Shoulder
The shoulder is the most flexible joint in the body that enables a wide range of movements including forward flexion, abduction, adduction, external rotation, internal rotation, and 360-degree circumduction. Thus, the shoulder joint is considered the most insecure joint of the body, but the support of ligaments, muscles, and tendons function to provide the required stability.
Bones of the Shoulder
The shoulder joint is a ball and socket joint made up of three bones, namely the humerus, scapula, and clavicle.
Humerus
The end of the humerus or upper arm bone forms the ball of the shoulder joint. An irregular shallow cavity in the scapula called the glenoid cavity forms the socket for the head of the humerus to fit in. The two bones together form the glenohumeral joint, which is the main joint of the shoulder.
Scapula and Clavicle
The scapula is a flat triangular-shaped bone that forms the shoulder blade. It serves as the site of attachment for most of the muscles that provide movement and stability to the joint. The scapula has four bony processes - acromion, spine, coracoid process, and glenoid cavity. The acromion and coracoid process serve as places for attachment of the ligaments and tendons.
The clavicle bone or collarbone is an S-shaped bone that connects the scapula to the sternum or breastbone. It forms two joints: the acromioclavicular joint, where it articulates with the acromion process of the scapula and the sternoclavicular joint where it articulates with the sternum (breast bone). The clavicle also forms a protective covering for important nerves and blood vessels that pass under it from the spine to the arms.
Soft Tissues of the Shoulder
The ends of all articulating bones are covered by smooth tissue called articular cartilage, which allows the bones to slide over each other without friction, enabling smooth movement. Articular cartilage reduces pressure and acts as a shock absorber during movement of the shoulder bones. Extra stability to the glenohumeral joint is provided by the glenoid labrum, a ring of fibrous cartilage that surrounds the glenoid cavity. The glenoid labrum increases the depth and surface area of the glenoid cavity to provide a more secure fit for the half-spherical head of the humerus.
Ligaments of the Shoulder
Ligaments are thick strands of fibers that connect one bone to another. The ligaments of the shoulder joint include:
- Coracoclavicular ligaments: These ligaments connect the collarbone to the shoulder blade at the coracoid process.
- Acromioclavicular ligament: This connects the collarbone to the shoulder blade at the acromion process.
- Coracoacromial ligament: It connects the acromion process to the coracoid process.
- Glenohumeral ligaments: A group of 3 ligaments that form a capsule around the shoulder joint and connect the head of the arm bone to the glenoid cavity of the shoulder blade. The capsule forms a watertight sac around the joint. Glenohumeral ligaments play a very important role in providing stability to the otherwise unstable shoulder joint by preventing dislocation.
Muscles of the Shoulder
The rotator cuff is the main group of muscles in the shoulder joint and is comprised of 4 muscles. The rotator cuff forms a sleeve around the humeral head and glenoid cavity, providing additional stability to the shoulder joint while enabling a wide range of mobility. The deltoid muscle forms the outer layer of the rotator cuff and is the largest and strongest muscle of the shoulder joint.
Tendons of the Shoulder
Tendons are strong tissues that join muscle to bone allowing the muscle to control the movement of the bone or joint. Two important groups of tendons in the shoulder joint are the biceps tendons and rotator cuff tendons.
Bicep tendons are the two tendons that join the bicep muscle of the upper arm to the shoulder. They are referred to as the long head and short head of the bicep.
Rotator cuff tendons are a group of four tendons that join the head of the humerus to the deeper muscles of the rotator cuff. These tendons provide more stability and mobility to the shoulder joint.
Nerves of the Shoulder
Nerves carry messages from the brain to muscles to direct movement (motor nerves) and send information about different sensations such as touch, temperature, and pain from the muscles back to the brain (sensory nerves). The nerves of the arm pass through the shoulder joint from the neck. These nerves form a bundle at the region of the shoulder called the brachial plexus. The main nerves of the brachial plexus are the musculocutaneous, axillary, radial, ulnar and median nerves.
Blood Vessels of the Shoulder
Blood vessels travel along with the nerves to supply blood to the arms. Oxygenated blood is supplied to the shoulder region by the subclavian artery that runs below the collarbone. As it enters the region of the armpit, it is called the axillary artery and further down the arm, it is called the brachial artery.
The main veins carrying de-oxygenated blood back to the heart for purification include:
- Axillary vein: This vein drains into the subclavian vein.
- Cephalic vein: This vein is found in the upper arm and branches at the elbow into the forearm region. It drains into the axillary vein.
- Basilic vein: This vein runs opposite the cephalic vein, near the triceps muscle. It drains into the axillary vein.
-
Shoulder Reconstruction Surgery
Shoulder reconstruction surgery is an operative procedure in which stretched or torn soft-tissue structures that surround the shoulder joint such as the capsule, ligaments, and cartilage, are repaired to secure the shoulder joint in place.
-
Reverse Shoulder Replacement
Conventional surgical methods such as total shoulder joint replacement are not very effective in the treatment of rotator cuff arthropathy. Reverse total shoulder replacement is an advanced surgical technique specifically designed for rotator cuff tear arthropathy, a condition where you suffer from both shoulder arthritis and a rotator cuff tear.
-
Complex Shoulder Reconstruction
Shoulder reconstruction is a surgical procedure performed in patients to alleviate shoulder instability, restoring its function and serving to prevent recurrent shoulder dislocations. Shoulder reconstruction surgery involves repair of torn or stretched ligaments so that they are better able to hold the shoulder joint in place.
-
Shoulder Labrum Reconstruction
The shoulder joint 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). The labrum is a ring of fibrous cartilage surrounding the glenoid, which helps in stabilizing the shoulder joint.
-
Shoulder Surgery
Shoulder surgery is a surgical procedure for the treatment of a shoulder injury or shoulder condition. The procedure involves repairing a diseased, damaged, or degenerated shoulder joint in order to eliminate pain and restore normal shoulder function.
-
AC Joint Repair
AC joint repair is a surgical procedure performed to repair damaged or torn ligaments and tendons of the acromioclavicular (AC) joint. Depending on the severity of the injury, the surgery can be done through tiny keyhole incisions arthroscopically, or as open surgery through a relatively larger skin incision.
-
Shoulder Capsular Repair
Shoulder capsular repair is a surgical procedure to treat shoulder instability that does not improve with more conservative or non-surgical methods.
-
Computer Navigation for Shoulder Replacement
Computer navigated shoulder replacement is an image-guided, minimally invasive surgical procedure in which the damaged or worn out articulating surfaces of the shoulder joint are removed and replaced with artificial prostheses under the assistance of advanced computer technology to relieve pain and restore normal functioning of the shoulder joint.
-
Acromioclavicular (AC) Joint Reconstruction
The acromioclavicular (AC) joint is one of the joints present within your shoulder. It is formed between a bony projection at the top of the shoulder blade (acromion) and the outer end of the clavicle (collarbone). The joint is enclosed by a capsule and supported by ligaments.
-
Latarjet Procedure
The shoulder joint provides a wide range of movement to the upper extremity, but overuse or trauma can cause instability to the joint. The Latarjet procedure is a surgical procedure performed to treat shoulder instability by relocating a piece of bone with an attached tendon to the shoulder joint.
-
Shoulder Stabilization
Shoulder stabilization surgery is performed to improve stability and function to the shoulder joint and prevent recurrent dislocations. It can be performed arthroscopically, depending on your particular condition, with much smaller incisions. Arthroscopic stabilization is a surgical procedure to treat chronic instability of the shoulder joint.
-
Shoulder Fracture Care
A break in the bone that makes up the shoulder joint is called a shoulder fracture. The clavicle (collarbone) and end of the humerus (upper arm bone) closest to the shoulder are the bones that usually are fractured. The scapula, or shoulder blade, is not easily fractured because of its protective cover of surrounding muscles and chest tissue.
-
Arthritis of the Shoulder
The term arthritis literally means inflammation of a joint but is generally used to describe any condition in which there is damage to the cartilage. Damage of the cartilage in the shoulder joint causes shoulder arthritis. Inflammation is the body's natural response to injury.
-
Clavicle Fracture
The break or fracture of the clavicle (collarbone) is a common sports injury associated with contact sports such as football and martial arts, as well as impact sports such as motor racing. A direct blow over the shoulder that may occur during a fall on an outstretched arm or a motor vehicle accident may cause the clavicle bone to break.
-
Shoulder Trauma
Shoulder injuries most commonly occur in athletes participating in sports such as swimming, tennis, pitching, and weightlifting. The injuries are caused due to the over usage or repetitive motion of the arms.
-
Shoulder Dislocation
Sports that involve overhead movements and repeated use of the shoulder at your workplace may lead to sliding of the upper arm bone from the glenoid. The dislocation might be a partial dislocation (subluxation) or a complete dislocation causing pain and shoulder joint instability.
-
Shoulder Labral Tear
Traumatic injury to the shoulder or overuse of the shoulder (throwing, weightlifting) may cause the labrum to tear. In addition, aging may weaken the labrum leading to injury.
-
Shoulder Fracture
The clavicle and end of the humerus closest to the shoulder are the bones that usually get fractured. The scapula, on the other hand, is not easily fractured because of its protective cover by the surrounding muscles and chest tissue.
-
Posterior Shoulder Instability
Posterior shoulder instability, also known as posterior glenohumeral instability, is a condition in which the head of the humerus (upper arm bone) dislocates or subluxes posteriorly from the glenoid (socket portion of the shoulder) as a result of significant trauma.
-
Shoulder Ligament Injuries
Shoulder ligament injuries are injuries to the tough elastic tissues present around the shoulder that connect bones to each other and stabilize the joint. The ligaments present in the shoulder are connected to the ends of the scapula, humerus, and clavicle bones which form the shoulder complex.
-
Internal Impingement of the Shoulder
Internal shoulder impingement can be described as a pathological condition resulting from repetitive impingement of the internal surface of the rotator cuff by the bones at the back of the glenohumeral joint.
-
Shoulder Bursitis
Shoulder bursitis, also known as subacromial bursitis, is a condition characterized by pain and inflammation in the bursa of the shoulder. The bursa is a fluid-filled sac present between the bone and soft tissue that acts as a cushion and helps to reduce friction during movement.
-
Shoulder Disorders
The shoulder is the most flexible joint in the body that enables a wide range of movements. Aging, trauma or sports activities can cause injuries and disorders that can range from minor sprains or strains to severe shoulder trauma.
-
Multidirectional Instability of the Shoulder
The shoulder consists of a ball and socket joint where the rounded end of the humerus (upper arm bone) fits into a socket (glenoid cavity) formed by the shoulder blade. The joint is stabilized by the surrounding capsule, ligaments, and tendons of the rotator cuff muscles.
-
Acromioclavicular (AC) Joint Injuries
The acromioclavicular (AC) joint in the shoulder is very important for shoulder strength, motion, and maintaining shoulder position. The joint is stabilized by various ligaments and a capsule, which can cause pain and affect normal joint function if damaged.
-
Snapping Scapula
Snapping scapula or snapping scapula syndrome is also known as scapulothoracic syndrome or scapulocostal syndrome. It is a condition characterized by painful clicking, snapping, or grinding of the shoulder blade. The sound occurs as a result of rubbing of soft tissues between the thoracic wall and the scapula.
-
Throwing Injuries of the Shoulder
Throwing injuries of the shoulder are injuries sustained as a result of trauma by athletes during sports activities that involve repetitive overhand motions of the arm as in baseball, American football, volleyball, rugby, tennis, track and field events, etc.
