skeletal system ALH 120

2 main parts of skeleton

1. Axial

2. Appendicular

Appendicular skeleton is made up of...

Limbs and girdles that are attached to the axial skeleton

Axial skeleton is made up of

Bones that form longitudinal axis of the body

5 Bone functions

1. Support

2. Protection

3. Movement

4. Storage

5. Blood cell formation

Support function of bone

1. Framework of body

2. Cradle soft organs

Protection function of bone

Protect soft organs (ex. rib cage, skull)

Movement function of bone

1. Attachment point for muscles

2. contraction of muscle = movement of bone

Storage function of bone

1. Calcium

2. Phosphorus

3. Fat in bone marrow

Blood cell formation function of bone

1. Blood cell formation

2. Blood cells form in marrow cavities

Hormone function in bone

Control movement of calcium to and from bones

Hematopoiesis

Formation of blood cells in the marrow cavities

Adult skeleton bone count

206 bones

2 main bone types

1. Compact

2. Spongy

Compact bone

1. Homogenous in nature

2. Appears dense and smooth

Spongy bone

1. Composed of needle-like pieces of bone

2. Have open spaces

4 bone shapes

1. Long

2. Short

3. Flat

4. Irregular

Long bone

1. Longer than they are wide

2. Compact

3. Make up limps

Short bone

1. Cube shaped

2. Spongy

3. (Ex.) Patella

Flat bone

1. Thin and flat

2. Spongy bone between 2 layers of compact

3. (Ex.) Sternum

Irregular bone

1. Any that is not 1 of the other 3

2. (Ex.) Vertebrae, facial bones

Diaphysis

1. Shaft of long bone

2. Majority of bone length

Periosteum

Connective tissue covering bone

Sharpey's fibers

Connective tissue fibers attaching periosteum to bone

Epiphysis

Thin layer of compact bone with spongy bone center

Articular cartilage

Covers the epiphysis

Epiphyseal line

1. Thin line in adult long bone

2. Remnant of Epiphyseal plate

Epiphyseal plate

Responsible for length growth in childhood

Endosteum

covering for the inner bone shaft

Medullary cavity

1. Center cavity of bone

2. Serves as fat storage (Adults= yellow marrow, Children= red marrow)

Red marrow location for adult

1. Spongy bone in flat bones

2. Epiphysis of some long bones

Osteocytes

1. Mature bone cells

2. Located in Lacunae

Lacunae

1. Small cavities

2. House osteocytes

3. Arranged in circles around Haversian canal

Haversian canal

1. Central canal in bone

2. Travel length of long bone

Osteon (Haversian system)

Complex consisting of a...

1. Haversian canal

2. Matrix

Canaliculi

1. Small canals

2. Radiate outward from Haversian canal

3. Provide nutrient system for entire bone

Volkmann's canals

1. AKA perforating canals

2. Complete nutrient system

3. Link between outside and inside of bone

4. Run cross-sectionally

Lamellae

1. Rings of hard calcified matrix

2. Surround Haversian canal

Ossification

1. Hyaline cartilage used as a map

2. Bone growth

3. Cartilage is replaced by bone

2 phases of ossification

1. Osteoblasts

2. Osteoclasts

Osteoblasts

Bone building cells

Osteoclasts

1. Bone destroying cells

2. Break down bone matrix releasing calcium into blood

Articular cartilage (Hyaline)

Remaining cartilage after completion of bone growth process

Widening bone growth

1. Osteoblastic activity in the periosteum adding new bone to face of diaphysis

2. Controlled by hormones

3. Completed in adolescence

2 main factors effecting bone

1. Calcium level in blood

2. Stress placed on bone

Hypercalcemia

Excess calcium in blood

Fracture

Results from exceeding bone strength

2 classification of fractures

1. Open

2. Closed

Closed fracture

Bone is contained in the skin

Open fracture

Bone penetrates the skin

Reduction

1. Alignment of the ends of a broken bone

2. Fracture treatment

Comminuted fracture

Bone breaks into many fragments

Compression fracture

Bone is crushed

Depressed fracture

Broken bone portion is pushed inward

Impacted fracture

Broken bone ends are forced into each other

Spiral fracture

Excessive twisting forces causing broken bone

Greenstick fracture

Incomplete break

4 phases of bone repair

1. Hematoma formation

2. Fibrocartilage callus forms

3. Bony callus forms

4. Bone remodeling occurs

Hematoma formation

Ruptured blood vessels in broken bone cause blood-filled swelling

Fibrocartilage callus

1. Granulation tissue formation (growth of new capillaries

2. Occurs in hematoma

3. Phagocytes dispose of dead tissue

4. Repair tissue holds bones together (splint)

Repair tissue in fibrocartilage callus

1. Cartilage matrix

2. Bony matrix

3. Collagen

Bony callus

1. Osteoblasts and osteoclasts populate area

2. Fibrocartilage callus replaced

3. Primarily spongy bone

Bone remodeling

1. Weeks to months

2. In response to mechanical stress placed on it

3. Continues until formation of strong permanent patch

3 parts of axial skeleton

1. Skull

2. Vertebral column

3. Bony thorax

2 sets bone sets of skull

1. Cranium

2. Facial

Sutures

Joins bones together

8 cranial bones

1. Front

2. Occipital

3. Ethmoid

4. Sphenoid

5/6. Parietal (R,L)

7/8. Temporal (R,L)

14 facial bones

1/2. Maxilla

3/4. Palatine

5/6. Lacrimal

7/8. Zygomatic

9/10. Nasal

11. Vomer

12/13. Inferior nasal conchae

14. Mandible

Paranasal sinuses

1. Hollow portions of bones surrounding nasal cavity

2. Functions... Lighten skull, Amplify sounds made as we speak

Hyoid bone

1. Related to mandible and temporal bones

2. Does not articulate with another bone

3. Movable base for tongue

4. Aids swallowing and speech

Vertebral column

1. Axial support

2. Extends from skull to pelvis

26 vertebral bones

7 cervical

12 Thoracic

5 lumbar

Sacrum

Coccyx

Sacrum

Formed by fusion of 5 vertebrae

Coccyx

Formed by fusion of 3-5 vertebrae

Intervertebral discs

Separates vertebral bones

Primary curvatures

1. Spinal curvatures of thoracic and sacral region

2. Present from birth

3. Form a C-shaped curvature in newborn

Secondary curvatures

1. Spinal curvatures of cervical and lumbar region

2. Develop after birth

3. Form an S-shaped curvature in adults

6 parts of vertebra

1. Body (centrum)

2. Vertebral arch

3. Vertebral foramen

4. Traverse processes

5. Spinous process

6. Superior/ inferior articular process

2 parts of Vertebral arch

1. Pedicle

2. Lamina

Thoracic cage (Bony thorax)

Protects organs of thoracic cavity

3 parts of thoracic cage

1. Sternum

2. Ribs

3. Thoracic vertebrae

3 types of ribs

1. True ribs (1-7 pairs)

2. False ribs (8-12 pairs)

3. Floating ribs (11-12 pairs

3 parts of appendicular skeleton

1. Limbs (appendages)

2. Pectoral girdle

3. Pelvic girdle

Appendicular skeleton bone count

126 bones

2 bones of pectoral girdle

1. Clavicle

2. Scapula

Pectoral girdle

1. Attach upper limbs to axial skeleton

2. Light, poorly reinforced girdle

3. Allows exceptional upper limb flexibility

Humerus

1. Forms the arm

2. Single bone

2 bones of the forearm

1. Ulna= medial

2. Radius= lateral

3 bones of the hand

1. Carpals= wrist

2. Metacarpals= palms

3. Phalanges= fingers/thumb

carpals

8 bones arranged in two rows of 4 per hand

Phalanges

1. 14 per hand

2. each finger has 3

3. each thumb has 2

Pelvic girdle

Formed by 2 coxal bones and sacrum

3 fused bones of pelvic girdle

1. Ilium

2. Ischium

3. Pubis

Pelvis

1. Two coxal bones, sacrum, coccyx

2. Supports weight of entire upper body

3. Protects organs

3 organs protected by pelvis

1. Reproductive

2. Urinary

3. Part of large intestine

Female pelvis

1. Inlet and outlet is larger

2. More circular

3. Shallower

4. Lighter and thinner

5. Ilia flare laterally

6. Sacrum is shorter and less curved

7. Ischial spines are shorter and farther apart

8. Pubic arch is more rounded

Femur

1. Thigh bone

2. Heaviest and strongest bone in body

2 bones of the lower leg

1. Tibia

2. Fibula

Tibia

1. Shin bone

2. Larger and medially oriented

Fibula

1. Thin and stick like

2. Lateral to tibia

3 bones of the foot

1. Tarsals= 7 bones

2. Metatarsals= 5 bones (sole of foot)

3. Phalanges= 14 bones (toes)