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.
Meanwhile, the first, tenth, eleventh, and twelfth (T1, T10, T11 and T12) vertebrae all contain a pair of full facets on their vertebral bodies to support ribs. T1 is unique among all thoracic vertebrae in supporting two pairs of ribs through a pair of facets and a pair of demi-facets.