Trauma
Question 123 of 216
A 28 year old man presents to the Emergency Department having injured his right shoulder playing basketball. You position the patient as shown in the image above. He is unable to maintain this position with his right arm as you push downwards on both arms. Which of the following muscles is most likely to be injured?
Answer:
This is the Empty Can Test, used to assess the supraspinatus muscle. The test is positive if the patient has pain or weakness.Shoulder Injuries
Trauma
Last Updated: 29th September 2022
Anterior shoulder dislocation
- Mechanism
- This is a common injury, which typically results from forced external rotation/ abduction of the shoulder. The humeral head usually dislocates to lie anteriorly and slightly inferiorly to the glenoid.
- Clinical features
- Patients often present supporting the affected arm with the uninjured arm.
- Flat shoulder deformity (loss of normal rounded appearance of shoulder).
- Step-off deformity at the acromion with a palpable gap below the acromion.
- Humeral head palpable anteroinferiorly to the glenoid.
- Evidence of complications.
- Complications
- Nerve damage - axillary, radial, brachial plexus
- Vascular damage - axillary artery
- Associated fracture e.g. humeral head, greater tuberosity, clavicle, acromion
- Recurrent shoulder dislocation
- Rotator cuff injury
- Hill-Sachs lesion (posterolateral humeral head compression fracture)
- Bankart lesion (avulsion of the anteroinferior glenoid labrum at its attachment to the anteroinferior glenohumeral ligament complex)
- Management
- Give analgesia and support in a temporary sling. X- ray before reduction to exclude associated fractures. X- rays show loss of congruity between the humeral head and the glenoid. The humeral head is displaced medially and inferiorly on an AP shoulder X- ray.
- Reduce under sedation/ analgesia, with full monitoring. The choice of technique is personal and depends partly upon familiarity. Apply minimal force to prevent humeral fracture or further soft tissue damage. In patients with habitual recurrent dislocation (and in a significant proportion of other patients as well), reduction may be easily achievable with minimal use of drugs [e.g. Entonox® or methoxyflurane (Penthrox®) alone]. Take time and perform the manoeuvre slowly.
- Reduction techniques
-
- Leverage techniques:
- Kocher's method
- The original technique is noted to be painless and excludes traction using leverage alone.
- Lie the patient back almost flat, and once sedation and analgesia are adequate:
- With the elbow flexed to 90°, slowly externally rotate the shoulder. Pause if there is any resistance and continue only when muscles relax.
- Slowly adduct the upper arm across the chest, with the shoulder still held in external rotation.
- Once adducted as far as possible, internally rotate the shoulder by flipping the forearm towards the opposite shoulder.
- Reduction may occur at any time during the manoeuvre— success is more likely if the patient is relaxed (avoid traction) and if initial external rotation reaches 90°.
- Complications have been associated with this technique if the procedure is not carried out correctly e.g. when traction is applied, when the procedure is carried out hastily. Complications include tearing of the subscapularis muscle and spiral fracture of the humeral head.
- External rotation technique
- Kocher's method
- Traction methods
- Modified Milch technique
- Hippocratic method
- Stimson's method
- Matsen's traction counteraction
- Spaso technique
- Eskimo technique
- Manes method
- Scapular manipulation
- Scapular manipulation technique
- Leverage techniques:
-
- After reduction, recheck pulses and sensation (including axillary and radial nerves), and obtain a check X-ray. Immobilise in a collar and cuff and body bandage. Local policy sometimes includes shoulder immobilisation webbing or braces as standard. Provide analgesia (e.g. co- dydramol) and arrange follow- up. If unsuccessful or difficult or if the shoulder has been dislocated for >24hr, refer for reduction under GA.
- Fracture-dislocation of the shoulder: Most involve fractures of the greater tuberosity associated with anterior dislocation of the shoulder. Reduce under sedation, as with uncomplicated dislocations— in most cases, the fracture will reduce satisfactorily, along with the dislocation. However, refer large or complex fracture–dislocations involving the humeral head, neck, or shaft.
Posterior shoulder dislocation
- This uncommon injury is easy to miss. It results from a blow onto the anterior shoulder or a fall onto the internally rotated arm. It may also occur during seizures or after an electric shock (when other injuries and medical problems may be partly responsible for it being initially overlooked).
- The patient presents with the shoulder internally rotated. AP shoulder X- ray may appear normal, but careful inspection reveals an abnormally symmetrical appearance of the humeral head (‘light bulb sign’) and loss of congruity between the humeral head and the glenoid. A modified axial shoulder X- ray (from above) or a translateral view confirms posterior dislocation.
- Manipulate under sedation— apply traction and external rotation to the upper limb at 90° to the body. If difficult, refer for reduction under GA. Treat and follow up as for anterior dislocation.
Luxatio erecta
- This is a rare inferior dislocation of the humeral head.
- The patient presents with the arm held abducted above the head. Check carefully for neurovascular complications.
- Reduce under sedation by traction in line with the abducted upper arm, followed by adduction of the shoulder. This may require reduction under GA. Treat and follow up as for anterior dislocation.
Clavicle fracture
- This is a common injury in children and adults alike.
- This injury results from direct trauma or from falls onto an outstretched hand or point of the shoulder.
- Check carefully for neurovascular complications (these are rare, but potentially life- threatening), and for associated rib fractures and pneumothorax.
- Treat with analgesia and a broad arm sling, and arrange fracture clinic follow- up. The vast majority of fractures unite satisfactorily with conservative treatment. Rarely, grossly displaced fractures are internally fixed.
Acromioclavicular joint injury
- These are common injuries which usually follow falls onto the shoulder.
- Look for tenderness, swelling, or a palpable step over the AC joint.
- X- rays show AC joint disruption (vertical subluxation of the AC joint by >1– 2mm).
- Grade I: minimal separation. Only AC ligaments are involved.
- Grade II: obvious subluxation, but still some apposition of bony ends.
- Grade III: complete dislocation of the AC joint, indicating rupture of the conoid and trapezoid ligaments, in addition to the AC ligaments.
- Treat with analgesia and support in a broad arm sling, and arrange follow- up for grade II and III injuries. These measures allow complete recovery in most cases. Occasionally, selected patients benefit from internal fixation.
Humeral neck/head fracture
- These result from direct trauma to the upper arm or from falls onto an outstretched hand.
- Examine for tenderness or swelling over the proximal humerus. Shoulder movements are usually limited by pain.
- X- rays typically reveal impacted or oblique fractures, with or without associated fractures of the greater and lesser tuberosities. Fractures may be classified as two- , three- , or four- part fractures, according to the number of fragments resulting (e.g. a fractured humeral neck combined with a fractured greater tuberosity will be a ‘three- part fracture’).
- Treat with a collar and cuff support, analgesia, and follow- up. Warn the patient to expect significant visible bruising to appear, extending down the arm towards the elbow (for this reason, it is helpful to document the lack of any clinical evidence of elbow injury at first presentation). Discuss with the orthopaedic team all comminuted, displaced, or markedly angulated humeral neck fractures as MUA and, occasionally, internal fixation/ hemiarthroplasty are indicated.
- Occasionally, there is an isolated fracture through the greater tuberosity, with no fracture through the surgical neck. Provide analgesia; treat in a sling/ collar and cuff, and arrange fracture clinic follow- up.
Scapular fracture
- This usually results from direct trauma and implies a forceful mechanism of injury.
- Check carefully for associated injuries to the thorax such as rib fractures or haemopneumothorax.
- Treat isolated fractures with a broad arm sling and analgesia, and arrange follow- up.
Rotator cuff tears
- Acute tears of the rotator cuff (the supraspinatus ruptures most commonly) usually follow chronic rotator cuff disease in patients >40y. They may follow trauma (e.g. fall with hyperabduction or hyperextension of the shoulder).
- Examine for decreased range of movement, weakness, crepitus, and tenderness over the cuff insertions and subacromial area. Check supraspinatus strength by testing resistance to abduction, but remember that pain from the acute injury may preclude a full assessment in the ED.
- Look for bony avulsions on X- ray (tensile strength of the cuff exceeds that of adjacent bone).
- Treat suspected rotator cuff tears conservatively initially with analgesia and support in a broad arm sling, followed by exercises/ physiotherapy at ~10 days. Arrange follow- up for patients with significantly decreased range of movement— complete tears (particularly in younger patients) may require surgical repair. Inability to actively abduct to 90° at ~10 days suggests a complete tear, which will be apparent on MRI.
| Muscle (Innervation) | Function | Assessment |
|---|---|---|
| Supraspinatus (suprascapular nerve) | Initiation of abduction of arm to 15 degrees at glenohumeral joint | Empty Can Test: Position the patient with arms elevated to 90 degrees in the scapular plane, with the elbow extended, and full medial rotation and pronation of the forearm with thumbs pointing downwards. Ask the patient to resist the downward force being applied to the forearm. Test is positive is patient has pain or weakness. |
| Infraspinatus (suprascapular nerve) | Lateral rotation of arm at glenohumeral joint | Infraspinatus Test: Position the patient with the arm fully adducted, with the elbow flexed to 90 degrees. Ask the patient to resist the medially directed force being applied to the arm. Test is positive if patient has pain or weakness. |
| Teres minor (axillary nerve) | Lateral rotation of arm at glenohumeral joint | Hornblower's Test: Position the patient with the arm elevated to 90 degrees in the scapular plane and the elbow flexed to 90 degrees. Ask the patient to laterally rotate the arm against resistance. Test is positive if patient has pain or weakness. |
| Subscapularis (subscapular nerves) | Medial rotation of arm at glenohumeral joint | Lift-off Test: Position the patient in full medial rotation with the dorsum of the hand on the lower back. Ask the patient to lift their hand away from their back against resistance. Test is positive if patient has pain or weakness. |
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
