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.
Both men and women have 24 ribs, twelve on each side. Each rib is attached to a spinal bone (thoracic vertebra) in the back. The first seven pairs of ribs join the breastbone (sternum) in the center of the chest. The front ends of the eighth, ninth, and 10th pairs are connected to the ribs above them. The 11th and 12th pairs are called âfloating ribs,â because they are anchored in place only by connective tissue. One in every few hundred people have an extra rib. These are called cervical ribs, because they arise from one of the spinal bones in the neck (cervical vertebrae).