crystal clinic orthopaedic center summit hand

Shoulder

Shoulder Anatomy

The shoulder is the most flexible joint in the body enabling 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

The shoulder 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.

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

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

Ligaments are the thick strands of fibers that connect one bone to another. The ligaments of the shoulder joint include

  • Coraco-clavicular ligaments: these ligaments connect the collarbone to the shoulder blade at the coracoid process
  • Acromio-clavicular ligament: this connects the collarbone to the shoulder blade at the acromion process 
  • Coraco-acromial 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 water-tight sac around the joint. Glenohumeral ligaments play a very important role in providing stability to the otherwise unstable shoulder joint by preventing dislocation.

Muscles

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

Tendons are strong tissues that join muscle to bone allowing the muscle to control the movement of the bone or joint. Two important group 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

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

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.

Conditions

  • AC Joint Injury (Shoulder Separation)

    Acromioclavicular joint (AC joint) dislocation or shoulder separation is one of the most common injuries of the upper arm.

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  • AC Joint 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.

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  • Axillary Nerve Palsy

    The axillary nerve provides function to the deltoid muscle of the shoulder. Injuries to the shoulder can damage this nerve leading to weakness or loss of shoulder movement.

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  • Bankart Lesion

    The labrum is a rim of fibrocartilage that borders the shoulder socket or glenoid. A Bankart lesion is an injury to the labrum at the lower front border of the socket that may be caused by shoulder trauma or repetitive or forceful throwing or lifting.

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  • Biceps Tendonitis at The Shoulder

    Bicipital tendonitis is the inflammation of the biceps tendon, the tissue that connects muscle to bone in your upper arm, causing pain in the upper arm and shoulder.

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  • Brachial Plexus Injuries

    The brachial plexus is a system of nerves extending from the neck to the armpit that supplies the arm with sensory and motor functions. Injury to these nerves can occur with forceful pulling or stretching of the arm.

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  • Calcific Tendonitis

    Calcific tendonitis is a condition in which calcium deposits develop within the tendons. It usually occurs in the rotator cuff tendons of the shoulder and can cause pain and affect shoulder movement.

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  • Clavicle Fractures

    Clavicle fracture, also called broken collarbone is a very common sports injury seen in people who are involved in contact sports such as football and martial arts as well as impact sports such as motor racing.

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  • Coracoclavicular Ligament Injury

    The coracoclavicular ligament connects the coracoid process of the shoulder blade with the clavicle (collar bone). It may be injured by trauma to the shoulder and usually occurs with a clavicular fracture or an injury to the acromioclavicular joint.

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  • Frozen Shoulder

    Frozen Shoulder

    Frozen shoulder, also called adhesive capsulitis is a condition characterized by pain and loss of motion in shoulder joint.

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  • Internal Impingement

    Shoulder impingement is the condition of inflammation of the tendons of the shoulder joint. It is one of the most common causes of pain in the adult shoulder.

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  • Long Thoracic Nerve Compression

    The long thoracic nerve passes through the neck, armpit and side of the chest to supply a muscle called the serratus anterior which helps stabilize the shoulder blade. Compression of the long thoracic nerve can lead to shoulder pain, difficulty raising the arm and abnormal protrusion of the shoulder blade.

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  • Os Acromiale

    Os acromiale is a condition in which the acromion, a bony projection from the shoulder blade fails to develop properly. This can lead to pain due to impingement, rotator cuff injury and arthritis.

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  • Pectoralis Major Tear

    The pectoralis major is a muscle over the chest that helps with movement of the shoulder because of its attachment to the upper arm bone. Rupture of the pectoralis major can occur due to participation in sports such as weightlifting.

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  • Proximal Humerus And Shaft Fractures

    Humerus is the upper arm bone and it forms two joints -shoulder joint and elbow joint. The proximal humerus is the upper end of arm bone that forms shoulder joint.

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  • Rotator Cuff Tears

    Rotator Cuff Tears

    Rotator cuff is the group of tendons in the shoulder joint providing support and enabling wider range of motion. Major injury to these tendons may result in tear of these tendons and the condition is called as rotator cuff tear.

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  • Scapular Fractures

    The shoulder is made up of the clavicle (collar bone), humerus (upper arm) and scapula (shoulder blade). The shoulder is a ball and socket joint where the ball of the upper arm bone articulates with the socket of the shoulder blade called the glenoid cavity.

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  • Scapular Winging

    Scapular winging is an abnormal protrusion of the scapula (shoulder blade) due to dysfunction of the muscles that stabilize it, mainly the serratus anterior muscle. Dysfunction of the serratus anterior occurs with injury to the long thoracic nerve.

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  • Shoulder Fractures

    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).

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  • Shoulder Arthritis

    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.

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  • Snapping Scapula

    Shoulder movements cause the scapula to glide smoothly over the ribcage due to the presence of fluid-filled sacs called bursae. An abnormal snapping sound or sensation may occur with movement of the scapula due to abnormalities of bursae and adjacent hard and soft tissues.

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  • Subacromial Impingement

    Shoulder impingement is the condition of inflammation of the tendons of the shoulder joint.

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  • Suprascapular Nerve Palsy

    The suprascapular nerve passes through a notch in the shoulder blade and supplies the supraspinatus and infraspinatus muscles. These are rotator cuff muscles that help with shoulder movements and may be affected by injury or compression of the nerve.

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  • Sub-coracoid Impingement

    Subcoracoid impingement is a condition in which the subscapularis muscle that stabilizes the shoulder joint undergoes compression between the coracoid process of the scapula (shoulder blade) and the lesser tuberosity of the humerus (upper arm bone). This can result in pain in the front of the shoulder which is worsened by certain shoulder movements.

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  • Suprascapular Nerve Compression

    The suprascapular nerve passes through a notch in the shoulder blade and may undergo compression in this region with prolonged use of backpacks or sports involving overhead arm movements. This can cause pain over the shoulder blade and difficulty with certain shoulder movements.

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  • Throwing Athletes Shoulder

    The shoulder joint is a ball and socket joint. A 'ball' at the top of the upper arm bone (the humerus) fits into a 'socket', called the glenoid, which is part of the shoulder blade (scapula).

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Procedures

  • Shoulder Injections

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

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  • Shoulder Arthroscopy

     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.

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  • Total Shoulder Replacement

    Total Shoulder Replacement

    The shoulder is a highly movable body joint that allows various movements of the arm. It is a ball and socket joint, where the head of the humerus (upper arm bone) articulates with the socket of the scapula (shoulder blade) called the glenoid.

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  • Reverse Total Shoulder Replacement

    Reverse Total Shoulder Replacement

    Reverse total shoulder replacement, is an advanced surgical technique specifically designed for rotator cuff tear arthropathy, a condition where the patient suffers from both shoulder arthritis and a rotator cuff tear.

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  • Fractures Care

    Bones are very rigid structures in the body mostly made up of calcium. They provide a basic structure to the skeletal body and allow us to do many tasks such as walking, running, holding, etc.

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  • Rotator Cuff Repair

    Rotator Cuff Repair

    Rotator cuff is the group of tendons in the shoulder joint providing support and enabling wider range of motion. Major injury to these tendons may result in tear of these tendons and the condition is called as rotator cuff tear.

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  • Shoulder Decompression

    The structures within the shoulder may undergo impingement for various reasons producing pain and limiting movement. Shoulder decompression surgery is performed to relieve areas of impingement and may be performed with an open or arthroscopic technique.

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  • Shoulder Release

    Scar tissue may develop in the shoulder after a shoulder injury or surgery, restricting movement of the shoulder. Shoulder release surgery is performed to improve shoulder movement by stretching, tearing or cutting through tight tissues.

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  • Nerve Decompression

    Suprascapular nerve is a mixed (sensory and motor) nerve that arises from the upper trunk of the brachial plexus.

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  • Ligament Repair/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).

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  • Tendon Transfers

    Tendon transfer surgery is a surgery to restore the lost functions of the hand by shifting functioning tendon from its initial attachment to the new one.

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  • Distal Clavicle Resection

    The acromioclavicular joint of the shoulder may become arthritic with age. Distal clavicle resection is surgery performed to relieve symptoms by removing or resecting the outer end of the clavicle. This surgery may be performed in an arthroscopic manner.

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  • Shoulder Ultrasound

    Shoulder ultrasound is a therapy that uses heat generated by high-frequency ultrasound waves to heal the injured tissues and improve joint function. The heat produced reduces pain and spasms and helps stretch the tissues.

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  • Acromioplasty

    The acromion is a projection of bone from the shoulder blade that articulates with the collar bone and overlies tendons of the rotator cuff muscles. Acromioplasty is a procedure to remove part of the acromion that is impinging on the tendons to relieve pain and improve shoulder movement.

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  • Arthroscopic Rotator Cuff Repair

    Rotator cuff is the group of tendons in the shoulder joint providing support and enabling wider range of motion. Major injury to these tendons may result in tear of these tendons and the condition is called as rotator cuff tear.

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  • Arthroscopic Shoulder Release

    Scar tissue may develop in the shoulder after a shoulder injury or surgery, restricting movement of the shoulder. Arthroscopic shoulder release is a minimally invasive procedure in which your surgeon makes small incisions and uses special instruments to cut through tight tissues.

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  • Arthroscopic AC Joint Arthritis Treatment

    Acromioclavicular (AC) joint arthritis is a condition that develops when the cartilage cushioning the AC joint in the shoulder begins to wear out.

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  • The American Board of  Orthopaedic Surgery
  • Allegheny General Hospital
  • University of Pittsburgh  Medical Center
  • University of Cincinnati College of Medicine
  • American Society for Surgery of the Hand
  • American Association for Hand Surgery: AAHS
  • Alpha Omega Alpha