The Circulatory System

Hearts have become iconic symbols of Valentine's Day, but when it comes to hearts in the real world, one size doesn't fit all — particularly in the animal kingdom.

Here is the science behind 13 Halloween horrors come to life.

A Nevada man is suing his doctor for allegedly leaving a nearly 5-foot wire in his body for more than a decade.

An injection of facial filler into her nose led to a rare eye complication.

A blood vessel disorder that most often affects fingers and toes can also show up in the nipples and cause problems with breast-feeding, according to a new report.

It has four chambers, blood vessels and it beats — sort of.

This unusual condition went undetected during the woman's lifetime.

A yo-yo champion experienced dramatic ups and downs for the circulation in his index finger.

An unusual X-ray shows a cartoonish heart seemingly floating in a child's esophagus.

Extreme heat due to climate change might increase congenital heart defects.

Signs of ancient plaque in mummies' hearts hint at cardiovascular disease.

People who experience a rare condition known as "broken-heart syndrome" need immediate medical attention, but often make a quick recovery.

There's yet another reason to make sure you're getting enough vitamin D.

A woman's beach vacation took an unexpected turn when she was hit so hard in the neck by a wave that it ruptured one of her arteries.

These volunteers quaffed blood for a good cause.

Women who are pregnant may not spend much time worrying about their own hearts, but a new study suggests they should.