Bones, Muscles, and Joints (for Teens)
Joints are the areas where two or more bones meet. Ball-and-socket joints, such as the shoulder and hip joints, allow backward, forward. The shoulder joint gives your arms more range of motion than any other part of the body. The two main bones of the shoulder are the humerus and the scapula meets the head of the humerus to form a glenohumeral cavity that acts as a. A joint is formed where two or more bones meet. There are three joints in the shoulder girdle: the glenohumeral joint (GH) is.
Cartilage is a stiff but flexible tissue that is good with weight-bearing which is why it is found in our joints. Cartilage has almost no blood vessels and is very bad at repairing itself.
Bone is full of blood vessels and is very good at self repair. It is the high water content that makes cartilage flexible. The muscles on the lateral side of the shoulder allow movement and stabilize the joint. These muscles are strong on the upper and back sides of the arm, but not on the underside. A strong outside force in this area can cause the head of the humerus to slip out of the glenoid socket, called dislocation. Since there is little bony stability in this joint, a number of ligaments and other soft tissues stabilize this joint.
The superior AC ligament is the most important horizontal stabilizer. The coracoclavicular ligaments help stabilize the clavicle vertically. The Sternoclavicular Joint SC Most of the rotation occurs at the sternoclavicular joint and joint stability comes from the soft tissues.
The posterior sternoclavicular joint capsule is the most important structure for preventing forward and backward displacement of the medial clavicle. The Rotator Cuff The rotator cuff consists of four muscle-tendon units that originate on the scapula and attach to the tuberosities of the humerus. The rotator cuff is the primary stabilizer during movement of the GH joint.
Both overuse and traumatic injuries to the rotator cuff are the most common problems in the shoulder girdle.
The Subacromial Space The subacromial space is beneath the acromion and above the rotator cuff. The subacromial bursa outlines this space and provides frictionless gliding of the rotator cuff beneath the arch formed by the acromion and coracoacromion. Bone spurs on the underside of the acromion narrow this space, irritate the bursa and contribute to tears in the rotator cuff. Bones of the Shoulder Girdle Click on image for larger labeled, picture.
The bones of the shoulder girdle include the humerus, the scapula, and the clavicle. There are four articulations movements in the shoulder named for their anatomic locations: The scapula is the most complex of the bones in the shoulder and is part of the shoulder girdle.
The scapula floats on the rib cage, and is attached to it only with muscles. There are three landmarks on the scapula; the spine, acromion and coracoid processes. The roof of the glenohumeral joint is formed by the acromion. The acromion articulates with the clavicle forming the acromioclavicular AC joint. A spine divides the back of the scapula into two sections. The muscles that attach below this spine are called infraspinatus muscles; the ones that attach above this spine are called supraspinatus muscles.
The humerus is the ball part of the ball-and-socket joint. The head ball of the humerus articulates within the glenoid fossa. Other than impingement, what else can cause rotator cuff damage? In young, athletic individuals, injury to the rotator cuff can occur with repetitive throwing, overhead racquet sports, or swimming.
This type of injury results from repetitive stretching of the rotator cuff during the follow-through phase of the activity. The tear that occurs is not caused by impingement, but more by a joint imbalance.
This may be associated with looseness in the front of the shoulder caused by a weakness in the supporting ligaments. What kind of symptoms does a patient have when the rotator cuff is injured? The most common complaint is aching located in the top and front of the shoulder, or on the outer side of the upper arm deltoid area.
The pain is usually increased when the arm is lifted to the overhead position. Frequently, the pain seems to be worse at night, and often interrupts sleep. Depending on the severity of the injury, there may also be weakness in the arm and with some complete rotator cuff tears the arm cannot be lifted in the forward or outward direction at all.
How is the diagnosis of rotator cuff disease proven? The diagnosis of rotator cuff tendon disease includes a careful history taken and reviewed by the physician, an x-ray to visualize the anatomy of the bones of the shoulder, specifically looking for acromial spur, and a physical examination.
Atrophy may be present, along with weakness, if the rotator cuff tendons are injured, and special impingement tests can suggest that impingement syndrome is involved. An MRI magnetic resonance imaging scan frequently gives the final proof of the status of the rotator cuff tendon. Although none of these tests is guaranteed accurate, most rotator cuff injuries can be diagnosed using this combination of exams. What is the initial treatment for rotator cuff disease and impingement?
If minor impingement or rotator cuff tendinitis is diagnosed, a period of rest coupled with medicines taken by mouth, and physical therapy will frequently decrease the inflammation and restore the tone to the atrophied muscles.
Activities causing the pain should be slowly resumed only when the pain is gone.
Sometimes a cortisone injection into the bursal space above the rotator cuff tendon is helpful to relieve swelling and inflammation. Application of ice to the tender area three or four times a day for 15 minutes is also helpful.
What is the second line of treatment if the rotator cuff pain and weakness persist? If there is a thickened acromion or acromial bone spur causing impingement, it can be removed with a burr using arthroscopic visualization.
This procedure can often be performed on an outpatient basis, and at the same time, any minor damage and fraying to the rotator cuff tendon and scarred bursal tissue can be removed.
Often this will completely cure the impingement and prevent progressive rotator cuff injury. If the rotator cuff is already torn, what are the options?
When the tendon of the rotator cuff has a complete tear, the tendon often must be repaired using surgical techniques. The choice of surgery, of course, depends on the severity of the symptoms, the health of the patient, and the functional requirements for that shoulder.
In young working individuals, repair of the tendon is most often suggested. In some older individuals who do not require significant overhead lifting ability, surgical repair may not be as important.
If chronic pain and disability are present at any age, consideration for repair of the rotator cuff should be given. What will happen if the rotator cuff is not repaired?
In some situations, the bursa overlying the rotator cuff may form a patch to close the defect in the tendon.
Although this is not true tendon healing, it may decrease the pain to an acceptable level. If the tendon edges become fragmented and severely worn, and the muscle contracts and atrophies, repair at that point may not be possible. Sometimes in this situation, the only beneficial surgical procedure would be an arthroscopic operation to remove bone spurs and fragments of torn tissue that catch when the arm is rotated.
This certainly will not restore normal power or strength to the shoulder, but often will relieve pain. How is a major injury to the rotator cuff tendon repaired surgically?
Anatomy of the Shoulder | North Arkansas Shoulder Care
The arthroscope is extremely helpful when repairing rotator cuff tendons, but sometimes it is necessary to add a "mini-open" procedure if the tendon is completely torn. Using the arthroscope at the beginning of the case allows visualization of the interior of the joint to facilitate trimming and removal of fragments of torn cuff tendon and biceps tendon. The next step utilizes the arthroscope to visualize the spur and thickened ligament beneath the acromial bone, while they are removed with miniature cutting and grinding instruments.
If it is necessary to suture a rotator cuff tear which has pulled off the bone, a two-inch incision can be made directly over the tear that has been visualized and localized using the arthroscope.
The deltoid muscle fibers can be spread apart so that strong stitches can attach the rotator cuff tendon back to the bone. If the tear is minimally retracted, small suture screw anchors may be used arthroscopically or open. How is my shoulder treated after surgery? In a minor operation for impingement, the shoulder is placed in a simple sling. If a full thickness tear of the rotator cuff was present and repaired, then the shoulder will be supported by an UltraSling or a SCOI postoperative brace.
The brace is very helpful because it will allow exercise of the elbow, wrist, and hand at all times, and places the arm in a position that promotes better blood circulation and relieves stress on the repaired rotator cuff tissues.
Anatomy of a Joint
In addition, the shoulder can be exercised in the brace much easier than when it is at the side in an immobilizer. What is the rehabilitation program after rotator cuff surgery? Depending on the type of surgery performed, the program will allow a period of time for healing of the soft tissues followed by time to regain range of motion and then strengthen the shoulder muscles, but particularly the rotator cuff.
In minor tendinitis and impingement syndrome, the program takes approximately two to three months. If the rotator cuff tendon has been completely torn, it may take six months or more before the atrophied muscles can resume their function and the range of motion of the arm is restored.
Frequently, pain relief is much quicker and return to daily activities is often possible by two to three months. How successful is rotator cuff surgery? Again, every case is unique.
In the young, healthy person with a minor rotator cuff impingement, surgery is predictably successful. As the injury becomes more severe, such as with a large bone spur and fragmentation of the tendon, then a perfect result cannot be expected.
Since it is necessary to trim back the unhealthy tendon before reattaching it to the bone, a decreased range of motion of the shoulder will often result. Despite this, pain relief and return of strength are usually well worth the minor decreased mobility.
The final outcome often depends on the willingness and ability of an individual patient to work on their postoperative physical therapy program.
Shoulder Instability Shoulder instability represents a spectrum of disorders, the successful management of which requires a correct diagnosis and treatment. The boundaries of this spectrum are represented by a subluxation event a partial dislocation which spontaneously reducesto a complete dislocation which often requires anesthesia to reduce the shoulder.
The majority of instabilities are traumatic in nature and the ball of the shoulder is unstable toward the front of the shoulder. It is this type of shoulder instability which we will concentrate on here.
In order for a shoulder to dislocate, the very important and delicate balance of soft tissues ligaments, capsule and tendons around the shoulder must become damaged.
What Is the Pectoral Girdle?
The older a patient is at the time of initial injury the lower the chances are for developing recurrent instability. It is for this reason we have become more aggressive in recent years in recommending early repair for this group of patients. We believe early repair reduces the likelihood of further injuring the shoulder with additional episodes of dislocation. The treatment for recurrent shoulder instability is usually surgical. This surgery is aimed at repairing the damaged capsule and ligaments directly.
This procedure can be done arthroscopically as an outpatient. There are also some physical differences in men and women. Scapula bone Unlike your clavicle, the scapula bone or shoulder blade is located at the back of your shoulder. The scapula provides an attachment point for a number of muscles in your shoulder and upper limbs to your neck and back.
Your scapula is divided into three borders: Pectoral girdle joints There are four main joints in the pectoral girdle: This joint is the point where your clavicle meets your sternum.
This joint provides the direct attachment between your upper extremity and axial skeleton, and also allows your clavicle to move in three different planes. Also known as the scapulocostal joint, this is where the scapula bone meets the ribs in the back of your chest.Shoulder Anatomy Animated Tutorial
This joint relies on surrounding muscle for control. This is the point where your clavicle meets the acromion of the scapula.