The shin of the nose is thin and movable over the nasal bones, but below is thick and adherent to the cartilage, and abundantly supplied with sweat and sebaceous glands. The lower portion is frequently affected by acne rosacea, which in cases of chronic dyspepsia sometimes causes considerable hypertrophy, to which the misleading name of 4 grog-blossoms ' has been given. Lipoma nasi is a diffuse irregular enlargement of the same portion, all the tissues, but especially the fatty elements, hypertrophying. Suppurative processes in this region are generally very painful, owing to the density of the tissue and the abundant nerve-supply. The upper part is supplied by the infratrochlear branch of the nasal, the middle by branches of the infra-orbital, and the lower by the nasal. The nasal nerve, being a branch of the ophthalmic of the fifth, explains the watering of the eyes, which occurs from painful affections of the nostril. The skin of the nose is plentifully supplied with blood by branches of the ophthalmic and facial arteries, and hence healing of wounds occurs very readily. Indeed, a portion of nose which had been cut off, but kept warm, has been successfully stitched on after an interval of nearly half an hour. On the other hand, on account of its exposed position, the nose is sometimes affected by frost-bite. The nose tends to become engorged with blood, especially in alcoholics, and sometimes becomes livid in persons suffering from obstructive heart disease, etc. While rodent ulcer sometimes attacks the skin at the junction of the ala and cheek, the cartilaginous portion of the nose is not infrequently destroyed by tubercular (lupus) and syphilitic ulcerations. Each ala of the nose is supported by an upper and lower lateral cartilage and several accessory cartilages. The upper cartilage is attached to the nasal bone and superior maxilla, and the lower one does not extend as far as the nostril. A nasal speculum should not be introduced beyond the limits of this cartilaginous portion. Various plastic operations (rhinoplasty) have been devised to remedy defects of the nose. In the Tagliocotian operation a flap is raised from the front of the upper arm, which is fixed in front of the face, and not separated from the arm until it has united to the face. A flap also has been cut from the forehead, and turned down to form a nose, the frontal artery supplying it with blood. The nasal bones are not infrequently fractured by direct violence, especially in their lower third. Such fractures are generally accompanied by considerable deformity, and, as the mucous membrane of the nose is generally lacerated, are compound. Free epistaxis and emphysema of the surrounding tissues, especially on blowing the nose, are liable to occur. As the nasal bones heal very readily (about seven days, according to Hamilton), an early attempt should be made to rectify any deformity, and as the meatus is rendered particularly narrow by the swelling of the parts, only a fine instrument (stout probe) should be introduced to aid the process. In some very severe injuries the nasal septum may also be damaged. The nasal' bones are frequently affected in infancy by hereditary syphilis, causing a permanent depression of the bridge of the nose, while the infant also 'snuffles.'
The nasal fossae, separated by the septum, include the anterior and posterior nares. The anterior nares, or apertures of the nostrils, are small, directed downwards, and are on a lower level than the fossae. The posterior nares, choanae, or posterior outlets, communicate with the naso-pharynx.
The nasal septum consists of the nasal spine of the frontal bone, vertical plate of the ethmoid, rostrum of the sphenoid, the vomer, and the palatal crests of the palate and superior maxillary bones, while the interval is filled in by the cartilaginous septum.
The cartilaginous nasal septum is generally deflected after the seventh year, due probably to continuation in vertical growth in the bones after they have met, or perhaps to the habit of blowing the nose with one hand. It is frequently attacked in acquired syphilis, producing perforation or even destruction, with consequent flattening of the nose, chrome-workers sometimes suffering from a similar affection. Congenital syphilis generally produces a depression of the bridge of the nose, and both forms may involve the bony framework, sometimes causing perforation of the hard palate.
The roof of the nasal fossae is arched, and formed anteriorly by the groove in the nasal bones, then by the cribriform of the ethmoid, and posteriorly by the sphenoidal turbinates. Its narrowness (1/8 inch) protects it to a large extent from injury from all but sharp-pointed instruments. The lyrnphatics of the nose run along the sheaths of vessels and nerves through the cribriform to the meninges, and thus meningitis may follow a septic condition in the nose.
Fracture involving the cribriform plate is sometimes associated with escape of cerebro-spinal fluid, the membranes being ruptured. Meningoceles occasionally protrude through the nasal roof, and may be mistaken for polypi ; but they more frequently present externally at the root of the nose through the suture between the nasal and frontal bones, where they have been mistaken for naevi.