Introduction to Anatomy PDF

Introduction Defenition: ANATOMY is a science that examines the relations between the normal shape and structure of the human body and the organs that constitute the body. The anatomist is called the person who deals with anatomy. ANATOMY Gross anatomy microscopic anatomy (cytology, histology)...

Introduction Defenition: ANATOMY is a science that examines the relations between the normal shape and structure of the human body and the organs that constitute the body. The anatomist is called the person who deals with anatomy. ANATOMY Gross anatomy microscopic anatomy (cytology, histology) developmental anatomy pathological anatomy systematic anatomy Systematic anatomy concentrates on various organ systems with cohesive functions, such as the nervous system with the brain and blood vessels and the respiratory system with the lungs and airways. Human body systems There are approximately 79 human anatomy organs, although there is no standard or universally accepted number. What would the result be if every one of these organs worked independently? Chaos! Therefore, they function in groups called systems. An organ system consists of many organs working together to accomplish similar tasks and reach a common goal. There are eleven systems in the human body: circulatory (blood supply), respiratory (breathing), digestive (digestion and absorption), nervous (sensation and movement), excretory (waste elimination), endocrine (hormonal control), reproductive, lymphatic (defense), skeletal (support), and muscular (movement) systems. The last two are usually combined into the musculoskeletal system. The different systems that can be found within the systematic anatomy are: The integument system: The organ system that protects the body from damage, and which consists of the skin and its appendages, such as hair and nails. The skeleton: Consists of bone and cartilage. Provides us with form and support and necessary for the muscles to be able to produce movements. Joint system: Consists of the joints and their associated ligaments that connect different skeletal parts and enable movement. Muscular system: Consists of muscles and tendons that contract to move or move the body and fluids (eg heart muscle cells). Nervous system: Consists of the central nervous system and the peripheral nervous system. Controls and coordinates functions in the various organ systems. Circulatory system: Consists of the cardiovascular system and the lymphatic system that transports bodily fluids. Cardiovascular system: Consists of the heart and blood vessels that supply the tissues with blood. Lymphatic system: Lymphatic vessels that drain lymph from the interstitium, carry it to the lymph nodes and then empty it into the bloodstream. Digestive system: Consists of the digestive tract from the mouth down to the anus and its associated organs and glands.  Respiratory system: Consists of the airways and lungs that oxygenate the blood and eliminate carbon dioxide from the blood. Urinary system: Consists of the kidneys, ureters, urethra and urethra that filter the blood and excrete waste in the form of urine. Reproductive system: Consists of the male and female genitals and its associated organs. Endocrine system: Consists of organs that secrete hormones. The hormones are organic molecules that are transported in the circulation to effector cells in the body. Learning anatomy is similar to building a house; if the foundation is strong then it will last for a lifetime. This subject is definitely difficult and filled to the brim with details, but the basics keep cropping up time and time again. You will constantly use them as reference when learning new anatomical concepts, thus mastering the fundamentals is essential. So, what are these foundations? In the realm of anatomy, they include: Terminology, planes, body movements Regions of the body Organ systems Regional neurovasculature The basic anatomical position All anatomical descriptions are based on a certain position to reduce the risk of misunderstandings. Here you can see a general description of the basic anatomical position The person stands upright with: -Head, eyes and toes pointing straight ahead -Arms hanging along the body with the palms facing forward -Legs close together and feet parallel Anatomical planes A plane is in fact a 2D slice through 3D space, which can be thought as a glass sheet. Actually they are different lines that used to divide the human body. Using anatomical planes allows for accurate description of a location, and allows you as the reader to understand what a diagram or picture is trying to show. There are three planes commonly used; sagittal, coronal and transverse. Sagittal plane –(median) a vertical line which divides the body into a left section and a right section. Coronal plane (frontal)– a vertical line which divides the body into a front (anterior) section and back (posterior) section. Transverse plane –(horizontal) a horizontal line which divides the body into an upper (superior) section and a lower (inferior) section. For example, a diagram may be labelled as a transverse section, viewed superiorly. This indicates that you are looking downwards onto a horizontal section of the body.  Anatomical positions Now when you know the basic anatomical position and using the correct anatomical terminology, you can describe any body part in relation to another body part. There are a number of terms used to describe the relationship between body parts or to compare the position between two different structures in relation to each other. The anatomical terms of location are vital to understanding and using anatomy. Medial and Lateral ‫وسطي وجانبي‬ Imagine a line in the sagittal plane, splitting the right and left halves evenly. This is the midline. Medial means towards the midline, lateral means away from the midline. Examples: The eye is lateral to the nose. The nose is medial to the ears. The brachial artery lies medial to the biceps tendon. Anterior and Posterior ‫األمامي والخلفي‬ Anterior refers to the ‘front’, and posterior refers to the ‘back’. Putting this in context, the heart is posterior to the sternum because it lies behind it. Equally, the sternum is anterior to the heart because it lies in front of it. Examples Pectoralis major lies anterior to pectoralis minor. The triceps are posterior to biceps brachii. The patella is located anteriorly in the lower limb. Superior and Inferior ‫أعلى وأقصر‬ These terms refer to the vertical axis. Superior means ‘higher’, inferior means ‘lower’. The head is superior to the neck; the umbilicus is inferior to the sternum. Here we run into a small complication, and limbs are very mobile, and what is superior in one position is inferior in another. Therefore, in addition to the superior and inferior, we need another descriptive pair of terms: Examples The shoulder joint is superior to the elbow joint. The lungs are superior to the liver. The appendix is inferior to the transverse colon. Proximal and Distal ‫قريب ومنبذ‬ The terms proximal and distal are used in structures that are considered to have a beginning and an end (such as the upper limb, lower limb and blood vessels). They describe the position of a structure with reference to its origin – proximal means closer to its origin, distal means further away. Examples: The wrist joint is distal to the elbow joint. The scaphoid lies in the proximal row of carpal bones. The knee joint is proximal to the ankle joint. Superior refers to a structure that is closer to the vertex, the highest point of the skull. Cranial relates to the skull and is a term used for directions to the head / skull. Inferior refers to a structure that is located closer to the sole of the foot. Posterior / dorsal refers to the back of the body while anteriorly refers to the front of the body. Medial is used to indicate that a structure is closer to the medial plane of the body.  For example, the little finger is more medial than the thumb in the basic anatomical position of the body. At the same time, the term "lateral" can be used to describe a structure that is further away from the medial plane of the body. The palmar surface refers to the side of the palm of the hand and fingers while the dorsal surface refers to the back of the hand and fingers. Proximal is used to describe that a structure is closer to the central parts of the body while distal is used to describe that a structure is further away from the central part of the body Terms of Location in Embryology Cephalic and Caudal Cephalic refers to the head of the embryo, while caudal refers to the tail (inferior) end. Cranial is often used instead of cephalic when describing a location of one structure relative to another. Examples: The vitelline duct lies caudally to the primitive brain. The foregut is cranial to the midgut. Ventral and Dorsal The term ventral refers to the anterior (front) aspect of the embryo, while dorsal refers to the posterior (back). Examples The gut tube lies ventrally to the spinal cord. The spinal cord is dorsal to the developing trachea Neuroembryological terms Rostral and caudal are only used to describe structures within the central nervous system, above the level of the spinal cord (e.g brainstem, cerebrum and cerebellum). They are more commonly used in neuroanatomy but can be applied to embryology. Rostral and Caudal Rostral is taken from the Latin rostrum, to mean towards the nose/beak. Rostral therefore refers to the anterior (front) aspect of the head. In this context, caudal refers to the posterior (back) of the head. Examples: The forebrain is rostral to the midbrain. The hindbrain is caudal to the midbrain Ventral and Dorsal As described above, ventral and dorsal refer to the anterior and posterior aspects of the body respectively. However in the context of the central nervous system, they have slightly different meanings. Ventral refers to the inferior region of the brain, while dorsal refers to the superior region (towards the scalp). Anatomical terms of movement Anatomical terms of movement are used to describe the actions of muscles upon the skeleton. Muscles contract to produce movement at joints, and the subsequent movements can be precisely described using this terminology. The terms used assume that the body begins in the anatomical position. Most movements have an opposite movement – also known as an antagonistic movement. We have described the terms in antagonistic pairs for ease of understanding. Flexion and Extension Flexion and extension are movements that occur in the sagittal plane. They refer to increasing and decreasing the angle between two body parts: Flexion refers to a movement that decreases the angle between two body parts. Flexion at the elbow is decreasing the angle between the ulna and the humerus. When the knee flexes, the ankle moves closer to the buttock, and the angle between the femur and tibia gets smaller. Extension refers to a movement that increases the angle between two body parts. Extension at the elbow is increasing the angle between the ulna and the humerus. Extension of the knee straightens the lower limb. ABDUCTION AND ADDUCTION Abduction and adduction are two terms that are used to describe movements towards or away from the midline of the body. Abduction is a movement away from the midline – just as abducting someone is to take them away. For example, abduction of the shoulder raises the arms out to the sides of the body. Adduction is a movement towards the midline. Adduction of the hip squeezes the legs together. In fingers and toes, the midline used is not the midline of the body, but of the hand and foot respectively. Therefore, abducting the fingers spreads them out. Medial and Lateral Rotation Medial and lateral rotation describe movement of the limbs around their long axis: Medial rotation is a rotational movement towards the midline. It is sometimes referred to as internal rotation. To understand this, we have two scenarios to imagine. Firstly, with a straight leg, rotate it to point the toes inward. This is medial rotation of the hip. Secondly, imagine you are carrying a tea tray in front of you, with elbow at 90 degrees. Now rotate the arm, bringing your hand towards your opposite hip (elbow still at 90 degrees). This is internal rotation of the shoulder. Lateral rotation is a rotating movement away from the midline. This is in the opposite direction to the movements described above. Elevation and Depression Elevation refers to movement in a superior direction (e.g. shoulder shrug), depression refers to movement in an inferior direction. Pronation and Supination This is easily confused with medial and lateral rotation, but the difference is subtle. With your hand resting on a table in front of you, and keeping your shoulder and elbow still, turn your hand onto its back, palm up. This is the supine position, and so this movement is supination. Again, keeping the elbow and shoulder still, flip your hand onto its front, palm down. This is the prone position, and so this movement is named pronation. These terms also apply to the whole body – when lying flat on the back, the body is supine. When lying flat on the front, the body is prone. Dorsiflexion and Plantarflexion Dorsiflexion and plantarflexion are terms used to describe movements at the ankle. They refer to the two surfaces of the foot; the dorsum (superior surface) and the plantar surface (the sole). Dorsiflexion refers to flexion at the ankle, so that the foot points more superiorly. Dorsiflexion of the hand is a confusing term, and so is rarely used. The dorsum of the hand is the posterior surface, and so movement in that direction is extension. Therefore we can say that dorsiflexion of the wrist is the same as extension. Plantarflexion refers extension at the ankle, so that the foot points inferiorly. Similarly there is a term for the hand, which is palmarflexion. Inversion and Eversion Inversion and eversion are movements which occur at the ankle joint, referring to the rotation of the foot around its long axis. Inversion involves the movement of the sole towards the median plane – so that the sole faces in a medial direction. Eversion involves the movement of the sole away from the median plane – so that the sole faces in a lateral direction. Opposition and Reposition A pair of movements that are limited to humans and some great apes, these terms apply to the additional movements that the hand and thumb can perform in these species. Opposition brings the thumb and little finger together. Reposition is a movement that moves the thumb and the little finger away from each other, effectively reversing opposition. Circumduction Circumduction can be defined as a conical movement of a limb extending from the joint at which the movement is controlled. It is sometimes talked about as a circular motion, but is more accurately conical due to the ‘cone’ formed by the moving limb. Protraction and Retraction Protraction describes the anterolateral movement of the scapula on the thoracic wall that allows the shoulder to move anteriorly. In practice, this is the movement of ‘reaching out’ to something. Retraction refers to the posteromedial movement of the scapula on the thoracic wall, which causes the shoulder region to move posteriorly i.e. picking something up.