• 206 total bones

  1. axial skeleton

     1. 80 bones

     2. along central axis

  2. appendicular skeleton

     1. 126 bones

• 4 main types of bones

1. Long bones

   1. greater in length than width

   2. standard example

   3. slightly curved

   4. majority of the bone is compact bone (tough)

   5. Ex: humerus, radius, ulna, femur, tibia, fibula

2. Short bones

   1. typically cubish in shape

   2. Ex: carpals

3. Flat bones

   1. two flat compact bones and spongy bone in the middle

   2. Ex: sternum, scapula, ilium

4. Irregular bones

   1. unique/complex shapes

   2. Ex: mandible, vertebrae, ishium

Axial Skeleton

Skull

• Purpose - protection of the brain

• Sutures - immovable joints between parts of the skulll

  • not fully developed at birth

    • soft spots - fontanels

  1. coronal suture

  2. sagittal suture

  3. lambdoidal suture

  4. fronto-nasal suture

1. Cranium

2. Facial bones

Cranium

• Total # - 8

• Frontal bone

  • makes forehead

  • roof of the orbit (eyesocket)

  • 1 of 3 bones that are the strongest bone of the body

    • we face the things we interact with (including dangerous ones) so protection of the brain

• Parietal bones

  • 2 of them

  • make up the largest portion of the cranium

• Temporal bones

  • 2 of them

  • on the sides

  • hole in the side - external auditory meatus

  • Mastoid Process (right behind ear and goes to sternum)

  • styloid process

    • looks like a small stylus

    • important for eating, talking, etc (the tongue)

• Occiptial bone

  • foramen Magnum - big hole in the back of the head where the spinal cord passes through

• Sphenoid bone

  • keystone of the cranium

    • touches every other bone of the cranium

  • behind the temple and stretches across the base of the skull

• Ethmoid bone (won’t have to label)

  • triangular shape the connected the septum to the back of the head

Facial Bones

• grows until around 16

• Nasal bones

  • 2 of these

  • bridge of the nose

• Maxilla

  • 2 of these

  • keystone of the face

    • touches every other bone of the face except the mandible

  • sinus

• Zygomatic

  • cheekbones

• Mandible

  • only moveable bone of the skull

  • strongest of the facial bones, but easiest to break (cause its free-moving)

    • only attached on the temporal bone

  • sockets for teeth

• Lacrimal bone

  • smallest bone of the face

  • right inside the orbit

  • hole inside for tearducts

• Palatine

  • L-shaped

  • roof of the mouth

  • helps with swallowing

• Inferior nasal conchae

  • important for air circulation

    • warms waves

  • inferior and superior shelves

• Vomer

  • base of the septum

  • separates nostrils into 2

    • need 2 nostrils just in case 1 doesn’t work

• Hyoid bone

  • attached to tongue

  • styloid process suspends it (two connected by ligaments)

  • freefloating bone

Vertebral Column

• 40% of height

• made up of

  • vertebrae

    • adult - 26, baby - 35

  • intervertebral discs

    • made of cartilage

      • provides cushion

    • over time, spine compresses and people can shrink

• Purpose:

  • protects spinal cord

  • supports the head

  • gives flexibility

1. Cervical - 7

   1. first one - atlas

   2. second one - axis

      1. provides rotation

2. Thoracic - 12

   1. 1 for each seat of ribs

3. Lumbar - 5

4. Sacrum - 5 fused into 1

   1. born with 5 separate vertebrae but fuse

5. Coccyx - 3 or 4 fused into 1

• Disorders

  • scolisis

    • uneven lateral curvature

  • Lordosis

    • normally in lumbar

    • pregnant females

    • people with a big belly

  • Kyphosis

    • hunchback

    • commonly in thoracic or cervical

    • people with bad postue

Sternum

• flat bone

• typically 6 inches long

• 3 different parts

  1. Menubrum

  2. Body

  3. xiphoid process

• one of 3 bones that could be strongest

  • strength comes from flexibility

Costals

• ribs

• Purpose:

  • to protect ribs, lungs, heart, liver

• coastal cartilage

  • connects ribs to sternum

  • makes ribs flexible

• true ribs - 1-7

  • have direct connection to sternum

• false ribs - 8-12

  • no direct connection to sternum

  • share a cartilage

  • floating ribs - last 2 pair (11, 12)

    • protects adrenal gland

Appendicular Skeleton

Pectoral Girdle

• Clavicle

  • commmonly known as collarbone

  • very curved

  • easy to break

• Scapula

  • shoulder blade

  • sits between ribs 2 and 7

  • 3 parts

    1. acromion process

       1. shelf

    2. corarcoid process

       1. where the pectorals attach

    3. Glenoid cavity

       1. space inbetween

       2. Rotator cuff muscles here

Attached to Pectoral Girdle

• Humerus

  • attached to pectoral girdle

  • longest and strongest bone of the upper limbs

• Radius

  • shorter of the two (ulna and radius)

  • on the thumb side

  • bicep attached here

• Ulna

  • longer of the two

  • pinky side

• Carpals

  • 6 in each hand

  • proximal row - closest to your body

  • distal row - farthest from the body

  • named for shape

  • Capral tunnel - when ligaments swell and press on nerves

• Metacarpals

  • hand bones

  • long bones

  • numbered 1-5

• Phalanges

  • furthest - distal

  • middle - medial

  • closest - proximal

  • thumb is missing medial

  • 14 phalanges, 28 total in upper body

  • thumb = pollex

Pelvic Girdle

• attaches to sacrum

• Ilium

  • largest of the pelvic bones

  • flat bone

  • lots of red bone marrow

• Ischium

  • middle part/butt bone

• Pubis/Pubic bone

  • pubic symphisis - cartilage between the pubic bone

    • gives ability stretch/flexiblity

      • needed for childbirth and walking

Attached to Pelvic Girdle

• Femur

  • 1 of 3 strongest bone

  • largest, heaviest bone

  • one of the more frequently broken bones

    • broken at the top in old people

• Patella

  • free-floating

  • helps knee function properly

• Tibia

  • strong

  • shin-bone

  • weight-bearing bone

  • common to have tiny stress-fractures

  • shin splints - muscle is detaching from bone

• Fibula

  • longer of the two

  • provides support

    • esp when off-balance

• Tarsals

  • calcaneous - heel bone

    • strong

  • talus - ankle bone

• Metatarsals

  • 10 total, 5 for each foot

  • numbered 1-5

• Phalanges

  • distal, medial, proximial

  • Big toe - hallux

Difference Between Women and Males

• pelvis in women are wider compared to the ribs

  • Women - 1:1

  • Males - 1.2:1

• hips in women are shorter and males are taller pelvis

  • easier travel through birth canal

• Male bones are thicker than female bones

• Males have bigger joints

• The female coccyx points straight down and the male coccyx curved in

• Female has a more circular pelvic girdle center/hole (male is more heart shaped)

Physiology of Bones

• Bones are strong but lightweight (hollow inside)

• dynamic - bones are constantly changing

• Ostology - study of bones

• Functions:

  1. Support

     1. provide framework

  2. Assists in movement

  3. Protection

     1. Ex: cranium protects

  4. Production of red blood cells

  5. Energy storage (yellow bone marrow)

• Parts of a Long Bone:

  • diaphysis - main portion of the bone

  • metaphysis - where long Bone growth in length happens

  • epiphyisis - ends of the bone

    • made of spongy bone

      • red bone marrow inside of spongy bone - makes RBC

  • articular cartilage

  • medullary cavity

  • periosteum

    • 2 layers

      1. fiborous layer (outer)

         1. dense, irregular connective tissue

      2. osteogenic

         1. inner

Histology

• 25% water

• 25% protein

• 50% minerals

Minerals

• lots of different compounds that make up mineral salts/bone matrices

• Ex:

  • Tricalcium Phosphate

  • Calcium Carbonate (limestone)

  • Magnesium Hydroxide

• bunch of different fluorides, sulfates, etc

• When the minerals in the bone hardens? - crystallization

  • also called calcification/mineralization

Ossification

• formation of bone

  • called calcification/mineralization/crystallization

• 2 types of ossification

  1. intramebraneous ossification

     1. happens in babies where bone is continuing to form

     2. when bone forms from within the bone and spreads out

        1. when bone connects = suture

  2. Endochondral ossification

     1. hyaline cartilage -

     2. bone that grows from the growth plate/metaphysis/epithesial line/epithesial plate/epithesial disk (all mean same thing)

        1. interstitial growth - growth in length

     3. apositional growth - growth in width/thickness

        1. occurs at periosteum

1. osteogrogenitor

   1. stem cells of bone

   2. first cells (precursors)

   3. can become any of the other cells

   4. can do mitosis

   5. found on surface of bone under skin of the bone (periosteum)

2. osteoblasts

   1. cells that actually form bone material

   2. secrete collagen and mineral salts into all of the surrounded materials and then isolate selves and lose mitosis ability (becoming osteocytes)

3. Osteocytes

   1. mature bone cell

   2. come from osteoblasts

   3. can do all regular functions of other cells

4. Osteoclasts

   1. destroy bone tissue - resporportion of bone tissue

   2. when bones broken, this gets rid of waste leaving room for repair

Bone Tissue

• Compact bone

  • mostly diaphysis and outside epiphysis

  • support and protection

    • tough, hard stuff

  • made up of osteocytes

  • Haversiansystems (underlined = main parts)

    • 50% mineral salts

    • gets nutrients through central canal

    • concentric lamellac

      • layers of crystallized bone

        • inside of layers are lots of little spaces called lacunae

          • single cell called osteocytes inside of lacunae

    • canaliculi - canals the connect different parts

• Spongy Bone

  • found in epiphysis of long bones and middle/center of flat bones

  • filled with red bone marrow than makes RBC

  • trabeculae - tiny little bone that have holes filled with red bone marrow

Bone Growth

Long Bone growth

• growth in length - epithesial line/growth plate

  • special kind of cartilage - hyaline cartilage

    • 4 zones/stages

      1. zone of resting cartilage

         1. chrondrocites - cartilage cells

         2. end closest to epiphysis filled with scattered chondrocites

            1. serve as glue, don’t function in bone growth

               1. keep epyhisis and diaphysis attached

      2. zone of proliferating cartilage

         1. multiplying cartilage cells

         2. as more cells, epiphysis and diaphysis grow apart

      3. zone of hypertrophic/maturing cartilage

         1. areas of cartilage thicken up

      4. zone of calcified cartilage

         1. new, oddly formed mineral salts crystalizing into bone

         2. becomes apart of bone material

  • growth plate is only place where length growth takes place

    • when damage to growth plate - stops growing

  • know bone is done growing when all zones except zone 1 are straight bone

• typically last bone to stop growing - clavicle

Stress on Bone

• Wolff’s law - a bone grows or remodels in response to forces/demands placed upon it

  • Observations supporting:

    • long bones typically thickest where their undeneath the most stress

    • curved bones thickest where likeliest to buckle

    • trabeculae form along lines of stress

    • large, bony projections occur where heavy, active muscles attach

Bone Breaks

• Fractures classified

  1. position of bone ends after fracture

  2. empleteness of break

  3. orientation of bone to long axis

  4. whether or not bones ends penetrate the skin