1) Correlation between arterial and venous blood gases
Much of the literature surrounding this concept is found in the Emergency Medicine literature. A prospective study involving 95 patients in Emergency Medicine Journal from 2007 comparing ABG and VBG samples drawn as close in time as possible concluded that VBG analysis for pH, bicarbonate, and pCO2 (but not paO2, not surprisingly) may be a reliable substitute for ABG analysis in the initial evaluation of an adult patient population presenting to the ED. Click on this link to read the full article.
2) Hypertrophic pulmonary osteoarthropathy
Hypertrophic pulmonary osteoarthropathy, also known as Bamberger-Marie disease, is periostitis of the long bones of the upper and lower extremities. It is thought to be a paraneoplastic manifestation of lung carcinoma. These patients often get clubbing and increased bone deposition on long bones. Their presenting symptoms are sometimes only clubbing and painful ankles. Check out this link for an interesting "Images in Clinical Medicine" in NEJM illustrating the paraneoplastic phenomena of hypertrophic pulmonary osteoarthropathy and tripe palms (or acanthosis palmaris).
3) Batson venous plexus
The Batson venous plexus is a network of valveless veins that connect the deep pelvic and thoracic veins draining the inferior end of the bladder, breast, and prostate to the internal vertebral venous plexuses. They are thought to to provide a hematogenous route for metastatic spread of rectal and prostate cancer to the vertebral column or brain. The plexus is named after anatomist Oscar Vivian Batson, who first described it in 1940.
