The subclavian artery and its branches in the ground squirrel, Citellus citellus

Abstract

The subclavian artery (a. subclavia) is the intrathoracic portion of the parent vessel to each thoracic limb in the ground squirrel. It arises on the left side from the arch of the aorta (a. subclavia sinistra) and on the right side subclavia dextra) as a terminal branch of the innominate artery (a. anonyma) not far from the thoracic inlet. Before they leave the thoracic cavity and continue as the axillary arteries (a. axillaris) each subclavian artery forms the following branches: The internal thoracic artery (a. thoracica interna) with its branches (a. musculophrenica, a. epigastrica cranialis, ramus intercostalis and ramus sternalis) supplies the diaphragm the last eight intercostal muscles, the abdominal and intercostal muscles and the thoracic mammary gland with blood. The supreme intercostal artery (a. intercostalis suprema) with its branches (a. intercostalis I, II, III and IV and truncus bronchoesophagicus of the right supreme intercostal artery) supplies the first four intercostal muscles, esophagus, lung and mediastinum. The vertebral artery (a. vertebralis) is the main vessel which supplies the brain. Its branches (rami spinales, a basilaris, a. ethmoidea interna, a. cerebelli nasalis, a. cerebri profunda, a. cerebri media and a. corporis callosi) supply the spinal cord, medulla oblongata, pons, cerebellum, caudal colliculi, mucous membrane of the nasal cavity, mesencephalon, diencephalon cerebral hemispheres and corpus callosum and hemisphere. The omocervical trunk (truncus omocervicalis) is a strong vessel, which with its branches (ramus descendens, a. cervicalis ascendens, a. transversa scapulae and cervicalis superficialis) supplies the deep ventral cervical muscles with associated brown fat tissue and lymphonodes as well as the subscapular and supraspinatus muscles. The transverse colli artery (a. transversa colli) branches into the extrinsic muscle of the shoulder. The deep cervical artery (a. cervicalis profunda) conveys blood to the dorsal cervical muscles. The axillary artery (a. axillaris) is a continuation of the subclavian artery. Its branches (a. thoracoacromialis, a. thoracica externa, a. profunda brachii) supply the lateral and medial shoulder muscles and dorsal antebrachium muscles. The brachial artery (a. brachialis) is a continuation of the axillary artery. Its branches (rami musculares, a. bicipitalis, a. collateralis ulnaris, a. nutritia humeri, a. collateralis radialis proximalis and a. collateralis radialis distalis) conveys blood to the triceps and biceps muscles, humerus and flexor muscle of the antebrachium. The median artery (a. mediana) is a continuation of the brachial artery. Its branches (rami musculares, a. interossea communis, a. radialis and a. ulnaris) supply the flexor and extensor digit muscles