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.
The upper nine ribs start at the spine, curve around and are joined at the front of the chest. Because the ribs are firmly attached at the back (the spine) and the front (the sternum), they allow for very limited motion in the spine. The lower three ribs do not join together at the front, but do function to protect the vital organs while allowing for slightly more motion.