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SKELETAL
SYSTEM
Bone & Tissue
Axial Skeleton
Appendicular Skeleton
Articulations
Bone Physiology
•
Types of Bone :
1. Long – when length is greater than width, arms and legs, act as
levers pulled by muscles
2. Short – about equal length, width, and thickness but irregularly
shaped, wrist and ankle, limited movement, completely covered in
ligament
3. Flat – actually thin or curved more often than flat, ribs, scapula,
sternum, and cranium, muscle attachment or protection
4. Irregular – don’t neatly fit into any other category, facial and hip
bones, vertebrae
5. Sesamoid – small bones embedded in certain tendons that pass
over a joint (knee or wrist) , patella and pisiform carpal
6. Accessory – mostly in the feet, some in the skull (sutural bones),
form when developing bones don’t fuse completely,
Gross Anatomy of Long Bones
•
•
•
•
Diaphysis – tubular shaft
Epiphysis – round end
Epiphyseal growth plate
Marrow :
– Yellow mostly adipose
– Red hemopoeisis (Blood
cell creation)
• Endosteum – lines the
trabeculae (
• Periosteum – lines the
outside of compact bone
Compact/Spongy Bone Tissue
• Haversian system
– Osteon (entire
section)
• Lamellae- rings
• Central canalcontains blood
vessels
• Perforating canal
• Lacunae- hole
containing bone cell
• Canaliculi- tiny canal
• Cancellous bone
(trabeculae- bands or
columns of
connective tissue
Bone Cells (define)
• Osteogenic (osteoprogenitor) – stem cell, highly mitotic, found deep in
the periosteum and endosteum layers.
• Osteoblast – “b” stands for build, these pump calcium and phosphate in
and out of bone matrix
• Osteocyte – main cell of fully developed bone, live in the lacuna and
extend out through the canaliculi into the matrix, develop from osteoblast,
maintain the bone homeostasis
• Osteoclast – “c” stands for clear, these clear or remove calcium from the
matrix, develop from white blood cells
• Bone-lining cells – regulate mineral salts movement in and out of adult
bones
Bone Growth- OSSIFICATION!!!
• Longitudinalepiphyseal growth plate
• Diameter and
fracture healingperiosteum
• Modeling- formation of
new bone layers on the
exterior and simultaneous
removal of bone from the
interior layer
• Remodelingstrengthening bones under
more stress and lightening
bones under less stress
Physiological Functions
• Calcium – enzyme function, membrane permeability, muscle
contraction, nerve impulses, blood clotting, bone formation
• Phosphate – acid / base balance
• Blood Cells – hemopoietic tissue, red bone marrow is the site
of the body’s main blood cell production
• Effects of hormones & nutrition – PTH (parathyroid
hormone) and CT(calcitonin) impact bone formation
• Effects of aging – old = loss the ability to use calciumWHAT then is the DESTINY of the bones????
Axial Skeleton
•
Skull:
– Sutures
– Fontanels –
soft spot on top of
infant head
– Bones:
1. Frontal
2. Parietal
3. Occipital
4. Temporal
5. Sphenoid
6. Ethmoid
•
Facial bones:
1. Mandible
2. Maxilla
3. Nasal
4. Zygomatic
• Other skull bones:
1. Hyoid- connects to
tongue
EAR BONES
2. Incus
3. Malleus
4. Stapes
•
Vertebral Column:
1. Cervical, neck (C1-C7)a)
b)
c)
d)
Atlas – C1 (#6) yes motion
Axis – C2 (#7) no motion
3-6 are typical
Vertebra prominins – C7
2. Thoracic, chest (T1-T12) –
articulate with ribs
3. Lumbar, back (L1-L5)- largest,
strongest, back muscles attach
4. Sacrum (5 fused vertebrae)give strength and stability to pelvis
5. Coccyx (4 fused vertebrae)vestige of embryonic tail
Typical Vertebrae
•
Functions:
1. Body
2. Vertebral arch:
a) Pedicles
b) Laminae- the curve of the arch
(houses the spinal cord!)
a) Vertebral foramen
3. Vertebral processes:
a) Spinous process
b) Transverse process
c) Articular processes (superior & inferior)
4. Intervertebral disk- fibrocartilage = flexible support
5. Primary curve – thoracic and sacral curves appear before birth
6. Secondary curve – cervical and lumbar curves after birth
The Thorax:
1. 12 thoracic
vertebrae ( posterior)
2. 12 pairs of ribs
(anterior):
a) 1-7 true ribs
b) 8-10 false ribs
c) 11 & 12 floating ribs
3. 12 costal cartilages
4. Sternum:
a) Manubrium
b) Body
c) Xiphoid process
5. Intercostal space
Appendicular Skeleton
•
Upper Extremities (limbs, 64 bones):
– Pectoral Girdle (all bones X 2):
1. Clavicle (collar bone) - most often broken bone
• Sternoclavicular joint (medial)
• Acromioclavicular joint (lateral)
2. Scapula (shoulder blade)
3. Humerous (upper arm)
4. Ulna (little finger side): larger of the two, medial bone
5. Radius (thumb side): lateral bone
6. Carpal bones (8 total):
a) Wrist
7. Metacarpals (5 bones):
a) Palm of hand
8. Phalanges (14 bones):
a) Metacarpophalangeal joint (MP joint, knuckles):
b) Thumb: I
1) 2 phalanges
2) Proximal and distal interphalangeal joint (IP joint)
c) Fingers: II – IV
1) 3 phalanges per finger
2) Proximal, middle, and distal
3) Proximal interphalangeal joint (PIP joint)
4) Distal interphalangeal joint (DIP joint)
•
Lower Extremities (legs, 62 bones):
–
Pelvic Girdle (limbs, 62 bones): Ossa coxae
1. Hip bone- really 3 (6) bones fused together, transfers weight to
femur, all 3 form the ball & socket joint
a) Ilium – superior lateral prominence of hip
b) Ischium – inferior, strongest to bear weight when seated
c) Pubis – anterior, joined by the symphysis pubis
2. Femur (thigh 2) – longest, strongest, heaviest bone
3. Patella (knee cap 2) – sesamoid bone in the quadricep femoris
tendon, prevents wearing across joint
4. Fibula (2)- smaller of the two bones in lower leg, adds strength to
ankle
5. Tibia (shin 2)- larger of two bones in lower leg, supports body
weight
6. Tarsals (ankle 14)- includes heelbone (calcaneus), raises body,
forward thrust for walking and running
7. Metatarsals (sole 10)- improves stability, absorbs shock
8. Phalanges (toes 28) – provides stability
Articulations
•
Types of joints
A. Fibrous: lack a joint cavity, tightly joined by
fibrous connective tissue, generally immovable in
adults
1) Sutures – skull only
2) Syndesmoses – collagenous fibers hold two
bones close together but not touching
(ulna/radius – moveable, tibia/fibula – not much
movement allowed)
3) Gomphoses - fibrous joint made up of a peg in
a socket (teeth)
B. Cartilaginous: no joint cavity, bones united by
a plate of hyaline cartilage
1) Synchondroses – permit growth not
movement, temporary joint formed by the
epiphyseal growth plate of long bones
2) Symphyses – fibrocartilaginous disks to absorb
shock (vertebrae and pubic symphysis)
C. Synovial: articular cartilage surrounded by
collaginous fibers and supported by ligaments,
allow for the greatest range of motion
1) Hinge
2) Pivot
3) Condyloid
4) Gliding
5) Saddle
6) Ball and Socket
Hinge Joints
• Uniaxial only
• Very strong
collateral
ligaments
• Permit flexion
and extension
• Elbow, finger,
knee, and ankle
Pivot Joints
• Uniaxial
• Rotates around a
central axis
• Atlantoaxial joint
between the atlas
and axis
vertebrae and the
radius/ulna
articulation
• http://davisplus.fadavis.com/
wilkinson/animations.cfm
Condyloid Joints
• Biaxial
• Metacarpophal
angeal
(knuckles)
joints except
the thumb
• Flexion/extensi
on,
abduction/addu
ction, and
circumduction.
Gliding Joints
• Almost always
small
• Flat articular
surfaces so one
bone slides on
another bone with
minimal axis of
rotation, if any
• Adjacent
vertebrae, carpals,
and tarsals
Saddle Joints
• Multiaxial –
movement in 3 or
more directions,
abduction/adduction
, opposition and
reposition
• Opposing articular
surfaces resemble
saddles, both have
concave and
convex surfaces
• Carpometacarpal
joint of thumb
Ball and Socket Joints
• Multiaxial Flexion,
extension, medial
(internal) rotation,
lateral (external)
rotation, abduction,
adduction, and
circumduction
• Globelike head of
one bone fits into
the cuplike concavity
of the other
• Most freely moving
joint of all, allowing
movement in almost
infinite number of
directions
• Shoulder and hip
The Knee