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Arthroscopy Of The Shoulder

Arthroscopy of the Shoulder: What Is Arthroscopy?

Last updated on:
15/04/2013

Contributing Author: Guy Slowik FRCS

Arthroscopy is a procedure that allows an orthopedic surgeon to see and operate inside a joint using a device called an arthroscope. The arthroscope is inserted into the joint through a tiny incision in the skin. Arthroscopy is both a diagnostic and surgical procedure.

An arthroscope is a pen-shaped instrument with a very small video camera attached to the end. Lenses inside the arthroscope transmit an image that is projected onto a television screen. The image can be magnified as much as 30 times, giving the orthopedic surgeon an exceptionally clear view of the inside of a joint. From this view, the surgeon can then operate inside the joint using small instruments inserted through separate tiny incisions.

Joint surgery has improved greatly since the arthroscope was introduced. The surgery is less traumatic, healing is faster, scarring is reduced, and recovery is quicker. Only a few tiny scars remain to show that the surgery was ever done.

Understanding the Shoulder

The shoulder is the most versatile joint in the human body. It has the widest range of motion, which means it can move in more directions than any other joint. The shoulder's versatility enables us to retrieve soup cans from the cupboard, hammer nails, swing golf clubs, roll bowling balls, and perform thousands of other activities.

The shoulder's flexibility is due to its unique structure. Like the hip, the main joint of the shoulder is a "ball-and-socket" joint. A "ball" at the top of the upper arm bone (the humerus) fits neatly into a "socket," called the glenoid, which is part of the shoulder blade (scapula).

But unlike the hip joint - where the ball sits in a deep, well-protected socket - the shoulder socket is very shallow. The surrounding ligaments, and muscles and tendons that move the shoulder joint, help to keep it stable.

Because of this anatomy, the shoulder is the most frequently dislocated major joint in the body. It's also prone to a variety of other injuries and chronic problems that can be painful and hinder a person's ability to perform ordinary tasks.

Three bones come together to form the shoulder. These bones are the collarbone (clavicle), the shoulder blade (scapula), and the upper arm bone (humerus). The acromion, a part of the shoulder blade, forms the top of the shoulder.

The shoulder is made up of four separate joints. The interrelated action of these four joints allows the complex and extremely wide range of movements of the shoulder.

  • The ball-and-socket joint, or glenohumeral joint, is the main joint of the shoulder.
  • The joint between the acromion (part of the shoulder blade) and the collarbone (the clavicle), is called the AC joint, or acriomio-clavicular joint. Arthritis of the shoulder most commonly affects this particular joint.
  • The junction between the collarbone and breastbone (the sternum), in the front of the chest, is called the sterno-clavicular joint. This joint anchors the shoulder to the chest wall
  • The fourth joint of the shoulder is between the shoulder blade and the back of five of the upper ribs, and is called the scapulo-thoracic joint. This joint provides added movement of the shoulder toward the front and back of the body.

The shallow socket of the shoulder is given some extra depth by a structure called the labrum, which is a thickening of tissue that attaches to and surrounds the socket. Damage to this structure from a shoulder dislocation often results in instability of the shoulder.

The ball-and-socket joint (glenohumeral joint) is reinforced and assisted in its movement by the rotator cuff, a combination of four tendons and associated muscles. The muscles arise on various parts of the shoulder blade, and their tendons attach to the upper arm bone. (Tendons are stringy tissues that attach muscle to bone.) One of the tendons of the biceps muscle runs through the shoulder joint and further helps to stabilize the joint.

The term "rotator cuff" refers to the group of four tendons that attach four shoulder muscles to the bone of the upper arm. Ordinarily, the rotator cuff moves freely in the space between the top of the upper arm and the upper part of the shoulder blade (the acromion), which overhangs the rotator cuff. In some people, for reasons not always known, this space is inadequate to allow the normal smooth gliding movements of the rotator cuff as it moves the arm. So when the arm is raised, the rotator cuff may be squeezed between the two bones.

Between the rotator cuff and the bony arch of the acromion lie two fluid-filled sacs called bursae. They protect the rotator cuff and allow smooth movement of the tendons over the bone.

Many shoulder problems are caused by injuries to the rotator cuff. If a tendon becomes inflamed or is partially torn, it can cause pain and limit shoulder movement. If a rotator cuff tendon tears completely, the corresponding muscle can no longer properly affect movement of the arm. This type of injury usually causes limitations in shoulder movement as a result of pain and weakness.

Nice To Know

Q. I don't recall injuring my shoulder. Why is it so painful?

A. Shoulder pain arises from the soft tissues (muscles, ligaments, and tendons) more often than from the bones. You need not have injured your shoulder. Pain can be caused by inflammation of the tendons (tendinitis), particularly the rotator cuff tendons and the biceps tendon; a tear of the rotator cuff due to wear and tear; bursitis (which is an inflammation of the bursa, the sac that separates some of the muscle layers and allows the tendons to glide smoothly); or other soft tissue problems as well as arthritis of the joint.

Facts About Shoulder Injuries

  • The shoulder is the most flexible joint in the body, but this flexibility also makes it susceptible to instability and injury.
  • According to the American Academy of Orthopedic Surgeons, about six million people each year go to the doctor for shoulder pain, dislocation, or other shoulder problems.
  • Each year, shoulder problems account for about 1.5 million visits to orthopedic surgeons (physicians who specialize in disorders of the bones, muscles, and related structures).
  • Most problems in the shoulder involve the muscles, ligaments, and tendons rather than bones.
  • Shoulder injuries can be caused by sports activities that involve excessive overhead motion (such as swimming, tennis, and pitching). But they also can be the result of everyday activities such as painting, hanging curtains, and gardening.
  • The arthroscope is the most accurate diagnostic tool for examining shoulder problems.
  • Recovery from arthroscopic surgery is generally faster and less painful than recovery from traditional open surgery.

 

 
 

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From Andrew Maynard - Chair of the University of Michigan Department of Environmental Health Sciences, with help from David Faulkner - 2013 Master of Public Health graduate.