DESCRIPTIVE ANATOMY: HISTORY, OBJECT OF STUDY, METHODS - ANATOMY AND PHYSIOLOGY - 2024

The descriptive anatomy, or systematic anatomy, is the branch of anatomy which is to characterize objective, from a morphological point of view, the body animal and human in terms of the location, position, size, shape, vascularization, innervation, parts and ratios of your organ systems.

It is the oldest and widest branch of anatomy. It is also the most fundamental since without it the other branches of anatomy would lack a common frame of reference and language. Anatomy, together with physiology (study of the functioning of the body), are the basis on which all medical sciences have been developed.

History

From ancient times to the Renaissance

In general little recognition has been given to the anatomical advancements of the ancient Egyptians. They were great embalmers and preparers of human and animal mummies, indicating that they had developed a good understanding of anatomy, which was captured in the Kahun gynecological papyrus (1825 BC) and the Ebers papyrus (1500 BC).

In Ancient Greece, dissecting the human body was taboo and forbidden. This impeded the advancement of the anatomy. What little was written was based on the dissection of animals, as well as external observation of the body of living and deceased people.

At Alexandria, Herófilo, 335-280 BC, based on often public dissections, made great anatomical advances. For example, he described motor and sensory nerve trunks, blood vessels, tendons, salivary glands or the prostate, in addition to the large organs. For this reason, Herophilus is often called the "father of anatomy."

Claudius Galenus (129–216), was the most famous physician of his time. He practiced dissections of animals correctly assuming that their organs were similar to humans. Although many of his works were lost, those that remained, a total of about 150, were the basis of anatomy and medicine until the end of the Middle Ages.

From the Renaissance to the present

Starting in the 15th century, the Renaissance extended freedom of thought from Italy to the rest of Europe, revitalizing scientific research, practically abandoned since pre-Christian times. At that time, Leonardo da Vinci, 1452–1519, made his extraordinary drawings of the musculature of the human body.

Soon after, Andreas Vesalius and his pupils, Gabriello Fallopio (1523–1562), and Girolamo Fabrici, (1537–1619), systematically dissected human bodies, including those of recently executed criminals. His techniques, illustrations, and descriptions began modern anatomical studies.

Marcello Malpighi, (1628–1694), in addition to such famous achievements as demonstrating William Harvey's (1578–1657) theory of blood circulation, made great contributions to descriptive anatomy. He described the structure of parts of the liver, brain, kidneys, spleen, bones, and deep layers of the skin.

From then on, there was a progressive accumulation of descriptive anatomy knowledge, exposed in anatomical atlases. For example, in 1858, Henry Gray (1827–1861) published the famous Anatomy, descriptive and surgical manual. Gray's work has been continually modernized by numerous authors and currently exists in several versions that remain among the most widely used anatomy texts.

Anatomic position

The language of descriptive anatomy requires extreme precision, particularly when it comes to locations and directions of structures in space. The first step in ensuring such precision and avoiding ambiguity requires a standard reference body posture, called the anatomical position.

In this position, the body is standing, with the feet slightly apart and pointing forward, the arms at the sides, the palms of the hands directed forward with the fingers together and straight, the face facing forward, the eyes open and focused at a distance, and the mouth closed. The face has a neutral expression.

Plans and sections

A plane is an imaginary surface that separates parts of the body or organs into two parts. A section is each of the parts separated by a plane.

A coronal plane is one that is oriented vertically, which is why it divides into an anterior and a posterior section.

A sagittal plane is one that is also oriented vertically, but is perpendicular to the coronal plane, thus dividing into a left and a right section. If the plane passes exactly in the middle, it is said to be a midsagittal plane.

A transverse plane, also called the horizontal or axial plane, divides into an upper and a lower section.

Anatomical location

Main terms

An anterior (or ventral) location refers to structures (eg, the nose) that are anterior to a coronal plane. A posterior (or dorsal) location refers to structures (eg, the spine) that lie behind a coronal plane.

A medial location refers to structures that, relative to others (for example, the nose relative to the eyes), are closer to a sagittal plane.

A lateral location refers to structures that, in relation to others (for example, the eyes with respect to the nose), are further away from a sagittal plane.

A superior location refers to structures that, in relation to others (for example, the head relative to the shoulders), are found higher in the coronal and sagittal planes.

An inferior location refers to structures that, in relation to others (for example, that of the shoulders with respect to the head), are found lower in the coronal and sagittal planes.

Other terms

A proximal location refers to a structure that is relatively close to an origin (eg, the tip of the finger relative to the base of the finger). A distal location refers to the opposite (for example, the hand relative to the elbow).

A cranial location refers to its condition of being directed towards the head (or having a superior location). A caudal location refers to its condition of being directed towards the tail (or having a lower location).

A rostral location refers to the condition of a cephalic structure being closer to the face in relation to another cephalic structure (for example the skin of the face with respect to the bones it covers).

A superficial location refers to structures close to the skin. A deep localization refers to the opposite. The terms superficial and deep are also used to refer to two main regions of the body: those that are outward and those that are below the subcutaneous fascia.

Methods and techniques

The classic and fundamental method used in descriptive anatomy is dissection. It consists of opening the human or animal body through cuts to observe the anatomical topography and the structure of its parts.

Dissection is the only method of direct observation and measurement of the human body, which is why it is carried out on cadavers, forming part of the comprehensive training of doctors. Prior to dissection, the corpse must have been preserved with glutaraldehyde or formaldehyde for at least six weeks.

Dissection can be complemented by other methods. For example, high resolution digital tomography. This is based on X-ray images taken sequentially throughout the body. These images are digitally combined to obtain a 3D image.

References

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2. Buja, LM, Krueger, GRF 2014. Netter's illustrated human pathology. Saunders, Philadelphia.
3. Drake, RL, Vogl, W., Mitchell, AWM 2005. Gray, Anatomy for Students. Elsevier, Madrid.
4. Drake, RL, Vogl, W., Mitchell, AWM, Tibbitts, RM, Richardson, PE 2015. Gray's atlas of anatomy. Churchill Livingstone, Philadelphia.
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15. Tubbs, RS, Shoja, MM, Loukas, M., Agutter, P. 2019. History of anatomy: an international perspective. Wiley, Hoboken.