The Skeletal System

In this class, you were introduced with the anatomy of skeletal system followed with the physiology of the system. Below are guides and videos links to help with your revisions. Remember, this guide must be used along side of your lecture notes.

 

First, you were introduced with terminology pertaining to the anatomical position. By now, you must be able to use terms:

  • medial – which is location closer to mid-line
  • lateral – which is location away from mid-line
  • proximal – location close to origin or joint
  • distal – location away from origin or joint
  • anterior – which is the opposite of posterior/dorsal
  • dorsal – which is opposite of ventral/anterior
  • superior – which is opposite of inferior

 

Here is an example use of anatomical terminology

 

Learning the skeletal system

The skeletal bones can be identified through four basic shapes. You have to know examples of bones that falls under each of these shapes:

  1. Long bones
  2. Short bones
  3. Irregular bones, and
  4. Flat bone

 

Bones carry certain characters that helps in their functions at providing support, for motion and protection. Again, you are recommended to understand the meaning of these terms and their appropriate examples. Among the characters of bone are:

  1. Fossa
  2. Sinus
  3. Foramen
  4. Meatus
  5. Condyles

 

The skeletal system can be systematically divided into two divisions. You have to know the example of bones for every components that make up this divisions.

  1. The axial skeleton – consists of the skull, hyaoid, sternum and ribs, and vertebral column
  2. The appendicular skeleton – consists of the upper extremities girdle (pectoral girdle) and lower extremities girdle (pelvic girdle)

 

The following is a summary of what we have covered so far

 

Relation of structure and function

From knowing the general features and functions of bones, you were introduced with examples of pathologies of the skeletal system.Through this, you should be able to appreciate how the structure of bones fit its functions. Among the skeletal pathologies that were introduced to you were:

  • Abnormalities of the vertebral column
  • Slipped disc/herniated disc
  • Osteoarthritis – which is different from rheumatoid arthritis
  • Damages to the calvarium (skullcap) and the face

 

The microscopic structure of the bones

Apart from gross anatomy of the skeletal system, you were also introduced to the microscopic structure of the bones. These microscopic details helps you understand how bones grow, heals from injury, or function as calcium storage and bone marrow production. Aspects that you must understand from microscopic anatomy of the bones are:

  1. The two types of bone tissues – spongy bone versus compact/dense  bone.
  2. Osteaon – as the functional unit of compact bone, and
  3. Types of bone cells – osteogenic cells, osteoblasts, osteocytes, and osteoclasts

 

Here is an excellent video on the microscopic structure of the bone

 

Here is an summary of how none repair and modelling occurs

 

Joint and movements

Finally, we end the topics with joints and movements. You are must be able to recall the four types of joints and where they are located:

  1. Bony joints / synostosis
  2. Fibrous joints
  3. Cartilaginous joints
  4. Synovial joints – which can be divided into ball and socket, condylar/ellipsoidal, saddle, plane/gliding, hinge, pivot.

 

The movement of the skeletal system happens at three different movement planes:-

  1. Frontal/coronal plane
  2. Sagittal plane, and
  3. Transverse plane

You should be able to recall and demonstrate movements on the above planes such as:

  • flexion and hyperflexion
  • extension and hyperextension
  • abduction and hyperabduction
  • adduction and hyperadduction
  • protraction versus retraction
  • circumduction versus rotation
  • supination versus pronation
  • dorsiflexion versus plantarflexion

 

Here is an example of movement on the three planes of movement

 

The next posting will touches on the muscle system.

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