Final answer:
Veins of the upper limbs, like the cephalic and median antebranchial veins, are crucial for blood drainage. Edema and varicose veins can occur if venous pressure increases or valves malfunction, leading to swelling and enlarged, twisted veins.
Step-by-step explanation:
The veins of the upper limbs, including the digital veins, palmar venous arches, radial vein, ulnar vein, and median antebrachial vein, are essential for draining blood from the fingers and hand back to the heart. These veins accompany their corresponding arteries and ensure the removal of deoxygenated blood and waste products from the upper extremities. The primary superficial veins—such as the cephalic vein and the median antebranchial vein—along with deeper ones, like the brachial vein, create a network that connects to the thoracic area's axillary vein.
Conditions such as edema and varicose veins can affect these venous networks. Edema is caused by the accumulation of fluid in tissues, often due to increased venous pressure or damage, and leads to swelling. Varicose veins develop when valves within the veins become defective, allowing blood to pool and veins to become enlarged, twisted, and visible on the skin's surface. In severe cases, varicose veins may require medical interventions to alleviate symptoms and prevent complications like thromboses.