244 THE LARYNX, BRONCHI ANT> OESOPHAGUS be felt between the flat of the fingers and the muscles from the floor of the posterior triangle to the tip of the mastoid. The line of the sternomastoid muscle is next palpated deeply under the muscle because the glands in this region may lie about 2-5 cm from the surface of the skin. This palpation is continued down to the clavicle. At this point the examiner's fingers will be in the midline and in a position to palpate the thyroid and trachea. Further palpation upwards in the midline allows an assessment to be made of laryngo- pharyngeal size and contour. In the submental region palpation laterally will include the submandibular glands and finally the parotids. The first thing to determine about a neck mass is whether it is in the skin or deep in the neck. For example, a sebaceous cyst below the ear lobe may closely resemble a small parotid pleomorphic adenoma. A midline mass is usually single. One may differentiate between a thyro- glossal cyst and a thyroid adenoma by asking the patient to swallow and to protrude the tongue; a thyroid adenoma does not move on putting out the tongue but the thyroglossal cyst does. Chondroma of the cricoid is bony hard. Dermoids lie above the hyoid bone while thyroglossal cysts are found below it. Posterior triangle masses are usually glandular in origin (apart from the bony hard cervical rib) and multiple. The commonest causes of small- or medium-sized unmatted soft nodes are infectious mononucleosis, toxo- plasmosis, brucellosis and cytomegalovirus. Nodes from tuberculosis or a reticulosis are usually larger, matted and firm. Supraclavicular masses are nearly always due to metastatic glands from lung or stomach cancer depending upon the side. Submandibular gland swellings present below the mandible but never extend below the level of the hyoid or behind the angle of the mandible. Parotid swellings are easily diagnosed as to site if they are diffuse but small masses in the tail may be confused with jugulodigastric nodes. Generally speaking, parotid masses here are found behind the ear lobe whereas jugulo- digastric gland enlargement is related to the angle of the mandible. The difficult area is around the carotid bulb, especially if the mass appears to pulsate. The differential diagnosis is between a carotid body tumour, an enlarged gland due to tuberculosis, reticulosis, metastatic cancer, or a tense infected branchial cyst. Vagal tumours and nasopharyngeal metastatic glands are generally higher. A simple branchial cyst is found in this area and usually presents no difficulty in diagnosis, but if the swelling is tense it may be an infected cyst, a pyocele or a parotid abscess—all of which are painful to the touch. Moving a painless pulsating mass does not help in diagnosis because not only carotid body tumours but also other masses lying on or adherent to the carotid artery are movable from side to side but not up and down. Painless pulsating lumps commit the patient to having angiography done. If this investigation is not performed a surgeon may find himself in the position of operating on a neck mass which proves to be a carotid body tumour when no preparations have been made for a carotid artery by-pass. Finally, the mobility of every mass must be assessed. If a gland is fixed it does not mean that it is inoperable. It all depends upon what it is fixed to and whether the structure to which it is fixed, e.g. the mandible, can be removed along with the gland.