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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

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