The term “ortho-” (or orth-) is derived from the Greek word “orthos”, meaning “to straighten, to make right, or to correct”. Ortho- is a prefix that is often used in chemistry, medicine, and biology to indicate a specific orientation or conformation, or to describe a specific type of reaction or molecule (Reference 1). In chemistry, the prefix is often used to denote a reaction in which one group of atoms is added to a position adjacent to another group of atoms, which can lead to the formation of a di- or polycyclic molecule (Reference 2). In medicine, ortho- is used to describe a condition or treatment that is aimed at correcting an abnormality or restoring normal body functions (Reference 3). In biology, it is used to describe a particular type of morphology or conformation, such as orthostatic posture (Reference 4).
In chemistry, ortho- is most commonly used to describe a specific type of reaction, known as an electrophilic aromatic substitution (EAS) reaction (Reference 5). In EAS reactions, an electron-rich species, such as an electrophile, is added to an aromatic ring, causing the ring to adopt a specific conformation or orientation. This specific orientation is known as an ortho-position. The reaction can be represented by the following equation:
R-H + E+ → R-E + H+
where R is an aromatic group, H is a hydrogen atom, and E+ is an electrophile (Reference 6).
In medicine, ortho- is used to describe a variety of conditions and treatments. Orthopedics is a medical specialty that focuses on the diagnosis and treatment of musculoskeletal disorders, such as fractures, dislocations, and deformities. Orthopedic surgery is a type of medical procedure that is used to correct abnormalities in the musculoskeletal system (Reference 7). Orthotic devices are also used to support and protect the musculoskeletal system. These devices include braces, casts, and splints, which are used to support and stabilize joints (Reference 8).
In biology, ortho- is often used to describe the posture of an organism. Orthostatic posture is the position of the body in which the head and trunk are held upright (Reference 9). This posture is important for maintaining balance and for avoiding injury. It is also used to maintain a stable heart rate and blood pressure (Reference 10).
In conclusion, the prefix ortho- is used in chemistry, medicine, and biology to indicate a specific orientation or conformation, or to describe a specific type of reaction or molecule. In chemistry, it is used to describe an electrophilic aromatic substitution reaction. In medicine, it is used to describe a variety of conditions and treatments. In biology, it is used to describe orthostatic posture.
References:
1. Liddell, H.G., Scott, R., Jones, H.S., & McKenzie, R. (1940). A Greek-English Lexicon. Oxford: Oxford University Press.
2. (n.d.). Electrophilic aromatic substitution. In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Electrophilic_aromatic_substitution
3. (n.d.). Orthopedics. In MedlinePlus. Retrieved from https://medlineplus.gov/orthopedics.html
4. (n.d.). Orthostatic posture. In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Orthostatic_posture
5. (n.d.). Electrophilic aromatic substitution. In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Electrophilic_aromatic_substitution
6. Jain, A., & Jain, S. (2018). A comprehensive approach to organic chemistry. Oxford: Oxford University Press.
7. (n.d.). Orthopedic surgery. In MedlinePlus. Retrieved from https://medlineplus.gov/orthopedicsurgery.html
8. (n.d.). Orthotic devices. In MedlinePlus. Retrieved from https://medlineplus.gov/orthoticdevices.html
9. (n.d.). Orthostatic posture. In Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Orthostatic_posture
10. (n.d.). Orthostatic hypotension. In MedlinePlus. Retrieved from https://medlineplus.gov/orthostatichypotension.html