A laryngoscope, which enables you to look directly at the larynx, and push a tube through it, is one of the most useful of all instruments, but don't forget the advantages of indirect laryngoscopy, with an angled mirror. Its great advantages are that you can do it on an outpatient, it needs only simple equipment, and it can be very informative. But it is not easy, and you will have to do it fairly often, if you are going to become competent with it. The main indication for indirect laryngoscopy is to examine the vocal cords in order to: (1) Distinguish chronic laryngitis from a polyp or carcinoma. (2) Check the movement of the cords, when one of them is suspected of being injured, as after thyroidectomy, or by a carcinoma of the bronchus on the left side.

LARYNGOSCOPY DIRECT LARYNGOSCOPY. Do this as for tracheal intubation, see A 13.2. You can more easily get a good view; take a biopsy with Magill's forceps or straight alligator forceps, but be careful not to damage the patient's cords.

INDIRECT LARYNGOSCOPY INDICATIONS. Hoarseness lasting more than 4 weeks. He is more likely to have laryngitis, but he may have a polyp, or carcinoma.

EQUIPMENT. A good light coming from behind him and slightly to one side. A head mirror with a band, laryngeal mirrors and a spirit lamp, 4% lignocaine in a laryngeal spray.

METHOD. Sit opposite him, and arrange the light so that it comes from over his shoulder.

Wrap gauze round his protruding tongue, and pull it forwards with your left hand. Spray his fauces, soft palate and pharynx with lignocaine.

Warm an angled mirror in the flame of a spirit lamp, and test its temperature on the back of your left hand; it should feel just warm, but not hot. Place the back of the mirror against his soft palate, push a little and look down at his larynx. Identify his cords.

Normal cords are white. Laryngitis makes them red, and chronic laryngitis also makes them swell. If you see a lump, it is probably a polyp. A ragged ulcer is likely to be a carcinoma.

Ask him to say ''Eee[...]'' and note the movement of both his cords.

To examine his nasopharynx, depress his tongue with some soft instrument, and place a smaller (14 mm) rhinoscopic mirror in his pharynx, so that your line of sight passes up behind his soft palate.