Anatomical Position & Body Planes PDF Lecture 1-3

# Anatomical Position - Standing erect position. - The eyes looking forward. - The arms by the sides of the trunk with palms of the hand facing forward. - Feet close together. # Planes - **Vertical Planes** - Sagittal Plane: - Midsagittal plane: vertical antero-post. Plane divides th...

# Anatomical Position - Standing erect position. - The eyes looking forward. - The arms by the sides of the trunk with palms of the hand facing forward. - Feet close together. # Planes - **Vertical Planes** - Sagittal Plane: - Midsagittal plane: vertical antero-post. Plane divides the body into right and left equal halves. - Parasagittal plane: Any vertical plane parallel to median plane on either side of the body. - Coronal plane: vertical, side to side plane, divides the body into anterior and posterior parts. - Transverse or horizontal plane: cross section of the body divides it into upper and lower segments. # Terms of Direction - Ventral (anterior) / Dorsal (posterior) - Superior (upper, cranial, cephalic) / Inferior (lower, caudal) - Medial / Lateral (in upper: radial, ulnar & in lower: tibial, fibular) # Terms of Movement - **Flexion**: Movement of bending, occurs when the anterior surface of the distal segment moves towards that of the proximal one. - **Extension**: Opposite of flexion with straightening of the joint. - **Abduction**: To draw a limb away from the median plane of the body. - **Adduction**: Reverse of abduction with bringing the limb back towards the median plane. - **Rotation**: Movement of a part around its long axis. If an anterior surface turns laterally, it is lateral rotation. If it turns medially, it is medial rotation. - **Circumduction**: Movement by the succession of the above movements. - **Pronation and Supination**: Turning the palm of the hand backwards and forwards respectively when the forearm is by the side of the body, or downwards and upwards respectively when the forearm is horizontal. - **Eversion and Inversion**: Special movement of turning the sole of foot outward and inward respectively. - **Protraction and Retraction**: Moving forwards and backwards as in the lower jaw. # Muscular System - Formed of contractile cells that are concerned with the production of movement both of the body as a whole and of the internal organs - **3 types of muscles** - Smooth - Cardiac - Skeletal ## Smooth (Visceral Muscles) - Formed of long spindle-shaped cells with central nuclei - Found in walls of visceral organs and blood vessels. - Controlled by involuntary parts of the nervous system. ## Cardiac Muscle - The myocardium forms the middle layer of the heart - It has the property of spontaneous rhythmic contraction that by impulses arising from SA node (the pacemaker of the heart). - Controlled by involuntary parts of the nervous system. ## Skeletal Muscle - 40% of total body mass - They are attached to their origins and insertions by white fibrous tissues forming rounded tendon or flat aponeurosis. ### Forms of Skeletal Muscles - ​Muscles with fibers parallel to the line of the pull: "Strap or ribbon-like" Give wide range of movement - Muscles with fibers oblique to the line of the pull: - Triangular (Fan-shaped): converge from origin to insertion as: Temporalis - Spiral Muscle: There is a twist between muscle fibers as pectoralis major. - Pennate Muscles: - Unipennate: Tendon forms along one margin of the muscle and the fibers slope into one side of the tendon (1/2 feather) as: flexor pollicis longus. - Bipennate: The tendon forms centrally, and the fibers slope into 2 sides of the central tendon like a feather as: rectus femoris. - Flat: Series of bipennate muscles alongside each other as middle fibers of the Deltoid. - Multipennate: Sloping fibers of a muscle converge from all sides to the central tendon as tibialis anterior. ## Action of Skeletal Muscle - **Prime mover**: Muscle concerned with the initiation of the particular movement. (biceps) - **Antagonist**: Muscle oppose and control the action of the prime mover. (Triceps) - **Fixator**: Muscle contracts isometrically to allow the prime mover act efficiently (shoulder fixators). - **Synergic**: Muscle acts to steady and eliminate unwanted movement in proximal joints while distal joints are in action (muscle on wrist when writing). # Skeletal System - The skeleton is composed of: cartilage & bones - Cartilage: Softer and less rigid than bone. It forms the temporary skeleton of the developing fetus and gradually replaced by bone. - Cartilage is retained throughout life in certain sites of the body as: - external ear - costal cartilage - air passages - articular surfaces of most bones. - Bone: Hard living tissue consists of osteocytes, fibers and matrix with calcification of its extracellular matrix. ## Forms of Bone - **Compact (ivory)**: Hard dense bone forms the outer layer of all bones and shafts of long bones. - **Spongy (cancellous)**: Looks like a sponge found inside the hard bone and ends of long bones. ## Development of Bones - **Membranous ossification**: Occurs in bones required urgently for support or protection of essential organs as those of the vault of the skull. - **Cartilagenous ossification**: At first, a model of the future bone is formed in cartilage, then ossified into 2 steps. ## Shapes of Bones - **Long bones**: Typical of the limbs, has a shaft and 2 expanded ends like: femur, tibia, humerus, radius, ulna. - **Short bones**: Subjected to pressure as: carpal and tarsal bones. - **Flat bones**: Like vault of skull, ribs, sternum and scapula. - **Irregular bones**: Not assigned to previous groups as: vertebrae. - **Pneumatic bone**: Contains air spaces (sinuses) as frontal and maxillary bones. - **Sesamoid bone**: Small bones deposited in muscle tendons as: patella. ## Parts of the Skeleton - **Axial Skeleton** (80 Bones) - Skull: 28 bones - Hyoid: 1 bone - Vertebrae: 26 bones - Sternum: 1 bone - Ribs: 24 bones - **Appendicular skeleton** (126 Bones) - **Upper Limbs** (64 Bones) - Shoulder girdle: 4 bones - Arm bones: 2 bones - Forearm bones: 4 bones - Wrist bones: 8 bones - Hand bones: 10 bones - Finger bones: 28 bones - **Lower Limbs** (62 Bones) - Pelvic girdle: 2 bones - Thigh bone: 2 bones - Knee: 2 bones - Leg: 4 bones - Ankle: 14 bones - Foot bones: 10 bones - Toe bones: 28 bones ## Function of Skeleton - Supports the body - Gives shape to the body - Allows Movement - Blood formation by bone marrow - Store of Calcium and Phosphorus - Protection of vital organs as: cranium for brain and vertebral column for spinal cord. ## Bone Markings in Practical - **Elevations**: Linear/ Rounded/ Pointed - **Depressions**: Elongated/ Rounded/ On edge - **Perforations**: Foramen/ Meatus/ Canal - **Heads** - **Condyles**: Condyles/ Trochlea ## Joints - **A joint** is the site where two or more bones are articulated together. - **Fibrous Joint**: The bony surfaces are joined by fibrous tissue. The bones are fixed together, or there is very little movement allowed. - **3 Types** - **Sutures**: Limited to flat bones of the skull where the margins of bones are serrated and articulate with each other. - **Syndesmosis**: Opposed bony surfaces are connected by the interosseous ligaent. (inf. tibio-fibular joint) - **Gomphosis**: Peg & socket joint, restricted to the fixation of teeth in the mandible and maxilla. - **Cartilagenous Joint**: The bones are united by intervening cartilage. - **1ry cartilagenous joint**: Bones are connected by hyaline cartilage. No movement. Temporary (ossifies). Site: Between epiphysis and diaphysis of long bones. - **2ry cartilagenous joint**: Bones connected by a disc of fibrocartilage. Limited degree of movement. Permanent (no ossify). Site: In midline of body as parts of sternum, symphysis pubis. - **Synovial Joint**: Bones involved are linked by fibrous capsule which is lined by synovial membrane. Freely mobile. Characteristics of synovial joint: Articular surfaces in contact but not in continuity, and covered by hyaline cartilage. Hyaline cartilage decreases friction. The joint is surrounded by a strong fibrous capsule. The capsule is lined by synovial membrane that secretes synovial fluid for lubrication. - **Classification of synovial joint** - **1-plane synovial joint**: Simple sliding movement (intercarpal & inter metacarpals) - **2-Uniaxial synovial joint**: - **Hinge joint**: Transverse axis (Elbow joint) - **Pivot joint**: Vertical axis (atlanto-axial joint - Saying no) - **3-Biaxial synovial joint**: - **Condyloid**: Biconcave surface articulates with the biconvex one (metacarpo-phalangeal joints). - **Ellipsoid**: Elliptical biconcave surface articulates with elliptical biconvex (wrist joint). - **Saddle**: The articulating surfaces are concavo-convex and convexo-concave (carpo-metacarpal joint of thumb). - **4-Poly-axial joint (Ball & Socket)**: Free movement in all directions. Hemispherical head in a cup-shaped surface (Hip & Shoulder) ## Stability of the Joint - Depends on: - Shape and size of articular surfaces - Ligaments - Surrounding muscles