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The shoulder is comprised of the clavicle (collarbone), scapula (shoulder blade), and humerus (upper arm bone), as well as numerous muscles, ligaments, and tendons. We utilize our shoulders for both mobility and stability, including lifting, pushing, and pulling. The shoulder is a common source of aches and pains, often the result of repetitive motion used in sports, at work, or during daily activities. Orthopedic injuries and conditions associated with shoulder discomfort range from tendinitis, arthritis, and bursitis to fractures, rotator cuff injuries, and instabilities. To read more about shoulder conditions, click here.

Shoulder Anatomy

At OrthoNorCal Orthopedic Specialists, our specialty-trained and experienced shoulder surgeons are recognized as leaders in the diagnosis and treatment of shoulder injuries and conditions. Common surgical procedures our shoulder surgeons perform include arthroscopic rotator cuff repair, arthroscopic labral repair, total shoulder replacement, reverse total shoulder replacement, complex fracture repair, biceps tendon repair, and shoulder resurfacing among many other techniques.

  • Shoulder Arthritis

    The most common cause leading to a shoulder replacement is osteoarthritis, or wear and tear arthritis. Osteoarthritis can occur without any injury to the shoulder, but it is uncommon.

  • Acromioclavicular (AC) Joint Osteoarthritis

    Osteoarthritis also called degenerative joint disease, is the most common form of arthritis. It occurs most often in older people.

  • Rotator Cuff Tear

    The shoulder joint has great range-of-motion, but not much stability. The rotator cuff tendons are one of the key reasons that the shoulder is so useful.

  • 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.

  • Shoulder Pain

    Pain in the shoulder may suggest an injury, which is more common in athletes participating in sports such as swimming, tennis, pitching, and weightlifting.

  • SLAP Tears

    The term SLAP (superior –labrum anterior-posterior) lesion or SLAP tear refers to an injury of the superior labrum of the shoulder.

  • Frozen Shoulder

    Frozen shoulder, also called adhesive capsulitis, is a condition in which you experience pain and stiffness in your shoulder.

  • Labral Tears of the Shoulder

    The labrum can become caught between the socket and the humerus and tear. This flap of tissue can move in and out of the joint and become caught between the humeral head and glenoid socket, causing pain, catching, and shoulder instability.

  • Little League Shoulder

    Little league shoulder is an injury to the growth plate of the upper arm bone at the shoulder joint of children. It is an overuse injury caused by repeated pitching or throwing, especially in children between the ages of 10 to 15 years.

  • 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.

  • 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.

  • Shoulder Instability

    Shoulder instability can be a common problem after a shoulder dislocation. Instability means that the shoulder is too loose and has a tendency to slip out of the socket (or glenoid).

  • Shoulder Trauma

    Shoulder injuries most commonly occur in athletes participating in sports such as swimming, tennis, pitching, and weightlifting.

  • 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.

  • Anterior Shoulder Instability

    Anterior shoulder instability, also known as anterior glenohumeral instability, is a condition in which damage to the soft tissues or bone causes the head of the humerus (upper arm bone) to dislocate or sublux from the glenoid fossa, compromising the function of the shoulder.

  • 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 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.

  • 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.

  • Bicep Tendon Rupture

    The biceps muscle is located in the front side of your upper arm and functions to help you bend and rotate your arm.

  • Shoulder Impingement

    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.

  • Glenoid Fractures

    Fractures of the glenoid are rare but can occur due to major trauma or during high-energy sports activities.

  • 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.

  • Overhead Athlete's Shoulder

    An overhead athlete is at increased risk of injury due to the mechanism associated with rapid shoulder elevation, external rotation, and abduction.

  • Subacromial Impingement Syndrome

    SAIS is the inflammation and irritation of your rotator cuff tendons. This occurs when the tendons rub against the outer end of the shoulder blade (the acromion) while passing through the subacromial space during shoulder movement.

  • Proximal Biceps Tendinitis

    Proximal biceps tendinitis is the irritation and inflammation of the biceps tendon at the shoulder joint. The biceps muscle is the muscle of the upper arm which is necessary for the movement of the shoulder and elbow.

  • 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.

  • 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.

  • AC Joint Separation

    AC joint separation, also known as shoulder separation, is a condition characterized by damage to the ligaments that connect the acromion to the collar bone.

  • Shoulder Tendonitis

    Shoulder tendonitis is a condition characterized by inflammation of the tendons which connect the muscles to the shoulder bones. Tendonitis of the rotator cuff tendons is known as rotator cuff tendonitis.

  • Rotator Cuff Re-tear

    Rotator cuff repair is a surgery to repair an injured or torn rotator cuff. A re-tear may occur a few years after surgery due to multiple reasons including aging, a massive previous tear (more than 5cm), fatty degradation of the tendons, inflammatory arthritis, and inappropriate rehabilitation.

  • Rotator Cuff Calcification

    Rotator cuff calcification is the abnormal accumulation of calcium deposits in rotator cuff muscles and tendons. The rotator cuff is a group of 4 muscles and tendons in the shoulder joint that join the head of the humerus to the shoulder.

  • Partial Rotator Cuff Tear

    A partial rotator cuff tear is an incomplete tear that involves damage to a part of the tendon. The tear can be at the top, bottom or inner side of the tendon and does not go all the way through the tendon completely.

  • Sternoclavicular (SC) Joint Disorders

    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.

  • 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.

  • 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.

  • Osteoarthritis of the Acromioclavicular (AC) Joint

    The acromioclavicular (AC) joint in the shoulder is a common spot for osteoarthritis to develop in middle age.

  • Shoulder Fracture

    A break in a bone that makes up the shoulder joint is called a shoulder fracture.

  • 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.

  • Calcific Tendonitis of the Shoulder

    Calcific tendonitis of the shoulder occurs when calcium deposits form on the tendons of your shoulder. The tissues around the deposit can become inflamed, causing a great deal of shoulder pain.

  • Shoulder Arthroscopy

    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.

  • Shoulder Joint Replacement

    Total shoulder replacement surgery is performed to relieve symptoms of severe shoulder pain and disability due to arthritis.

  • Revision Shoulder Replacement

    Total shoulder replacement is the replacement of the head of the humerus (upper arm bone) and the glenoid cavity (cavity of the shoulder blade) into which the humerus fits, with artificial prostheses to relieve pain, swelling, and stiffness caused due to damage of cartilage at the articulating surfaces.

  • Reverse Shoulder Replacement

    Conventional surgical methods such as total shoulder joint replacement are not very effective in the treatment of rotator cuff arthropathy.

  • Minimally Invasive Shoulder Joint Replacement

    Shoulder joint replacement is a surgical procedure that replaces damaged bone surfaces with artificial humeral and glenoid components to relieve pain and improve functional ability in the shoulder joint.

  • Rotator Cuff Repair

    The rotator cuff is a group of 4 muscles in the shoulder joint including the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles originate in the scapula and attach to the head of the humerus through tendons.

  • SLAP Repair

    A SLAP repair is an arthroscopic shoulder procedure to treat a specific type of injury to the labrum called a SLAP tear.

  • 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.

  • Shoulder Stabilization

    Frequent dislocations of the shoulder joint can lead to chronic shoulder instability. Surgery to stabilize the shoulder may be recommended when conservative treatment options fail.

  • 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.

  • 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).

  • 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.

  • 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.

  • 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.

  • Subacromial Decompression

    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.

  • Shoulder Resurfacing

    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.

  • 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.

  • Arthroscopic Frozen Shoulder Release

    An arthroscopic frozen shoulder release is a minimally-invasive shoulder surgery performed to relieve pain and restore normal function using a special instrument called an “arthroscope”.

  • Periprosthetic Shoulder Fracture Fixation

    A periprosthetic shoulder fracture is a fracture that occurs in the bone adjacent to a shoulder prosthesis.

  • Arthroscopic Superior Capsular Reconstruction (SCR)

    Superior Capsular Reconstruction is a surgical procedure to repair massive, irreparable rotator cuff tears. The surgery involves reconstruction of the superior capsule of the shoulder joint using an autograft (tissue from the same person) or an allograft (tissue from a donor).

  • Bony Instability Reconstruction of the Shoulder

    The shoulder is the most flexible joint in the body. Injury and trauma can tear or stretch the labrum and/or ligaments, causing loosening and instability of the shoulder joint which can lead to partial or complete dislocation of the joint.

  • Intraarticular Shoulder Injection

    The shoulder is prone to different kinds of injuries and inflammatory conditions. An intraarticular shoulder injection is a minimally invasive procedure to treat pain and improve shoulder movement.

  • Ultrasound-Guided Shoulder Injections

    An ultrasound is a common imaging technique that employs high-frequency sound waves to create images of organs and other internal structures of the body.

  • 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.

  • Triceps Repair

    Triceps repair is a surgical procedure that involves the repair of a ruptured (torn) triceps tendon. A tendon is a tough band of fibrous tissue which connects muscle to bone and works together with muscles in moving your arms, fingers, legs, and toes.

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 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.
  • American Orthopaedic Society for Sports Medicine
  • American Association for Hand Surgery
  • American Academy Of Orthopaedic Surgeons
  • The American Board of Pediatrics
  • North American Spine Society
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