Trauma to the shoulder is common. Injuries range from a separated shoulder resulting from a fall onto the shoulder to a high-speed car accident that fractures the shoulder blade (scapula) or collar bone (clavicle). One thing is certain: everyone injures his or her shoulder at some point in life.
The shoulder is made up of three bones:
- Scapula (shoulder blade)
- Clavicle (collar bone)
- Humerus (arm bone)
These bones are joined together by soft tissues (ligaments, tendons, muscles, and joint capsule) to form a platform for the arm to work.
The shoulder is made up of three joints:
- Glenohumeral joint
- Acromioclavicular joint
- Sternoclavicular joint
The shoulder also has one articulation, which is the relationship between the scapula (shoulder blade) and the chest wall.
The main joint of the shoulder is the glenohumeral joint. This joint comprises a ball (the humeral head) on a golf-tee-shaped joint (the glenoid of the scapula).
TYPES OF SHOULDER INJURIES
There are many types of shoulder injuries:
- Fractures are broken bones. Fractures commonly involve the clavicle (collar bone), proximal humerus (top of the upper arm bone), and scapula (shoulder blade).
- Dislocations occur when the bones on opposite
sides of a joint do not line up. Dislocations can involve any of three
- A dislocation of the acromioclavicular joint (collar bone joint) is called a “separated shoulder.”
- A dislocation of the sternoclavicular joint interrupts the connection between the clavicle and the breastbone (sternum).
- The glenohumeral joint (the ball and socket joint of the shoulder) can be dislocated toward the front (anteriorly) or toward the back (posteriorly).
- Soft-tissue injuries are tears of the ligaments, tendons, muscles, and joint capsule of the shoulder, such as rotator cuff tears and labral tears.
Fractures of the clavicle or the proximal humerus can be caused by a direct blow to the area from a fall, collision, or motor vehicle accident.
Because the scapula is protected by the chest and surrounding muscles, it is not easily fractured. Therefore, fractures of the scapula are usually caused by high-energy trauma, such as a high speed motor vehicle accident. Scapula fractures are often associated with injuries to the chest.
SYMPTOMS OF FRACTURES
Symptoms of fractures about the shoulder are related to the specific type of fracture.
- Swelling and bruising
- Inability to move the shoulder
- A grinding sensation when the shoulder is moved
- Deformity — “It does not look right”
Specific Findings: Proximal Humerus Fracture
- A severely swollen shoulder
- Very limited movement of the shoulder
- Severe pain
Most fractures are diagnosed with X-rays of the area and by physical examination. Sometimes, additional imaging techniques, such as computed tomography, are necessary.
Most fractures of the proximal humerus can be treated without surgery if the bone fragments are not shifted out of position (displaced). If the fragments are shifted out of position, surgery is usually required. Surgery usually involves fixation of the fracture fragments with plates, screws, or pins or it involves shoulder replacement.