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67 Cards in this Set
- Front
- Back
*Axial Skeleton
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~80 bones segregated into 3 regions
a)Skull b)Vertebral column c)Bony thorax |
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The Skull
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1~Skull body’s most complex bony structure is formed by cranium & facial bones
2~Cranium – protects brain & is site of attachment for head & neck muscles 3~Facial bones: a)Supply framework of face, sense organs & teeth b)Provide openings for passage of air & food c)Anchor facial muscles of expression |
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Anatomy of Cranium
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1~8 cranial bones -2 parietal, 2 temporal, frontal, occipital, sphenoid & ethmoid
2~Cranial bones are thin & remarkably strong for their weight |
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Frontal Bone
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1~Forms anterior portion of cranium
2~Articulates posteriorly w parietal bones via coronal suture 3~Major markings include supraorbital margins, anterior cranial fossa & frontal sinuses (internal & lateral to glabella) |
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Parietal Bones & Major Associated Sutures
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1~Form most of superior & lateral aspects of skull
2~4 sutures mark articulations of parietal bones a)Coronal suture –Articulation between parietal bones & frontal bone anteriorly b)Sagittal suture –Where right & left parietal bones meet superiorly c)Lambdoid suture –Where parietal bones meet occipital bone posteriorly d)Squamosal or squamous suture –Where parietal & temporal bones meet |
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Occipital Bone & Its Major Markings
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1~Forms most of skull’s posterior wall & base
2~Major markings include posterior cranial fossa, foramen magnum, occipital condyles & hypoglossal canal |
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Temporal Bones
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~Form inferolateral aspects of skull & parts of cranial floor
~Divided into 4 major regions –Squamous, tympanic, mastoid & petrous ~Major markings include zygomatic, styloid & mastoid processes & mandibular & middle cranial fossae ~Major openings include stylomastoid & jugular foramina, external & internal auditory meatuses & carotid canal |
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Sphenoid Bone
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~Butterfly-shaped bone that spans width of middle cranial fossa
~Forms central wedge that articulates w all other cranial bones ~Consists of a central body, greater wings, lesser wings & pterygoid processes ~Major markings: Sella turcica, hypophyseal fossa & pterygoid processes ~Major openings include foramina rotundum, ovale & spinosum; optic canals; & superior orbital fissure |
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Ethmoid Bone
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~Most deep of skull bones; lies between sphenoid & nasal bones
~Forms most of bony area between nasal cavity & orbits ~Major markings include cribriform plate, crista galli, perpendicular plate, nasal conchae & ethmoid sinuses |
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Wormian Bones
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~Tiny irregularly shaped bones that appear within sutures
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Facial Bones
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~Fourteen bones of which only mandible & vomer are unpaired
~Paired bones are maxillae, zygomatics, nasals, lacrimals, palatines & inferior conchae |
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Mandible & Its Markings
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~Mandible (lower jawbone) is largest, strongest bone of face
~Its major markings include coronoid process, mandibular condyle, alveolar margin & mandibular & mental foramina |
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Maxillary Bones
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~Medially fused bones that make up upper jaw & central portion of facial skeleton
~Facial keystone bones that articulate with all other facial bones except mandible ~Their major markings include palatine, frontal & zygomatic processes, alveolar margins, inferior orbital fissure & maxillary sinuses |
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Zygomatic Bones
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~Irregularly shaped bones (cheekbones) that form prominences of cheeks & inferolateral margins of orbits
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Other Facial Bones
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~Nasal bones –Thin medially fused bones that form bridge of nose
~Lacrimal bones –Contribute to medial walls of orbit & contain a deep groove called lacrimal fossa that houses lacrimal sac ~Palatine bones –2 bone plates that form portions of hard palate, posterolateral walls of nasal cavity & a small part of orbits ~Vomer –Plow-shaped bone that forms part of nasal septum ~Inferior nasal conchae –Paired, curved bones in nasal cavity that form part of lateral walls of nasal cavity |
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Orbits
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~Bony cavities in which eyes are firmly encased & cushioned by fatty tissue
~Formed by parts of 7 bones – frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal & ethmoid |
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Nasal Cavity
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~Constructed of bone & hyaline cartilage
~Roof – formed by cribriform plate of ethmoid ~Lateral walls – formed by superior & middle conchae of ethmoid, perpendicular plate of palatine & inferior nasal conchae ~Floor – formed by palatine process of maxillae & palatine bone |
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Paranasal Sinuses
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~Mucosa-lined, air-filled sacs found in 5 skull bones –Frontal, sphenoid, ethmoid & paired maxillary bones
~Air enters paranasal sinuses from nasal cavity & mucus drains into nasal cavity from sinuses ~Lighten the skull & enhance resonance of voice |
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Hyoid Bone
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~Not actually part of skull but lies just inferior to mandible in anterior neck
~Only bone of body that does not articulate directly w another bone ~Attachment point for neck muscles that raise & lower larynx during swallowing & speech |
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*Vertebral Column
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~Formed from 26 irregular bones (vertebrae) connected in such a way that a flexible curved structure results:
1~Cervical vertebrae – 7 bones of neck 2~Thoracic vertebrae – 12 bones of torso 3~Lumbar vertebrae – 5 bones of lower back 4~Sacrum – bone inferior to lumbar vertebrae that articulates w hip bones |
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*Vertebral Column: Curvatures
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1~Posteriorly concave curvatures –Cervical & lumbar
2~Posteriorly convex curvatures –Thoracic & sacral ~Abnormal spine curvatures include scoliosis (abnormal lateral curve), kyphosis (hunchback) & lordosis (swayback) |
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Vertebral Column: Ligaments
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~Anterior & posterior longitudinal ligaments –Continuous bands down front & back of spine from neck to sacrum
~Short ligaments connect adjoining vertebrae together |
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Vertebral Column: Intervertebral Discs
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~Cushion-like pad composed of 2 parts:
1~Nucleus pulposus –Inner gelatinous nucleus that gives disc its elasticity & compressibility 2~Annulus fibrosus – surrounds nucleus pulposus w a collar composed of collagen & fibrocartilage |
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General Structure of Vertebrae
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~Body or centrum –Disc-shaped, weight-bearing region
~Vertebral arch –Composed of pedicles & laminae that, along w centrum, enclose vertebral foramen ~Vertebral foramina –Make up vertebral canal through which spinal cord passes ~Spinous processes project posteriorly & transverse processes project laterally ~Superior & inferior articular processes –Protrude superiorly & inferiorly from pedicle-lamina junctions ~Intervertebral foramina – Lateral openings formed from notched areas on superior & inferior borders of adjacent pedicles |
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Cervical Vertebrae
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~7 vertebrae (C1-C7) are smallest, lightest vertebrae
~C3-C7 are distinguished w an oval body, short spinous processes & large, triangular vertebral foramina ~Each transverse process contains a transverse foramen |
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Cervical Vertebrae: Atlas (C1)
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~No body nor a spinous process
~Consists of anterior & posterior arches & 2 lateral masses ~Superior surfaces of lateral masses articulate w occipital condyles |
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Cervical Vertebrae: Axis (C2)
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~Has a body, spine & vertebral arches as do other cervical vertebrae
~Has dens or odontoid process, which projects superiorly from body & is cradled in anterior arch of atlas ~Dens is a pivot for rotation of atlas |
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*Regional Characteristics of Vertebrae:
Thoracic Vertebrae |
~12 vertebrae (T1-T12) all of which articulate w ribs
~Major markings include 2 facets & 2 demifacets on heart-shaped body, circular vertebral foramen, transverse processes & a long spinous process ~Location of articulate facets prevents flexion & extension, but allows rotation of this area of spine |
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*Regional Characteristics of Vertebrae:
Lumbar Vertebrae |
~5 lumbar vertebrae (L1-L5) are located in small of back & have an enhanced weight-bearing function
~Have short, thick pedicles & laminae, flat hatchet-shaped spinous processes & a triangular-shaped vertebral foramen ~Orientation of articular facets locks lumbar vertebrae together to provide stability |
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*Regional Characteristics of Vertebrae:
Sacrum |
~Consists of 5 fused vertebrae (S1-S5), which shape posterior wall of pelvis
~Articulates w L5 superiorly, & w auricular surfaces of hip bones ~Major markings include sacral promontory, transverse lines, alae, dorsal sacral foramina, sacral canal & sacral hiatus |
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*Regional Characteristics of Vertebrae:
Coccyx (Tailbone) |
~Coccyx is made up of 4 (in some cases 3 to 5) fused vertebrae that articulate superiorly w sacrum
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Bony Thorax (Thoracic Cage)
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~Thoracic cage is composed of thoracic vertebrae dorsally, ribs laterally & sternum and costal cartilages anteriorly
~Functions: a)Forms a protective cage around heart, lungs & great blood vessels b)Supports shoulder girdles & upper limbs c)Provides attachment for many neck, back, chest & shoulder muscles d)Uses intercostal muscles to lift & depress thorax during breathing |
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Sternum
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(Breastbone)
~A dagger-shaped, flat bone that lies in anterior midline of thorax ~Results from fusion of 3 bones –Superior manubrium, body & inferior xiphoid process ~Anatomical landmarks include jugular (suprasternal) notch, sternal angle & xiphisternal joint |
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*Ribs
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~12 pair of ribs form sides of thoracic cage
~All ribs attach posteriorly to thoracic vertebrae ~Superior 7 pair (true, or vertebrosternal ribs) attach directly to sternum via costal cartilages ~Ribs 8-10 (false, or vertebrocondral ribs) attach indirectly to sternum via costal cartilage ~Ribs 11-12 (floating or vertebral ribs) have no anterior attachment |
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Structure of a Typical True Rib
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~Bowed, flat bone consisting of a head, neck, tubercle & shaft
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*Appendicular Skeleton
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~Made up of bones of limbs & their girdles
~Pectoral girdles attach upper limbs to body trunk ~Pelvic girdle secures lower limbs |
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*Pectoral Girdles
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(Shoulder Girdles)
~Consist of anterior clavicles & posterior scapulae ~They attach upper limbs to axial skeleton in a manner that allows for maximum movement ~They provide attachment points for muscles that move upper limbs |
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Clavicles (Collarbones)
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~Slender, doubly curved long bones lying across superior thorax
~Acromial (lateral) end articulates w scapula & sternal (medial) end articulates w sternum ~Provide attachment points for numerous muscles & act as braces to hold scapulae & arms out laterally away from body |
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Scapulae
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(Shoulder Blades)
~Triangular, flat bones lying on dorsal surface of rib cage, between second (Shoulder Blades) 7th ribs ~Scapulae have 3 borders & 3 angles ~Major markings include suprascapular notch, supraspinous & infraspinous fossae, spine, acromion & coracoid process |
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Upper Limb
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~Consists of arm (brachium), forearm (antebrachium) & hand (manus)
~37 bones form skeletal framework of each upper limb |
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Arm
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~Humerus is sole bone of arm
~It articulates w scapula @ shoulder & radius and ulna @ elbow ~Major markings: 1~Proximal humerus includes head, anatomical & surgical necks, greater & lesser tubercles & intertubercular groove 2~Distal humerus includes capitulum, trochlea, medial & lateral epicondyles & coronoid and olecranon fossae 3~Medial portion includes radial groove & deltoid process |
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*Forearm
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~Bones of forearm are radius & ulna
~They articulate proximally w humerus & distally w wrist bones ~They also articulate w each other proximally & distally at small radioulnar joints ~Interosseous membrane connects 2 bones along their entire length |
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*Bones of Forearm:
Ulna |
~Lies medially in forearm & is slightly longer than radius
~Forms major portion of elbow joint with humerus ~Its major markings include olecranon, coronoid process, trochlear notch, radial notch, & styloid process |
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*Bones of Forearm:
Radius |
~Lies opposite (lateral to) ulna & is thin at its proximal end, widened distally
~Superior surface of head articulates w capitulum of humerus ~Medially, head articulates w radial notch of ulna ~Major markings include radial tuberosity, ulnar notch, & styloid process |
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Hand
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~Skeleton of hand contains wrist bones (carpals), bones of palm (metacarpals) & bones of fingers (phalanges)
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Carpus (Wrist)
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~8 bones:
a)Scaphoid, lunate, triquetral & pisiform proximally b)Trapezium, trapezoid, capitate & hamate distally |
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Metacarpus (Palm)
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~5 numbered (1-5) metacarpal bones radiate from wrist to form palm
a)Their bases articulate w carpals proximally & w each other medially & laterally b)Heads articulate w phalanges |
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Phalanges
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(Fingers)
~14 miniature long bones in each hand ~Fingers (digits) are numbered 1-5, beginning w thumb (pollex) ~Each finger (except thumb) has 3 phalanges –Distal, middle & proximal ~Thumb has no middle phalanx |
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*Pelvic Girdle
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~Hip is formed by a pair of hip bones (os coxae or coxal)
~Together w sacrum & coccyx, these bones form bony pelvis ~Pelvis: a)Attaches lower limbs to axial skeleton w strongest ligaments of body b)Transmits weight of upper body to lower limbs c)Supports visceral organs of pelvis |
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Ilium
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~Large flaring bone that forms superior region of coxal bone
~Consists of a body & a superior winglike portion called Ala ~Broad posterolateral surface is called gluteal surface ~Auricular surface articulates w sacrum (sacroiliac joint) ~Major markings include iliac crests, 4 spines, greater sciatic notch, iliac fossa, arcuate line & pelvic brim |
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Ischium
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~Forms posteroinferior part of hip bone
~Thick body articulates w ilium & thinner ramus articulates w pubis ~Major markings include ischial spine, lesser sciatic notch & ischial tuberosity |
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Pubis
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~Forms anterior portion of hip bone
~It articulates w ischium & ilium ~Major markings include superior& inferior rami, pubic crest, pubic tubercle, pubic arch, pubic symphysis & obturator foramen (along w ilium & ischium) |
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Comparison of Male & Female Pelvic Structure
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1~Female pelvis
a)Tilted forward, adapted for childbearing b)True pelvis defines birth canal c)Cavity of true pelvis is broad, shallow & has greater capacity 2~Male pelvis a)Tilted less forward b)Adapted for support of heavier male build & stronger muscles c)Cavity of true pelvis is narrow & deep |
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The Lower Limb
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~3 segments of lower limb are thigh, leg & foot
~They carry weight of erect body & are subjected to exceptional forces when one jumps or runs |
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*Femur
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~Sole bone of thigh, largest & strongest bone in body
~It articulates proximally w hip & distally w tibia & fibula ~Major markings include head, fovea capitis, greater lesser trochanters, gluteal tuberosity, lateral & medial condyles & epicondyles, linea aspera, patellar surface & intercondylar notch |
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Leg
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~Tibia & fibula form skeleton of leg
~They are connected to each other by interosseous membrane ~They articulate w femur proximally & w ankle bones distally ~They also articulate w each other via immovable tibiofibular joints |
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*Tibia
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~Receives weight of body from femur & transmits it to foot
~Major markings include medial & lateral condyles, intercondylar eminence, tibial tuberosity, anterior crest, medial malleolus & fibular notch |
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*Fibula
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~Sticklike bone w slightly expanded ends located laterally to tibia
~Major markings include head & lateral malleolus |
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Foot
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~Skeleton of foot includes tarsus, metatarsus & phalanges (toes)
~Supports body weight & acts as a lever to propel body forward in walking & running |
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Tarsus
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~Composed of 7 bones that form posterior half of foot
~Body weight is carried primarily on talus & calcaneus ~Talus articulates w tibia & fibula superiorly & calcaneus inferiorly ~Other tarsus bones include cuboid and navicular & medial, intermediate & lateral cuneiforms |
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Calcaneus
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~Forms heel of foot
~Carries talus on its superior surface ~Point of attachment for calcaneal (Achilles) tendon of calf muscles |
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Metatarsus & Phalanges
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1~Metatarsals:
a) (1-5) long bones that articulate w proximal phalanges b)Enlarged head of metatarsal 1 forms “ball of foot” 2~Phalanges a)14 bones of toes b)Each digit has 3 phalanges except hallux, which has no middle phalanx |
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Arches of Foot
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~3 arches maintained by interlocking foot bones & strong ligaments
~Allow foot to hold up weight ~Arches are: 1~Lateral longitudinal –Cuboid is keystone of this arch 2~Medial longitudinal –Talus is keystone of this arch 3~Transverse –Runs obliquely from one side of foot to the other |
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Developmental Aspects: Fetal Skull
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~Infant skull has more bones than adult skull
~At birth, fetal skull bones are incomplete & connected by fontanels ~Fontanels: a)Unossified remnants of fibrous membranes between fetal skull bones b)4 fontanels are anterior, posterior, mastoid & sphenoid ~Skull bones such as mandible & maxilla are unfused |
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Developmental Aspects: Growth Rates
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~At birth, cranium is huge relative to face
~Mandible & maxilla are foreshortened but lengthen with age ~The arms & legs grow at a faster rate than head & trunk, leading to adult proportions |
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Developmental Aspects: Spinal Curvature
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~Only thoracic & sacral curvatures are present at birth
~Primary curvatures are convex posteriorly, causing infant spine to arch like a 4-legged animal ~Secondary curvatures –Cervical & lumbar –Are convex anteriorly & are associated w child’s development |
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Developmental Aspects: Old Age
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~Intervertebral discs become thin, less hydrated & less elastic
~Risk of disc herniation increases ~Loss of stature by several centimeters is common after age 55 ~Costal cartilages ossify causing thorax to become rigid ~All bones lose mass |