Introduction to Anatomy Lecture PDF

Introduction to Anatomy The word Anatomy has Indo-European root. In Greek, called anatome meaning “dissection”. Latin as anatomia; Old French as anatomie; English still as anatomie. It’s a subject seen as enigma surrounded in mystery. The notion because of the intricate nature of human body. Hence t...

Introduction to Anatomy The word Anatomy has Indo-European root. In Greek, called anatome meaning “dissection”. Latin as anatomia; Old French as anatomie; English still as anatomie. It’s a subject seen as enigma surrounded in mystery. The notion because of the intricate nature of human body. Hence the need to carefully dissect and inspect cadaver. It revolves around dissection in keeping with old tradition. Dissection, an environment in which sense of touch and sight enhances understanding of human body. Definition: Study of normal body structure. It consist of the knowledge of exert form, position, size and relationship of the various structures of the human body in healthy condition.  History of anatomy The study began as early as 1600 BC. Hippocrates earliest medical scientist demonstrated basic understanding of musculoskeletal structures (Carola et al., 1992). Though much of his work was based on speculation. Galen compiled much of the knowledge obtained by previous writers furthered inquiry into function of organs by performing vivisection on animals. Sixteenth century witnessed major conceptual change the era of modern anatomy. Mondino de Liuzzi and Alessandro Achillini were the first to dissect cadavers and conduct public anatomical demonstrations (Carola et al., 1992). The rebirth of anatomy era: Andreas Vesalius was the first challenge to the Galenic doctrine The treatise, De humani corporis fabrica published by Andreas Vesalius gave clear descriptions of major body organs (William, 1999; Cushing, 1962) because he got permission to dissect human bodies. Andreas Vesalius works were improved upon by Columbus his successor who rectified and improved on the anatomy of the bones. He gave a correct account of the shape and cavities of the heart, the pulmonary artery, aorta and their valves. Leonardo da Vinci was the first to notice an abnormality in a dissected corpse. However, autopsy came of age with the works of Giovanni Morgagni regarded as the father of modern pathology (Carola et al., 1992). Marcello Malpighi conducted extensive studies in human anatomy and histology using microscope. Amongst his findings were the inner layer of the skin, outer part of the cerebral area of the brain etc. Antonie van Leeuwenhoek used single lenses to achieve magnifications from 40-270 diameters. He was able to see the infusion of many protozoa of different shapes and sizes. The discipline also progressed to establish a growing source of knowledge in histology and developmental biology. Another major breakthrough in the history of anatomy occurred through radiological advances in 20th century in which scientists made remarkable connections between anatomy and physiology. It enabled researchers to integrate the study of anatomy with the other disciplines, including biochemistry, genetics and biophysics. A radiological advance is the very foundation of successful imaging. Sectional anatomy involves the use of labelled Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) (Carola et al., 1992).  Branches of anatomy Anatomy is a subject that grew overtime following advances in technology. It has developed to include; gross anatomy, developmental anatomy, histology, cytology, comparative anatomy, pathological anatomy, functional anatomy, anthropological anatomy and surface anatomy. Gross anatomy: The study of various structures in the body visible to the naked eyes. Developmental anatomy: The study of the human organism involving various stages of intrauterine development from the fertilized ovum up to birth. Histology: It is the study of the minute structures invisible to the naked eyes. Cytology: The study of cells in the body. Comparative anatomy: The study of the structure of different animals by the consideration of adult forms in the line of human ancestry. Pathological anatomy: The study of disease conditions of tissues, organs and systems. Functional anatomy: An aspect of anatomy that overlaps with physiology. It is concerned with the study of functions of normal body parts. Anthropological anatomy: It is an aspect of science that is concerned with the comparison of the anatomy of different races of mankind. Surface or superficial anatomy: The study of anatomical landmarks that can be readily identified from contours or other reference points on the surface of the body. More often, with the knowledge of the surface anatomy, physicians can gauge the precise position of the anatomy of the associated disease structures. Anatomical orientations: It is the imaginary planes through the body used to describe its orientations. A person in the standard anatomical position is standing up erect with the feet planted on the ground, the face straight, and the arms hanging at the sides with the palms of the hands facing in the same direction as the face.  Basic anatomical terms The terms in anatomy centre on two major areas: Anatomical planes and sections Directional terms Anatomical planes are imaginary flat surfaces that pass through the body and they include: Sagittal/median plane – separates the body into left and right halves. Coronal/frontal plane – separates the body into front and back halves Transverse/cross plane – separates the body into superior and inferior halves. Oblique plane – is an imaginary line that cuts cross either from left to right or front to back of the body.  Directional terms Cranial/superior/rostral: This indicates a structure nearer the head. Caudal/inferior: This indicates a structure farther away from the head. Anterior/ventral: This indicates that the part being described is nearer the front of the body than the back. Posterior/dorsal: This mean nearer the back of the body. Medial: This indicates a structure nearer the midline. Lateral: This indicates a structure farther from the midline. Proximal: It is that part of a structure (bone) which is the nearest to point of attachment of the limb to the body. Distal: It is that part of a structure (bone) which is the farthest away from the point of attachment of the limb to the body. Superficial: It indicates that a structure is the closest to the body surface. Deep: It indicates that a structure is further away from the outer body surface. Ipsilateral: This indicates that a structure is on the same side of a lateral side of hemisphere. Contralateral: It indicates that a structure has crossed to the opposite side to be situated on a lateral side of the hemisphere. External/internal: Mostly commonly used for describing the body wall or the walls of cavities and hollow viscera. Embryology: Study of formation and development of embryo from conception to when born as infant. In broader terms includes entire development period. Development does not stop at birth. Apart from growth is the development of teeth and breast etc. However most development stop at age 25 years. Prenatal period: Zygote result from fertilization of oocyte by a sperm- the beginning of human being. Morula: Is when 16 blastomeres have formed- a solid mass of cells. Blastocyst: After morula reaches the uterus fluid passes into it forming a cavity-blastocyst. Embryo: Embryo forming cells groups as inner cell mass (embryoblast) seen at morula stage. This term is not used until 2nd wk. when bilaminar embryonic disc is formed. Foetus: After embryonic period, developing human is called foetus. During this period (9wks – birth) many systems further develop. Post-natal stage: Changes occurring after birth. Infancy: Refers to first year after birth. New-born: First 2wks after birth. Childhood: A period of 15 months until 12-13 years. Puberty: Between age 12 to 15 years for girls and 13 to 16 years for boys during which secondary sexual characters are formed. Adolescence: Period of 3-4 years after puberty. It extends from earliest signs of sexual maturity until the attainment of physical, mental and emotional maturity.