Next Lesson - Conditions of the Arm
Core
Want to brush up on anatomy before you begin looking at conditions? Head to our articles on Bones of the Upper Limb and Muscles of the Shoulder for more information!
Shoulder dislocations occur when the humeral head (the ball at the top of the upper arm bone) is displaced out of the glenoid fossa (the shallow socket of the shoulder blade). They can be divided into three categories: anterior, posterior and inferior dislocations.
Anterior dislocations are the most common. They make up over 95% of all shoulder dislocations. Anterior dislocations are usually caused by a blow to the posterior shoulder. They can also happen when the arm is pushed posteriorly while the hand is placed behind the head. Both push the humeral head forwards, out of the glenoid fossa. They present with an externally rotated and abducted arm.
Posterior dislocations are far less common and are caused by epileptic seizures, electrocution, lightning strikes or a blow to the anterior shoulder. A blow pushes the humeral head posteriorly. They present with an internally rotated and adducted arm, often with limited external rotation. Obvious shoulder deformity may be minimal.
Inferior dislocations are very rare and are caused by hyperabduction (the arm being forced up above the head). They present with an abducted arm, usually with a flexed elbow (arm placed behind head).
Injuries that can happen alongside a shoulder dislocation, and that are checked for because they change treatment, include:
- Bankart lesion: a tear of the glenoid labrum (the ring of cartilage around the edge of the shoulder socket)
- Hill-Sachs lesion: a dent in the humeral head, caused by the lip of the glenoid fossa hitting the humeral head during the injury.
- Rotator cuff muscle tear (the rotator cuff is the group of four muscles and their tendons that hold the humeral head in the socket)
- Damage to axillary artery/nerve (the artery and nerve in the armpit)
Treatment of shoulder dislocations involves an X-ray to confirm the dislocation and check for a fracture, pain relief or sedation, and reduction (putting the joint back in place). The nerves and blood supply of the arm are checked before and after reduction. Early movement is then encouraged as soon as the pain allows, with physiotherapy. Surgery is sometimes needed, for example to reduce the risk of the joint dislocating again. People under 25 should be seen by a shoulder surgeon within 6 weeks, to consider whether surgical repair is appropriate.
Diagram - An X-ray of a shoulder dislocation with Bankart and Hill-Sachs lesions
Creative commons source by Mikael Häggström, M.D. [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
Impingement syndrome, also called rotator cuff tendinopathy (disease or damage of a tendon), is the impingement of rotator cuff muscle tendons on the coracoacromial arch (the arch of bone and ligament over the tendons). Here, impingement means the tendons are pinched or squeezed. It is linked to:
- Thickening of the coracoacromial ligament
- Inflammation of a rotator cuff muscle tendon
- Subacromial osteophytes (bony spurs under the acromion, the bony tip of the shoulder blade that forms the top of the shoulder)
Each of these reduces the space under the acromion that the tendons pass through. Impingement syndrome causes pain, weakness and reduced range of motion when the shoulder is flexed and/or abducted. A ‘painful arc’ between 60° and 120° of abduction suggests the pain is coming from under the acromion. The source may be the rotator cuff tendons or the bursa (a fluid-filled sac that cushions the tendon). The sign alone does not prove a tear or show exactly what is causing the pain.
Diagnosis is based on a targeted medical history and physical examination. An X-ray is not routinely needed in primary care. It is considered if there has been trauma, if the person is not improving with treatment, or if there are red flags (signs of a more serious problem). Treatment starts with pain relief: paracetamol first, then a non-steroidal anti-inflammatory drug (NSAID) if needed. A short period of rest in the acute phase is followed by gradually increasing activity with physiotherapy exercises. A corticosteroid (steroid) injection can be considered. People who have not benefited from at least 6 weeks of non-surgical treatment are referred to secondary care for specialist assessment. Any decision about surgery is made through shared decision-making, because the evidence for it is limited. In a large UK trial (CSAW, short for Can Shoulder Arthroscopy Work?), keyhole (arthroscopic) surgery to remove bone and soft tissue under the acromion was no better than a placebo operation (keyhole surgery without that removal).
Adhesive capsulitis, commonly known as ‘frozen shoulder’, is a condition involving thickening and scarring (fibrosis) of the joint capsule, the tissue around the glenohumeral (shoulder) joint. There is also a variable inflammatory component (some inflammation, which differs between people). It presents with pain that often worsens at night, and with stiffness that makes the shoulder hard to move. It moves through three overlapping phases (painful, stiff and resolution) and usually settles within 18 to 24 months, although some people have symptoms for several years. It is more common in people with diabetes.
Frozen shoulder is more common in people who have previously had it in the opposite shoulder. In one study of 60 patients followed for an average of 3.4 years, 22 (37%) later developed it in the other shoulder. Developing it in the other shoulder was more common in people with diabetes and in people under 50. The diagnosis is made from the history and examination. Both active movement (the person moving their own arm) and passive movement (the examiner moving it) are restricted, especially turning the arm outwards (external rotation). X-rays are not routinely needed, but can be used to exclude other causes such as arthritis. Treatment starts with pain relief: paracetamol first, then an oral NSAID if needed. A corticosteroid (steroid) injection into the joint can be considered early if progress is slow, alongside physiotherapy. A small number of people are referred to a specialist (secondary care), where options include manipulation of the shoulder under general anaesthetic or capsular release (surgery to release the tight joint capsule).
Rotator cuff tears refer to damage to any of the rotator cuff muscles (the four muscles that move and steady the shoulder joint): supraspinatus, infraspinatus, teres minor and subscapularis. The most common muscle to tear is supraspinatus. Risk factors include certain repetitive actions (e.g. overhead activity like painting ceilings), smoking, and a family history of rotator cuff tears.
This injury is often without symptoms. When it does cause symptoms, the usual one is pain over the top and outer side of the shoulder. It is made worse by raising the arm or by overhead activities, and sometimes there is pain at night. Tears become more common with age. Which movement is weakened depends on the tendon that is torn. Supraspinatus tears weaken the start of abduction (lifting the arm out to the side), infraspinatus and teres minor tears weaken turning the arm outwards (external rotation), and subscapularis tears weaken turning it inwards (internal rotation). This weakness can make normal daily activities such as brushing hair difficult and painful.
Treatment usually includes pain relief and physical therapy. Surgery is an option for large acute tears, or for young individuals with full thickness tears (tears that go right through the tendon). A suspected acute tear after an injury (trauma, pain and weakness) needs urgent referral to a specialist shoulder clinic, because a delayed diagnosis makes surgical repair less likely to succeed.
Calcific Supraspinatus Tendinitis
Calcific supraspinatus tendinitis occurs when macroscopic deposits (deposits large enough to see) of hydroxyapatite crystals (a calcium compound) accumulate in the tendon of the supraspinatus muscle. It presents with shoulder pain aggravated by flexion and abduction, as well as mechanical symptoms such as stiffness, snapping or catching sensations.
Diagnostic tests include X-rays (which reveal larger deposits) and ultrasound scans (to pick up smaller deposits that an X-ray may have missed). Most cases settle in time without treatment. When treatment is needed, it can include NSAIDs for pain management, physical therapy, a steroid injection, barbotage (using a needle to suck up or break up the calcium deposits) or surgery (rarely used). NICE advises that shock wave therapy (pulses of sound energy aimed at the deposit) should only be used in the context of research, because the evidence that it works is inadequate.
Image - An X-ray of calcific supraspinatus tendinitis indicated by the red circle
Creative commons source by Emilios Pakos, Ioannis Gkiatas, Georgios Rakkas, Dimitrios Papadopoulos, Ioannis Gelalis, Marios Vekris and Anastasios Korompilias [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
Edited by: Dr. Maddie Swannack
About 80% of all clavicle fractures are mid-clavicular fractures. They are usually caused by a fall onto the side of the shoulder or a blow to the shoulder, and sometimes by a fall onto an outstretched hand. A displaced mid-clavicular fracture presents with a dropped shoulder and adduction of the arm. A displaced break leaves two pieces: the medial fragment (nearer the breastbone) and the lateral fragment (nearer the shoulder). Sternocleidomastoid (a neck muscle) elevates the medial fragment. The weight of the upper limb lowers the lateral fragment, while pectoralis major (a chest muscle) pulls the lateral fragment medially. A displaced mid-clavicular fracture can sometimes push the sharp end of the bone against the skin (‘skin tenting’). Rarely, the bone breaks through the skin, which is called an open fracture. An open fracture increases the chance of infection and makes the fracture harder to treat. Displaced fractures may require surgery to realign the fragments, but most fractures can be treated by wearing a sling to restrict movement whilst the bone heals.
Image - An X-ray of a mid-clavicular fracture
Creative commons source by Majorkev [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
The brachial plexus is a network of nerves that starts in the neck, from the fifth cervical to the first thoracic spinal nerves (C5 to T1). It runs down into the armpits (axillae) and has important motor and sensory functions in the upper limbs.
An upper brachial plexus injury, also known as ‘Erb’s Palsy’ or ‘Duchenne’s Palsy’, describes damage to the fifth and sixth cervical spinal nerve roots (C5 and C6) in the neck. It is most often a birth injury, caused by shoulder dystocia (shoulders getting stuck in the birth canal) during delivery. In older children and adults, it can follow trauma that forcefully pushes the shoulder down and increases the angle between the neck and shoulder.
This condition presents with internal rotation and adduction of the arm at the shoulder, extension of the arm at the elbow, pronation of the forearm (turning the palm backwards) and wrist flexion. This arm position is sometimes called ‘Waiter’s tip’. It also causes paraesthesia (altered sensation, such as pins and needles or numbness) in the C5 and C6 dermatomes (the areas of skin supplied by those nerve roots): the lateral arm, lateral forearm, thumb and index finger.
Many babies with a brachial plexus birth injury recover without surgery (reviews report about two-thirds to three-quarters). Surgical repair of the nerves is considered if recovery is absent or severely delayed, so a baby who is not recovering needs early referral to a specialist.
Image - A small child with an Upper Brachial Plexus injury, Erb's Palsy ("waiter's tip"). Notice the backward-facing hand, caused by internal rotation and adduction of the arm at the shoulder, forced extension of the arm at the elbow, forced pronation of the forearm and wrist flexion
Public Domain Image, edited by Dr. Marcus Judge
A lower brachial plexus injury, also known as ‘Klumpke’s Palsy’, describes damage to the eighth cervical and first thoracic spinal nerve roots (C8 and T1). It is usually caused by forced hyperabduction (the arm being forced up above the head) at the shoulder. An example is falling from monkey bars and catching the bar with one hand at the last minute, which yanks the arm up above the head. In some (rare) cases it is due to impingement (pressure on the nerves) from a Pancoast tumour (a tumour at the apex of the lung).
This condition presents with a claw hand (fingers bent into a claw shape). It also causes paraesthesia (altered sensation) in the C8 and T1 dermatomes (the areas of skin supplied by those nerve roots): the ring and little fingers, medial border of the hand and medial forearm.
Treatment depends on the cause and how severe the injury is. Surgical repair of the nerves is considered if there is not enough improvement.
Image - A Lower Brachial Plexus Injury, Klumpke’s Palsy and the classic "Claw Hand" it presents with
Public Domain Image, edited by Dr. Marcus Judge
Diagram - The anterior view of the five main nerves that come from the brachial plexus, on the arm. Axillary in red, median in green, musculocutaneous in orange, radial in yellow and ulnar in blue
Creative commons source by Kinstudent [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
'Winged Scapula' is a condition that most often occurs with paralysis of the long thoracic nerve. This nerve originates from the C5, C6 and C7 spinal nerve roots (the fifth, sixth and seventh cervical roots) as they enter the brachial plexus. So winged scapula is not technically a brachial plexus injury, but it is very closely associated. The long thoracic nerve normally supplies (innervates) the serratus anterior muscle. This muscle is on the side of the chest and rotates the scapula so that the arm can abduct. When this muscle is paralysed, the scapula twists out of position and becomes prominently visible beneath the skin. Long thoracic nerve paralysis can be caused by direct trauma to the path of the nerve, or by over-stretching, such as in overhead weight-lifting. It can also be caused by neuralgic amyotrophy (a nerve condition with severe pain followed by weakness). Published groups of patients differ on which cause is most common. In one group of 128 people with winging on one side, neuralgic amyotrophy explained most long thoracic nerve palsies (61 of 70). In another group of 197 people with serratus anterior paralysis, exertion (35%) or trauma (26%) preceded most cases. Less often, winging is caused by paralysis of the spinal accessory nerve, which supplies the trapezius muscle.
Winging of the scapula is most visible when the shoulder is flexed and the arm is pressed against a wall (as shown in the image below).
Treatment ranges from pain relief (analgesia) and lifestyle modifications (like avoiding overhead work), to surgery. Recovery can take up to about 2 years, and some people are left with residual winging or weakness. Surgery may be considered for people with severe symptoms who have not recovered after about 12 months of non-surgical treatment, but opinions differ because many people keep improving for up to 2 years, so the timing is a specialist decision.
Diagram - Posterior view of a patient with 'Winged Scapula'. Note the protrusion of the right scapula compared to the left.
Public domain image
Reviewed by: Dr. Thomas Burnell and Dr. Marcus Judge
Edited by: Dr. Maddie Swannack
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