Human Skeleton Anatomy PDF

Skeleton of Human body  Main objectives 1- Bones Definitions. 2- Functions & structures of bones. 3- Types of bones. 4- Terms related to features of bones. 5- Axial skeleton & appendicular skeleton.  Definitions to skeletal system This system is formed of bones and cartilage, wh...

Skeleton of Human body  Main objectives 1- Bones Definitions. 2- Functions & structures of bones. 3- Types of bones. 4- Terms related to features of bones. 5- Axial skeleton & appendicular skeleton.  Definitions to skeletal system This system is formed of bones and cartilage, which is connected together through joints to form(skeleton of the body). Osteology : is the science that deals with the study of bones.  Definitions to skeletal system Cartilage: is a types of CT , which have an ability to bends, more flexible than the bones. Joint: is the end to end junction between bones, bones and cartilage at the site of articulation  Functions of the bones The bones form the skeleton, which gives the framework of the body ,shape and length. Attachment of muscles, which response to Movement: of the body.  Functions of the bones protective functions: for some vital organs e.g. the lungs and heart. storage the calcium salts: as gives the rigidity of bone haemopoietic function: for production of blood cells.  Structures of bones Bones is hard CT, due to calcium salt deposit. Histologically there are two types of bones: – Spongy (cancellous ) bone: Is delicate meshwork of bone substance. Consist of trabeculae (thin irregular shape plates)  Structures of bones Compact bone: Is dense hard materials. Lies in the shaft of the long bones and cortex of other bones. It consist of lamellae cylindrical system (haversian canals  Types of bones Morphologically , the bones divide in to: – Long bones: Longer than wide. It has upper and lower ends. There is a shaft between the two end. Lies in the limbs. E.G. femur.  Description of long bone Epiphysis: is cancellous bone ends, which covers cartilage for articulation. Diaphysis: is compact bone shaft which, which consist of bone medullary cavity. Epiosteum: is a layer covers the bone from outside. Endosteum: is a layer which lying the bone cavity.  Types of bones Short bones: Are cuboidal in shape. They are found in hand and foot ( carpal and tarsal). E.G trapezoid bone.  Types of bones Flat bones: They are thin and flatten. It has surfaces and margins. E.G. sternum.  Types of bones Irregular bones: Are irregular in shape. They have many processes like vertebrae and pelvic bones. E.G lumber vertebrae.  Types of bones Sesamoid bones: They are embedded with in the tendons, when to cross the joint. E.G : patella.  Types of bones Pneumatic bones: They have air filled cavity. E.G. facial bones around the nose. E.G: maxillae.  Types of bones Sutural bones: They are located between the suture of the skull as premaxilla and vomer. E.G : vomer bone  Ossification of the bones Ossification: – is the process of bone formation from specialized mesenchymal tissue of embryo. – They are two types of ossification: Membranous ossification. Cartilaginous ossification.  Ossification of the bones Cartilaginous ossification: The bone is formed by replacement of the cartilaginous model in to the bone. Example as in the long bones of the limbs. E.G : femur.  Ossification of the bones Membranous ossification: The bone is formed directly from the CT membrane. Example as in flat bones of the skull frontal and parietal bones. E.G: parietal bone.  Blood supply of the bones The bones receives blood supply from: – Nutrient arteries: which enter the through the nutrient foramen. – Periosteal arteries. – Metaphyseal arteries. – Epiphyseal arteries.  Nerve supply of the bones Those are nerve fibers distributed through the blood vessels to enter the canal system of the bones as: –Sympathetic nerve fiber: to supply the bone as the vasomotor innervations. –Sensory nerve fibers: for general sensation( bone is painful)  Surface features of the bones/ elevation & projection term definition process Elongated projection in the bone tubercle Rounded small elevation Tuberosity large tubercle. trochanter Large tuberosity usually with square cut margin. Spine Pointed or sharp projection. Line Faint linear elevation. Ridge Linear elevation with sharp border. border Line or ridge which separates the surfaces. crest Thick ridge Surface features of the bones/ depression term definition Fossa or fovea Depression below the surface. Sulcus or groove Elongated depression having two edges. notch Deficient part of the bone. meatus tube like passage.  Surface features of the bones/perforation Term definition Foramen Hole connecting two surfaces fissure cleft between two bones. Canal A passage with two openings. hiatus narrow passage with one opening is seen, the other is hidden.  Surface features of the bones/ articular surfaces term definition Head rounded end of the bone. Condoyle Epicondyle/ Round or oval projection (beside the condoyle) facet small smooth circumscribed flat or concave surface. Trochlea pulley-shaped projection capitulum Looking like a small head. Organization of the human skeleton The human skeleton is consist of 206 bones, articulated to each other and give the framework of human body. – These bones are organized in two groups: – Axial skeleton: includes the skull ,ribs and vertebrae. – Appendicular skeleton: includes the bones of upper and lower limbs. both the upper and lower limbs connected to the axial skeleton through the shoulder and pelvic girdles respectively.  Bones of the axial skeleton skull It provide provides protection for the brain. it formed of 22 bones, and consist of: – Clavaria or brain box: the upper and posterior part( skull cap). – Facial bones: the anterior part of the skull. The bones of skull: – moveable : mandible – Immoveable: the rest of 21 bone articulating though the suture.  Bones of the skull Most of skull bones are made up of external and internal plates of compact bone separated by spongy (diploes) bone. The bones of the skull are either single or paired: Single bone paired bones Frontal parietal Occipital Temporal Ethmoid maxilla Sphenoid Nasal bone vomer Zygomatic bone mandible Lacrimal bone Palatine bone Inferior nasal concha.  Normal positions of the skull The features of the skull can could be described as : Norma frontalis : is anterior view of skull, which show: – Frontal bone. – Nasal bones. – Maxillae and zygomatic bones. – Single anterior nasal aperture. – Two orbital opening.  Normal positions of the skull Norma verticalis: – from the vertical (superior) view, which shows: Frontal bone. Parietal and occipital bones. Coronal, sagittal and lambdoid sutures. Norma occipitalis: – It is posterior view of the skull, which shows : Occipital bone. External occipital protuberance. Superior and inferior nuchal lines.  Normal positions of the skull – Norma lateralis: Lateral view, which shows: Temporal and parietal bones. Zygomatic arch, which divides the skull into temporal & infratemporal fossae. External auditory meatus – The mandible: It is moveable bone of the lower jaw. It is formed of (body) horse show shaped and 2 rami.  Cranial cavity of the skull It the interior part of the base of the skull( basalis interior). –It formed of three cranial fossae as: Anterior cranial fossa. Middle cranial fossa. Posterior cranial fossa. –All these fossae occupied by the different part of brain.  Vertebral column The vertebral column is consist of (33- 34) segmental of vertebrae: – the first 7 cervical vertebrae. – The second 12 thoracic vertebrae. – The third 5 lumber vertebrae. – the (5 & 3 or 4) form single unit of sacrum and coccyx respectively. The functions of vertebral column are – Support the above head and trunk of the body. – Protect the spinal cord.  Characteristics of typical vertebra Body : is disk shaped anterior portion, that gives strength to the bone. the bodies of vertebrae separated from each other by intervertebral disc. Neural foramen: lies behind the body, which is formed of : – (2 ) pedicles anteriorly. – (2 ) laminae posteriorly. The succession of vertebral foramina form the vertebral canal, which contain the spinal cord.  Characteristics of typical vertebra There are seven processes project from each vertebra: – (1) Spinous process: projects posteriorly from the vertebral foramen. – (2) transverse processes: project from the vertebral foramen on each sides (RT &LT). – (2) superior articular processes: project above to articulated with inferior articular process of the vertebral above. – (2) inferior articular processes: project downwards to articulate with vertebral below.  The characters of each vertebra vertebra NO body Spinous Transverse Vertebral process process foramen Cervical 7 small, and oval shape Short & bifid Has foramen Large, transversium. triangular. thoracic 12 Large, heart shape. Long, Articulated with Small, 2 facets for articulation directed tubercle of rib. circular. with ribs. down wards. lumber 5 Large kidney shape. Short, thick Long, slender large., & horizontal circular sacrum 5 Triangular shape with Form median Form lateral Form (fused apex downwards. sacral crest sacral crest sacral ) canal coccyx 3-4 Small triangular shape no no No canal (fused attaches to the sacrum )  Development of the vertebral column At birth the vertebral column has C shaped curve, which is called primary curvature, then later on another curvatures appears as secondary curvatures. The vertebral column is divided in to 4 regions as: – Cervical region: 2ry curvature. – Thoracic region: 1ry curvature. – Lumber region: 2ry curvature. – Sacral region: 1ry curvature.  Abnormal curvatures of vertebral column Lordosis: – increased forward curvature of the lumber region. Kyphosis: – increased backward curvature of the usually in the thoracic region. Scoliosis: – lateral curvature of vertebral column usually in thoracic region. Abnormal curvatures of the vertebral column  Thoracic cage Ribs: – There are 12 pairs of ribs, attached posteriorly the vertebrae as (costovertebral joints). – Their anterior ends have a different attachment as: The upper 7 pair (true) ribs : – Attached direct to the sternum by their costal cartilage to form (sternocostal joints). The 8th , 9th and 10th ( false) ribs: – Are attached to the costal cartilage above as (interchondral junction) to form costal margin. The 11th and 12th (floating) ribs: – Have no anterior attachment.  Important feature of the ribs Head: – Articulated with thoracic vertebrae. Neck: – Constriction between the head and tubercle. Tubercle: – Articulated with transverse process of its corresponding vertebra. Angle: – It’s a sharp turn in the rib. Shaft: – Thin and flat , with lower border sharp, upper border broad and have costal groove on its inner surface.  Bones of appendicular skeleton The upper limb (32) bones: – Shoulder girdle: (2) scapula clavicle. – Upper arm: one bone called humerus. – Forearm: (2) radius. ulna. – Hand: carpal bones (8): Metacarpus (5): Phalanges (14): – 3 phalanges in each finger except the thumb, which contain only 2 phalanges.  Bones of appendicular skeleton The lower limb (31) bones: – Pelvic girdle: is only one bone Hip bone. – Thigh: is only one also called femur. – Leg: (2) Tibia Fibula. – Foot: Tarsus(7). Metatarsal (5). Phalanges (14) – 3 in each toe except the big toe has just 2.