The nose is comprised of 2 nasal airways which lie side by side like 2 rooms with a common wall & 2 outer walls. The doorways into the rooms are analogous to the nostrils. The outer walls are made of bone & nasal lining(mucosa). The common wall is called the septum. Just above the nostrils it is only mucosa (mucosal septum). Just above that it is cartilage sandwiched between 2 layers of mucosa (cartilagenous septum) and above that the cartilage is replaced by bone (boney septum).