IB SEHS Chapter One

Musculoskeletal Anatomy

Chapter One Objectives

By the end of this chapter, students should be able to:

1. Describe the anatomy and function of the axial and appendicular skeleton.

2. Identify the four types of bones.

3. Draw and identify the different parts of a long bone.

4. Outline the functions of cartilage, tendons, and ligaments.

5. Define a joint and distinguish between different types of joint in relation to how much movement is possible.

6. Outline the features of a synovial joint.

Chapter One Objectives continued…

7. Identify and describe the different types of synovial joints.

8. Distinguish between the different types of muscle.

9. Outline the general characteristics that are common to muscle tissue.

10. Describe the structure of skeletal muscle.

11. Define what the origin and insertion of a muscle is and identify these for a selection of muscles.

12. Use anatomical terminology to describe the location of bones and muscles.

Musculoskeletal System

Musculoskeletal System – the combination of the skeletal system and the muscular system.

(ex. Cardiorespiratory system – Heart and lungs)

Skeletal system – is comprised of the bones and joints.

Muscular system – is comprised of the muscles.

The musculoskeletal system plays a vital role in allowing us to do all the movements needed for daily life.

Anatomical Terminology

1. Inferior – below or further away from the head.

2. Superior – above or nearer to the head.

3. Proximal – nearer to where a limb attaches to the body.

4. Distal – further away from where a limb attaches to the body.

5. Posterior – behind or nearer to the back.

Anatomical Terminology

6. Anterior – in front of or nearer to the front.

7. Internal – located inside or further away from the surface.

8. External – located on or near the surface.

9. Lateral – further away from the midline of the body.

10. Medial - closer to the midline of the body.

Skeletal System

*Made up of bones, cartilage, ligaments, and joints

*Accounts for approximately 20% of our body weight

*SS roughly determines the shape and size of the body

*There are 206 bones in the skeletal system and is divided into two parts:

1. Axial Skeletal System

2. Appendicular Skeletal System

Function of the Skeletal System

1. Protection of vital organs.

2. Support and maintenance of posture.

3. Providing attachment points for the muscles.

4. Storage and release of minerals such as calcium and phosphorus.

5. Blood cell production or haemopoiesis.

6. Storage of energy.

Axial System

*Contains 80 bones

*Includes: skull, ribs, sternum, and vertebral column

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Axial SkeletonDescription

The skull sits on top of the vertebral column and is divided into the cranium and the face.

It protects the brain, bones of the skull, the eyes, ears and contains the teeth.

Axial SystemDescription

*Vertebral Column – contains 33 vertebrae and are all stacked on top of each other to form the column.

*The VC is strong and flexible. It bends anteriorly (forward), posteriorly (backwards), laterally (sideways), and rotates.

*It is divided into sections:

1. Cervical - 7

2. Thoracic - 12

3. Lumbar – 5

4. Sacral – 5

5. Coccygeal - 4

Cervical Vertebrae

Cervical Vertebrae – are the smallest and have more movement than the thoracic and lumbar vertebrae.

Thoracic Vertebrae – are less mobile because the ribs attach to the sides of each vertebrae and therefore restrict movement.

Lumbar Vertebrae – are the biggest and strongest as they play a major role in weight bearing and therefore absorb high compression loads.

Sacral Vertebrae – transmit weight from the body to the pelvis and the legs.

Appendicular System

1. Appendicular Skeleton is involved in movement.2. It is made up of:

*Pectoral (shoulder girdle) which is formed by the clavicles an scapulae.

*The clavicle articulates with the sternum on the anterior side. This is the only bony connection between the pectoral girdle and the axial skeleton.

Features of the Vertebrae

1. Body – the largest and flattest part.

2. Vertebral Foramen – is the hole towards the back of each vertebrae. As the vertebrae line up a canal is formed. This canal allows the spinal cord to run through.

3. There is a gap on each side of the vertebrae which allows nerves to emerge from the spinal cord. Each spinal nerve innervates a different area of the bod.

Features of the Vertebrae

Bodies of vertebrae do not touch each other. Instead they are separated by an intervertebral disc. These discs have a tough outer ring of fibrocartilage called – Annulus Fibrosus.

Nucleus Pulposus – is a soft, gel like, elastic structure in the middle of each disc.

Features of the Vertebrae

These discs make the vertebral column more flexible as they flatten out and bulge to the sides when they are compressed making them important shock absorbers.

Please now refer to pages 27, 28, and 29 in “The Anatomy Coloring Book”