{'fraction_non_alphanumeric': 0.02, 'fraction_numerical': 0.0, 'mean_word_length': 5.968354430379747, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Anatomy and pathophysiology of varicose veins.

The venous anatomy of the leg is described with special reference to the superficial venous system. The histologic and histochemical differences between varicose and normal veins are presented. The pathophysiology of varicose veins is related to congential or acquired abnormalities of the deep venous system, venous valves, and/or fascial or vein wall weakness. Increased deep venous pressure may be both proximal and distal in etiology, arising from arteriovenous anastomoses, incompetent communicating veins, or venous obstruction. Primary valvular incompetence arises from venous obstruction (thrombosis), thrombophlebitis, or valvular agenesis. Secondary valvular incompetence occurs from deep venous obstruction or increased venous distensibility (usually secondary to circulating estrogens). Finally, fascial weakness of the vein wall or supporting fascia provided a genetic basis for the pathophysiology of varicose veins. Understanding the anatomy and pathophysiology of varicose veins should lead to a more rational and efficacious treatment.