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Functions of Bone
Support and Protection
• shape and form
• underlying tissue protection
Functions of Bone
Body Movement
• LeversBlood Cell Formation• hematopoiesisStorage of Inorganic Salts• quantity of calcium phosphate initiates
osteoblasts and osteoclasts• osteoporosis
Functions of Bone
Organization of the SkeletonAxial Skeleton• skull, hyoid, vertebral
column, thoracic cage
Appendicular Skeleton• pectoral girdle and upper
limbs
• pelvic girdle and lower limbs
Cranial BonesFrontal• anterior; superior to eyes
Parietal• posterior to frontal• bulge on head
Occipital• posterior and base of
cranium
Temporal• lateral and base
Cranial Bones
Sphenoid and ethmoid
• create sinuses• sinusitis
Functions of the CraniumEnclose and protect the
brain
Paranasal sinuses
• reduce weight
• increase intensity of voice through resonance
Jaw BonesMaxillary bone• upper jawMandible• MovableCleft Palate
Infantile Skeleton development - SkullIncomplete development
Many fontanels (“soft spots”)• permit movement between bones; allow skull
to be compressed during birth• Allow for continued brain growth• Eventually fuse - sutures
Proportions are quite different from those in an adult skull
• small face• prominent forehead• large orbits
Typical Vertebrae• Drum shaped body
• Body and bony arch surround spinal cord
• Notches provide the foramen for spinal nerves
3 Types of VertebraeCervical
• first 7
Thoracic
• middle 12
Lumbar
• last 5
Scoliosis
Cervical VertebraeBony axis of neck
Atlas• 1st vertebrae• supports and balances head
Axis• 2nd vertebrae• provides pivot of head
Thoracic Vertebrae• Larger than
cervical
• Facets articulate with the ribs
Lumbar VertebraeLarge and strong
Support most body weight
Sacrum• 5 fused vertebrae
Coccyx (tailbone)• 4 fused vertebrae• lowest part of vertebral column
Infantile Skeleton development – Vertebral Column
Spinal curvatures well developed – Primary curvatures
• Thoracic
• Sacral
Cervical curvature
• Develops as baby learns to lift his/her head
Lumbar curvature
• Develops during learning to sit and walk
Disorders
Spina Bifida
• Vertebrae do not completely develop
• Genetic – quad screen test
Spina Bifida
Disorders
Herniated Disk
• Elastic portion of disk degenerates
• Back pain; loss of muscular function
Thoracic CageShaped like an inverted coneRibsThoracic vertebraeSternum
• Manubrium, body, xiphoid process
Costal Cartilage
• attach ribs to sternumWhy articulate with cartilage
instead of bone?
Functions of the Thoracic Cage• Support pectoral girdle and arms
• Protect organs
–Heart and lungs
• Aid in breathing
Ribs• 12 pairs
–first seven are true
–last five are false
• Curves around chest and slope downward
• Articulate with transverse process on vertebrae
SternumBreast bone
Articulates with the clavicle
Red marrow
• produces RBCSternal puncture
• thin compact bone so easy to obtain marrow for diagnosis
Pectoral Girdle • Incomplete ring• 2 Clavicles (collar bone)
– slender, elongated– hold shoulders in place– attachment site for
muscles of the arm, chest, back
• 2 Scapula (shoulder blade)– broad, triangular bones– articulates with humerus
Upper LimbHumerus
• articulates with radius & ulna
Radius
• elbow to wrist
• articulates with humerus, ulna, wrist
Ulna
• overlaps humerus
• articulates laterally with radius
Hand
• carpals, metacarpals, phalanges
Pelvic GirdlePelvis• sacrum, coccyx, girdle2 Coxal bones (3 fused
bones)• Ilium (hipbone)• Ischium (“butt” bone
tuberosity• Pubis
• Fused at the symphysis pubis
Lower Limb• Femur– knee to hip– longest bone in the body
• Tibia– shinbone
• Fibula– lateral to tibia– bears no weight
• Foot– Tarsals, metatarsals, phalanges– calcaneus
Male v. Female Skeleton Male• larger• hip bones more narrow• more bone mass
Female• wider hip bones• angle at symphysis pubis is greater• less bone mass