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Thermal Physiology and Thermoregulation
Published in James Stewart Campbell, M. Nathaniel Mead, Human Medical Thermography, 2023
James Stewart Campbell, M. Nathaniel Mead
In the feet, non-exercise glomus dilation appears less often and less intense than in the hands (Figure 5.12a). The foot veins, while initially located in the subdermal fat over the metatarsals and tarsals, dive deep at the ankle to accompany the anterior tibial artery. This deep venous system is invisible to infrared imaging until reaching the groin. The subdermal great saphenous vein progresses up the medial leg from just in front of the medial malleolus of the ankle to the groin, where it meets the larger femoral vein. The small saphenous vein starts behind the lateral malleolus of the ankle and runs subdermally up the back of the leg to the knee. Both saphenous veins may be seen by infrared occasionally, and these veins frequently generate varicosities that are thermally visible, smaller superficial leg veins may also become varicose (Figure 5.12b).
Pre-, intra-, and post-treatment use of duplex ultrasound (thermal and non-thermal)
Published in Joseph A. Zygmunt, Venous Ultrasound, 2020
The common peroneal nerve (CPN) also has a sensory–motor function (Figure 9.25a,b). It is a distal branch of the sciatic nerve and can run along the lateral fibular head. Injury to the common peroneal nerve can result in foot drop, with loss of sensation on the top of the foot. Incidence of injury with surgery to the small saphenous vein has been reported at 2%–4.7% [26]. The relationship between the saphenopopliteal junction and the common peroneal nerve is well studied [27]. Due to the proximity of this nerve to the lateral fibular head, many practitioners use precautions with compression dressings or wraps so as to not cause entrapment and irritation of this nerve.
Anatomy of veins and lymphatics
Published in Ken Myers, Paul Hannah, Marcus Cremonese, Lourens Bester, Phil Bekhor, Attilio Cavezzi, Marianne de Maeseneer, Greg Goodman, David Jenkins, Herman Lee, Adrian Lim, David Mitchell, Nick Morrison, Andrew Nicolaides, Hugo Partsch, Tony Penington, Neil Piller, Stefania Roberts, Greg Seeley, Paul Thibault, Steve Yelland, Manual of Venous and Lymphatic Diseases, 2017
Ken Myers, Paul Hannah, Marcus Cremonese, Lourens Bester, Phil Bekhor, Attilio Cavezzi, Marianne de Maeseneer, Greg Goodman, David Jenkins, Herman Lee, Adrian Lim, David Mitchell, Nick Morrison, Andrew Nicolaides, Hugo Partsch, Tony Penington, Neil Piller, Stefania Roberts, Greg Seeley, Paul Thibault, Steve Yelland
The small saphenous vein begins behind the lateral malleolus as a continuation of the lateral marginal foot vein and passes to the popliteal fossa. It moves from a subcutaneous plane to become sub-fascial in a saphenous compartment at about midcalf in most limbs. Duplication is very uncommon.
Numerical study of hemodynamics in a complete coronary bypass with venous and arterial grafts and different degrees of stenosis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Shila Alizadehghobadi, Hasan Biglari, Hanieh Niroomand-Oscuii, Meisam H. Matin
One of the most prevalent cardiovascular diseases is coronary artery disease which is the leading cause of death all over the world (Wong 2014). The stenosis or blockage of the artery brings about a reduction of blood flow to the heart muscle and therefore causes problems for blood supply to the heart. One of the main treatments for the coronary artery blockage is bypass surgery in which an alternative graft is used to compensate for the blood flow reduction through the coronary artery (Arima et al. 2005; Deb et al. 2013). This graft is connected to the aorta from upstream and to the coronary artery from downstream. Internal thoracic artery (ITA) and small saphenous vein are the commonly used vessels in bypass. The main issue encountered after the bypass surgery is stenosis or partial blockage of the graft which occurs due to the variations in the hemodynamic conditions leading to the failure of the grafting. The hemodynamic conditions strongly depends on the mechanical properties of the artery tissues. Since the accurate experimental evaluation of the parameters is almost elusive due to the challenges associated with the ultrasonic velocity measurement, numerical simulations can examine the flow conditions and hemodynamics conveniently but with some limitations. Owida et al. (2012) provided an overview on numerical simulations of the flow pattern and wall shear stress in the occluded coronary arteries.
Clinical and immunologic differences in cellulitis vs. pseudocellulitis
Published in Expert Review of Clinical Immunology, 2021
Michael Goldenberg, Henry Wang, Trent Walker, Benjamin H Kaffenberger
Superficial venous thrombosis (SVT) shares many risk factors with deep venous thrombosis (DVT), including senescence, obesity, malignancy, and other hypercoagulable states, but the most important risk factor for SVT is DVT [47]. The symptoms of SVT such as erythematous tender indurated cutaneous cords with swelling and warmth are mostly due to vein wall and surrounding tissue inflammation [47]. Purpura surrounding the cord is common. Cancer patients are at risk for migratory superficial venous thrombosis which may be misdiagnosed as cellulitis [48]. Venous thrombosis initially develops over a week when platelets and erythrocytes form a mesh occluding a superficial vein [49]. Over the next 7 weeks, the initial thrombus is replaced by fibrin, before in turn being replaced by collagen after 54 weeks. Endothelial cells start to re-encompass the thrombus when fibrin predominates during the first 7 weeks of thrombus formation. Initially, neutrophils progress the thrombus from platelets to fibrin, and eventually macrophages progress the fibrin clot to a collagenous one. Additionally, T-lymphocytes and macrophages filled with hemosiderin conglomerate and remain within the thrombus. Within two months, fibroblasts place enough collagen within the thrombus for it to appear hyalinized while leaving tortuous cavities in the center. Loosely arranged collagen fibers promote neovascularization and densely arranged collagen fibers house scant immune cells. The result of the thrombus maturation process may include collagenous tissue integrating into the venous wall, restoring vessel patency, and promoting vein wall fibrosis [49]. The most common site of superficial venous thrombosis are the greater and small saphenous veins in the lower extremities [47]. Superficial venous thrombosis can be distinguished from cellulitis by a lack of fever and a history of immobilization or cancer [34a]. Furthermore, thrombosis can be confirmed on duplex scan [34a]. Superficial venous thrombosis can be managed similarly to deep venous thrombosis with therapeutic anticoagulation, although definitive management algorithms have not been widely agreed upon [47].