Section Ii. of the Larynx and Trachea.

Inflammation, ulceration, œdema, necrosis of the cartilages, tumors and false membranes are the more usual pathological conditions of these parts that may claim the attention in a post-mortem examination.

=Inflammation= of the mucous membrane of the larynx (laryngitis) and trachea, will appear as a diffused redness, with some thickening of the membrane, and within which may be traced many small, congested blood-vessels. It may be important to distinguish the redness of inflammation, from that attending the early stage of decomposition, which, it is an interesting fact to know, first appears in these parts. Immediately after death, the mucous membrane is pale, except in death from suffocation or laryngitis. In a day or two it becomes of a dusky red, which is distinguished from that of inflammation by the absence of congested vessels; the redness of decomposition, also, having a superficial filmy appearance, as if washed with dirty wine.

=Ulceration= of the larynx commences in the mucous membrane, but may extend to the deeper parts. The more usual location is upon the epiglottis, or on the margin of the glottis and vocal cords. Impairment of the voice to a greater or less degree, will have attended either inflammation or ulceration of the vocal cords. It is to be borne in mind, however, that aphonia may arise from some impairment of the nerves of the larynx, in which case, a post-mortem examination will fail to reveal any morbid condition of the mucous membrane or vocal cords.

Pulmonary consumption we sometimes find accompanied with the presence of ulcers upon the posterior walls of the larynx, with evidence of inflammation in the surrounding parts. Whether these arise from tubercles in the mucous membrane, or ulceration of the mucous follicles, is uncertain.

=Œdema= of the larynx, is attended with great swelling of the mucous membrane, from serous effusion into the submucous tissues, and frequently attends chronic inflammation of the parts, with ulceration. It may, however, be of an erysipelatous character, occurring as the result of exposure to infection. The surface appears red, pulpy and swollen, from infiltration of the submucous tissue. Œdema of the larynx, is confined to the parts around the epiglottis, and margins of the glottis, never descending below the true vocal cords, owing to the close adhesion of the mucous membrane to the fibrous structure of the cord, without any intervening areolar tissue.

=Necrosis of the Cartilages= of the larynx, may occur in the advanced stage of laryngitis with ulceration. In this manner the epiglottis, with the arytenoid, the cricoid, and even thyroid cartilages may, to a greater or less extent, be destroyed.

=Abscesses= may also form, where the cartilages are so much involved, these in some cases breaking upon the outside, and establishing fistulous communications through which air may escape during respiration.

=Tumors= of the larynx, may be found first, outside of the cavity, imbedded in some portion of its tissues; and may include encysted, fatty or fibrous tumors; or, second, they may be found in the interior, springing from the mucous membrane, and resembling polypi in their form and structure. They are sometimes granular or cauliflower-like in appearance, and vary in size from a pea to a hazel-nut.

=False Membranes= may be found in the larynx and trachea in fatal cases of croup or diphtheria. In croup, the membrane adheres but slightly to the mucous structure beneath, which will be found red and congested, but may form a complete tubular lining to both larynx and trachea, extending also into the bronchial tubes. It is usually tougher in the larynx and upper portion of the trachea, becoming softer and more gelatinous in the lower portion of the trachea and bronchial tubes. Much difference of opinion has been entertained as to the nature of this substance. It may, however, be considered as a morbid secretion from the inflamed mucous surfaces, in a semi-fluid form, which, in consequence of the presence of albuminous matter, coagulates upon exposure to air.

The false membrane of croup may generally be distinguished from that of diphtheria by the fact, First, That the latter is usually confined to the fauces, sometimes extending to the larynx, rarely to the trachea. Second, That diphtheritic membrane occurs more in patches, is tougher, is more directly incorporated with the mucous surface beneath, and is removed with more difficulty. Third, A microscopic examination shows the membrane to be composed mainly of fibrine in a fibrillated condition, with granular corpuscles and pus cells.