CT Sacrum & Coccyx - Video Lesson

Hey everybody, welcome back. This lesson is about the sacrum and coccyx as seen in CT imaging. We'll start with a volume rendered image. This is a CT volume rendered image of the pelvis in the AP projection. We are specifically looking at the lower two segments of the vertebral column called the sacrum and coccyx. The sacrum consists of five fused vertebral segments. Beyond the sacrum is the coccyx. The coccyx marks the last segment of the vertebral column and helps to protect the soft tissue structures of the pelvis. It is also formed by a few fused vertebral segments. The lateral edges of the upper sacral spine articulate with the pelvis to form the sacroiliac joint, also called the SI joint. This lateral segment of the sacrum is called the sacral alla, or lateral mass. The lateral mass of the sacrum is equivalent to the transverse processes in the typical vertebrae. This segment of the pelvis is called the ileum. The anterior rim of the first sacral vertebrae