided relates to the external structure of the human nose rather than aircraft components.
The external nose consists of several parts contributing to its structure and function. The root is the area located between the eyebrows, while the bridge extends from the root to connect with the rest of the nose. The 'dorsum nasi' refers to the entire length of the nose. At the very tip is the apex, which is surrounded by the nostrils, formed by the alae on either side. Each ala is a cartilaginous structure that constitutes the lateral side of the naris (nostril opening). Lastly, the philtrum is the concave surface that links the apex of the nose to the upper lip.