Muscular Branches

VA obstruction causes hemodynamic problems in approximately one third of patients with posterior circulation ischemia (Caplan et al. 2004). Asymmetrical caliber of the two VAs is normal. In the neck multiple nuchal and muscular branches provide a network for potential collateral pathways, that can be activated in VA obstruction. 

Muscular branches of the vertebral artery in the neck. At positions distal to a vertebral obstruction, these muscular branches may receive blood retrogradely from occipital and ascending pharyngeal branches of the external carotid artery, or from the deep and ascending cervical arteries. In addition, anastomoses can develop between branches of the subclavian artery and external carotid artery when the common carotid artery is obstructed. 

Gastroduodenal, pancreaticoduodenal arcade. Also called muscular branches. 

PIA (3), muscular branch of ramus dorsalis (4), and radicular artery of ramus dorsalis (5). c Curved MPR proving continuity between ASA (J), AKA (2), PIA (3), and aorta... 

As the arteries travel toward the peripheral organs and tissues, they branch and become smaller. Furthermore, the walls of the vessels become less elastic and more muscular. The smallest arterial vessels, arterioles, are composed almost entirely of smooth muscle with a lining of endothelium. 

ShmerUng, M.D., Buzueva, IJ. and Filyushina, E.E. (1984). The electronic microscopic study of grayling skeletal muscles at rest and with muscular loads (In Russian). In Studies of fish locomotion energetics , pp. 61-68. Nauka, Novosibirsk, Siberian Branch. 

The structure of the bladder, ureter, and urethra are similar in that they contain three layers, the mucosa, muscularis, and serosa. In the bladder (Figure 3.16) the inner layer (mucosa) when empty is infolded and it is made up of transitional epithelium. The lamina propria that is found below contains collagen and elastic fibers in the deeper layer. The muscularis is prominent and contains muscle fibers that are arranged in branching bundles separated by connective tissue. Muscular contraction causes expulsion of fluid from the bladder into the ureter. The connective tissue between the muscle fiber bundles merges with the connective tissue of the serosa. The serosa is continuous with the peritoneal lining. 

Cardiac muscles, as is evident from their name, make up the muscular portion of the heart. While almost all cardiac muscle is confined to the heart, some of these cells extend for a short distance into cardiac vessels before tapering off completely. The heart muscle is also called the myocardium. The heart muscle is responsible for more than two billion beats in a lifetime. The myocardium has some properties similar to skeletal muscle tissue, but it is also unique. Like skeletal muscles, myocardium is striated however, the cardiac muscle fibers are smaller and shorter than skeletal muscle fibers averaging 5-15 micrometers in diameter and 20-30 micrometers in length. In addition, cardiac muscles align lengthwise more than side-by-side compared to skeletal muscle fibers. The microscopic structure of cardiac muscle is also unique in that these cells are branched such that they can simultaneously communicate with multiple cardiac muscle fibers. 

Chalkiadis GA, Branch KG. Cardiac arrest after isoflurane anaesthesia in a patient with Duchenne s muscular dystrophy. Anaesthesia 1990 45(l) 22-5. 

A spectrum of end-organ ischemic complications can occur with embolotherapy. Bowel infarction can complicate splanchnic embolization targeting bleeding or could result from inadvertent non-target embolization from an upstream source [88]. Gallbladder infarction or bile duct necrosis can complicate hepatic artery embolization or che-moembolization [89, 90]. Splenic abscess and overwhelming sepsis can occurs following splenic embolization [91]. Skin necrosis and nerve injury have been reported as a result of ethanol embolization of vascular malformations [53, 54]. Buttock muscular necrosis, buttock claudication and sexual dysfunction can occur as a result of internal iliac branch embolization, especially when distal or bilateral [92-95]. 

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