Left Shoulder Anatomy
You’re probably wondering about the left shoulder anatomy. There are several bones and tendons in the shoulder. The glenohumeral joint and rotator cuff are important components of your shoulder. You’ll also want to know about the supraspinatus and subscapularis. These bones and tendons all work together to support and stabilize the shoulder.
The Glenohumeral Joint
The glenohumeral joint is a complex group of structures that allow the arm to move freely. This joint’s anatomy varies from person to person. Having an understanding of normal anatomy is crucial for treating patients with a wide range of shoulder conditions. Understanding these variations is also useful in rehabilitating shoulder function after pathologic conditions. This article aims to provide an anatomical guide for restoring stability and function in the clinic.
The glenohumeral joint is supported by the rotator cuff muscles. These muscles attach to the tubercles of the humerus and fuse with the joint capsule. They act as stabilizers of the glenoid joint anteriorly and facilitate internal rotation and abduction of the humerus. In addition, the posterior cord of the brachial plexus innervates the subscapularis muscle.
The Rotator Cuff
Shoulder pain is usually caused by a tear in the rotator cuff. However, it can also occur in other parts of the shoulder such as the elbow. In cases of pain in the shoulder, the best treatment is to see a specialist. He or she will conduct a physical examination and ask you about the causes of your pain. An MRI can also help to diagnose rotator cuff pathologies.
Rotator cuff problems are common and affect between two and four million people in the United States each year. While most injuries can be resolved with rest, a complete tear may require surgery.
The Supraspinatus
The supraspinatus muscle is a long, thin tendon with two bellies, one on the anterior end and one on the posterior end. Injuries to this muscle can limit the ability to elevate the arm. However, due to its structural integrity, the anterior fibers and belly may be preserved during surgery. This is important for postoperative recovery.
The supraspinatus muscle attaches to the upper end of the scapula and extends to the ball of the humerus. A bursa separates these two muscles, decreasing friction on the bone. The supraspinatus muscle inserts on the humerus behind the subscapularis, a smaller muscle in the arm.
The Subscapularis
The subscapularis of the left shoulders is one of the most powerful muscles of the rotator cuff. It is responsible for controlling the range of motion of the shoulder. A tear in the subscapularis tendon is rare and usually occurs as a result of a larger rotator cuff rupture. However, it is important to consider its role in shoulder motion and to have the diagnosis confirmed prior to surgery. This will help guide the surgical approach and the patient’s functional prognosis.
The SSC is composed of multiple muscular and tendinous bundles. The upper two-thirds of the muscle are flattened tendons. Each bundle has a different insertion location. The lower end of the tendon is surrounded by a fibrous capsule.
The Acromion
The acromion is a bony extension of the scapula (shoulder blade) that extends over the shoulder joint. This part of the shoulder is connected to the clavicle and articulates with it anteriorly to form the acromioclavicular joint. The acromion is particularly important for shoulder stability and a wide range of motion. The acromion is also a common source of pain in the shoulder, and acromion injuries can cause severe inflammation.
Surgical treatment may be an option, though it may not be appropriate for every patient. The outcome of the surgery will depend on a number of factors, including age, occupation, and associated degenerative conditions. In general, about 85% of patients achieve satisfactory results. The time between the onset of symptoms and the surgery may also play a role. Surgery is most effective if it is performed within three weeks of onset of symptoms.
The Scapula
The scapula is a bone of the shoulder joint. It has two surfaces, a smooth costal surface and a convex posterior surface. The subscapular fossa takes up most of the posterior surface, and there is a scapular spine that separates into two fossae, the superior supraspinous fossa and the inferior infraspinous fossa. The scapula also has coracoid and acromion processes. They articulate with the head of the humerus.
Pain in the scapula is often accompanied by pain in the other muscle groups. In addition, some shoulder pain is a symptom of rotator cuff tears. Other conditions that cause pain in the shoulder blade may include arthritis, spinal stenosis, and pressure on nerves.
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