The Musculoskeletal System

The Musculoskeletal System

The third main body system we will look at is the Musculoskeletal system. This system can be broken down into two smaller sections:-

  1. The Skeletal system - Consisting of the bones.

  2. The Muscular system - Consisting of the muscles and tendons.

The Skeletal System

The diagram below shows some the main bones of the Skeletal system:-

The Skeletal system has two main functions:-

  1. Protection - Bone is a very hard and strong material which is used to protect vulnerable organs of the body (e.g. the Skull protects the Brain).

  2. Movement - By giving the Muscular system a solid point to work from, bones are responsible for all movement of the body.

Composition of Bone

Bone is a living material within the body, constantly changing and growing. Bone consists of both organic and inorganic materials.

Bone is made from living cells and hard minerals such as Calcium. This makes bone a living substance.

A bone heated strongly in an oven becomes brittle. This is because the living cells will have been destroyed.

A bone placed in acid will become rubbery and flexible. This is because the hard minerals will have been removed.

Bone Structure

The diagram below shows the structure of a bone:-

Where :-

  1. Compact bone - Made of tightly packed bone cells, this hard layer is responsible for the bone's strength.

  2. Spongy bone - Made of loosely packed bone cells, this soft layer is responsible for the bone's flexibility.

  3. Bone marrow - Soft tissue filling the core of the bones, this bone marrow is responsible for the production of red blood cells.

Joints of the Body

In order for the body to move, the bones has to move past each other easily. Where bones need to move around each other, the bones are shaped in a special way to allow that movement, in the form of joints.

The diagram below shows the some of the main joint types within the human body:-


In medicine, a prosthesis is an artificial device that replaces a missing body part, which may be lost through trauma, disease, or a condition present at birth. Prostheses are intended either to restore the normal functions of the missing body part or for cosmetic reasons. These include the visible prosthetics on the outside of the body, such as artificial limbs or eyes, or inside the body such as replacement hips and other joints.

Below are some examples of Prostheses:-

Prosthetic joints within the body

Prosthetic lower leg

Prosthetic Eye

Child's Prosthetic Arm

Dental Implant

Types of Control

When the prosthesis is used to replace a functional part of a limb, such as a hand or arm there are three main methods of controlling that limb:-

  1. Passive - A Passive or Cosmetic prosthesis is designed with appearance in mind rather than controllability as they do not move. Advanced plastics and pigments uniquely matched to the patient's own skin tone allow a modern day prosthesis to take on an amazingly life-like appearance. Even details such as freckles, hair and fingerprints can be included, bringing the prosthesis to the point where it's nearly indistinguishable from the original missing arm or leg.

  2. Body-Powered - Body-powered prostheses are powered by the person's own body using a mechanical principle. The key component of this type of device is a body harness. Targeted movements of the shoulder girdle and torso control individual elements of the harness. Pull-release cables then activate the corresponding components of the prosthesis, for example to open the hand.

  3. Myoelectric - Myoelectric prostheses use the existing muscles in the remaining limb to control its functions. One or more sensors fabricated into the prosthetic socket receive electrical signals when the person intentionally engages specific muscles in remaining limb. Sensors relay information to a controller, which translates the data into commands for the electric motors and moves the joints in the prosthesis.

The video below shows a short documentary on the advances in modern Prosthetics:-

Advances in modern production techniques such as 3d printing have allowed prostheses to be made that combine function with aesthetic principles too. This allows the prostheses to appear very realistic, or to simply make them more enjoyable to wear for the user.

The images below show some aesthetically designed prostheses:-

Hyper-realistic Prosthetic Leg

Prosthetic Arms

3d printed Titanium leg

Case Study - Limbitless Solutions

Limbitless Solutions is a charitable organization which is part the University of Central Florida. They specialize in creating and donating personalized 3D-printed prosthetic arms for children.

Limbitless Solutions aim to empower confidence and increase accessibility in the limb difference community through art-infused bionics. They combine engineering and art to promote access and engagement in STEAM (science, technology, engineering, art, and math) education.

The video below shows a myoelectric prosthetic arm designed by Limbitless Solutions in the style of Iron Man for a child:-

Case Study - The Alternative Limb Project

The Alternative Limb Project was founded by Sophie de Oliveira Barata, using the unique medium of prosthetics to create highly stylised wearable art pieces.

Merging the latest technology with traditional crafts, Sophie’s creations explore themes of body image, modification, evolution and transhumanism, whilst promoting positive conversations around disability and celebrating body diversity

The video below shows a prosthetic arm designed by Sophie in the form of a Vine. This particular limb was created for the model and body confidence advocate Kelly Knox.

Born without her lower left arm, Kelly chooses not to use prosthetics as an aid, but as an accessory to express her personality and explore aspects of her identity:-

The completed piece, The Vine, is a botanical tentacle which contains 26 individual vertebrae that allow movement in the arm to be fluid and curve around objects.

The Vine is controlled by round sensors in Kelly’s shoes, which sit under her big toes. These sensors allow the Vine to move side to side and to curve. By pressing on the sensors with different pressure, Kelly can control the speed and direction of the Vine’s movement.

For more information on the project, click the link below:-

Prosthetics & Orthotics

Working in Prosthetics & Orthotics you would help people who need an artificial limb or a device to support or control part of their body.You would create devices which would give them greater independence and could hugely improve their quality of life,

Your work would assist people who find it physically difficult to move. You could work with people recovering from a stroke or who have rheumatoid arthritis, diabetes or cerebral palsy.

A prosthesis is a device that replaces a missing part of a person’s body. As a prosthetist, you would design and fit artificial limbs (prostheses) to replace limbs lost through amputation or which are missing at birth.

An orthosis is fitted to an existing part of the body. As an orthotist, you would design and fit surgical appliances (orthoses) such as braces, callipers, neck collars and splints. They support people’s limbs or the spine to relieve pain, help people move or prevent physical conditions getting worse. A person might wear the orthosis permanently or just use it temporarily.



A Career in Prosthetics & Orthotics

Salary: from £22,000 to £68,500 per year

Prosthetist working hours: shifts, including evenings and weekends, providing cover 24 hours a day, seven days a week (including public holidays).

Typical entry requirements: You’ll need to take a three or four year university degree to become an prosthetist or orthotist. In Scotland this course is only offered by Strathclyde University.

Entry requirements for university Highers (or equivalent) including Maths and either Biology, Physics or Chemistry at grade AAAB or AABBB.

Skills required:

  • Cooperating

  • Supporting

  • Verbal communication

  • Working with technology

  • Designing

  • Problem solving

  • Empathising

  • Social conscience

  • Taking initiative

  • Making decisions

Muscular System

To make bones move, they must be attached to a pair of muscles by strong tissue called Tendons. When a muscle contracts, it pulls the bone in that direction. The pair of muscles works in opposition to each other (when one contracts the other relaxes).

For example :-

  1. To bend your arm, your bicep must contract, while your tricep relaxes.

  2. To straighten your arm, your tricep must contract, while your bicep relaxes.

The diagram below shows parts of the Muscular system that allow the arms and legs to move, as well as an example of a tendon:-

Case Study - Robert the Bruce

The two sections of the Musculoskeletal system have a large effect on each other. The bones are pulled and stretched by the muscles, which leaves marks behind. These marks can be used to understand things about a person, even if only their skeleton remains.

An example of this process was performed on the skull of Robert the Bruce.

Robert the Bruce was the King of Scotland from 1306 to 1329. He is most famous for fighting the first war of Scottish Independence against England. His most famous victory was the Battle of Bannockburn near Stirling, where a small Scottish force led by the Bruce fought and defeated a much larger English army.

This campaign ultimately securing Scotland as an independent nation until the two crowns were unified together in 1707. This war was popularised in the the film Braveheart.

In 2016, scientists from the University of Glasgow completed a 3D computer facial reconstruction of Robert the Bruce. The process of facial reconstruction is shown below.

The image below shows a plaster cast of the skull thought to belong to Robert the Bruce:-

By using highly detailed laser scans of this plaster cast, a 3D model of the skull is created as shown below:-

All skulls show markings on them which can be used to identify where muscles and other soft tissues were attached, and as such can be used to develop an image of the tissues over the skull:-

By looking at artwork showing Robert the Bruce, as well as written descriptions, hair and eye colour as well as clothing can then be added to complete the reconstruction:-

The video below shows a news bulletin summarising the facial reconstruction of Robert the Bruce.


You would diagnose, prevent, treat and study illness by looking at cells and tissue samples from patients and dead bodies.

You would work with doctors, nurses and other medical staff.

Your work would play an important part in the diagnosis of disease. It would be your responsibility to make sure that patients get the right treatment as early as possible.

You could become a forensic pathologist, specialising in performing autopsies on dead bodies to discover the cause of death. You would try to find out whether people died accidentally or by suicide or murder. You may sometimes have to go to court to give evidence in criminal cases.

You could also work as a veterinary pathologist and study animal disease. In this case you would have to train as a vet before specialising in pathology.


Working as a Pathologist

A Career as a Pathologist

Salary: from £22,000 to £90,000 per year

Pathologist working hours: Monday to Friday between 9am and 5pm. You may be expected to work occasional weekends and night shifts in emergencies. There are often part-time hours and opportunities for flexible working.

Typical entry requirements: You'll need to become a doctor and specialise in pathology as your career progresses. Your training would include:

A 5-year degree in medicine (SCQF Level 10), recognised by the General Medical Council (GMC)

A 2-year foundation course in general training

6 years of specialist training to become a consultant in a pathology specialism

The Royal College of Pathologists has more information about becoming a pathologist.

To enter a medical degree (SCQF level 10) requires National 5 qualifications and at least five Highers at AAAAB or above, usually achieved at one sitting. Most people also study Advanced Highers in science subjects.

Skills required:

  • Resilience

  • Making decisions

  • Attention to detail

  • Analysing

  • Written communication

  • Supporting

  • Social conscience

  • Researching

  • Observation

  • Problem solving