The midclavicular line is a fictional line used as an anatomical reference point on the human body. It is a vertical line running from a spot in the middle of the clavicle to the point where it meets the hip bone. A number of anatomical features of interest are located along the midclavicular line and people learn to locate it, along with other reference points, during medical school.
The middle of the clavicle can sometimes be a difficult point to find, and studies conducted by anatomy researchers have shown that there is actually a great deal of variance in placing the midclavicular line. Much of the clavicle is hidden, except in very thin patients, where the bone stands out markedly over the chest, and people may not remember exactly how far this bone extends, making it difficult to find the midpoint. Some people orient the midclavicular line with the nipple, but in fact this line does not intersect with the nipple when it is drawn properly.
One point of interest along the midclavicular line is the heart. When listening for a heartbeat, this line can be used as a reference to find a location for listening. The liver is also located along this line, as is the gallbladder. By drawing an imaginary line down the body, people can find these organs more easily for palpation and ultrasound examination. In people suspected of having conditions like liver enlargement, being able to pinpoint the spot where the organ is supposed to be can be helpful.
This is one among many lines used as reference points on the torso. Other vertical lines include the midsternal line, for example. Horizontal lines are also used to divide the torso into segments running in the other direction. When writing up findings about a patient, doctors may use these lines as reference points in the description so any physician reading can visualize the location of the findings under discussion. This is particularly useful for people like pathologists, who do not see the patient in person, but may want information about the precise location where a sample was collected.
Points of orientation are also used in anatomy so that descriptions in textbooks and other materials are standardized. Instead of using vague and relative references, people can be extremely precise and concise in descriptions of features on the human body. People in medical school are expected to learn the terminology associated with anatomical positioning so they can communicate clearly and accurately with colleagues in professional practice.