Encyclopaedia Britannica, 11th Edition, "Armour Plates" to "Arundel, Earls of" / Volume 2, Slice 6

by Various

The external carotid artery ascends through the upper part of the side of the neck, and behind the lower jaw into the parotid gland, where it divides into the internal maxillary and superficial temporal branches. This artery gives off the following branches:—(a) Superior thyroid to the larynx and thyroid body; (b) Lingual to the tongue and sublingual gland; (c) Facial to the face, palate, tonsil and sub-maxillary gland; (d) Occipital to the sterno-mastoid muscle and back of the scalp; (e) Posterior auricular to the back of the ear and the adjacent part of the scalp; (f) Superficial temporal to the scalp in front of the ear, and by its transverse facial branch to the back part of the face; (g) Internal maxillary, giving muscular branches to the muscles of mastication, meningeal branches to the dura mater, dental branches to the teeth, and other branches to the nose, palate and tympanum; (h) Ascending pharyngeal, which gives branches to the pharynx, palate, tonsils and dura mater.

The subclavian artery is the commencement of the great arterial trunk for the upper limb. It passes across the root of the neck and behind the clavicle, where it enters the armpit, and becomes the axillary artery; by that name it extends Subclavian system. as far as the posterior fold of the axilla, where it enters the upper arm, takes the name of brachial, and courses as far as the bend of the elbow; here it bifurcates into the radial and ulnar arteries. From the subclavian part of the trunk the following branches arise:—(a) Vertebral, which enters the foramen at the root of the transverse process of the 6th cervical vertebra, ascends through the corresponding foramina in the vertebrae above, lies in a groove on the arch of the atlas, and enters the skull through the foramen magnum, where it joins its fellow to form the basilar artery; it gives off muscular branches to the deep muscles of the neck, spinal branches to the spinal cord, meningeal branches to the dura mater, and an inferior cerebellar branch to the under surface of the cerebellum. The basilar artery, formed by the junction of the two vertebrals, extends from the lower to the upper border of the pons Varolii; it gives off transverse branches to the pons, auditory branches to the internal ear, inferior cerebellar branches to the under surface of the cerebellum, whilst it breaks up into four terminal branches, viz. two superior cerebellar to the upper surface of the cerebellum, and two posterior cerebral which supply the tentorial and mesial aspects of the temporo-sphenoidal lobes, the occipital lobes, and the posterior convolutions of the parietal lobes. (b) Thyroid axis, which immediately divides into the inferior thyroid, the supra-scapular, and the transverse cervical branches; the inferior thyroid supplies the thyroid body, and gives off an ascending cervical branch to the muscles of the neck; the supra-scapular supplies the muscles on the dorsum scapulae; the transverse cervical supplies the trapezius and the muscles attached to the vertebral border of the scapula. (c) Internal mammary supplies the anterior surface of the walls of the chest and abdomen, and the upper surface of the diaphragm. (d) Superior intercostal supplies the first intercostal space, and by its deep cervical branch the deep muscles of the back of the neck.

The axillary artery supplies thoracic branches to the wall of the chest, the pectoral muscles, and the fat and glands of the axilla; an acromio-thoracic to the parts about the acromion; anterior and posterior circumflex branches to the shoulder joint and deltoid muscle; a subscapular branch to the muscles of the posterior fold of the axilla.

The brachial artery supplies muscular branches to the muscles of the upper arm; a nutrient branch to the humerus; superior and inferior profunda branches and an anastomotic to the muscles of the upper arm and the region of the elbow joint.

The ulnar artery extends down the ulnar side of the front of the fore-arm to the palm of the hand, where it curves outward toward the thumb, and anastomoses with the superficial volar or other branch of the radial artery to form the superficial palmar arch. In the fore-arm the ulnar gives off the interosseous arteries, which supply the muscles of the fore-arm and give nutrient branches to the bones; two recurrent branches to the region of the elbow; carpal branches to the wrist joint: in the hand it gives a deep branch to the deep muscles of the hand, and from the superficial arch arise digital branches to the sides of the little, ring, and middle fingers, and the ulnar border of the index finger.

The radial artery extends down the radial side of the front of the fore-arm, turns round the outer side of the wrist to the back of the hand, passes between the 1st and 2nd metacarpal bones to the palm, where it joins the deep branch of the ulnar, and forms the deep palmar arch. In the fore-arm it gives off a recurrent branch to the elbow joint; carpal branches to the wrist joint; and muscular branches, one of which, named superficial volar, supplies the muscle of the thumb and joins the ulnar artery: in the hand it gives off a branch to the thumb, and one to the radial side of the index, interosseous branches to the interosseous muscles, perforating branches to the back of the hand, and recurrent branches to the wrist.

The branches of the aorta which supply the viscera of the thorax are the coronary, the oesophageal, the bronchial and the pericardiac. The coronary arteries, two in number, are the first branches of the aorta, and arise opposite the anterior and left Visceral branches. posterior segments of the semilunar valve, from the wall of the aorta, where it dilates into the sinuses of Valsalva. They supply the tissue of the heart.

The oesophageal, bronchial and pericardiac branches are sufficiently described by their names.

The branches of the aorta which supply the viscera of the abdomen arise either singly or in pairs. The single arteries are the coeliac axis, the superior mesenteric, and the inferior mesenteric, which arise from the front of the aorta; the pairs are the capsular, the two renal, and the two spermatic or ovarian, which arise from its sides. The single arteries supply viscera which are either completely or almost completely invested by the peritoneum, and the veins corresponding to them are the roots of the vena portae. The pairs of arteries supply viscera developed behind the peritoneum, and the veins corresponding to them are rootlets of the inferior vena cava.

The coeliac axis is a thick, short artery, which almost immediately divides into the gastric, hepatic and splenic branches. The gastric gives off oesophageal branches and then runs along the lesser curvature of the stomach. The hepatic artery ends in the substance of the liver; but gives off a cystic branch to the gall bladder, a pyloric branch to the stomach, a gastro-duodenal branch, which divides into a superior pancreatico-duodenal for the pancreas and duodenum, and a right gastro-epiploic for the stomach and omentum. The splenic artery ends in the substance of the spleen; but gives off pancreatic branches to the pancreas, vasa brevia to the left end of the stomach, and a left gastro-epiploic to the stomach and omentum.