ductus

Ductus is a Latin noun meaning duct or tube, and in anatomy it is used to name tubular structures that convey fluids or other substances. In English-language anatomy, many names retain the Latin form ductus, while the everyday word duct is also used to refer to such structures.

Ductus arteriosus is a fetal vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the non-functioning lungs before birth. After birth, it normally closes and becomes the ligamentum arteriosum. If it remains open (patent ductus arteriosus), it can cause abnormal circulatory patterns and may require treatment.

Ductus venosus is another fetal structure that shunts a portion of umbilical vein blood flow directly to the inferior vena cava, bypassing the liver. At birth it closes and becomes the ligamentum venosum. Failure of closure can affect fetal circulation, while postnatal closure is a standard part of normal development.

Ductus deferens, or the vas deferens, is the muscular duct that transports sperm from the epididymis to the ejaculatory ducts. It is a component of the male reproductive tract and is the target of sterilization procedures such as vasectomy.

Ductus choledochus is the historical name for the common bile duct, the conduit that carries bile from the liver and gallbladder to the duodenum. Modern terminology typically uses “common bile duct,” but older anatomies may still reference ductus choledochus.

The term ductus is primarily a historical and descriptive label in anatomy, used to denote tubes that carry fluids within various organ systems.