Anatomy PDF

# Anatomy It is the branch of science, which concerns (deals), with the form and structure of the tissues and organs that compose the body. The word "Anatomy" is of Greek origin and literally means cutting a part (Gross or macroscopic anatomy). ## Microscopic anatomy or Histology: Is the branch o...

# Anatomy It is the branch of science, which concerns (deals), with the form and structure of the tissues and organs that compose the body. The word "Anatomy" is of Greek origin and literally means cutting a part (Gross or macroscopic anatomy). ## Microscopic anatomy or Histology: Is the branch of science, which studies the finer details of structure and minute organisms. ## Developmental anatomy or Embryology: Is the branch of science, which study the changes which organisms undergo during their development. This term is usually limited in its application to the earlier phases of development during which the tissues and organs are formed. ## Ontogeny: It is the term used to designate the entire development of the individual. ## Phylogeny: It is the ancestral history of the species i.e. the relation between the anatomy of the individual and that of his ancestors (historical development). ## Comparative anatomy: Is the description and comparison of the structure of animals, and forms the basis for their classification. Studying the genetic relationship of various groups of animals and to elucidate the significance of many facts of structure which are otherwise quite obscure. It provide general laws of form and structure that constitute the science of morphology or philosophical anatomy. ## Special anatomy: Is the description of the structure of a single type or species, e.g., anthropotomy, hippotomy. ## Veterinary anatomy: Is the branch which deals with the form and structure of the principal domesticated animals. It is usually descriptive in character. The horse is generally selected as the type to be studied in detail and to form a basis for comparison of the more essential differential characters. ## Systematic anatomy: In this respect the body is regarded as consisting of systems of organs or apparatus which are similar in origin and structure and are associated in the performance of certain functions. The divisions of systematic anatomy are: 1. **Osteology:** Means the description of the skeleton (bones & cartilages) whose functions are support and protection of the soft parts of the body. 2. **Arthrology:** Means the description of the joints, whose function are to make the ridig segments of the bones movable, and to hold them together with strong fibrous bands and ligaments. 3. **Myology:** Means the description of the muscles and the accessory structures that function to put the bones and joints into useful motion. 4. **Splanchnology:** Means the description of the viscera which includes: * Digestive System * Respiratory System * Urogenital System * Urinary Organs * Genital Organs 5. **Angiology:** Means the description of the organs of circulation (heart, arteries, veins, lymphatics and spleen) 6. **Neurology:** Means the description of the nervous system whose function to control and coordinate all other organs and structures. 7. **Esthesiology (Sense Organs):** Deal with the study of the eye and ear. 8. **Common Integument:** Deal with study of the skin and its structures, whose chief functions are as a protective envelop of the body. ## The topographic anatomy: It is designates the methods by which the relative positions of the various parts of the body are accurately determined. It presupposes a fair working knowledge of systematic anatomy. ## Topographic terms: In order to indicate the position and the direction of parts of the body, certain descriptive terms are employed. In the explanation of these terms, it is assumed that they apply to a quadruped in the normal standing position. ## Anatomical plans: 1. **Median plane:** is the plane, which divides the body longitudinally into right & left similar halves. The term "median" has been also applied to a plane dividing the limb longitudinally into similar halves (right & left). 2. **Sagittal plane (s):** is a plane parallel to the median plane on either side. Sagittal planes close to the median plane sometimes termed paramedian e.g. right paramedian - left paramedian. 3. **Transverse plane (s):** is a plane that cut the long axis of the body perpendicular to the median plane and sagittal planes. With respect to limb, part or organ, a transverse plane is perpendicular to the long axis of limb, part or organ. 4. **Frontal plane:** is perpendicular to the median and transverse planes. - **Medial (internal):** is the structure or part nearer (than another) to the median plane. - **Lateral (external):** is the structure or part farther (than another) from the median plane. - **Cranial (anterior):** is the head end of the body. It refers to the structure or part nearer (than another) to the head of the animal. - **Caudal (posterior):** is the tail end of the body. It refers to the structure or part nearer (than another) to the tail of the animal. =With respect to parts of the head, the term rostral is used instead of cranial. - **Ventral:** the structures directed toward the plane of support (the ground). It refers to the structure or part nearer (than another) to the ground. - **Dorsal:** the opposite surface to ventral. It refers to the structure or part farther (than another) from the ground. - The terms superficial and deep (profundus) indicate relative distance from the surface of the body. ## Certain terms are (applied) to the limbs: - **Proximal:** it refers to the structure or part nearer than another to the long axis of the body. - **Distal:** it refers to the structure or part farther (than another) from the long asxis of the body. Below the carpus (in the fore limb): - The term dorsal is used to indicate cranial. - The term palmar is used to indicate caudal. =Below the tarsus (in the hind limb): - The term dorsal is used to indicate cranial. - The term plantar is used to indicate caudal. ## GENERAL OSTEOLOGY ### Osteology: It is the science which deals with study of the bones. ### The skeleton: It is a framework of hard structures (bones and cartilages) which support and protect the soft tissues of the animal body. ### Classification of the skeleton: **Endoskeleton** - Is embedded in the soft tissues. - It is derived mainly from the mesoderm, except the notochord (primitive axial skeleton) which is of endodermal origin. **Exoskeleton** - Is situated externally and is derived from the ectoderm. - e.g. Shells of many invertebrates, the scales of fishes & the feathers, hairs and hoofs of the higher vertebrates. ### Functions of the skeleton or bones: 1. Protect the soft tissues like spinal cord, heart, brain, viscera,...etc 2. Support the body and attachment of muscles. 3. Levers for locomotion. 4. Storage of minerals like calcium, phosphate and others. 5. Blood cells formation (by red marrow). ### Classes of bones: The bones are divided into 4 classes according to theik shape and function. 1. **Long bones:** - They are elongated and cylindrical with enlarged extremities. - They occur in the limbs where they act as supporting columns and as levers. - The cylindrical or tubular part termed the shaft or body (corpus) which encloses the medullary cavity which contains marrow. - Examples: humerus, femur, radius and tibia 2. **Flat bones:** - They are plate like and expanded in two directions. - They give sufficient area for the attachment of muscles. - They provide protection to the organs which they cover. - Examples: scapula, ilium, ribs and bones of skull. 3. **Short bones:** - They have similar dimensions in length, breadth and thickness. - Consist mainly of spongy substance? - Their function is diffusing and reducing concussion - Examples: carpus and tarsus. 4. **Irregular bones:** - They have irregular shape such as the vertebrae and the bones of the cranial base. - They are median and unpaired. - Their functions are various and not so clearly specialized. ### *Types of bones* - Sesamoid - Pneumatic = ### Structure of bones: The bone consists of an external shell of dense compact substance, within which is a loosely arranged spongy substance. In long bone, the shaft is hollowed to form the medullary cavity. 1. **The compact substance:** - The compact substance differs greatly in thickness in various situations in accordance with the stress and strain to which the bone is subjected. It encloses the Haversian canal. - In long bones, it is thick in or near the middle part of the shaft, thins toward the extremities and becomes very thin, smooth and denser on joint surface. 2. **The spongy substance:** - It consists of delicate bony plates and spicules which run in various directions and forming spongy appearance. - The intervals or spaces between the plates are termed marrow spaces occupied by bone marrow. - The spongy substance forms the bulk of short bones and the extremities of long bones and extends a variable distance along the shaft also. 3. **The periosteum:** - It is a thin strong membrane which invests the outer surface of the bone except where the bone is covered with cartilage. The adhesion of periosteum to the bone differs greatly in various places. - The periosteum is composed of 2 layers: - An outer protective fibrous layer. - An inner cellular osteogenic layer which during active growth is well developed but later it becomes much reduced. - Function: - Growth and repair for the bone. - Route for nerves and vessels. 4. **The endosteum:** - It is a thin fibrous membrane which lines the medullary cavity and the larger Haversian canals. 5. **The bone marrow:** - It occupies the spaces of the spongy bone and the medullary cavity of the long bones. - In adult, there are 2 types of marrow; red and yellow. The yellow marrow (in adult) is ordinary adipose tissue, formed by regressive changes in the red marrow including fatty infiltration and fatty degeneration. - In the young subject, there is only red marrow which is a blood forming substance (hemopoietic organ since it is the source of red cells, hemoglobin, granular white cells and platelets). - N.B. Red marrow is persistent in the sternum throughout life, thus this is a convenient place for aspiration and examination. ### *Structure of long bone.* ### Vessels and nerves supplying the bones: - **A) Vessels:** There are 2 main sets of arteries, the periosteal and the medullary arteries: 1. **The periosteal arteries** ramify in the periosteum and give off many small branches which enter minute openings on the Haversian (nutrient) canals of the compact substance. Other branches enter the extremities of the long bones and supply the spongy bone and marrow in them. 2. **The nutrient or medullary artery** enters the nutrient foramen (in case of long bones), passes in a canal through the compact substance and ramifies in the marrow. Its branches anastomose with the central branches of the periosteal arteries. 3. **Epiphyseal arteries:** enter the bone at the epiphysis. 4. **Metaphyseal arteries:** enter the bone at the metaphysis. 5. **The larger veins** of the spongy bone do not accompany the arteries but emerge chiefly near the articular surfaces. 6. **The lymph vessels** exist as perivascular channels in the periosteum and the Haversian canals of the compact substance. The larger lymph vessels proceed usually in company with veins. Lymph spaces exist at the periphery of the marrow. - **B) Nerves:** Nerve fibers accompany the blood vessels of the bone. Some fibers are vasomotor but some are sensory to the periosteum. ### Blood Supply of a Long Bone ### Chemical composition of bone: - In vivo bone contains between 10% and 20% water. Dried bone consists of organic and inorganic matter in ratio of 1:2. - The organic matter (35%) includes bone cells and collagen fibers which gives the bone its toughness and elasticity, while the inorganic matter (65%) mostly calcium and phosphorus and gives hardness to the bone tissue. - The bone is composed of gelatin, phosphates of lime, carbonate of lime, phosphate of magnesia and carbonate and chloride of sodium. ### Physical properties of bones: 1. **Colour:** - a- yellowish white in fresh dead bone. - b- white when boiled and bleached. 2. **Specific gravity** of fresh compact bone 1.9 3. The bone is **very hard and resistant to pressure**. ### Descriptive terms: The surfaces of the bones present a great variety of eminences and depressions, as well as perforations. The prominences and cavities may be articular, or nonarticular, furnishing attachment to muscles, tendons, ligaments or fascia. A number of descriptive terms are used to designate these features, and the followings are some of those in general use: ### Terms of the bones | | Projections | Depressions | | :--------------- | :---------- | :------------------------------- | | Articular | | | | | Head | Glenoid cavity | | | Condyle | Cotyloid cavity | | | Trochlea | Facet | | | | | | Non-articular | | | | | Process | Fossa | | | Eminence | Fovea | | | Epicondyle | Sulcus | | | Trochanter | Sinus | | | Tuberosity | Fissure | | | Tubercle | Canal | | | Ridge | Foramen | | | Spine | Notch | ### Articular depressions: - Glenoid cavity تجويف عنابي او أروح is a shallow articular depression. e.g glenoid cavity of scapula. - Cotyloid cavity تجويف حقي or acetabulum is a deeper one. e.g acetabulum of pelvic bone. - Facet سطيح تمفصلي is a flat smooth articular surface. e.g facets between carpal bones. ### Articular projections: - A head رأس )Caput) is a rounded articular projection at the end of a bone; it may be joined to the shaft by a constricted part, the neck (Collum).e.g head of humerus and femur. - A condyle لقمة )Condylus) is an articular eminence which is somewhat cylindrical.e.g lateral and medial condyle of femur. - A trochlea بكرة is a pulley-like articular mass (2 rounded projections with a groove between them). e.g trochlea of humerus and femur. ### Non articular depressions: - Fossa = ditch = نقرة - Fissure = cleft = شق - groove = sulcus = اخدود او ميزاب - canal = قناة - Fovea = pit = حفرة - Notch = incisura cut in bone = - foramen-hole = - sinus or antrum = جيب هوائي an air-cavity. ### Non articular projections: - Process نتوء = prominence or projection. e.g anconeal process of ulna. - A tuberosity حدبة( )Tuber Tuberositas) is a large; rounded projection; a tubercle. e.g deltoid tuberosity of humerus. - )Tuberculum( حديبة is a smaller one. - Trochanter مدور is around prominence for attachment of muscles, e. g., the trochanters of the femur. - Epicondyle فوق اللقمة is a non-articular projection in connection with a condyle. - A spine (Spina( شوكة or spinous process (Processus spinosus) is a pointed projection. - A crest (Crista( عرف او حافة حادة is a sharp ridge. - A line (Linea( خط او حافة منخفضة is a very small low ridge.