the level of the hyoid bone it receives the large common facial vein, while at an inferior level it receives the superior and middle thyreoid veins which are often greatly enlarged in goitres. By the term deep cervical glands is included a broad chain of lymph glands which is closely related to the internal jugular vein, and which stretches from the transverse process of the atlas to the root of the neck. The chain is in reality made up of subsidiary glandular groups, each of which receives its lymph vessels from fairly well-defined areas. In the first place, the chain may be divided into an upper and a lower portion, the former situated above the bifurcation of the common carotid artery, the latter below it. Each of these divisions is again subdivided into a medial and a lateral chain. Of the four groups, the superior medial is the most important, as it is there that disease first manifests itself in the vast majority of cases. The reason for this predilection is the fact that this group of glands, in addition to receiving efferent lymph vessels from the glands of the circular chain, receives also lymph vessels directly from the nasal part of the pharynx, including the palatine and pharyngeal tonsils. These latter structures are now known to provide the chief portals of entrance through which the tubercle bacilli reach the efferent lymph vessels. Wood, of Philadelphia, has succeeded in tracing the lymph vessels from the palatine tonsils directly into one of the glands of this group, namely, that situated a little below the angle of the mandible, under cover of the anterior border of the sternomastoid immediately below the posterior belly of the digastric. The relations of the deep surface of this gland are important. It lies upon the anterior surface of the internal jugular, in the angle between it and the common facial vein. It plays such an important rôle in tuberculous adenitis that it is now termed by surgeons the tonsillar lymph gland. In the great majority of cases it is the first gland in the neck to show signs of tuberculous enlargement. When the superior medial deep cervical glands become enlarged they form a swelling which projects from beneath the sterno-mastoid forwards into the carotid division of the anterior triangle. The mass soon becomes adherent to the general envelope of deep cervical fascia, and, if the disease is allowed to run its course, the latter becomes perforated, with the result that a subcutaneous tuberculous abscess soon develops. The glands are also liable to become adherent to the digastric muscle, and to the stylo-mandibular ligament, which separates them from the submaxillary lymph glands. The most important adhesions, however, from the surgeon's point of view, are to the common facial and internal jugular veins. The superior lateral group of deep cervical glands lies postero-lateral to the internal jugular upon the origins of the splenius and the levator scapulæ muscles. They are smaller in size than the medial group, but when enlarged they may form a swelling which projects across the posterior triangle as far as the trapezius. They are embedded in a quantity of fibro-fatty tissue which supports the accessory nerve and the cervical plexus. Wood has shown that the lymph vessels from the pharyngeal tonsil, after piercing the posterior wall of the pharynx, pass downwards and laterally behind the sheath of the great vessels to enter the glands situated deeply, just below the tip of the mastoid process. The inferior medial group forms a somewhat narrow chain, which is continued down the anterior aspect of the internal jugular as far as its junction with the subclavian. Above the bifurcation of the common carotid artery this chain is continuous with the superior medial jugular group, while, below, it comes into relation with the superior mediastinal glands. The inferior lateral group of deep cervical glands is continuous above with the superior lateral group. Like the superior lateral group, they lie altogether behind the internal jugular vein, upon the levator scapulae, the scalenus medius, and the brachial plexus. The most inferior glands of the group, viz., the supraclavicular, are subdivided into a superficial and a deep cluster by the omo-hyoid muscle and the middle layer of deep cervical fascia. They receive their afferent vessels from the subclavicular group of axillary glands. The hypoglossal nerve is deeply placed in the carotid triangle, being overlapped by the internal jugular vein and the inferior border of the posterior belly of the digastric muscle. It crosses forwards, superficial to the occipital and internal and external carotid arteries, immediately below the origin of the superior sterno-mastoid branch of the first-mentioned vessel. The vagus nerve descends vertically, within the carotid sheath, behind and between the carotid vessels and the internal jugular vein; care must be taken not to include it when ligaturing the common carotid or internal jugular. Surgically, the accessory is the most important nerve in the anterior triangle; it enters the substance of the sterno-mastoid muscle 1 in. below the tip of the mastoid process. A portion of the nerve is resected in the treatment of spasmodic wry-neck, and it is always exposed in the removal of the medial group of deep cervical glands. The course of the nerve may be mapped out upon the surface by drawing a line from a point midway between the tip of the mastoid process and the angle of the mandible to a little above the middle of the posterior border of the sterno-mastoid muscle, and thence across the posterior triangle to the anterior border of the trapezius, beneath which it passes at the level of the seventh cervical spine. The deeper guides to the nerve are the posterior belly of the digastric, and the internal jugular vein which it crosses, very obliquely, from above downwards and backwards below and in front of the transverse process of the atlas (felt as a distinct bony landmark midway between the tip of the mastoid and the angle of the mandible). The cervical sympathetic lies in the posterior wall of the vascular compartment of the neck, and may be reached by an incision along the posterior border of the sterno-mastoid: the anterior surfaces of the roots of the transverse processes of the vertebræ are the deep guides to the nerve. The cervical plexus, which lies deep to the superior half of the sterno-mastoid upon the levator scapula and scalenus medius muscles, may be exposed through an incision along the posterior border of the upper half of the sterno-mastoid muscle. The phrenic nerve, the most important branch of the cervical plexus, arises one inch above the carotid tubercle and descends almost vertically upon the scalenus anterior; it is overlapped by the lateral margin of the internal jugular vein. Although frequently exposed by the surgeon in removing the lower medial group of deep cervical glands, the phrenic nerve is protected from injury by being covered by the prevertebral fascia. The muscular or lower carotid triangle is an important triangular intermuscular space bounded by the anterior border of the sterno-mastoid, the anterior belly of the omo-hyoid, and the sterno-hyoid. Behind this space, and forming, as it were, its floor, is a still deeper space bounded by the longus colli and scalenus anterior muscles. It may with advantage be termed the prevertebral intermuscular triangle, or, from the fact that it contains the vertebral artery, it may be termed the vertebral arterial triangle. At its apex is the prominent anterior tubercle of the transverse process of the sixth cervical vertebra. By making an incision along the anterior border of the left sterno-mastoid muscle, and passing through this triangle, the surgeon reaches, in order from before backwards, the internal jugular vein, the common carotid artery, the vagus, the thoracic duct, the middle cervical ganglion of the sympathetic, the inferior thyreoid artery, the vertebral vessels, the recurrent nerve, and the oesophagus. The most important bony landmark in this triangle is the prominent anterior tubercle of the transverse process of the sixth cervical vertebra. The common carotid artery may be compressed against this tubercle, which is therefore termed the "carotid tubercle." It is the most important guide to the vertebral artery, which enters the foramen in the transverse process of the sixth cervical vertebra. The cervical portion of the œsophagus, which begins at the level of the cricoid cartilage, descends behind, and a little to the left of, the trachea. To expose it, the surgeon, after passing through the above-mentioned muscular triangle, divides the pretracheal fascia, and passes between the trachea and the carotid sheath down to the longus colli muscle medial to the inferior thyreoid artery and vertebral vessels. The lower pole of the corresponding lobe of the thyreoid gland is retracted medially along with the trachea. The oesophagus lies in the loose cellular tissue in front of the prevertebral fascia; hence it can be mobilised sufficiently to admit of its being brought to the surface. The oesophagus may also be exposed through an incision in the median plane, the trachea, which is freely movable, being displaced to the right side. In opening the oesophagus care must be taken not to injure the recurrent nerve, which ascends in the groove between it and the trachea, and also that the loose submucous cellular interval must not be mistaken for the lumen of the tube. The recurrent nerve must be avoided also in operations connected with the thyreoid gland; it is most liable to be injured during the application of a ligature to the inferior thyreoid artery, which arches medially in front of the nerve to reach the posterior surface of the gland. THE THORACIC DUCT. The thoracic duct, after entering the root of the neck between the oesophagus and the pleura, ascends to about an inch above the clavicle. At this level it arches laterally behind the lower part of the carotid sheath in front of the vertebral vessels. Great care must therefore be taken not to injure the duct in removing the lymph glands which lie in the loose cellular tissue behind the inferior part of the internal jugular vein, between it and the vertebral vein at the medial border of the scalenus anterior. In addition to those glands a few small lymph glands lie adjacent to the lateral aspects of the cervical portions of the trachea and œsophagus. They receive their afferent vessels from the larynx, trachea, œsophagus, and thyreoid gland. POSTERIOR TRIANGLE. The roof of the posterior triangle is formed by the general envelope of deep cervical fascia, while the fascia which covers the muscles forming its floor, as well as that covering the brachial nerve trunks and the subclavian artery, is a lateral continuation of the prevertebral fascia. The lateral deep cervical and supraclavicular lymph glands are embedded in the cellular tissue between these two layers of fascia. In removing these glands, every endeavour should be made to preserve the motor nerves. The accessory nerve, after entering the posterior triangle at the junction of the superior and middle thirds of the posterior border of the sterno-mastoid muscle, crosses the triangle superficially, and parallel to the levator scapulæ. It leaves the triangle by passing under cover of the anterior border of the trapezius, at the junction of its middle and inferior thirds. The lesser occipital nerve curves round the accessory from below upwards, superficially, just at the posterior border of the muscle; it furnishes, therefore, a useful guide to the position of that important motor nerve. The dorsalis scapula nerve (O.T. nerve to the rhomboids) crosses the triangle, inferior to the accessory, and enters the septum between the levator scapulæ and scalenus medius muscles. The supra-scapular nerve is seen arising from the lateral edge of the upper trunk of the brachial plexus, a little above the posterior belly of the omo-hyoid muscle. The loops of the cervical plexus lie under cover of the upper part of the sterno-mastoid muscle, between it and the origins of the levator scapulæ and the upper part of the scalenus medius muscles. The posterior belly of the omo-hyoid, which forms the superior boundary of the subclavian division of the posterior triangle, passes beneath the posterior border of the sterno-mastoid at a point about one inch above the clavicle. The external jugular vein, usually visible through the skin, runs in a line from the angle of the jaw to the middle of the clavicle; it is the vessel which is generally opened to relieve the right side of the heart in asphyxia. The lumen of the vein is kept patent where it pierces the fascia of the subclavian triangle; hence a wound of the vein in that situation is liable to be followed by the suction of air into the circulation during inspiration. The third part of the subclavian artery can be compressed against the first rib by pressing downwards and backwards, immediately above the clavicle, a little behind the posterior border of the sterno-mastoid muscle. To map out the course of the subclavian artery in the neck, draw a line, convex upwards, from the superior border of the sterno-clavicular articulation to the middle of the clavicle, the highest part of the arch to reach from to 1 in. above the bone. To ligature the vessel in the third part of its course, an angular incision is made along the middle of the superior border of the clavicle and the inferior part of the posterior border of the sterno-mastoid muscle. The most important guides to the vessel are the posterior belly of the omo-hyoid, the lateral border of the scalenus anterior, and the scalene tubercle of the first rib. The close relation of the vessel to the lowest trunk of the brachial plexus and to the cervical pleura must be kept in mind. In the rare instances in which a cervical rib is present the subclavian artery lies either in front of it, or arches above it, according to the degree of development of the rib. The subclavian vein lies below, and anterior to, the artery, altogether under cover of the clavicle. Entering the posterior triangle, from behind the lateral border of the scalenus anterior, are the trunks of the brachial plexus. They lie upon the scalenus medius, and can be felt, through the skin, immediately above and behind the third part of the subclavian artery. The anterior ramus of the fifth cervical nerve supplies the rhomboids, the abductors and lateral rotators of the arm, and the flexors and supinators of the forearm; that of the sixth the serratus anterior, the adductors and medial rotators of the arm, and the extensors and pronators of the forearm; that of the seventh the flexors and extensors of the wrist; that of the eighth the flexors and extensors of the fingers; that of the first thoracic all the small muscles of the hand. The carotid tubercle lies between the anterior rami of the sixth and seventh cervical nerves. The fifth and sixth cervical nerves are those which suffer most when the plexus is injured by forcible depression of the shoulder while the head is bent to the opposite side, such as occurs, for instance, in the "Obstetrical Paralyses" of Duchenne. To expose the trunks of the brachial plexus an incision is made from the junction of the middle and inferior thirds of the posterior border of the sternomastoid downwards and laterally to the junction of the lateral and intermediate thirds of the clavicle. The relation of the lowest trunk of the brachial plexus to the first rib is important in relation to those forms of brachial neuritis in which the motor and sensory symptoms indicate pressure on the anterior ramus of the first thoracic nerve. Wood Jones has shown that the sulcus for the subclavian artery on the superior surface of the first rib frequently lodges the lowest trunk of the brachial plexus as well as the artery, and that the more the first thoracic nerve contributed to the plexus the deeper is the sulcus. In two cases the writer has cured the neuralgia and the partial paralysis of the intrinsic muscles of the hand supplied by the first thoracic nerve by removing the portion of the first rib containing the "sulcus nervi brachialis.' The symptoms were due to the portion of the first thoracic nerve which goes to join the brachial plexus being stretched and pressed upon by the first rib as it crosses its inner edge to join the eighth cervical nerve. Although similar symptoms may be produced by the first thoracic nerve being stretched across a cervical rib, the surgeon must not expect to find this anomaly in all cases; and when a skiagram has been obtained, care must be taken not to mistake a well-developed posterior tubercle of the transverse process of the seventh cervical vertebra for a foreshortened view of a rudimentary cervical rib. In the median line of the neck posteriorly is the nuchal furrow, at the bottom of which are the cervical spines and the ligamentum nucha. At the superior part of the furrow, about two inches below the external occipital protuberance, is the large spine of the epistropheus, which can be distinctly felt; a line drawn from it laterally and slightly upwards to the transverse process of the atlas corresponds to the position of the inferior oblique muscle and, therefore, to the inferior margin of the sub-occipital triangle. The course of the deep part of the greater occipital nerve may be mapped out by drawing a line from the centre of the above-mentioned line to a point one inch lateral to the external occipital protuberance. In the floor of the suboccipital triangle is the posterior arch of the atlas upon which the vertebral artery lies. THE THORAX. For the convenience of topographical description, clinicians, by the use of vertical and transverse lines, have arbitrarily divided the surface of the chest into |