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INTRODUCTION to ANATOMY JUAN PAULO A. TABALOC, M.D.  BASIC ANATOMY Anatomy is the science of the structure and function of the body. Clinical anatomy is the study of the macroscopic structure and function of the body as it relates to the...

INTRODUCTION to ANATOMY JUAN PAULO A. TABALOC, M.D.  BASIC ANATOMY Anatomy is the science of the structure and function of the body. Clinical anatomy is the study of the macroscopic structure and function of the body as it relates to the practice of medicine and other health sciences Basic anatomy is the study of the minimal amount of anatomy consistent with the understanding of the overall structure and function of the body Anatomic terms used in relation to position. Note that the subjects are standing in the anatomic position.  Descriptive Anatomic Terms Terms Related to Position All descriptions of the human body are based on the assumption that the person is standing erect, with the upper limbs by the sides and the face and palms of the hands directed forward. This is the so-called anatomic position.  Median Sagittal Plane Paramedian - Planes situated to one or the other side of the median plane and parallel to it Medial - A structure situated nearer to the median plane of the body than another Lateral - a structure that lies farther away from the median plane than another Coronal Planes These planes are imaginary vertical planes at right angles to the median plane.  Horizontal or transverse plane Right angles to the median and coronal planes Divides the body into superior or inferior  Anterior and posterior - used to indicate the front and back of the body Palmar and Dorsal surfaces - used in place of anterior and posterior Plantar and dorsal surfaces – used in describing the foot Proximal and Distal - describes the relative distances from the roots of the limbs Superficial and deep - denote the relative distances of structures from the surface of the body  Superior and inferior - denote levels relatively high or low with reference to the upper and lower ends of the body Internal and external - used to describe the relative distance of a structure from the center of an organ or cavity Ipsilateral - refers to the same side of the body Contralateral - refers to opposite sides of the bod Supine - lying on the back Prone - lying face downward  TERMS RELATED TO MOVEMENT Joint - A site where two or more bones come together Flexion - a movement that takes place in a sagittal plane Extension - straightening the joint and usually takes place in a posterior direction Lateral flexion - a movement of the trunk in the coronal plane  TERMS RELATED TO MOVEMENT Abduction - a movement of a limb away from the midline of the body in the coronal plane Adduction - a movement of a limb toward the body in the coronal plane Rotation - term applied to the movement of a part of the body around its long axis Medical rotation Lateral rotation Some anatomic terms used in relation to movement. Note the difference between flexion of the elbow and that of the knee.  Pronation of the forearm - medial rotation of the forearm in such a manner that the palm of the hand faces posteriorly Supination of the forearm - a lateral rotation of the forearm Circumduction - combination in sequence of the movements of flexion, extension, abduction, and adduction  Protraction - to move forward Retraction - to move backward Inversion - the movement of the foot so that the sole faces in a medial direction Eversion - the opposite movement of the foot so that the sole faces in a lateral direction Additional anatomic terms used in relation to movement. BASIC STRUCTURES  SKIN General structure of the skin and its relationship to the superficial fascia. Note that hair follicles extend down into the deeper part of the dermis or even into the superficial fascia, whereas sweat glands extend deeply into the superficial fascia.  2 parts of the Skin 1. Epidermis - the superficial par 2. Dermis - the deep part The dermis of the skin is connected to the underlying deep fascia or bones by the superficial fascia, otherwise known as subcutaneous tissue. Appendages of the Skin Nails hair follicles sebaceous glands sweat glands  Nails - keratinized plates on the dorsal surfaces of the tips of the fingers and toes – root of the nail - The proximal edge of the plate – nail folds - With the exception of the distal edge of the plate, the nail is surrounded and overlapped by folds of skin – nail bed - surface of skin covered by the nail Hairs grow out of follicles, which are invaginations of the epidermis into the dermis The follicles lie obliquely to the skin surface, and their expanded extremities, called hair bulbs, penetrate to the deeper part of the dermis. Each hair bulb is concave at its end, and the concavity is occupied by vascular connective tissue called hair papilla. A band of smooth muscle, the arrector pili, connects the undersurface of the follicle to the superficial part of the dermis The pull of the muscle also causes dimpling of the skin surface, so-called gooseflesh. Sebaceous glands pour their secretion, the sebum, onto the shafts of the hairs as they pass up through the necks of the follicles. Sebum is an oily material that helps preserve the flexibility of the emerging hair. It also oils the surface epidermis around the mouth of the follicle. Sweat glands are long, spiral, tubular glands distributed over the surface of the body, except on the red margins of the lips, the nail beds, and the glans penis and clitoris. The various skin creases on the palmar surface of the hand and the anterior surface of the wrist joint. The relationship of the nail to other structures of the finger is also shown. CLINICAL NOTES SKIN INFECTIONS The nail folds, hair follicles, and sebaceous glands are common sites for entrance into the underlying tissues of pathogenic organisms such as Staphylococcus aureus. Paronychia - Infection occurring between the nail and the nail fold Infection of the hair follicle and sebaceous gland is responsible for the common boil. A carbuncle is a staphylococcal infection of the superficial fascia  SKIN INFECTIONS Sebaceous Cyst Shock Skin Burns Skin Grafting Section through the middle of the right arm showing the arrangement of the superficial and deep fascia. Note how the fibrous septa extend between groups of muscles, dividing the arm into fascial compartments. Fasciae 2 Types of Fasciae superficial fascia - also called subcutaneous tissue, a mixture of loose areolar and adipose tissue that unites the dermis of the skin to the underlying deep fascia deep fascia - membranous layer of connective tissue that invests the muscles and other deep structures Retinacula - In the region of joints, the deep fascia may be considerably thickened to form restraining bands Extensor retinaculum on the posterior surface of the wrist holding the underlying tendons of the extensor muscles in position.  CLINICAL NOTES Fasciae and Infection A knowledge of the arrangement of the deep fasciae often helps explain the path taken by an infection when it spreads from its primary site. In the neck, for example, the various fascial planes explain how infection can extend from the region of the floor of the mouth to the larynx. MUSCLE 3 Types of Muscle Skeletal Muscle - produce the movements of the skeleton -they are sometimes called voluntary muscles and are made up of striped muscle fibers - A skeletal muscle has two or more attachments. The attachment that moves the least is referred to as the origin, and the one that moves the most, the insertion. Belly - the fleshy part of the muscle Tendons- the ends of a muscle are attached to bones, cartilage, or ligaments by cords of fibrous tissue Aponeurosis - flattened muscles are attached by a thin but strong sheet of fibrous tissue Raphe- an interdigitation of the tendinous ends of fibers of flat muscles Origin, insertion, and belly of the gastrocnemius muscle. Examples of (A) a tendon, (B) an aponeurosis, and (C) a raphe. Different forms of the internal structure of skeletal muscle. A relaxed and a contracted muscle are also shown; note how the muscle fibers, on contraction, shorten by one third to one half of their resting length. Note also how the muscle swells. pennate muscles - Muscles whose fibers run obliquely to the line of pull unipennate muscle - one in which the tendon lies along one side of the muscle and the muscle fibers pass obliquely to it bipennate muscle - one in which the tendon lies in the center of the muscle and the muscle fibers pass to it from two sides multipennate muscle - may be arranged as a series of bipennate muscles lying alongside one another SKELETAL MUSCLE ACTION Prime mover : A muscle is a prime mover when it is the chief muscle or member of a chief group of muscles responsible for a particular movement. Antagonist : Any muscle that opposes the action of the prime mover is an antagonist. Fixator : A fixator contracts isometricallyto stabilize the origin of the prime mover so that it can act efficiently Synergist: In many locations in the body the prime mover muscle crosses several joints before it reaches the joint at which its main action takes place. Different types of muscle action. A. Quadriceps femoris extending the knee as a prime mover, and biceps femoris acting as an antagonist. B. Biceps femoris flexing the knee as a prime mover, and quadriceps acting as an antagonist. C. Muscles around shoulder girdle fixing the scapula so that movement of abduction can take place at the shoulder joint. D. Flexor and extensor muscles of the carpus acting as synergists and stabilizing the carpus so that long flexor and extensor tendons can flex and extend the fingers.  NERVE SUPPLY OF SKELETAL MUSCLE motor point - The nerve enters the muscle at about the midpoint on its deep surface, often near the margin; the place of entrance  Nerve fibers Motor fibers – Alpha – Gamma Sensory fibers Sympathetic fibers  NAMING OF SKELETAL MUSCLES Individual muscles are named according to their shape, size, number of heads or bellies, position, depth, attachments, or actions.  CLINICAL NOTES Muscle Tone Muscle Attachments Muscle Shape and Form  Smooth Muscle Smooth muscle consists of long, spindle- shaped cells closely arranged in bundles or sheets. Peristalsis - By their contraction, the longitudinal fibers pull the wall of the tube proximally over the contents.  Cardiac Muscle Cardiac muscle consists of striated muscle fibers that branch and unite with each other. Cardiac muscle is supplied by autonomic nerve fibers that terminate in the nodes of the conducting system and in the myocardium.  CLINICAL NOTES Necrosis of Cardiac Muscle The cardiac muscle receives its blood supply from the coronary arteries. A sudden block of one of the large branches of a coronary artery will inevitably lead to necrosis of the cardiac muscle and often to the death of the patient.  JOINTS - A site where two or more bones come together, whether or not movement occurs between them Fibrous Joints The articulating surfaces of the bones are joined by fibrous tissue and thus very little movement is possible. Cartilaginous Joints 2 types. primary cartilaginous joint - one in which the bones are united by a plate or bar of hyaline cartilage.. secondary cartilaginous joint - one in which the bones are united by a plate of fibrocartilage and the articular surfaces of the bones are covered by a thin layer of hyaline cartilage  Synovial Joints The articular surfaces of the bones are covered by a thin layer of hyaline cartilage separated by a joint cavity The cavity of the joint is lined by synovial membrane The synovial membrane is protected on the outside by a tough fibrous membrane referred to as the capsule of the joint The articular surfaces are lubricated by a viscous fluid called synovial fluid. Articular discs - In certain synovial joints, for example, in the knee joint, discs or wedges of fibrocartilage are interposed between the articular surfaces of the bones.  Fatty pads are found in some synovial joints lying between the synovial membrane and the fibrous capsule or bone.  Synovial joints can be classified according to the arrangement of the articular surfaces and the types of movement that are possible. Plane joints: In plane joints, the apposed articular surfaces are flat or almost flat, and this permits the bones to slide on one another. Hinge joints: Hinge joints resemble the hinge on a door, so that flexion and extension movements are possible. Pivot joints: In pivot joints, a central bony pivot is surrounded by a bonyâligamentous ring and rotation is the only movement possible. Condyloid joints: Condyloid joints have two distinct convex surfaces that articulate with two concave surfaces. Ellipsoid joints: In ellipsoid joints, an elliptical convex articular surface fits into an elliptical concave articular surface. Saddle joints: In saddle joints, the articular surfaces are reciprocally concavoconvex and resemble a saddle on a horse’s back. Ball-and-socket joints: In ball-and-socket joints, a ball-shaped head of one bone fits into a socketlike concavity of another. Examples of three types of joints. A. Fibrous joint (coronal suture of skull).B. Cartilaginous joint (joint between two lumbar vertebral bodies). C. Synovial joint (hip joint).  STABILITY OF JOINTS The stability of a joint depends on three main factors: the shape, size, and arrangement of the articular surfaces; the ligaments; and the tone of the muscles around the joint.  Articular Surfaces Ligaments 1. Fibrous ligaments prevent excessive movement in a joint but if the stress is continued for an excessively long period, then fibrous ligaments stretch. 2. Elastic ligaments, conversely, return to their original length after stretching. Muscle Tone The three main factors responsible for stabilizing a joint. A. Shape of articular surfaces. B. Ligaments. C. Muscle tone. Examples of different types of synovial joints. A. Plane joints (sternoclavicular and acromioclavicular joints). B. Hinge joint (elbow joint). C. Pivot joint (atlantoaxial joint). D. Condyloid joint (metacarpophalangeal joint). E. Ellipsoid joint (wrist joint). F. Saddle joint (carpometacarpal joint of the thumb). G. Ball-and- socket joint (hip joint).  Nerve Supply of Joints The capsule and ligaments receive an abundant sensory nerve supply. A sensory nerve supplying a joint also supplies the muscles moving the joint and the skin overlying the insertions of these muscles, a fact that has been codified as Hilton’s law.  Clinical Notes Examination of Joints Dislocated - When the bones of a joint are no longer in their normal anatomic relationship with one another Gonococcal arthritis affects large synovial joints such as the ankle, elbow, or wrist tuberculous arthritis also affects synovial joints and may start in the synovial membrane or in the bone  Ligaments A ligament is a cord or band of connective tissue uniting two structures. Commonly found in association with joints, ligaments are of two types.  CLINICAL NOTES Damage to Ligaments Joint ligaments are very prone to excessive stretching and even tearing and rupture.  Bursae A bursa is a lubricating device consisting of a closed fibrous sac lined with a delicate smooth membrane.  Synovial Sheath A synovial sheath is a tubular bursa that surrounds a tendon.  CLINICAL NOTES Trauma and Infection of Bursae and Synovial Sheaths Bursae and synovial sheaths are commonly the site of traumatic or infectious disease. Four bursae related to the front of the knee joint. Note that the suprapatellar bursa communicates with the cavity of the joint. B. Synovial sheaths around the long tendons of the fingers. C. How tendon indents synovial sheath during development, and how blood vessels reach the tendon through the mesotendon.  Blood Vessels Three types: 1. Arteries 2. Veins 3. Capillaries  Arteries transport blood from the heart and distribute it to the various tissues of the body by means of their branches.The smallest arteries,