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.
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 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 or 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.
Rotator Cuff Tear
A rotator cuff is a group of tendons in the shoulder joint that provides support and enables a wide range of motion. A major injury to these tendons may result in rotator cuff tears.
The shoulder is a highly mobile ball and socket joint. The ball of the upper arm bone (humerus) is held in place at the socket (glenoid) of the shoulder blade (scapula) by a group of ligaments.
Shoulder impingement is the inflammation of the tendons of the shoulder joint. It is one of the most common causes of pain in the shoulder. Shoulder impingement is also called swimmer’s shoulder, tennis shoulder or rotator cuff tendinitis.
The term SLAP (superior –labrum anterior-posterior) lesion or SLAP tear refers to an injury of the superior labrum of the shoulder.
Frozen shoulder, also called adhesive capsulitis, is a condition in which you experience pain and stiffness in your shoulder. The symptoms appear slowly, worsen gradually and usually take one to three years to resolve on their own.
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.
Shoulder instability is a chronic condition that causes frequent dislocation of the shoulder joint.
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.
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.
A break in a bone that makes up the shoulder joint is called a shoulder 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.
Proximal Humerus Fractures
Fractures of the proximal humerus are common in elderly individuals suffering from osteoporosis. In younger individuals, a severe trauma such as a fall from a height on an outstretched hand or motor vehicle accident can cause these fractures.
Baseball and Shoulder Injuries
Shoulder injuries in baseball players are usually associated with pitching. While this overhand throwing activity can produce great speed and distance for the ball, when performed repeatedly, can place a lot of stress on the shoulder.
Sternoclavicular Joint (SC joint)
The sternoclavicular joint is the joint between the breastbone (sternum) and the collar bone (clavicle). The SC joint is one of the 4 joints that complete the shoulder and is the only joint that links the arm to the body.
Treatment of 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.
Acromioclavicular (AC) Arthritis
The acromioclavicular joint is part of the shoulder joint. It is formed by the union of the acromion, a bony process of the shoulder blade, and the outer end of the collar bone or clavicle.
Bicep Tendon Rupture
The biceps tendon is a tough band of connective fibrous tissue that attaches your biceps muscle to the bones in your shoulder on one side and the elbow on the other side.
Shoulder Labral Tear with Instability
The shoulder consists of a ball-and-socket joint formed by the upper end of the humerus (upper arm bone) and a cavity in the shoulder blade called the glenoid.
Proximal Biceps Tendon Rupture
The biceps muscle is the muscle of the upper arm which is necessary for the movement of the shoulder and elbow. It is made of a ‘short head’ and a ‘long head’ which function together.
Long Head Biceps Tendon Rupture
Your biceps muscle has two heads, a long head, and a short head, which are both attached to the shoulder. The long head of the biceps tendon is a tough band of connective fibrous tissue that attaches the long head of the biceps to the top of the shoulder socket.
Multidirectional Instability of the Shoulder
Instability may be described by the direction in which the humerus is subluxated or dislocated from the glenoid. When it occurs in several directions it is referred to as multidirectional instability.
Massive Retracted Rotator Cuff Tear
A tear in the rotator cuff can cause pain and disability. It can occur from degeneration of the rotator cuff due to overuse or from a sudden injury. Massive rotator cuff tears involve tears in two complete tendons of the rotator cuff.
Your shoulder consists of a ‘ball-and-socket joint’. The humerus (upper arm bone) has a rounded head (ball) that is attached to the glenoid cavity (socket) in the shoulder blade.
Rotator Cuff Pain
The rotator cuff consists of a group of tendons and muscles that surround and stabilize the shoulder joint. These tendons allow a wide range of movement of the shoulder joint across multiple planes. Irritation or injury to these tendons can result in rotator cuff pain.
Periprosthetic Shoulder Infection
A periprosthetic shoulder joint infection is a very rare, but devastating complication of shoulder replacement surgery characterized by infection of the tissues surrounding your shoulder prosthesis.
Proximal Biceps Tenodesis
Proximal biceps tenodesis is the surgical reattachment of a torn proximal biceps tendon, which connects the upper part of your biceps muscle to the shoulder.
Failed Shoulder Surgery
Failed shoulder surgery is a surgery that did not meet expectations and resulted in recurring pain or other unwanted symptoms. All surgeries are associated with risks, some have a higher risk than others.
Bicep Tendon Rupture at Shoulder
The biceps muscle is present on the front of your upper arm and functions to help you bend and rotate your arm. The biceps tendon is a tough band of connective fibrous tissue that attaches your biceps muscle to the bones in your shoulder on one side and the elbow on the other side.
Revision Shoulder Replacement
Total shoulder replacement usually has good results, but a revision surgery may occasionally be necessary due to persistent pain, infection, stiffness, weakness, instability, hardware loosening, malposition or fracture.
Shoulder Joint Replacement
Total shoulder replacement surgery is performed to relieve these symptoms. In this surgery, the damaged articulating parts of the shoulder joint are removed and replaced with artificial prostheses.
Reverse Shoulder Replacement
Conventional surgical methods such as total shoulder joint replacement have been shown to be significantly ineffective in the treatment of rotator cuff arthropathy.
ORIF of the Scapula Fractures
ORIF/open reduction and internal fixation is a surgical procedure employed for the treatment of a scapula fracture not amenable to non-surgical conservative treatment.
SC Joint Injury Reconstruction
The sternoclavicular (SC) joint is the joint between the breastbone (sternum) and the collar bone (clavicle). Injuries to this joint are called sternoclavicular joint injuries and can include stretching or tearing of the ligaments.
A SLAP tear can be treated through an arthroscopic surgical procedure called a SLAP repair.
Arthroscopic Bankart Repair
The labrum can sometimes tear during a shoulder injury. A specific type of labral tear that occurs when the shoulder dislocates is called a Bankart tear.
Shoulder Labrum Reconstruction
Traumatic injury to the shoulder or overuse of the shoulder by excessive throwing or weightlifting can cause a labral tear. In addition, the aging process may weaken the labrum, leading to injury secondary to wear and tear.
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 instability is a chronic condition that causes the frequent dislocation of the shoulder joint. A dislocation occurs when the end of the humerus (the ball portion) partially or completely dislocates from the glenoid (the socket portion) of the shoulder.
Arthroscopy is a minimally invasive diagnostic and surgical procedure performed for joint problems. Shoulder arthroscopy is performed using a pencil-sized instrument called an arthroscope.
Distal Clavicle Excision
Distal clavicle excision is a procedure which involves removal of the outer end of the clavicle (collarbone) to treat shoulder pain and disability due to arthritis or impingement.
A capsular release of the shoulder is surgery performed to release a tight and stiff shoulder capsule, a condition called frozen shoulder or adhesive capsulitis. The procedure is usually performed arthroscopically through keyhole-size incisions.
Pectoralis Major Tears/Repairs
The pectoralis muscle is a large fan-shaped muscle comprised of the pectoralis major and pectoralis minor muscles that stretch from the armpit to the collarbone and down across the lower chest region on both sides of the chest.
Mumford Distal Clavicle Excision
A Mumford distal clavicle excision is a surgical procedure which involves excision or resection of the outer (distal) end of the clavicle, also called the collar bone.
ORIF of the Clavicle Fractures
ORIF/open reduction and internal fixation is a surgical procedure employed for the treatment of a clavicle fracture not amenable to non-surgical conservative treatment.
Subacromial decompression is a surgical procedure performed for the treatment of a condition called shoulder impingement. In shoulder impingement, the degree of space between the rotator cuff tendon and shoulder blade is decreased due to irritation and swelling of the bursa or due to development of bone spurs.
The shoulder is an active joint is prone to injuries and may also get affected by conditions such as arthritis, which results in impaired functioning and related discomfort.
Acromioclavicular Joint (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).