The Skeletal System

The Skeletal System

1. Is made up of two parts

   • The Axial Skeleton
     • which consists of 80 bones along the midline of the body.
   • The Appendeciular
     • which consists of 126 bones that make up our limbs.
       • Bones themselves are categorized into five groups called
         • the Long Bone
           • an example being the humerus or femur.
         • the Short Bone
           • Such as our fingers (phalanges).
         • the Sesamoid Bone
           • like our knee cap aka Patella.
         • the Irregular Bone
           • such as those that make up our spine.
         • the Flat Bone
           • which is the type of bone our skulls are.
         • But what allows bones to move when muscles pull on them?
           • They move because of Joints. Humans have three types called:
             • Fibrous
               • which are unable to move.
             • Cartilagenous
               • Allow for slight movement, found within the spine.
             • Synovial; which there are six kinds of.
               • Hinge Joint
                 • an example of this would be the elbow (the humerus and ulna)
               • Ball and Socket joint
                 • an example of this would be the hip or shoulder joints
               • Gliding joint
                 • which are found within the tarsals and carpals, in our feet and hands.
               • Pivot joint
                 • an example of this would be the joint between the atlas and axis.
               • Saddle Joint
                 • which is found in the thumb
               • Ellipsoid joint
                 • which is found in the wrist

2. What are the types of injuries that can happen to the skeletal system?

   • Bones experience fractures which are divided into three types called:
     • Simple fractures
       • these are breaks on the surface of the bone while it is intact.
         • an example would be stress fractures (over repeated use) or hairline fractures.
     • Compound fractures
       • these happen when the bone is split into two pieces.
         • for example breaking your femur in half.
     • Comminuted fractures
       • which occur when the bone, or a part, is shattered.
         • this happens commonly during major car accidents.
     • Bones are also prone to disease such as osteoporosis.
       • This is a degenerative condition that causes bones to become fragile and brittle.
         • Women are more prone to this then men are but
           • it can be combated with a balanced diet rich in calcium, weight bearing exercise, a healthy lifestyle (no smoking etc.).
   • Joints experience different types of injuries called:
     • Cartilage Damage.
       • Cartilage is what reduces the damage bones would take while they move in their joints.
         • This begins to wear out over our life span, but can also happen quickly causing sharp pains within the joint.
     • Sprains.
       • This occurs when the ligaments holding bones are overstretched.
         • First degree means that only a few fibres were overstretched.
         • Second degree means some fibres in the ligament tore.
         • Third degree means the ligament is almost completely torn.
     • Dislocations and Seperations.
       • Dislocations occur when a bone leaves its joint.
       • Seperations occur when ligaments holding bones together are torn.

3. How do muscles attach to bone?

   • Muscles attach on bones by way of tendons or attaching to the surface of the bone. Not to be confused with ligaments which hold bones together
     • The place where a muscle attaches to the bone is known as a landmark