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Skeletal System
Chapter 11
Bone Basics

Osseous tissue
 Mainly
Ca & P
206 bones
 Classified by shape and composition

Skeletal system

Function
 Support
 Protection
 Aid
in movement
 Blood formation
(hematopoiesis)
 Mineral storage
Types of Bone Tissue

Spongy (cancellous bone)
 porous
 found in the interior of
bones
 contains many blood
vessels
 inside short / irregular
bones
 most of epiphysis (red
marrow)
More Spongy Bone
Compact Bone
 cortical
or dense
bone
hard
material…solid
bone
very few cells, solid
matrix
Bone types
Long(a): length > width
 Short (c) length= width
 Flat: (b) thin & flat
 Irregular( d): complex
shapes
 Sesamoid: round like
patella

Bone Structure
Proximal Epiphysis (end)
Diaphysis (shaft)
Distal Epiphysis (end)
Bone Structure

Articular Cartilage
 End
of all bone surfaces where
joints form
 (hyaline
cartilage)
Periosteum
outer layer
initiates bone growth,
repair, and development
contains vessels and nerves
Endosteum
-inner layer
 -lines medullary cavity

Medullary Cavity
-”hollow” portion of the
diaphysis
 -contains bone marrow

Yellow Marrow
found in most bones
 contains fat cells,
blood vessels, and nerves

Red Marrow


located in spongy gone
-site of red and white blood
cell formation
Compact Bone
Yellow Marrow
Bone composition
Ca3(PO4)2 & CaCO3
 Cartilage
 Dense connective tissue
 Collagen
 Osteocytes

 Osteoblasts/osteocyte:
produce matrix
 Osteoclasts: dissolve bone
Microscopic structures

Dense bone
 Osteocytes:



located in bony chambers called lacunae
Form concentric circles around central canals
Transport nourishment & waste through caniculi.
 Intercellular


material
Collagen
Inorganic salts - Ca3(PO4)2 & CaCO3
 Osteon



Central canal, caniculi, & lacunae
Cemented together by compact bone
Orientation & arrangement of units help bone resists
compressive forces
Microscopic structure
 Central
canal
Blood vessels & nerves
 Nourishment

 Volkman’s


canal’s
Communication between surface of the bone and
medullary cavity.
Spongy bone
 Osteocytes:
Located in lacuna separated by trabeculae
 Nourished through caniculi by diffusion

Histology
Spaces for bone cells
Bone system
Sheets of matrix
Osteocyte communication
Thin plates
Longitudinal Blood
vessel passage
membrane
Transverse Blood vessel
passage
Bone development & Growth


1st 2 months of life
Develop 2 ways

embrionic membrane – intramembranous
bones



~week 5
Include skulls flat bones, clavicle & mandible
From from osteoblasts
 hyaline


cartilage- endochondral bones
All other bones
Form from chondroblasts
Bone growth & development

Growth
 Interstitial
growth: length
 Appositional growth: width
Bone remodeling & repair
New matrix and bone re-absorption
continue through life.
 Bones under the greatest stress more
frequently
 Maintains homeostasis by continually
adding minerals to system

Repair
Bleeding & inflammation lead to a
procallus
 Fibroblasts secrete dense connective
tissue to replace procallus
 Chondroblasts & osteoblasts then
gradually building an osseous callus
 Osseous callus then goes through
remodeling until it is healed.

Organization of the skeleton

206 bones (adult)
 Axial=




80 bones
28 skull
26 vertebrae
25 thorax
1 hyoid
 Appendicular



= 126
4 shoulder
60 upper limb/60 lower limb
2 pelvis
Surface features of bones
Condyle
Knuckle, large smooth rounded
surface
Occipital condyle, femoral condyle
Facet
Smooth articular surface
Between vertebral bones
Fissure
Narrow opening or cleft
Orbital fissure of sphenoid
Foramen
Opening or hole
Foramen magnum
Fossa
Depression or groove
Glenoid cavity of scapula
Process
Any projection from the surface
Styloid process
Spine
A narrow or pointed projection
Spine of scapulas, spinous process
Trochanter
A large blunt process
Greater trochanter femur
Tubercle
Small rounded process
Greater tubercle humerus
Tuberosity
Rounded , elevated area of
bone that is usually roughened
Deltoid tuberosity, tibial tuberosity
Other features
Meatus
Tubelike passageway
External auditory meatus
Crest
Narrow, ridgelike projection
Iliac crest
Fovea
Small pit or depression
On head of humerus
Fontanel
Soft region between bones
Fontanel of infant skull
Sutures
(wormian bones)
Interlocking line of union
Small bones found in suture
Sutures of cranium
sinus
Air-filled cavity with in a
bone
Frontal sinus
Axial Skeleton

Skull
 Bones(
22 together)
8 cranial
 13 facial & the mandible

 Cranium
Protects and houses the brain
 Contains sinuses

Drain fluids
 Reduce weight of bones
 Give resonance to your voice

 Bones
of cranium
Frontal bone-1
 Parietal-2
 Occipital-1
 Temporal-2
 Sphenoid-1
 Ethmoid-1

 Sutures:
immovable joints
between skull bones

Coronal suture


Between frontal bone and both
parietal bones
Between right & left parietal
bones
Lambdoidal suture


coronal
Sagittal suture


squamosal
Between parietal bones &
occipital lobe
Squamosal suture

Between temporal and parietal
bones
Sagittal suture
lambdoidal
Skull: cranium

Frontal bone




Forehead
Forms Superior orbit
Supraorbital foramen
Frontal sinus
cranium

Parietal bones(2)


Meet at sagittal suture
Temporal bones(2)






Squamosal suture 1
External auditory meatus 2
Madibular fossa 3
Zygomatic process 4
Styloid process 5
Mastoid process 6
1
4
3
2
5
6
 Occipital
bone
Posterior & floor of head
 Lambdoidal suture
 Foramen magnum



Permits passage of spinal cord
Occipital condyles

Articulates with atlas(C1) for
head movement

Sphenoid bone


Single butterfly
shaped bone
Foramen





Optic
rotundum
Superior and inferior
orbital fissures
Sella turcica
Sinuses(2)

Ethmoid
 Cribiform
plate
 Crista galli
 Perpendicular plate
 Nasal conchae
 sinuses
Facial Bones

Maxillary bones (2)

Form







Attachment for teeth
Palatine process


Drain into nasal cavity
Alveolar process


foramen
Sinuses


face & upper jaw
Floor of orbit
Roof of mouth
Walls of nasal cavity
Hard palate
Cleft palate/cleft lip
Anterior nasal spine
Infraorbital foramen
Nasal
spine
Patients with clefts: (A) incomplete unilateral cleft of the lip, (B) unilateral cleft of the
lip, alveolus, and palate, (C) bilateral cleft of the lip, alveolus, and palate, (D) isolated
(median) cleft palate.
Stoll et al. BMC Medical Genetics 2004 5:15 doi:10.1186/1471-2350-5-15
Facial bones

Palatine bones (2)
 L-shaped
posterior to
maxillary
 Form




Roof of mouth
Floor of nasal cavity
Lateral walls of nasal
cavity
Membrane attachment
is soft palate
Facial bones

Zygomatic bones (2)
 Form


Cheek
Lateral orbit
 Temporal

process
Zygomatic arch
Facial bones

Nasal bones (2)
 Rectangular
bones
meet at the midline of
the bridge of the nose.
 End of nose is all
cartilage
Facial bones

Lacrimal bones(2)




Posterior lateral to nasal
bones
Anterior to sphenoid
Form medial wall of orbit
Vomer(1)


w/ perpendicular plate of
ethmoid form nasal septum
Forms the Midline of nasal
cavity
Facial bones

Mandible (1)






Lower jaw
Body
Ramus
Coronoid process
Mandibular condyle articulates
with fossa in temporal bone to
form TMJ.
Alveolar process


Hold lower teeth
Foramen


Mental
mandibular
Axial

Hyoid
 Does
not articulate
with any other bone
 Suspended from the
styloid process or
temporal bone
 Supports tongue
Vertebral column
1. Description



extends from skull to pelvis
26 bones (adult) 33
child/young adult
intervetebral disks

fibrocartilage disk
2.Function

Support head & neck

Movement

rotation & bending
Vertebral column
3. Curvatures

Primary( fetal )



Concave anteriorly
thoracic, pelvic or sacral
Secondary (weight
bearing)

convex posteriorly

Cervical


Hold head up
lumbar

Support upright
posture/walking
Vertebral column
4. Structure
a. body, thick
b. pedicles
c. Laminae
vertebral arch
d. spinous process
e. transverse process
f. vertebral foramen
a
b
f
e
c
d
Vertebral column
5.Cervical Vertebrae ( 7 )
a. transverse foramina
b. Bifurcated (forked) spinous
process
c. Atlas- C1



articulates w/ occipital bone
no spinous process
rotates on dens of axis
d. Axis- C2


ondontoid process (dens)
first spinous process
e. C-7 large process at bottom of
neck
Vertebral column
6.Thoracic
vertebrae:(12)
a. Spinous process
sloped downward
b. rib articulations
c. forward flexion of
trunk
Vertebral column
7. Lumbar vertebrae (5)
a. largest

support body weight
b. transverse process

sharp posterior angle
c. spinous process

thick & horizontal
Vertebral column
8. Sacrum ( 1 )
a. fused spinous process
 1 adult, 5 infant bones
 Fuse ~10-25 years of age
b. foramina for vessel/nerves
9. Coccyx ( 1 )
a. 4 bones fuse ~ age 25
b. shock absorber for sitting
Thoracic cage
1.Costals ( ribs )
- 12 pair
-True ribs – 7 pair
Attach directly to sternum
- False ribs- 5 pair


1st 3 Attach via cartilage
last 2 float w/ no anterior
attachment
2.Sternum ( breast bone)
- Manubrium

Clavicle & 1st rib
attachment
- Middle body

Ribs 2-7
- Xiphoid process


Inferior tip points
posteriorly
False rib attachment
Appendicular skeleton
1. Pectoral(shoulder) girdle
A. Function

Support of upper limb

muscle attachment
B.Structures
1. clavicle( 2 )
a. only bony attachment of
arm to axial skeleton
 -sternum medially

-acromion process of
scapula laterally
b. braces freely moving
scapula
c. weak structure
 -easily fractured

-joints easily sprained
B. Structures
2. Scapula( 2 )
a. acromion process
( end of scapular spine )
 -forms acromioclavicular joint (ac jt.)

-only bony attachment of scapula to
axium
b. glenoid fossa articulates with head of
humerus
 -glenohumeral joint (gh jt.)

-fossa deepened by labrum (cartilage)
c. muscle attachment to thorax
posteriorly
2. Upper Limb
A. Structures
1.Humerus Aka: upper arm
a. fractures at neck
2.Radius Aka: forearm
a. shorter of 2 forearm
bones

thumb or lateral side
b. rotates over ulna to
pronate hand
3. ulna aka: forearm
a. olecranon process

makes elbow prominence
b.styloid process

bump on wrist
4. Carpals (8) are short bones
Aka : wrist bones or carpus
a. concave anteriorly= makes
carpal tunnel
-passage for nerves and tendons
b. (lateral >medial, proximal >
distal rows)
-scaphoid, lunate, triquitrum, pisiform
-trapezium, trapezoid, capitate, hamate
Palmer surface
3
4
5. Metacarpals (5) are long bones
Aka: hand bones
2
5
a. framework of palm
b. connect carpals to phalanges
c. numbered 1-5, thumb to pinky
1
6. Phalanges ( 14 ) are long bones
Aka: digits or fingers
a. proximal- closest to mc
b. middle
digits 2-5
c. distal- end or tip
d. Thumb or Pollux
-only proximal & distal
e. polydactyly –extra digits
Lower Limb & pelvis
3. Pelvic Girdle
 A. Function
 Support
of trunk
 Attachment of lower limb
 Muscle attachment
 Protection of pelvic organs

-bladder, intestine, internal reproductive
organs
B. Structures
1. Coxae( 2 ) or Coxa

a. Ilium-largest most superior



iliac crest
ASIS (anterior superior iliac
spine)
SI joint posteriorly
b. Ishium- lowest portion, L shaped

tuberosity, supports weight while sitting
c. Pubis- lower anterior portion

-anteriorly form symphysis pubis

- pubic arch
 < 90˚ =male
 > 90˚ = female
2. Pelvis : Coxae, sacrum & coccyx
a. . Greater or False pelvis
-above linea terminalis
-lumbar vertebrae, iliac crests &
abdominal wall
b. Lesser or True pelvis
-below linea terminalis
-sacrum, coccyx, lower ilium, ishium &
pubis bones
-child passes through cavity during birth
Linea
terminalis
II. Lower Limb
Structures
 Femur (long bone)




Aka: thigh bone
longest bone in the body
Head articulates with acetabulum
to form Hip joint
-fovea capitus (pit in the head)


Trochanter (greater & lesser)


large process for muscle
attachment
Condyles- medial & lateral



ligament attachment
form knee
-hyaline cartilage
Epicondyle-medial & lateral

-attachment for ligament & muscle

Patella (sesamoid bone)



aka: kneecap
Function as a lever for low leg
Enbedded in quadraceps/patellar tendon

Osgood
schlatters
Tibia
aka: shin bone


larger of 2 low leg bones
proximal- lateral & medial condyles


Form knee joint
Menisci ( meniscus)



deepens articulation & cushions
hyaline cartilage
tibial tuberosity


attachment for patellar ligament
distal-medial malleolus


-aka ankle bone
-1/2 of ankle joint with talus
Fibula


Non-weight bearing bone
lateral malleolus


-completes ankle joint with talus& tibia
Interosseous membrane connects to tibia
& fibula


-length of shafts
-surface for muscle attachment
Tarsals (7)
Aka: ankle bones
framework of foot & arch
cuniform 1
cuniform 2
cuniform 3
Cuboid
distal row
medial to lateral
navicular
talus (ankle)
-only free moving bone
calcaneous (heel)
distal row
medial to lateral
-largest
Metatarasals (5)
Aka: foot bones
a. numbered 1-5 like hand
b. distal end (heads) forms ball of foot
longitudinal (medial) arch
transverse arch (across ball of foot)
Phalanges or Phalanx (14)
a. proximal- closest to metatarsals
b. middle
c. distal- end or tip
Great toe or Hallux
-only proximal & distal
digits 2-5 only
Longitudinal arch