1. Skeletal System 206 BONES IN THE BODY
While the average adult has 206 bones, some people have an extra pair of ribs.
A baby’s skeleton has over 300 bones; some fuse as they grow.
More than half the body’s bones are in the hands and feet.
Bone is five times stronger than a steel bar of the same weight.
Females usually have smaller, lighter skeletons than males

2. FUNCTIONS Supports body and provides shape. Protects internal organs.
Movement and anchorage of muscles.
Mineral storage. (Calcium and phorphorus) (99% of the body’s calcium is in the bones and teeth)
Hemopoiesis

3. BONE FORMATION
Embryo skeleton starts as osteoblasts (primitive embryonic cells) – then change to cartilage.
At 8 weeks, OSSIFICATION begins. (Mineral matter begins to replace cartilage)
Infant bones soft because ossification not complete at birth.
FONTANEL - Soft spot on baby’s head (disappear at one year of age)

4. STRUCTURE OF LONG BONE DIAPHYSIS – shaft
EPIPHYSES – ends (near the ends of long bones is the epiphyseal plate – the site where bones lengthen as children grow)
MEDULLARY CAVITY – center of shaft, filled with yellow bone marrow, which is mostly fat cells, also cells that form white blood cells.
ENDOSTEUM – lines marrow cavity

5. Shaft is made of COMPACT BONE – made up of tiny tubules of bone (osteons) forms strong outer shell(the body’s second hardest material after enamel)
Ends are SPONGY BONE. Ends contain red marrow where red blood cells are made.
(75% of the body’s bone is compact and 25% is spongy bone)
PERIOSTEUM – tough, outside covering of bone – contains blood vessels, lymph

6. AXIAL & APPENDICULAR SKELETON
AXIAL – skull, spinal column, ribs, sternum, hyoid
APPENDICULAR – shoulder girdle, arms, pelvis, legs

7. Skull 1 frontal 2 parietal 2 temporal 1 occipital 1 ethmoid 1 sphenoid
2 nasal
1 vomer
2 inferior concha
2 maxilla
2 lacrimal
2 zygomatic
2 palatine
1 mandible
1 sphenoid

8. SKULL FACTS The skull contains 22 bones
Eight bones form the cranial vault and support the brain
The face is made up of 14 bones
The skull houses the tiny bones (ossicles of the middle ear – three on each side

9. Spine – Vertebral Column
ENCLOSES THE SPINAL CORD
Vertebrae – separated by pads of cartilage =
intervertebral discs-have a tough, flexible outer case & a soft, jelly-like center, & cushion & protect the vertebrae)
Cervical vertebrae (7)
Thoracic vertebrae (12)
Lumbar vertebrae (5)
Sacrum
Coccyx

10. SPINAL FACTS
A human neck has the same number of vertebrae as a giraffe
Spinous processes form knobbles that protrude under the skin covering the spine.
Intervertebral disks act as shock absorbers to prevent damage from sudden jolts.
Lumbar vertebrae are the strongest – they must support the weight of the upper body

11. Ribs and Sternum
Sternum divided into 3 parts – bottom tip is XIPHOID PROCESS
12 pairs of ribs
first 7 are true ribs – connected to sternum by cartilage
next 3 are false ribs – cartilage connects them to 7th rib (not sternum)
next 2 are floating

12. Appendicular Skeleton
clavicle – collar bone
scapula – shoulder blade
humerus – upper arm
radius and ulna – lower arm
carpals – wrist bones – held together by ligaments
metacarpals – hand bones

13. phalanges – fingers
pelvis – 3 bones (ilium, ischium, and pubis)
femur – upper leg, longest and strongest bone in body
tibia and fibula – lower leg
patella – kneecap

14. tarsal bones – ankle
calcaneus – heel bone
metatarsals – foot bones

15. JOINTS
Joints are points of contact between 2 bones – classified according to movement:
SYNOVIAL FLUID – lubricating substance in joints
BALL AND SOCKET JOINT – bone with ball-shaped head fits into concave socket of 2nd bone. Shoulders and hips. (has the greatest range of motion)
HINGE JOINTS – move in one direction or plane. Knees, elbows, outer joints of fingers.

16. PIVOT JOINT – those with an extension rotate on a 2nd, arch shaped bone. Radius and ulna, atlas and axis.
GLIDING JOINTS – flat surfaces glide across each other. Vertebrae of spine.
SUTURE – immovable joint

17. JOINT FACTS The knee is the body’s largest joint
The smallest joints link the three bones in the middle ear
Most large, movable joints are lubricated by synovial fluid
Muscles around the joint contract to produce movement.

18. Types of Motion
FLEXION – the act of bending a limb or decreasing the angle between two bones
EXTENSION – act of increasing the angle between 2 bones which results in straightening motion
ABDUCTION – away from midline
ADDUCTION – movement toward midline

19. ROTATION – allows a bone to move around one central axis ex: pivot to say no
CIRCUMDUCTION – circular movement at a joint
PRONATION – turning palm of hand downward
SUPINATION – turning palm of hand upward or lying on back

20. Disorders of the Bones and Joints
FRACTURE – a break
TREATED BY:
CLOSED REDUCTION – cast or splint applied
OPEN REDUCTION – surgical intervention with devices such as wires, metal plates or screws to hold the bones in alignment (internal fixation)
TRACTION – pulling force used to hold the bones in place – used for fractures of long bones

21. GREENSTICK – in children, bone bent and splintered but never completely separates
DISLOCATION – bone displaced from proper position in joint
SPRAIN – sudden or unusual motion, ligaments torn but joint not dislocated
STRAIN – overstretching or tearing muscle

22. SIMPLE FRACTURE
COMPOUND FRACTURE
COMMINUTED FRACTURE

23. Diseases of Bones ARTHRITIS – inflammation of one or more joints
(leads to pain swelling, and deformity – at least 20 different types)
OSTEOPOROSIS – bones become brittle due to lack of calcium absorption. Usually occurs after menopause

24. ABNORMAL CURVATURES OF THE SPINE:
KYPHOSIS – hunchback
LORDOSIS – swayback
SCOLIOSIS – lateral curvature

25. Diagnosis and Treatment:
ARTHROSCOPY – examination into joint using arthroscope with fiber