Anatomy introduction Wahdan 1 final.pdf

introduction ANATOMICAL TERMS Anatomical Positions 1. Erect anatomical position: This is standard position used to describe the anatomy of the human body. ▪ Human body is standing erect. ▪ Eyes & face are looking forwards. ▪ Upper limbs ar...

introduction ANATOMICAL TERMS Anatomical Positions 1. Erect anatomical position: This is standard position used to describe the anatomy of the human body. ▪ Human body is standing erect. ▪ Eyes & face are looking forwards. ▪ Upper limbs are hanging by the sides of the body. ▪ Palms are facing forwards. ▪ Thumbs are directed laterally. ▪ The lower limbs are close together. Erect anatomical position 1 introduction 2. Supine position: The body lies on its back. 3. Prone position: The body lies on its face. 4. Lateral decubitus position: The body lies on its side (right or left). 5. Lithotomy position: The body lies on its back with flexion of hip and knee and abduction of hip joints. Supine position Prone position Lithotomy position 2 introduction Anatomical Planes 1. Median (Sagittal) plane : It is the vertical plane which passes in the middle line of the body dividing it longitudinally into equal right and left halves. 2. Paramedian plane: It is a vertical plane parallel to and nearby the median plane. It may be right or left. It divide the body into 2 vertical unequal parts. 3. Coronal (Frontal) plane: It is a vertical plane which divides the body vertically into an anterior part towards the front of the body and a posterior part towards the back. 4. Horizontal plane: It is the transverse plane which runs horizontally dividing the body into an upper and lower parts at any level of the body. 3 Planes of the Body introduction Anatomical Planes 4 introduction Terms of Position Term Meaning Anterior = Ventral In front or nearer to the front of the body. Posterior = Dorsal = Behind or nearer to the back of the Retro- body. Superior =Upper Near to the upper end of body. =Cranial Inferior =Lower = Near to the lower end of body. Caudal Median Exactly in the middle line Medial Nearer to the median plane. Lateral Away from the median plane. Proximal Nearer to the root of the limb. Distal Away from the root of the limb. Superficial Towards the skin or body surface. External = Outer Nearer or on the surface of the body. Deep Away from the skin or body surface. Internal = Inner Inside the organ or the body. Peri- Around Endo Inside or lining a structure Para Beside Inter Between Epi and sub Just above and just below respectively Supra and infra Most superior and most inferior respectively 5 introduction Terms of Position TERMS OF NUMBER Uni- = Mono- One Bi- = Di- Two Tri- Three Quadri- Four Multi- = Poly- Many Oligo- Little 6 introduction Example for Terms of Position 7 introduction Example for Terms of Number Monocytes Biceps Triceps Quadriceps Multifidus 8 introduction FASCIA ⁕ It is a type of connective tissue which have the following features : ▪ It lies deep to the skin. ▪ It covers the body wall and limbs. ▪ It binds and connects different body structures together. ▪ It is divided into superficial, deep and internal fasciae. 9 introduction A- Superficial Fascia: A layer of loose connective tissue lies immediately deep to the skin. It connects the skin to the underlying structures. The superficial fascia contains a variable quantity of fat which is more in females than in males. ▪ Fat is abundant in gluteal region, anterior abdominal wall and breast. ▪ Fat is less in the limbs and absent in the eyelids, penis and scrotum. Functions of the superficial fascia: 1. It prevents heat loss from the body, so it acts as thermal insulator and allows storage of energy (due to the presence of fat). 2. It acts as a medium conducting the cutaneous nerves, blood vessels and lymphatics which supply the skin. 3. It contains subcutaneous muscles, as in face (muscles of express- ion), in the neck (platysma) and in the scrotum (dartos muscle). Muscles of expression Platysma Dartos muscle Palmaris brevis 10 introduction 4. It contains special types of glands , as mammary glands, sweat glands, and superficial lymph nodes. 5. It softens and smoothens the surface of the body. 6. It facilitates the movement of skin over the underlying structures. 7. It gives size & contour of certain parts of the body e.g. breast. B- Deep Fascia: A membrane composed of compact and regular collagen fibers. It is inelastic. It is well defined in the limbs and very strong and thick in the palm and sole. It is absent in the face and in the anterior wall of abdomen. Parts and Functions: 1. Formation of broad sheets: ▪ They surround the muscles and the different structures of the upper and lower limbs. ▪ They keep the underlying structures in position. ▪ They give attachment to some muscles. 11 introduction 2. Formation of intermuscular septa and interosseous membranes: They separate different groups of muscles which have different actions and nerve supply. 3. Formation of retinacula: They are localized transverse thick- ened bands of deep fascia present at wrist and ankle joints. They keep the tendons in position during movements of joints. 4. Formation of palmar aponeurosis (in palm) and plantar aponeurosis (in sole): They are very thick, strong and protective layers of deep fascia. They protect blood vessels, nerves and tendons. 5. Formation of sheaths around big blood vessels: e.g. ▪ Femoral sheath around the femoral blood vessels in lower limb. ▪ Carotid sheath around the carotid arteries and internal jugular vein in the neck. Broad sheet of deep fascia Intermuscular septa 12 introduction sheaths around big blood vessels Interosseous membrane Carotid sheath Palmar aponeurosis Plantar aponeurosis & ankle retinacula 13 introduction BONES ⁕ Definition & properties : ▪ It is a special type of hard connective tissue which forms the skeleton. ▪ It is formed of :  Bone cells.  Intercelluar matrix composed of collagen fibers , organic protein substance and inorganic salts ( mainly calcium phosphate & carbonate which are responsible for handness of bone ). ⁕ Functions of Skeleton: 1-Gives the specific shape to the body. 2-Provides the central axis of the body and the skeleton of both upper and lower limbs. 3-Protects the vital organs: the skull protects the brain, and thoracic cage protects the heart and lungs. 4-Provides surface area for muscular attachment. 5- Acts as levers for muscle contraction & movements. 6-Transmits and supports the body weight e.g. vertebral column transmits the weight of the head and trunk to the bony pelvis then through the bones of lower limbs to the feet and lastly to the ground. 6-Forms the joints to make an important part of the locomotor system. 7- Forms the blood elements in the red bone marrow. 8-Stores calcium & phosphorus salts. ⁕ Classification of Skeleton: I) According to the position in the body: 1- Axial skeleton: Skull, mandible, hyoid, sternum, ribs and vertebral column ( i.e bones of head , neck & trunk ). 2- Appendicular (peripheral) skeleton: in upper and lower limbs 14 introduction II) According to the process of ossification (Bone formation): a-Intra-membranous ossification b-Intra-cartilaginous ossification ▪ e.g. clavicle , mandible and skull ▪ e.g. in long bones, vertebrae, ribs cap. and base of skull. ▪ The bones develop directly from ▪ The mesoderm is changed at first mesodermal connective tissue into a cartilage model, and then membrane. the cartilage is dissolved and ▪ It begins at one or more centers of disappears, and displaced by bone. ossification. 15 introduction ▪ Bone formation starts during the 5th. week of intra-uterine fetal life by appearance of primary centers of ossification and continues after birth by appearance of secondary centers of ossification. 16 introduction Intra-cartilaginous ossification III) According to structure of bones : 1- Compact ( hard or ivory )bones : ▪ It is the outer hard mass covering the surface of all bones. 2- Cancellous ( spongy ) bones : ▪ It is a network of trabeculae lying inside compact bones espescially in the ends of long bones ( epiphysis & metaphysis ). ▪ In between these trabeculae there are many spaces filled with bone marrow. IV) According to the shape of bones: 1- Long bones Site: Present in upper and lower limbs. Structure: two ends (epiphyses) and a shaft (diaphysis) in between. N.B : Physis means growth plate. a) Epiphysis:  It is the expanded upper and lower ends of the long bone.  It is used for articulation and its articular surface is covered with a layer of articular hyaline cartilage. 17 introduction b)Diaphysis (Shaft):  A tube of compact bone (cortex) with a central medullary cavity lined with endosteum and is filled with bone marrow (soft vascular tissue).This meullary cavity doesn’t extend to the epiphysis or the metaphysis.  The shaft is covered with fibro-cellular sheath called periosteum which formed of : Superficial layer formed of fibrous tissue. Deep layer formed of fibrous tissues , osteoblast ( bone forming cells ) , sensory nerve fibers and blood vessels ( supply the underlying bone).  The long bones increase in diameter from periosteum.  In the growing long bones, the epiphysis and the diaphysis are separated by a disc of hyaline cartilage called epiphyseal cartilage which is responsible for the growth in length. b) Metaphysis:  It lies in the upper and lower parts of the long bone just close to the epiphyseal cartilage.  It is the most active part of long bone and contains the newly formed bone , formed by the epiphyseal cartilage , which gradually migrate towards the diaphysis. Structure of long bones 18 introduction 2) Short Bones: Site: e.g. carpal bones (in hand) and tarsal bones (in foot). Structure: consist of spongy bone covered with thin layer of compact bone 19 introduction 3) Flat Bones: Site: e.g. bones forming skull cap , scapula and ribs. Structure: consist of two thin plates of compact bone with middle layer of spongy bone. In bones of skull, the plates of compact bone are called outer and inner tables and the layer of the spongy bone in between is called diploe. Function: 1- Protection. 2- Muscular attachment 20 introduction 4) Pneumatic Bones: Bones containing air Site: Skull bones mainly those surrounding the nose (e.g. maxillary and frontal bones) and contain air cavities called paranasal sinuses. Structure: It is formed of compact bone which may contain one air cavity (maxillary sinus) or multiple small air cells (mastoid air cells). Functions: 1. They decrease the weight of skull. 2. They lead to resonance of voice. 3. They have a highly vascular mucosa to warm the inspired air. 5- Irregular Bones: Shape and Site: Bones of irregular shape with projecting processes e.g. vertebrae. Structure: They are similar in structure to the short bones. Vertebra 21 introduction 6- Sesamoid Bones: Structure: small nodules of bones. Site: embedded in some muscle tendons e.g. patella (largest sesamoid bone, embedded in the tendon of quadriceps femoris in front of knee joint). Function: They diminish friction between tendons and underlying bones. 7- Sutural bones : Small bones embedded in the sutures of the skull. ❖ N.B: All bones formed of outer layer of compact bone and inner layer of spongy bone except diaphysis of long bones and neumatic bones. 22 introduction ⁕ Growth of bones: ▪ The long bones increase in length from the epiphyseal cartilages by proliferation of its cells.  When the bone becomes mature, the cells of the epiphysial plate stops division and ossifies resulting in fusion between epiphysis and diaphysis.  The epiphyseal plate at one end of the shaft of long bone ossifies earlier than that at the other end, which continues adding bone to the shaft for another 2 to 3 years before it undergoes ossification as well. This end is called the growing end.  Fusion of the epiphysis and diaphysis is under hormonal control.  It occurs in females earlier than males by about 2 years. ▪ The long bones increase in width from osteoblasts in the periosteum around the external bone surface. At the same time, osteoclasts in the endosteum break down bone on the internal bone surface, around the medullary cavity. 23 introduction ⁕ Arterial supply of bones : 1) Nutrient artery: ▪ It enters the middle 1/3 of the shaft through an oblique nutrient foramen and runs away from the growing end of bone. N.B : Mnemonic to remember the direction of entry of nutrient arteries is TOWARDS THE ELBOW I FLOW, AWAY FROM THE KNEE I FLEE. ▪ Then it divides in the medullary cavity into ascending and descending branches directed towards the upper and lower metaphyses to anastomose with the metaphyseal arteries. ▪ It supplies the inner 2/3 of the thickness of the cortex of the shaft & bone marrow. 2) Epiphyseal arteries: ▪ They supply the epiphysis and they anastomose with the metaphyseal arteries after the ossification of the epiphyseal plate of cartilage. 24 introduction 3) Metaphyseal arteries: ▪ They enter the bone through minute foramina to supply metaphysis. ▪ They anastomose with the nutrient artery and with the epiphyseal arteries after ossification of the epiphyseal cartilage. 4) Periosteal arteries: they supply the outer ⅓ of the cortex of the shaft and they communicate with other arteries. 5) Arteries of the attached muscles. 25 introduction ⁕ Terms of external features of bones : Bony Elevations : Term Meaning Head Rounded end of bone , not necessarily directed upwards. Neck Constricted bone follows the head. Process It is an elongated projection with a blunt end. Spine It is an elongated projection with a pointed tip. Tubercle, They are localized rounded elevations. The tubercle is the tuberosity smallest while the trochanter is biggest and tuberosity is and medium-sized. trochanter Condyle It is a convex elevated articular surface. Epicondyle It is a localized elevation of small size situated just above a condyle or articular surface. Hamulus It is a slender curved bony process which resembles a hook. Cornu= It is a curved bony process which resembles a horn. Coronoid Crest An elongated ridge which usually lies on the top of a bone. Ridge A linear elevation. Line Slightly elevated or just a rough linear landmark. Border Separates 2 surfaces , it may be sharp or blunt. 26 introduction 27 introduction 28 introduction ⁕ Bony Depressions, Grooves and Canals : Term Meaning Fossa A depression on a surface. Fovea is a small fossa. Notch A semicircular depression , on a surface or a border. It has 2 limiting edges. Incisura A notch-like depression on a border. Groove or An elongated depression sulcus Fissure A long cleft between flat bones, e.g. skull. Hiatus A narrow gap or passage with one opening is seen & the other is hidden. Foramen It is a hole through a bone. Aperture It is a large hole Canal It is a track of some length in a bone having 2 open ends. Meatus A bony canal having one closed end Impression A slight indentation or depression. 29 introduction 30 introduction ⁕ Sex Differences in Bones : 1- Characters of bones: Male bones are heavy and thick while female bones are light and thin. 2- Muscle attachment: Tubercles, tuberosities and ridges are more prominent in male bones and less prominent in female bones. 3- The bony pelvis: The cavity of the pelvis is wider and shorter in female than male to adapt pregnancy and delivery. 31 introduction CARTILAGE ⁕ Properties: 1. It is a rubbery type of connective tissue, it is tough and resilient. 2. It has no blood vessels, nerves or lymphatics. 3. Gets its nutrition by diffusion from the blood vessels of perichondrium. 4. It consists of mature cartilage cells (chondrocytes), fibers and matrix. 5. Resists compression forces and friction. 6. It has great capacity of growth by multiplication of the chondroblasts (immature cartilage cells). ⁕ Types of Cartilage: I) Hyaline Cartilage : (Glass-like) Characters: Commonest type of cartilage in human body. Matrix: Translucent. Cartilage cells: numerous small rounded cells. Ossification by age: Occurs in certain sites e.g. in larynx and epiphyseal cartilages. Sites: 1) In the developing bones in the fetus. 2) In the epiphyseal plates of the long bones. 3) The articular cartilage in joints. 4) The costal cartilage and xiphoid process. 5) Nasal cartilages. 6) The larynx (except the epiglottis) and tracheal rings. 32 introduction 33 introduction II) White fibrocartilage : Characters: a) Matrix: Opaque because it is rich in collagen bundles. b) Cartilage cells : Few in number. Sites: Intervertebral discs & symphysis pubis. Ossification in old age: Does not occur. III) Yellow elastic fibrocartilage : Characters: a) Matrix: Yellow in appearance because it is rich in yellow elastic fibers. b) Cartilage cells: Abundant. Sites: 1. Auricle of the ear. 34 introduction 2. Epiglottis of the larynx. Ossification in old age: Does not occur. 35