The Language Of Anatomy by Prof. Dr. Muhammad Imran Qureshi Anatomy is a descriptive science; therefore, descriptive terminology is a valuable tool to understand the science of Anatomy. Most of the anatomical terms are derived from Greek or Latin, but some of the more recent terms are of German and French origin. A few are also from Arabic origin. Some terms refer to common plants or animals e.g. the term “Vermis” means Worm; “Cochlea” means snail shell; “Cancer” means Crab and “Uvula” means little grape. Interestingly, certain terms suggest war like environment of ancient Greece or Rome. “Thyroid” for example means Shield, “Xyphos” means sword and “Sella” mean Saddle. Some anatomical structures bear the names of persons who discovered or described them for the first time. Such terms are called “Eponyms”. examples are “Scarpa’s Fascia”, “Hunter’s Canal” etc. FRAME OF REFERENCE FOR ANATOMICAL STUDIES Early anatomists faced a great deal of problems in communication. e.g. by just saying “a boil on the back” does not give precise information about its location. In order to solve this problem, the anatomists sat together and devised a frame of reference for anatomical description. This frame of reference is called “The Anatomical Position” Anatomical Position: It is a schematic convention for describing the relative morphology of the human body. All terms in the study of anatomy refer to when the body is in this position. In this position, The Person is oriented: In an erect standing position with head held straight and eyes looking straight forwards; Arms by the sides and palms facing forwards with fingers and thumb extended; Legs approximated and feet directed forward and perpendicular to the body. Planes of the Body Plane (L. planus) a flat surface determined by the position of at least three points in space. It is not a line. Line needs two points only. 1 | Page PLANES OF REFERENCE In order to visualize and study the structural arrangements of various organs, the body may be sectioned (cut) and diagrammed according to three fundamental planes of reference: • A Sagittal Plane, • A Coronal Plane, and • A Transverse Plane A knowledge of these terms helps the doctor understand and interpret the X-Rays, CT Scans and MRI Scans. Sagittal or Median Plane: (L. Sagitta: an arrow) It is an imaginary vertical plane that passes through the centre of the body and bisects it into TWO externally Symmetrical halves. Any plane that is passing Off centrally but parallel to the median plane is referred to as the “Para sagittal” plane Coronal or Frontal Plane: (Gr. Korone: a Crown) It is an imaginary vertical plane that passes at right angles to the sagittal plane and divides the body into front and rear parts. The portion of the body in front of this plane is called “anterior” and the one rear to it or behind it is called “posterior”. Transverse Plane (Cross Sectional Plane): Any plane that runs at right angles to both the sagittal and coronal planes is called a “Transverse Plane”. More precisely, it is a plane that runs at right angle to the long axis of the body or part of the body (cf: Horizontal Plane) Transverse Plane (Cross Sectional Plane): The Transverse planes are used in CT scans and MRI. These planes divide the body into superior and inferior parts. The transverse sections in CT scan are studied from below (as if the examiner is examining from the foot end of the patient). In such a study, the organs of the body appear on the opposite side e.g. Liver though a right sided organ, appears to the left of the examiner. Similarly, the stomach, though a left sided organ appears to the right. 2 | Page Sections: Longitudinal, Transverse and Oblique Sections Longitudinal sections These are parallel to the long axis of the body or any of its parts. This term does not take into account the position of the body. Transverse sections (cross sections) The body or any of its parts are cut at right angles to their longitudinal axis. Oblique sections Any sections of the body, that is neither longitudinal nor transverse, falls into this category. Many sections made anatomically or using radiographic techniques are often slightly oblique. ANATOMICAL TERMINOLOGY Terminology [L. terminus=term + Logy=study] The science which deals with the investigation, arrangement, and construction of terms. Every subject starts with terminology. Without terminology it is very difficult to learn and understand any subject. Human being (Insan) has got an inherent ability to name different things. This ability to name different things is a great blessing of ALLAH. He has taught Adam this terminology. And He taught Adam the names (terms) of all things; then He set these before angels and asked, “Tell Me the names of all these things if you are right”. They replied, “Glory be to You. You alone are free from defect. We possess only that much knowledge which You have given us. Indeed, You alone are All-Knowing and All-Wise”. Then ALLAH said to Adam, “Tell them the names of these things”. When Adam told them the names of all those things, ALLAH declared, “Did I not tell you that I know those truths about the 3 | Page Heavens and Earth which are hidden from you. I know what you disclose and what you have been hiding. Al-Baqarah 2, 31-33. Part 1. In 1896, the German anatomical society met in Basle and approved a list of 5000 terms known as Basle Nomina Anatomica (BNA). The rules set down were: • Each part shall have only one name • Each term shall be in Latin or Greek • Each term shall be as short and simple as possible • The terms shall be merely memory signs • Related terms shall be similar e.g. radial nerve, radial artery, ulnar nerve, ulnar artery. • Adjectives, in general, shall be arranged as opposites e.g. major and minor, superior and inferior. The first revision of the BNA was made in 1933 by the Anatomical Society of Great Britain and Ireland. From 1950 onwards, the International Anatomical Nomenclature Committee was formed which meets every 5 years to revise and approve any changes in the nomenclature. Now English equivalents of Latin names are adopted and accepted e.g. “musculus deltoideus” (the common shoulder muscle) is “deltoid muscle” in English. A simple name for “aponeurosis muscular bicipitis brachii” is “bicipital aponeurosis” in English. In older terminologies, various structures were attributed the names of the persons who described them for the first time (such names are called ‘eponyms’). These have been discarded because they give no idea about the type or location of the structure e.g. • Eustachian tube (auditory tube, pharyngotympanic tube) • Fallopian tubes (uterine tubes) • Angle of Louis (sternal angle). We now know that the origin of most of the anatomical terms is from Latin and Greek. If we learn the origins of these terms, they make a lot of sense. The term “deciduous teeth” for example, is used for milk teeth. The word “Decidua” is derived from Latin and it means, “falling off”. It is very appropriate because as the child grows older, the teeth fall off. The same term is also used for a gravid uterus because the maternal part of placenta that develops from the uterus, also falls off after delivery. Similarly, the Arabic terms are also very sensible terms e.g. the term saphenous is pertaining to or associated with saphena. Saphena [L.; Gr. saphēnēs manifest] [Ar. Saphena the boat] the saphenous vein is a long venous channel which collects deoxygenated blood from the lower limb and pours it into femoral vein. Anatomists all over the world have agreed to use the same descriptive terms of position and direction. These terms enable us to describe the body clearly and indicate the position of its parts relative to each other. 4 | Page Terms of Position Remember that Anatomy is a science of “RELATIONS”, so all the terms that we use are “Relative terms”. In order to describe a structure or part of the body, we always have to relate it to some other structure or part. These terms are used to describe and compare the relationship of different structures or parts of the body according to their location. While using these terms the “anatomical position” should always be kept in mind. MEDIAL AND LATERAL Medial: When a Structure is situated nearer to the median plane of the body than another is said to be medial to the other. e.g. the eye is medial to the ear. Lateral: When a structure lies farther (away) from the median plane as compared to another, it is said to be lateral to the other. e.g. in the forearm, the radius is lateral to the ulna. MEDIAN When a structure is located at the median plane, it is said to be median in location. e.g. the Nose, sternum, Umbilicus etc. are median in location. ANTERIOR AND POSTERIOR Anterior: means nearer the front of the body. e.g. the sternum is anterior to the heart. Posterior: means nearer to the back. e.g. the vertebral column is posterior the heart. So, to describe the relationship of two structures, one is said to be anterior to the other and vice versa. VENTRAL AND DORSAL In the trunk the word “ventral” (venter = belly) is also commonly used in place of “anterior” and “dorsal” (dorsum = back) is used in place of “posterior”. PALMAR or VOLAR AND DORSAL In describing the hand, the terms palmar or Volar and dorsal are used in place of anterior and posterior respectively. So, the terms “palmar or volar” and “anterior” are synonymous while the terms “dorsal” and “posterior” are synonymous.