Medical Terminology: The Musculoskeletal System

1. What is The Musculoskeletal System?
The musculoskeletal system provides both structure and function for the body. The bones protect and support the vital organs. The skeleton is divided into the axial and appendicular areas. The axial skeleton protects the vital organs, surrounding the central nervous system (CNS) and thoracic cavity. The appendicular skeleton attaches to the axial skeleton and consists primarily of the limbs.
Bones are classified by both their shape and their composition. Short bones (like the phalanges) are found in the fingers and toes. Long bones (like the humerus or femur) are found in the limbs. Irregular bones are named for their shapes and are found in the joints of the ankle or wrist and in the middle ear.
Flat bones (ribs or scapula) protect inner organs. The outer layer of bone tissue is a dense compact bone tissue called the cortex.
Blood supply for the bone travels through small blood vessels within haversian canals located longitudinally within the cortical bone area. The inner layer is spongier, cancellous tissue that has spaces filled with marrow. Production of blood cells occurs within the red bone marrow. Yellow bone marrow is composed primarily of fat cells.
Osteoblasts (bone-building cells) and osteoclasts (bone-resorbing cells) are found in the outer layer of the bone. Joints are the areas in which two or more bones come together. Joints are described as being freely movable (synovial joints like the hip), partially movable (pelvic bones), or immovable (suture lines in the skull).
Synovial joints are lined with synovium. This membrane secretes synovial fluid to lubricate the joint and act as a shock absorber during motion or weight bearing. Synovial joints have a variety of range of motion, including flexion, extension, rotation, circumduction, supination, pronation, abduction, adduction, inversion, and eversion.
Partially movable joints have specific small amounts of motion that are typical of the joint space. Pelvic bones and individual joints between the vertebral bones are partially movable. Immovable joints are areas in which bones come together, but no movement is allowed. Muscles work in groups, with one set of muscles relaxing as another set contracts to create motion. A small amount of muscle contraction is typical to maintain muscle tone within the muscles.
Skeletal muscle is striated and voluntary. Connective tissues are the pieces that hold other parts together. Tendons attach muscles to bones; ligaments attach bones to bones. Cartilage provides a smooth surface within joints to ease movement and provide cushioning to weight-bearing joints. Bursa are small fluid-filled sacs, within joint areas or adjacent to bone, that provide cushioning at points of friction.

2. Carpal Tunnel Syndrome
The median nerve that passes through the carpal tunnel in the anterior wrist is compressed, resulting in pain and a numb sensation to the thumb, and index finger, middle finger, and lateral aspect of the fourth finger in the hand. This is often the result of repetitive hand motions and may be related to work or hobbies. Carpal tunnel syndrome tends to be more common in women.

3. Fractures
Excess stress or direct trauma is placed on a bone, causing a break. This results in damage to surrounding muscles and tissue, leading to hemorrhage, edema, and local tissue damage. Initially after the fracture, bleeding in the area leads to hematoma formation at the site. Inflammatory cells enter the area. Granulation tissue replaces the hematoma. Cellular changes continue and a nonbony union known as a callus develops. Osteoblasts continue to enter the area. Fibrous tissue in the fractured area changes to bone. The fracture site may be just a crack in the bone, without displacing any of the bone itself.
A fracture that does not go all the way through the bone is considered an incomplete fracture. The fracture may also go all the way through a bone, breaking it into two (or more) pieces, which is referred to as a complete fracture.
The surrounding muscle tissue that attaches above and below the fracture area in a limb will continue to create tension on their attachment points to the bone and pull the pieces further out of alignment. Some fractured bone pieces may penetrate through the skin; this is known as an open or compound fracture. Those that do not penetrate the skin are considered closed or simple fractures.

4. Gout
Gout is a metabolic disorder in which the body does not properly metabolize purine-based proteins. As a result, there is an increase in the amount of uric acid, which is the end product of purine metabolism.
As a result of hyperuricemia, uric acid crystals accumulate in joints, most commonly the big toe (podagra), causing pain when the joint moves. Uric acid is cleared from the body through the kidneys. These patients may also develop kidney stones as the uric acid crystallizes in the kidney.
A person may also develop secondary gout. This is caused by another disease process or use of medication, such as thiazide diuretics or some chemotherapeutic agents.

5. Osteoarthritis
Osteoarthritis is a degenerative joint disease caused by the wear and tear of the articular cartilage. As the protective joint cartilage is worn away, the underlying bone becomes exposed, causing the exposed bones to rub.
Degenerative changes within the bone tissue produce small areas of regrowth, causing jagged joint spaces and bone spurs. These rough areas project out into soft tissue or joint spaces, causing pain.

6. Osteomyelitis
Osteomyelitis is an infection of the bone. In an adult, it is most commonly caused by direct contamination of the site during trauma, such as an open fracture. Bacteria that cause infections elsewhere in the body may also enter the bloodstream and become deposited into the bone, starting a secondary infection site there.
This is more common in children and adolescents. Some of the patients have been treated with antibiotics previously for the initial infection. The causative organism is not always identified.
More than three-fourths of the identified organisms are Staphylococcus aureus. Acute infection is associated with inflammatory changes in the bone and may lead to necrosis. Some patients develop chronic osteomyelitis.

7. Osteoporosis
Osteoporosis is a decrease in bone density, making bones more brittle and increasing the risk of fracture. The body continuously replaces older bone with new bone through a balance between osteoblastic and osteoclastic activity.
When bone-building activity does not keep up with bone-resorption activity, the structural integrity of the bone is compromised. Increased age, lack of physical activity, poor nutrition, having a small frame, and being Caucasian, Asian, or female all increase the risk of osteoporosis.
Osteoporosis can also occur as a secondary disease, because of another condition. These causes include use of medications such as corticosteroids or some anticonvulsants, hormonal disorders (e.g., Cushing’s or thyroid), and prolonged immobilization.

8. Arthrogram
An X-ray of a joint area is taken after the injection of a contrast material has been injected into the joint space to enhance its visibility. In a double-contrast study, a solution is injected, followed by air. This may be done to better assess the possibility of bone chips or torn ligaments within the joint space.

9. Arthroscopy
Arthroscopy is a fiberoptic scope used to visually examine the joint, performed under some type of anesthesia (local, epidural, conscious sedation, or general). This is done to perform surgery concurrently, diagnose injuries to joint spaces, and assess response to prior treatments.

10. Bone Scan
This is a peripheral intravenous injection of a bone-seeking radiopharmaceutical followed by a 2- to 3-hour delayed imaging. The patient must lie still for the duration of the scanning, about 30. to 60. minutes. It is done to diagnose osteomyelitis, bone tumors, metastatic disease, fractures, and unexplained skeletal pain.
The practitioner should encourage fluids after the injection to flush the radiopharmaceutical. The practitioner should also monitor for reaction to the radiopharmaceutical: rash, itching, hives. Computed tomography (CT) scan and computerized axial tomography (computer-manipulated pictures of radiologic images) should not be obstructed by overlying anatomy.
The patient must lie still during the exam for clear images. This is done to detect fractures and bone metastasis.

11. Electromyography (EMG)
Multiple small needle-type electrodes are inserted into muscle areas to test muscle potential. The patient may be asked to move the area to allow for measurement during minimal and maximal contraction of the muscle. The amount of muscle and nerve activity is recorded graphically.
There may be some discomfort during the testing. Certain medications may need to be stopped before testing: muscle relaxants, stimulants, caffeine. After the testing, the patient may complain of pain or anxiety. The test is done to detect neuromuscular, peripheral nerve disorders, or lower motor neuron disorders, and may be done in conjunction with nerve conduction studies.

Basic Questions
Musculoskeletal System

1. What is the function of the axial skeleton?
The axial skeleton protects the vital organs, surrounding the central nervous system and thoracic cavity.

2. What is the purpose of flat bones?
Flat bones (ribs or scapula) protect inner organs.

3. What are haversian canals?
Blood supply for the bone travels through small blood vessels within haversian canals located longitudinally within the cortical bone area.

4. Where are blood cells produced?
Production of blood cells occurs within the red bone marrow.

5. What are osteoblasts?
Osteoblasts are bone-building cells.

6. What are osteoclasts?
Osteoclasts are bone-resorbing cells.

7. What is synovium?
Synovial joints are lined with synovium. This membrane secretes synovial fluid to lubricate the joint and act as a shock absorber during motion or weight bearing.

8. Where is bone marrow located?
Within the cortical bone area, there is an inner layer of more spongy, cancellous tissue that has spaces filled with marrow.

9. How do muscles work with bone?
Muscles work in groups, with one set of muscles relaxing as another set contracts to create motion. A small amount of muscle contraction is typical to maintain muscle tone within the muscles.

10. What are tendons?
Tendons attach muscles to bones.

11. What are ligaments?
Ligaments attach bones to bones.

12. What is cartilage?
Cartilage provides a smooth surface within joints to ease movement and provide cushioning to weight-bearing joints.

13. What are bursa?
Bursa are small fluid-filled sacs, within joint areas or adjacent to bone that provide cushioning at points of friction.

14. What is carpal tunnel syndrome?
The median nerve that passes through the carpal tunnel in the anterior wrist is compressed, resulting in pain and a numb sensation to the thumb, and index finger, middle finger, and lateral aspect of the fourth finger in the hand.

15. What is a callus?
Initially after the fracture, bleeding in the area leads to hematoma formation at the site. Inflammatory cells enter the area. Granulation tissue replaces the hematoma. Cellular changes continue and a nonbony union known as a callus develops. Osteoblasts continue to enter the area. Fibrous tissue in the fractured area changes to bone.

16. What is an incomplete fracture?
A fracture that does not go all the way through the bone is considered an incomplete fracture.

17. What is a compound fracture?
Some fractured bone pieces may penetrate through the skin; this is known as an open or compound fracture.

18. What is a simple fracture?
Those that do not penetrate the skin are considered closed or simple fractures.

19. What is gout?
Gout is a metabolic disorder in which the body does not properly metabolize purine-based proteins. As a result, there is an increase in the amount of uric acid, which is the end product of purine metabolism.

20. What is osteoarthritis?
This is a degenerative joint disease caused by the wear and tear of the articular cartilage. As the protective joint cartilage is worn away, the underlying bone becomes exposed, causing the exposed bones to rub.

21. What is osteomyelitis?
Osteomyelitis is an infection of the bone.

22. What is a common cause of osteomyelitis in adults?
In an adult, it is most commonly caused by direct contamination of the site during trauma such as an open fracture. Bacteria that cause infections elsewhere in the body may also enter the bloodstream and become deposited in the bone, starting a secondary infection site there.

23. What is osteoporosis?
Osteoporosis is a decrease in bone density, making bones more brittle and increasing the risk of fracture. The body continuously replaces older bone with new bone through a balance between the osteoblastic and osteoclastic activity.

24. What is an arthrogram?
An X-ray of a joint area is taken after the injection of a contrast material has been injected into the joint space to enhance its visibility. In a double-contrast study, a solution is injected, followed by air. This may be done to better assess the possibility of bone chips or torn ligaments within the joint space.

25. What is a confrontation test?
This test assesses the patient’s peripheral vision by gazing at the health care provider’s nose.