The Skeletal System I: PDF

THE SKELETAL SYSTEM DR AISHA MOHD DIN Department of Basic Sciences  Learning Outcome Features of the skull Features of the vertebral column and thoracic cage Features of the pectoral girdle and upper limb bones Features of the pelvic girdle and lower limb bon...

THE SKELETAL SYSTEM DR AISHA MOHD DIN Department of Basic Sciences  Learning Outcome Features of the skull Features of the vertebral column and thoracic cage Features of the pectoral girdle and upper limb bones Features of the pelvic girdle and lower limb bones  Overview of the Skeleton Regions of the skeleton – axial skeleton = central axis skull, vertebral column, ribs, sternum and sacrum – appendicular skeleton = limbs and girdles Number of bones Loading… – start at 270 at birth, decreases with fusion – 206 in typical adult skeleton BONE TISSUE DR AISHA MOHD DIN Department of Basic Sciences  Understand how bones are classified by their macroscopic and microscopic features Understand how bone is developed and physiologically controlled. I 3 Composed of bones, cartilages, and ligaments joined tightly together to form a strong, flexible framework for the body Skeleton functions Support Protection Movement Electrolyte balance Loading… Acid-base balance Blood formation Osseous tissue Connective tissue with a hardened matrix Deposition of calcium phosphate and other minerals Mineralization and calcification  Classified based on shape and corresponding function Four categories Long bones Short bones Irregular bones Flat bones Loading…  Epiphysis Ends of the bone Composed of cancellous (spongy) bone Contains red bone marrow Layered with hyaline cartilage Diaphysis Shaft of the bone Composed of compact bone Medullary cavity Contains yellow bone marrow Epiphyseal plate (children and adolescent)  Bone consist of cells, fibers & ground substance Osteoblasts Four main types of bone Bone-forming cells cells Found along endosteum and Osteogenic periosteum (osteoprogenitor) cells are Stress and fracture stimulate cells stem cells found in the to multiply and rebuild bone endosteum  Osteocytes Octeoclasts Former osteoblasts that Bone-dissolving cells have been trapped in their Have 3 or 4 nuclei lacunae Ruffled border secrete hydrogen Maintain bony matrix (H+) and chloride (Cl– ) ions into Strain sensors (regulate bone remodeling) the extracellular fluid  Matrix composed of inorganic and organic components Inorganic component 85% Hydroxyapaptite Composed mainly of CaPO4 salt Organic components Protein and carbohydrate Collagen Gives bones a combination of flexibility  Osteon (haversian system) Basic structural unit of compact bone Central (haversian) canal surrounded by concentric lamellae (matrix) Perforating canals Loading… Transverse or diagonal passages into the central canal Originate at nutrient foramen  Composed by a network of spicules and trabeculae Spaces filled with red marrow Beams arranged to sustain stress commons.wikimedia.org  In an adult, red bone marrow occupies the medullary cavities in the regions colored red Red marrow turns to fatty yellow bone marrow and no longer produces blood Yellow bone marrow occurs in the long bones of the limbs  Ossification or osteogenesis Formation of bone Ossification methods Intramembranous ossification Endochondral ossification  Produces flat bones of skull and clavicles Starts with osteoid End with diploe  Bone develops from a hyaline model Begins around the sixth week of fetal development and continues into a person’s 20s Vertebrae, ribs, scapulae, pelvic bones, bones of the limbs  Bones grow in length and width Bone Elongation (Growth in length) Involves epiphyseal plates Result from multiplication of chondrocytes Epiphyseal plate is depleted in the late teens to early twenties and leaves a dense spongy bone called epiphyseal line No gap between epiphysis and diaphysis when the epiphyseal plate is depleted (on x-ray) A person cannot grow taller Closes at different ages in different bones and in different regions of the same bone  Closure in various bones is often used Appositional growth where the deposition of new tissue at the surface Occurs by intramembranous ossification at the bone surface Osteoblasts in the inner layer of periosteum deposit osteoid tissue on the bone surface, calcify it, and become trapped in it as osteocytes Marrow cavity widens as bone increases in diameter Osteoclasts of the endosteum dissolves tissue on the inner bone surface to increase the marrow cavity diameter  Absorption of old bone and deposition of new Replaces about 10% of the skeletal tissue per year Repairs microfractures, releases minerals into the blood, and reshapes bones in response to use and disuse Osteoclasts removes matrix and get rid of unnecessary mass Loading… Osteoblasts deposit new osseous tissue and thicken the bone Bones give evidence of a person’s sex, race, height, weight, exercise habits, nutritional status, and medical history Remodeling of bone depends on a precise balance between deposition and resorption, between osteoblasts and osteoclasts  Mineral deposition Calcium and phosphate are allowed to reach their solubility product Precipitate in the matrix Ectopic ossification Abnormal calcification of soft tissue (lungs, brain, eye, muscles, arteries Mineral resorption HCl secreted by osteoclasts Acid phosphatase enzyme Digest collagen  muscle tak bolen relax Hypocalcemia Leads to excessive excitability of nervous system Muscle tremors, spasms (inability of the muscle to relax) muscle weakness Hypercalcimia Leads to depression of nervous system, muscle weakness, sluggish reflexes and sometimes cardiac arrest  Regulated by three hormones Calcitonin Secreted by parafollicular cells in thyroid Promote deposition of calcium in the bone Decreases calcium level in blood Inhibit osteoclasts, promote osteoblast activity (particularly in pregnant women) Parathyroid hormone Secreted by parathyroid glands Promotes bone resorption Increases calcium level in blood Raise osteoclast population Promotes calcium reabsorption in kidneys Promotes calcitriol synthesis Calcitriol Increases calcium level in blood Promotes more calcium absorption by intestine Promotes reapsorption from skeleton  Osteoporosis Sever loss of bone density Osteoclast more active than osteoblasts Osteosarcoma Most common and deadly form of bone cancer Metastasizes quickly Osteogenesis imperfecta Brittle bones Defect in collagen deposition (genetic disorder)  Long bones of the limbs stop growing in childhood, Growth of other bones is unaffected A person has a short stature but a normal-sized head and trunk Failure of the chondrocytes in the metaphysis to multiply and enlarge Spontaneous mutation that can arise any time DNA is replicated  3. 2 - ~ area for muscle to sit ~ no liquid or so on = v - origin muscle Transation - v-adalekuk D - tendon O-bones Surface Features of Bones proximal end attack to it -tendons f ↑ Loading… & muscle sit inside dorsal end Axial and Appendicular Skeleton Axial skeleton in brown – skull, vertebrae, sternum, ribs, sacrum and hyoid Appendicular skeleton in green – pectoral girdle – upper extremity – pelvic girdle – lower extremity THE SKULL  The Skull Contains: Neurocranium neurocranium (Cranial vault) Viscerocranium (facial skeleton) viscerocranium  The Skull 22 bones joined together by sutures Cranial bones surround cranial cavity – 8 bones in contact with meninges – calvaria (skullcap) forms roof and walls Facial bones support teeth and form nasal cavity and orbit – 14 bones with no direct contact with brain or meninges – attachment of facial and jaw muscles  Neurocranium Formed by 10 bones - 4 single bones - 3 paired bones Flat bones Bony case of the brain and its membranous coverings (meninges) Dome-like roof Roof: calvaria -skullcap Floor: cranial base -basicranium Neurocranium Loading… Base of skull Foramen magnum Base of skull occipital Cordial  Cranial Fossa Frontal lobe temporal lobe sevebelum 3 basins that comprise the cranial floor or base – anterior fossa holds the frontal lobe of the brain – middle fossa holds the temporal lobes of the brain – posterior fossa contains the cerebellum A Swelling of the brain may force tissue through foramen magnum resulting in death  Neurocranium v i hard because weak o there's many joints ~  Frontal Bone Forms forehead and part of the roof of the cranium Forms roof of the orbit Contains frontal sinus  Parietal Bone Cranial roof and part of its lateral walls Temporal lines of temporalis muscle Temporal lines  Parietal Bone Bordered by 4 sutures – coronal, sagittal, lambdoid and squamous Temporal Bone Lateral wall and part of floor of cranial cavity – squamous part zygomatic process mandibular fossa and TMJ – tympanic part external auditory meatus (ear canal) styloid process – mastoid part mastoid process filled with air sinuses – mastoiditis from ear infection Openings in Temporal Bone Carotid canal – passage for internal carotid artery supplying the brain Jugular foramen – irregular opening between temporal and occipital bones – passageway for drainage of blood from brain to internal jugular vein  Occipital Bone Rear and base of skull Foramen magnum holds spinal cord Skull rests on atlas at occipital condyles External occipital protuberance for nuchal ligament Nuchal lines mark neck muscles Skull in Infancy and Childhood - space for it to growth Spaces between unfused bones called fontanels – filled with fibrous membrane – allow shifting of bones during birth and growth of brain 2 frontal bones fuse by age six  Neurocranium ANTERIOR FONTANELLE to allow the brain to grow largest diamond shape bounded by halves of frontal & parietal bones fused at 18 months of age becomes ‘Bregma’  Neurocranium POSTERIOR FONTANELLE Small triangular shape bounded by parietal & occipital bones fused at 6-8 months of age becomes ‘Lambda’  Viscerocranium Formed by 15 irregular bone Ethmoid bone -6 paired bones -3 singular bones Sphenoid Bone Lesser wing Greater wing Body of sphenoid Medial and lateral pterygoid processes Sphenoid Bone Body of the sphenoid – sella turcica – houses pituitary gland Lesser wing – optic foramen Greater wing – foramen rotundum and ovale for trigeminal nerve – foramen spinosum for meningeal artery Sphenoid Bone Sphenoid sinus Ethmoid Bone Between the orbital cavities Lateral walls and roof nasal cavity Loading… Cribriform plate and crista galli Ethmoid air cells form ethmoid sinus Perpendicular plate forms part of nasal septum Concha (turbinates) on lateral wall  Maxillary Bones Forms upper jaw – alveolar processes are bony points between teeth – alveolar sockets hold teeth Forms inferomedial wall of orbit – infraorbital foramen Forms anterior 2/3’s of hard palate  Maxillary Bones Behind the incisors (front teeth) is a pair of incisive foramina Palatine processes meet at the intermaxillary suture at about 12 weeks of fetal development Failure to join causes cleft palate  Locations of Paranasal Sinuses inflam/infected - Sinusitis Maxillary sinus fills maxillae bone Other bones containing sinuses are frontal, ethmoid and sphenoid.  Palatine Bones L-shaped bone Posterior 1/3 of the hard palate Part of lateral nasal wall Part of the orbital floor Zygomatic Bones Forms angles of the cheekbones and part of lateral orbital wall Zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal bone Lacrimal Bones Form part of medial wall of each orbit Lacrimal fossa houses lacrimal sac in life – tears collect in lacrimal sac and drain into nasal cavity  Nasal Bones Forms bridge of nose and supports cartilages of nose Often fractured by blow to the nose  Inferior Nasal Conchae A separate bone Not part of ethmoid like the superior and middle concha or turbinates Vomer Inferior half of the nasal septum Supports cartilage of nasal septum  Mandible Only movable bone newy) – jaw joint between mandibular fossa and condyloid process Holds the lower teeth Attachment of muscles of mastication – temporalis muscle onto coronoid process – masseter muscle onto angle of mandible Mandibular foramen nerve supply Mental foramen - giveinjection e J nerve  Bones Associated With Skull Auditory ossicles – malleus, incus, and stapes Hyoid bone not with attach any other – suspended from bones styloid process of skull by muscle and ligament – greater and lesser horn a lot of -of muscle Major Skull Cavities THE VERTEBRAL COLUMN  The Vertebral Column can calge 33 vertebrae and > slip disc intervertebral discs of fibrocartilage Five vertebral groups – 7 cervical in the neck – 12 thoracic in the chest – 5 lumbar in lower back – 5 fused sacral – 4 fused coccygeal Variations in number of lumbar and sacral vertebrae -D  AXIAL SKELETON weeko-week 7 Primary curvature (1°) · bones start to Develop in fetal period develop Curve of the thoracic and sacral -concave anteriorly -C- shaped Newborn Spinal Curvature Spine exhibits one continuous C- shaped curve Known as primary curvature  AXIAL SKELETON Secondary curvature (2°) Develop in infancy & childhood concave posterially Curve of the cervical and lumbar > - Xanterially -Concave posteriorly -inverse S-shaped > - Adult Spinal Curvatures S-shaped vertebral column with 4 curvatures kenebentuk S Secondary curvatures develop after birth – lifting head as it begins to crawl develops cervical curvature – walking upright develops lumbar curvature Abnormal Spinal Curvatures growth spurt during teenager From disease, posture, paralysis or congenital defect Scoliosis from lack of proper development of one vertebrae Kyphosis is from osteoporosis Lordosis is from weak abdominal thoracic region Y give the lumbar region curve muscles  General Structure of Vertebra Body cordteen Spinal Vertebral foramen - form vertebral canal Neural arch – 2 lamina arch – 2 pedicles arch Processes – spinous, transverse and articular Intervertebral Foramen and Discs between two Intervertebral foramen – Notches between - - adjacent vertebrae – passageway for nerves spinal - · a lot coming of nerve out of the spinal cord through - intervertabral foramen  Intervertebral Discs Intervertebral discs – bind vertebrae together – absorb shock (smoking ( – spinal flexibility – gelatinous nucleus pulposus surrounded by anulus fibrosus (ring of fibrocartilage) – herniated disc pressures spinal nerve or cord Typical Vertebra  Cervical Vertebrae Cl - C7 Body: short Vertebral foramen: large & triangular Foramen transversarium for -vertebral artery & veins to Through pass (C1-6) - Spinous process: short & bifid Typical cervical vertebrae looks the same is C3, C4, C5 and C6 - Atypical cervical -berbera vertebrae: C1,C2 & C7  Vertebral C1 (atlas) No body No spinous process Ring-shaped bone Has a facet for dense that will articulate with dense of C2 vertebra C attach to skull sits on facet for occipital condyle  Vertebral C2 (Axis) Strongest cervical vertebra Has a dense Articulate with facet for dense on C1 pivot joint The Unique Atlas and Axis Atlas (C1) supports the skull – concave superior articular facet nod your head in “yes” movement – ring surrounding large vertebral foramen anterior and posterior arch no vertebral body Axis (C2) – dens or odontoid process is held in place inside the vertebral foramen of the atlas by ligaments – allows rotation of head -- “no” Atlas and Axis Articulation Cl 22 much stronger joint  Vertebra C7 Long, non-bifid spinous process Large transverse process Small foramen transversarium Transmit only vertebral veins vertebratein Evetebud 4-c-ada vertebral artery enters vertebral vein vein C7-only have vertebral  Typical Thoracic Vertebrae Larger body (heart-shaped) than cervical but smaller than lumbar Spinous processes pointed and angled downward Superior articular facets face posteriorly permitting some rotation between adjacent vertebrae Rib attachment – costal facets on vertebral body and at ends of transverse processes for articulation of ribs  Lumbar Vertebrae Thick, firm body and blunt, squarish spinous process Superior articular processes face medially – lumbar region resistant to twisting movements  Sacrum (Anterior View) 5 sacral vertebrae fuse by age 26 Anterior surface – smooth and concave – sacral foramina were intervertebral foramen used to be nerves and blood intervertebral foramen vessels – 4 transverse lines indicate line of fusion of vertebrae Sacrum (Posterior View) Median sacral crest Lateral sacral crest I Posterior sacral foramina Sacral canal ends as sacral hiatus Auricular surface is part of sacroiliac joint  Bone heat & a  Coccyx Single, small bone – 4 vertebrae fused by the age of 20 – Co1 to Co4 Attachment site for muscles of pelvic floor Cornua – hornlike projections on Co1 for ligaments attach coccyx to sacrum Fractured by fall or during childbirth Thoracic Cage Consists of thoracic vertebrae, sternum and ribs Attachment site for pectoral girdle and many limb muscles Protects many organs Rhythmically expanded by respiratory muscles to draw air into the lungs  Rib Structure Flat blade called a shaft inferior margin has costal groove for nerves and vessels Proximal head and tubercle are connected by neck Articulation head with body of vertebrae tubercle with transverse process Numbered Rib Articulations Transverse inferior costal facet costal facet superior costal facet T6  True and False Ribs True ribs (1 to 7) attach to sternum - - with hyaline - cartilage without - False ribs (8-10) hyaline cartilage = Floating ribs (11-12) 12 pairs of ribs in both sexes Elfalse PECTORAL GIRDLE  Pectoral Girdle Attaches upper extremity to the body Scapula and clavicle Clavicle attaches medially to the sternum and laterally to the scapula to davide attach – sternoclavicular joint scapula – acromioclavicular joint Scapula articulates with the humerus – glenohumeral or shoulder joint – easily dislocated due to loose attachment  Clavicle S-shaped bone, flattened dorsoventrally Inferior - marked by muscle and ligament Sternal end rounded -- acromial end flattened  Scapula Triangular plate overlies ribs 2 to 7 Spine ends as acromion process Coracoid process = muscle attachment Subscapular, infraspinous and supraspinous fossa Glenoid fossa = socket for head of humerus Scapular Features 8-0 UPPER LIMB  Upper Limb 30 bones per limb Brachium (arm) = humerus Antebrachium (forearm) = radius and ulna (radius on thumb side) Carpus (wrist) = 8 small bones(2 rows) Manus (hand) = 19 bones(2 groups) – 5 metacarpals in palm – 14 phalanges in fingers  Humerus Hemispherical head Anatomical neck Greater and lesser tubercles and deltoid tuberosity Intertubercular groove holds biceps tendon Rounded capitulum articulates with radius Trochlea articulates with ulna Olecranon fossa holds - extend masuk olecranon process of ulna & flex 1/ keluar Storm Forearm muscles attach to elbow & job big fossa medial and lateral epicondyles  perform neve Ulna and Radius connected to digits ↑ Radius O – head articulates with capitulum – radial tuberosity Ulna – olecranon and trochlear notch Interosseous membrane – ligament attaches radius to ulna along interosseous margin of each bone  PRONATION AND SUPINATION Involve rotation of the radius at the radioulnar joint Pronation: movement of the distal end of the radius over the ulna  Carpal Bones Form wrist – flexion, extension, abduction and adduction 2 rows (4 bones each) – proximal row = scaphoid, lunate, catch triquetrum and pisiform –try to distal row = trapezium, pretty trapezoid, capitate and D und to o hamate & looks She Ist Metacarpals and Phalanges Phalanges are bones of the fingers – thumb or pollex has proximal and distal phalanx – fingers have proximal, middle and distal phalanx Metacarpals are bones of the palm – base, shaft and head PELVIC GIRDLE  Pelvic Girdle Girdle = 2 hip bones * bone that connect to Pelvis = girdle and sacrum axis is sternum. Supports trunk on the legs and protects viscera fused 5 Sacrum = 51  Pelvic Girdle Each hip bone is joined to the vertebral column at the sacroiliac joint Anteriorly, pubic bones are joined by fibrocartilage to form pubic symphysis Loading… Pribrocartilage  Pelvic Inlet and Outlet during labour delivery , the points here are soften False and true pelvis separated at pelvic brim Infant’s head passes through pelvic inlet and outlet  - the Hip Bone whereelemade Acetabulum is hip joint socket Ilium – iliac crest and iliac fossa – greater sciatic notch contains sciatic nerve Pubis – body, superior and inferior ramus D Ischium – ischial tuberosity bears body weight – ischial spine – lesser sciatic notch between ischial spine and tuberosity – ischial ramus joins inferior pubic ramus  Comparison of Male and Female bigger is cause host a narrow boarder baby fefus Female lighter, shallower pubic arch( >100 degrees), and pubic inlet round or oval Male heavier, upper pelvis nearly vertical, coccyx more upright, and pelvic inlet heart-shaped LOWER LIMB thigh bone Femur and Patella (Kneecap) Nearly spherical head and constricted neck – ligament to fovea capitis Greater and lesser trochanters for muscle attachment Posterior ridge called linea aspera Medial and lateral condyles and epicondyles found distally · Patella = triangular sesamoid Sesamoid bone  condyse Tibia b will sit medial Lateral all leg is on tibia on the thats why big to of Ebula carry our dyweight C its = Tibia is thick, weight- bearing bone (medial) Broad superior head with 2 flat articular surfaces Cartilage medial and lateral is to prevent condyles pain – roughened anterior. surface palpated below patella (tibial tuberosity) - > - articulate – distal expansion = with foot medial malleolus For foot points.  Fibula part of knee joints. not Slender lateral strut stabilizes ankle Does not bear any body weight – spare bone tissue Head = proximal end Lateral malleolus = distal expansion Joined to tibia by interosseous membrane  The Ankle and Foot Tarsal bones are shaped and meta arranged differently from carpal bones due to load- bearing role of the ankle Talus is most superior tarsal bone – forms ankle joint with tibia and fibula – sits upon calcaneus and articulates with navicular ~ Calcaneus forms heel Distal row of- tarsal bones heel bone – & cuboid, medial, intermediate and lateral cuneiforms The Foot Remaining bones of foot are similar in name and arrangement to the hand Metatarsal I is proximal to the great toe (hallux) – base, shaft and head Phalanges – 2 in great toe proximal and distal – 3 in all other toes proximal, middle and distal  Embryonic Limb Rotation Rotation of upper and lower limbs in opposite directions – largest digit medial in foot and lateral in hand – Elbow flexes posteriorly and knee flexes anteriorly 8-0 normal feet flat feet Foot Arches - & plantar region of the foot Sole of foot not flat on ground 3 springy arches absorb stress – medial longitudinal arch from heel to hallux – lateral longitudinal arch from heel to little toe – transverse arch across middle of foot Arches held together by short, strong ligaments – pes planis (flat feet) calcaneus – person less tolerant of prolonged standing and walking  PATHOLOGY OF THE APPENDICULAR SKELETON Pathology of the Appendicular Skeleton Amelia Complete absence of one or more limbs occur during fetal development  Pathology of the Appendicular Skeleton Meromelia Partial absence of a limb Absence of the long bones, Hands or feet attached directly to the trunk Abnormalities are usually hereditary Can be induced by teratogenic chemicals affects the long limb humerus , radius , ulna affected tibia , fibula is not developed. inherited Pathology of the Appendicular Skeleton Polydactyly Presence of extra fingers or toes Pathology of the Appendicular Skeleton Clubfoot Congenital deformity in which outwards the feet are adducted and plantar flexed (soles turned medially) THANK YOU