Figure 52-2. A, Medial aspect of the bony framework of the lateral wall of the right nasal cavity. The lateral boundary of the piriform aperture is formed by the nasal bone and the maxilla; that of the choana is formed by the medial pterygoid plate of the sphenoid bone. Note the line of the spheno-occipital junction. B, Lateral aspect of the medial wall (nasal septum) of the right nasal cavity. The lower limit of the ethmoidal contribution to the septum varies widely. The attachment of the septal cartilage to the vomer and the maxilla allows considerable movement without dislocation. Click for high resolution image: A or B.