What causes a pulmonary embolism? Blood clots can form for a variety of reasons. Pulmonary embolisms are most often caused by deep vein thrombosis, a condition in which blood clots form in veins deep in the body. The blood clots that most often cause pulmonary embolisms begin in the legs or pelvis.
All ribs are attached posteriorly to the thoracic vertebrae. The neck of the rib is the flattened part that extends laterally from the head. The neck is about 3 cm long, and is placed in front of the transverse process of the lower of the two vertebrae with which the head articulates.
Human anatomy. Humans have 24 ribs (12 pairs). The first seven sets of ribs, known as true ribs (costae verae) also known as vertebrosternal ribs, are directly attached to the sternum through the costal cartilage. Rib 1 is unique and harder to distinguish than other ribs. It is a short, flat, C-shaped bone. The vertebral attachment can be found just below the neck and the majority of this bone can be found above the level of the clavicle. Ribs 2 through 7 have a more traditional appearance and become longer and less curved as they progress downwards.