Anatomical terms of location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes.
The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal").
International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, Terminologia Anatomica for humans and Nomina Anatomica Veterinaria for animals. These allow parties that use anatomical terms, such as anatomists, veterinarians, and medical doctors, to have a standard set of terms to communicate clearly the position of a structure.
Main terms[edit]
Superior and inferior[edit]
Superior (from Latin super 'above') describes what is above something[20] and inferior (from Latin inferus 'below') describes what is below it.[21] For example, in the anatomical position, the most superior part of the human body is the head and the most inferior is the feet. As a second example, in humans, the neck is superior to the chest but inferior to the head.
Other terms and special cases[edit]
Anatomical landmarks[edit]
The location of anatomical structures can also be described in relation to different anatomical landmarks. They are used in anatomy, surface anatomy, surgery, and radiology.[45]
Structures may be described as being at the level of a specific spinal vertebra, depending on the section of the vertebral column the structure is at.[45] The position is often abbreviated. For example, structures at the level of the fourth cervical vertebra may be abbreviated as "C4", at the level of the fourth thoracic vertebra "T4", and at the level of the third lumbar vertebra "L3". Because the sacrum and coccyx are fused, they are not often used to provide the location.
References may also take origin from superficial anatomy, made to landmarks that are on the skin or visible underneath.[45] For example, structures may be described relative to the anterior superior iliac spine, the medial malleolus or the medial epicondyle.
Anatomical lines are used to describe anatomical location. For example, the mid-clavicular line is used as part of the cardiac exam in medicine to feel the apex beat of the heart.
