Bone Function

7.4 – 7.12

• Support and Protection

–Give shape to

•Head

•Face

•Thorax

•Limbs

–Supports

•Backbone – body weight

–Protection

•Skull – eyes, ears, brain

•Rib cage – heart, lungs,

•Pelvic girdle – internal reproductive organs

• Body Movement

–Bones give attachment points for muscles

–Act as levers giving mechanical advantage

• Blood Cell Formation

–Occurs in:

•marrow in medullary cavities of long bones

•spaces in spongy bone

• larger osteonic canals

–Marrow types

•Red marrow – produces RBC’s, WBC’s and platelets – abundant in infants

Marrow types cont.• In adult –

–Spongy bone,

–Skull

–Ribs

–Sternum

–Clavicles

–Vertebrae,

–Pelvis

•Yellow marrow – stores fat –in adults

• Storage of inorganic salts

–Mostly calcium phosphate

–Released

•Blood levels low – parathyroid secretes hormones that get osteoclasts to get to work breaking down bone tissue

Salt storage cont.

• Blood Calcium level high- inhibits osteoclast activity – calcitonin from thyroid gland stimulates osteoblasts to build bone tissue

Skeletal Organization (7.5)

• Skeleton divided into two major portions

–Axial Skeleton

•Bony and cartilaginous parts of head neck and trunk

–Appendicular skeleton

•Bones of upper and lower limbs

What Axial bones do

• Skull – cranium (brain case) and facial bones

• Hyoid bone

–In neck between lower jaw and larynx

–Supports tongue – helps in swallowing

• Vertebral column

–Vertebrae separated by cartilaginous disks

–Protects nerve cord

–Toward distal end is fused section sacrum and coccyx (tail bone)

• Vertebral column

–Thoracic Cage

–Ribs (BBQ)

•12 pairs

•Protect upper abdominal cavity

•Articulated w/ vertebrae posteriorly

• Sternum – anterior portion where ribs attach

Appendicular skeleton

• Pectoral girdle

–Made of scapula and clavicle (collar bone)

–Connects bones of upper limbs to axial skeleton

–Aids upper limb movement

Posterior view Anterior view

• Upper limbs

–upper arm bone*

•Humerus

–2 lower arm bones*

•Radius –

•Ulna –

–*Articulate at elbow joint

• Hand

–8 carpals (wrist bones)

–5 metacarpals (bones palm)

–14 phalanges (finger bones)

7.6 Skull• Cranium

–Protect brain

–Muscle attachment points

•For chewing

•Head movements

–Paranasal sinuses

•Lined with mucous membrane

•Lighten weight of head

• Bones of skull

–Frontal bone

•Supraorbital foramen

–Opening where blood vessels

and nerves go to forehead

Frontal sinuses

• Parietal bones

–Two bones behind the frontal bone

–Fused along midline with sagittal suture and with the coronal suture along the frontal bone

–Occipital bone

•Forms back of skull

•Foramen magnum allows

nerve fibers to pass out of the brain

Lambdoidalsuture

• Temporal bones

–Side of skull

–External auditory meatus

•Lead to middle ear

–Mandibular fossae

•Articulates w/ mandible

–Mastoid process

•Attachment place for neck muscles

–styloid process

•Anchors muscles associtatedwith tongue and pharynx

–Zygomatic process

•Helps form prominence of cheek

• Sphenoid bone

–Anterior portion of cranium

–Forms base of cranium, side of skull, floor and side of the orbits

–Sella turcica – location of pituitary gland

• Ethmoid bone

–Two masses on each side nasal cavity

• Joined by cribiform plates forming roof of nasal cavity

–Crista galli

•attachment point for membranes that enclose the brain

• Facial skeleton

–13 immoveable bones and the moveable jawbone

–Maxillae

•Upper jaw and anterior portion of the mouth

–Palatine bones

•Posterior part hard palate

–Zygomatic bones

• Lacrimal bones

–Thin bone located in medial wall of each orbit

• Nasal bones

–Thin fused at midline

–Form bridge of nose

• Vomer bone

–Forms part of nasal septum

• Inferior nasal conchae

–Supports mucus membranes in nasal cavity

• Mandible (jaw bone)

–Horseshoe shaped

–Mandibular condyles articulate with mandibular fossae of temporal bones

–Coronoid process

•Attachment point for muscles used for chewing

–Alveolar arch

•Place for lower teeth

Infant skull

• Incompletely developed

• Fibrous membranes connect cranial bones

–Frontanels (soft spots)

–Allow for compression to more easily pass through birth canal

Vertebral column (26 bones)

• Forms vertical axis of skeleton

• Composed of vertebrae

• Intervertebral disks – cushion vertebrae

• Supports head and trunk

• Protects spinal cord

Cervical vertebrae

• 7 cervical vertebrae

–Form bony axis of neck

–Have transverse foramina (passageway for arteries going to brain)

–2 distinct ones

•Atlas – first vertebrae supports head

–Two kidney shaped facets articulate with occipital condyles of skull

•Axis – 2nd vertebrae

–Tooth-like dens (odontoid process)

Cervical vert. cont.

2 distinct onesAtlas – first vertebrae supports head

Two kidney shaped facets articulate with occipital condyles of skull

•Axis – 2nd vertebrae

– Tooth-like dens (odontoid process)

–odontoid process lies in ring of atlas – allows head to turn from side to side

• 12 thoracic vertebrae

–Beginning at the 3rd vertebrae they become increasingly larger in size as going distal from skull (support more weight)

–Has long pointed spinous process

–Facets on sides articulate with ribs

• 5 lumbar vertebrae (total so far 22)

–In small of back

–Increasingly larger in size as going inferiorly

• Sacrum

–5 fused vertebrae

–Dorsal sacral foramen

•Nerves / blood vessels pass through

–Pelvic sacral foramen

•Nerves / blood vessels pass through

• Coccyx (tail bone)

–Lowest part vertebral column

–Usually 4 fused bones

–Ligaments attach it to sacral hiatus

7.8 Thoracic Cage• Consists of

–Ribs

–Thoracic vertebrae

–Sternum

–Costal cartilages

• Function

–Support shoulder girdle

–Protect viscera

–Role in breathing

• Ribs

–Usual number 12

•One for each thoracic vertebrae

•First 7 “true ribs” attached to sternum via costal cartilage

•Next 3 false ribs not directly attached

•Last 2 floating – not attached to sternum

Floating ribs

• Sternum

–Breastbone

–3 parts

•Manubrium

–Articulates with clavicles

•Body

•Xiphoid process

7.9 Pectoral Girdle

• Consists of

–2 clavicles

–2 scapulae

• Function

–Support upper limbs

–Attachment for muscles controlling them

• Clavicles (collar bone)

–Brace freely moveable scapula

–Hold shoulder in place

–Provide attachment point for muscles of upper limbs, chest, back

• Scapulae

–Spine divides posterior surface

–Leads to two processes

•Acromion process

–Tip of shoulder

–Articulates with clavicle

–Attachment of upper limb, chest muscles

Scapula cont.

•Coracoid process

–Attachment upper limb, chest muscles

–Glenoid cavity

•Articulates with head of humerus

Acromion process

Coracoid process

Glenoid cavityspine

• Upper limbs

–Consists of

•Humerus

•Radius

•Ulna

•hand

• Humerus

–Long bone that joins with the scapula

–Greater tubercles

–Lesser tubercles

•Attachment point muscles

• Humerus

–Surgical neck

•common place of fractures

–Deltoid tuberosity

•Attachment point deltoid

• Radius

–Located thumb side of forearm

–Crosses over ulna when hand turned palm facing backwards

–Head articulates with humerus

• Radius cont.

–Radial tuberosity attachment point of biceps, brachii

–Styloid process – attachment for ligaments of wrist

• Radius parts

head

Radial tuberosity

styloid process

• Ulna

– longer than radius

–Wrench-like opening (trochlear notch)

•Articulates with humerus

–Olecranon process

–Coronoid process

Muscle attachment points

Ulna cont.

–Head

•Articulates w/ ulnar notch radius

• Joins wrist bone (triquetrum)

–Styloid process

•Attachment point wrist ligaments

• Ulna parts

Head of ulna

Olecranon process

Styloid process

Trochlear notch

Coronoid process

Ulnar notch radius

• The hand

–Wrist

•8 small carpals (4 x 2) – carpus

•Articulates with

–Proximal – radius and fibrocartilaginous disk on ulnar side

–Distal – metacarpal bones

Hand cont

–palm

•5 metacarpals

–Form framework of palm

–Distal end form knuckles of fist

–Numbered 1-5 starting with thumb

• Hand cont.

–Fingers

•Phalanges

–3 phalanges for finger except thumb

»Proximal

»Middle

»Distal

–Thumb lacks middle phalanx

• Hand labeled

Learn all 27 bones of hand

• Pelvic Girdle

–2 coxal bones

•Articulate with each other and sacrum

•With sacrum and coccyx form pelvis

•Supports trunk of body

•Attachment point lower limbs

Pelvic girdle cont.

•Protects

– urinary bladder

–Parts large intestine

–Internal reproductive organs

• Coxal bone

–3 major sections

• Ilium

–Largest section

–Forms prominence of hips (iliac crest)

–Attachment point ligaments muscles

–Joins sacrum at sacroiliac joint

• Ischium

–Lowest portion of coxal bone

–Ischial tuberosity rough surface

•Attachment point for muscles ligaments

–supports weight when sitting

–Has ischial spine

• pubis

–Anterior portion coxal bone

–Two join at symphysis pubis and form the pubic arch

–Forms obturator foramen

–Arch allows to tell male female

• Lower limb

–Consists of

•Femur

•Tibia

•Fibula

•Tarsals

•Metarasals

•phalanges

• Femur–Longest bone

–From hip to knee

–Head forms hip joint with acetabulumof coxal bone

–Trochanter process (greater /lesser)

•Attachment for muscles of lower limbs

•& buttock

–Lateral & medial condyles

•Articulate with tibia

• Tibia (shin bone)

–Larger of 2 leg bones

–Proximal end

•Medial and lateral condyles

–Articulate with femur condyles

–Tibial tuberosity

•Attachment point patellar ligament

–Distal end

•Medial malleolus

–Attachment point ligaments

• Fibula

–Lateral side tibia

–Proximal head

•Articulates with tibia

•below lateral condyle

•Does not bear body weight

–Lateral malleous

•Articulates with ankle

•Protrudes lateral side

• Foot

–Consisists of•7 tarsal bones (tarsus)

–Talus moves freely joins tibia / fibula

–Remaining 6 bones bound firmly together

•Calcaneus (heel bone)

–Largest bone of foot

–Supports weight body

–Attachment point muscles of foot

• Metatarsal bones

–5 bones of the instep

–Distal end forms ball of foot

–Tarsals and metatarsals bound by ligaments form arches of foot

•Arch acts as shock absorber

Foot cont.

• Phalanges (toes)

–Similar to fingers

–Each toe has 3 phalanges except big toe

–Big toe lacks middle phalnax

• The foot

• Joints

–Fibrous joints

•Between bones in close contact

•Thin layer of connective tissue joins bones

–Sutures in skull

•No movement (usually)

• Cartilaginous joint

–Disks of fibro or hyaline cartilage connects bones

–Separate vertebrae in vertebral column

–Act as shock absorbers

–Allow limited movement

–Also found in symphysis pubis and first rib with sternum

• Synovial joints

–Allow free movement

–More complex

–Articular ends of bone covered with hyaline cartilage

–Tubular capsule

•Outer layer ligaments

• Inner layer synovial membrane

–Secrets synovial fluid to lube joint

–Menisci (some joints)

•Shock absorbing pad of fibrocartilage

Synovial joints cont.

• Six types synovial joints

–Ball and socket

•Movement in all planes

•Rotation around central axis

•Shoulder joints

•Hip joints

• Condyloid joint

–Oval shaped condyle one bone into elliptical cavity of another bone

–Joints of metacarpals and phalanges

–Movement in different planes

–No rotational movement

• Gliding joints

–Nearly flat or slightly curved

–Most joints in wrist and ankle and articular processes of vertebrae

–Allow sliding and twisting movement

• Hinge join

–Convex surface of one bone into concave surface of another

–Elbow

–Joints of phalanges

–Movement one plane

• Pivot joint

–Cylindrical surface of one bone rotates with within ring of another bone

–Movement around a central axis

–Joint between proximal ends of radius and ulna

• Saddle joint

–Between bones having articulating surfaces that are both concave and convex

–Variety of movements

–Joint between carpal (trapezium) and metacarpal of thumb

• Types joint movements

–Typically one end of muscle attached to fixed point and other to moveable side of joint

–When muscles contract they pull moveable end (insertion) pulled toward fixed end (origin)

• Flexion

–Bending parts so angle decreases and parts come closer (bending of knee)

• Extension

–Straightening of part so angle increases

–Parts move farther apart

• Dorsiflexion

–Bending of foot at ankle toward shin

• Plantar flexion

–Bending of foot at ankle toward sole

• Hyperextension

–Excess extension of parts at a joint beyond anatomical position

• Abduction

–Moving part away from midline

• Adduction

–Moving part toward midline

• Rotation

–Moving part around axis

• Circumduction

–Moving part so that its end follows circular path

• Pronation

–Turning the hand so palm is downward or turning foot so medial margin is lowered

• Supination

–Turning of hand so that palm is upward

• Eversion

–Turning foot so sole is outward

• Inversion

–Turning of foot so that sole is inward

• Retraction

–Moving part backward

• Protraction

–Moving part forward

• Elevation

–Raising part

• Depression

–Lowering of part