Shoulder Pain and Anatomy

The clavicle or collarbone is an S-shaped bone connecting 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 breastbone. The clavicle also protects important nerves from the spine and blood vessels from the heart that pass under it to the arm.

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 with minimal friction enabling smooth movement. Articular cartilage acts as a shock absorber during the loading of the shoulder bones.

The glenoid labrum, a ring of fibrous cartilage that surrounds the glenoid cavity, provides extra stability to the glenohumeral joint. It 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 the thick strands of fibres 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
• Coraco-acromial ligament: It connects the acromion process to the coracoid process
• Glenohumeral ligaments: A group of ligaments that are confluent with the capsule around the shoulder joint and connect the head of the arm bone to the shoulder blade's glenoid cavity. The capsule forms a water-tight sac around the joint. Glenohumeral ligaments are important in stabilising 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 comprises four 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 muscle and is the largest and strongest muscle around the shoulder.

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.

Two bicep tendons join the upper arm's bicep muscle to the shoulder. One is attached to the long head of the muscle and the other to the short head.

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 help move the humerus and stabilise the ball on the shoulder joint socket.

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 and skin 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 shoulder region 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 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 deoxygenated blood back to the heart include:

• Axillary vein: drains into the subclavian vein
• Cephalic vein: is found in the forearm and arm. It drains into the axillary vein.
• Basilic vein: runs on the inside of the forearm and arm and joins the brachial veins in the upper arm to form the axillary vein.

What is Shoulder Pain?

Shoulder pain can result from many factors, including injury, disease, or conditions affecting the structures within the shoulder joint. The shoulder is a complex joint with multiple bones, tendons, and muscles that allow for a wide range of movement. As a result, it's quite prone to injury and other conditions.

Causes of Shoulder Pain

Some common causes of shoulder pain include:

• Rotator Cuff Injuries: This usually occurs due to the damage to the muscles and tendons that surround the shoulder joint. These injuries are common among people who frequently perform overhead motions, such as athletes or manual labourers.
• Shoulder Arthritis: Arthritis is inflammation of one or more of your joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age. 
• Shoulder Impingement: This happens when the top of the shoulder blade (acromion) puts pressure on the underlying soft tissues when the arm is lifted away from the body. As the arm is lifted, the acromion rubs, or "impinges" on, the rotator cuff tendons and bursa. This can lead to bursitis and tendinitis, causing pain and limiting movement.
• Labral SLAP Tears: The labrum is a piece of fibrocartilage (rubbery tissue) attached to the rim of the shoulder socket that helps keep the ball of the joint in place. SLAP stands for Superior Labrum Anterior and Posterior, which means the tear is at the top of the labrum, both in the front and back. These tears can result from acute trauma or repetitive shoulder motion and are often found in athletes.
• Trauma & Sports Injuries: Trauma such as falls or accidents can cause a wide range of shoulder injuries, from fractures and dislocations to tears of the tendons or ligaments. Sports requiring repetitive overhead movements, such as swimming, weightlifting, or throwing sports (javelin throwing, fast bowling), can also lead to various types of shoulder pain and injury.
• Tendonitis: This is a tendon inflammation, often resulting from a repetitive, minor impact on the affected area or a sudden, more serious injury.
• Bursitis: This is an inflammation of the bursa, which is a small, fluid-filled sac that acts as a cushion between a bone and other moving body parts such as muscles or tendons.
• Frozen Shoulder: Also known as adhesive capsulitis, this condition is characterised by stiffness and pain in your shoulder joint. Signs and symptoms may begin gradually, worsen over time and then resolve, usually within two years.
• Dislocated Shoulder: This happens when the arm's upper bone is forced out of your shoulder blade's socket. A severe injury often causes it, and it can cause intense pain.
• Fractures: These are broken bones, and in the shoulder, it usually involves the clavicle (collarbone) or humerus (upper arm bone).

Shoulder Pain Treatments

Treatment options for shoulder pain vary based on the underlying cause. It could range from rest, physiotherapy, and medication to manage pain and inflammation to surgical interventions in severe cases. It's important to seek medical attention if shoulder pain is severe, persistent, or accompanied by other concerning symptoms.

Dr Mwaturura performs a range of surgeries that solve many shoulder problems, including:

• Acromioclavicular Joint Stabilisation
• Rotator Cuff Repair
• Shoulder Stabilisation 
• Reverse Total Shoulder Replacement
• Shoulder Joint Replacement
• Bankart Repair