T&O III

Question 1

A 62-year-old female with marked osteoarthritis presents with nodes over the distal interphalangeal joint of her right index and ring fingers.

Answer 1

Heberden’s node

Heberden’s nodes occur at the distal interphalangeal joints in familial generalised osteoarthritis.

Bouchard’s nodes occur at proximal interphalangeal joints.

The square thumb deformity which is also seen in osteoarthritis of the hand results from a deformity of the thumb carpometacarpal joint.

Question 2

A 54-year-old female with rheumatoid arthritis presents with a deformity of her right middle finger in which there is flexion at the proximal interphalangeal joint and extension at the distal interphalangeal joint.

Answer 2

Boutonnière lesion

Rheumatoid arthritis results in synovitis of the metacarpophalangeal joints with filling of the hollow between metacarpal heads when the fingers are flexed and synovial swelling of the extensor tendon sheaths. Tendons may rupture producing a boutonnière deformity. (The central slip of the extensor expansion detaches from its insertion at the base of the middle phalanx. This allows the two slips to fall sideways and the proximal interphalangeal joint to protrude between the two, producing the characteristic deformity).

A swan neck deformity occurs by flexion at the metacarpophalangeal joint, proximal interphalangeal joint extension and flexion at the distal interphalangeal joint.

Question 3

A 41-year-old woman had a lump at the base of the distal phalanx of the left middle finger excised by the GP. The lump has rapidly recurred.

Answer 3

Ganglion

Ganglions occur most frequently on the dorsum of the wrist or foot but occasionally are related to the long flexor tendons in the palm or the peroneal tendons at the ankle.

At operation a tense unilocular cyst is seen communicating with the synovial membrane of a joint or a tendon sheath. They probably result from a leakage of synovial fluid with secondary fibrous encapsulation.

Recurrence is high (approximately 30%) following surgical excision.

Question 4

Elective resection of Crohn’s leaving 40 cm of small bowel.

Answer 4

Long term total parenteral nutrition (TPN)

Adequate quantities of amino acids, glucose, fat, minerals and vitamins produce a hypertonic solution. Therefore it is necessary to infuse this solution through a central venous line rather than a peripheral line.

Complications of TPN include

Phlebitis
Thrombosis
Pneumothorax
Haemothorax
Air embolism
Arterial damage
Septicaemia.
A good selection criterion is required based on a nutritional assessment.

Question 5

At laparotomy a resection of 30 cm of ischaemic large and small bowel are resected.

Answer 5

Normal diet

The small intestine is 4 m long and perfectly adequate nutrition can be maintained after half has been resected. Long-term survival has been recorded if 45 cm of jejunum is left intact along with the duodenum and colon. Less than 45 cm of intact jejunum and the patient will develop short bowel syndrome (progressive malnutrition) and will require long term intravenous feeding. Malabsorption of vitamin B12 and bile salts occurs when greater than 50 cm of the terminal ileum has been resected.

Question 6

Pancreatectomy for multiple endocrine tumours.

Answer 6

Oral diet with supplemental exocrine enzymes

Following resection of the entire pancreas the patient will lose exocrine enzymatic function and will develop steatorrhoea. These patients require frequent nutritional assessment and support if necessary. They also require life long supplementation of exocrine enzymes, for example, creon.

Question 7

Burns patients.

Please select the most appropriate answer from the given list for his fluid requirements in the first 24 hours.

Head, neck, back and buttocks

Answer 7

(Head and neck) 9% + (back and buttocks) 18% = 27%:
27 x 70 x 4 = 7.5 l

When a burn occurs it is important to estimate the extent and depth of the burns. The simplest way to estimate the extent of a burn for an adult is the rule of nines.

In this rule

The arms account for 9%
Legs 18%
Perineum 1%
Head 9%
Front of torso 18% 
Back of torso 18%
of the total body surface area.

Note that this rule tends to be less accurate in children, as the head is comparatively larger than the rest of the body.

Question 8

Burns patients

Please select the most appropriate answer from the given list for his fluid requirements in the first 24 hours.

Right circumferential leg and perineum

Answer 8

(Leg) 18% + (perineum) 1% = 19%:
19 x 70 x 4 = 5.3 l

The depth of a burn is determined as partial thickness (spares the dermis) to full thickness (epidermis and dermis destroyed). Burns of less than 10% can be treated orally with salt containing fluids.

Hypovolaemic shock tends to occur when burns affect more than 10% of the total body surface area. The degree of shock is proportional to the total area burned and the depth.

Burns of 10-30% require intravenous fluids and burns greater than 30% require a rapid infusion.

Question 9

Burns patients

Please select the most appropriate answer from the given list for his fluid requirements in the first 24 hours.

Left circumferential arm and neck

Answer 9

2-3 crystalloid
(Arm) 9% + (neck) 1% = 10%:
10 x 70 x 4 = 2.8 l

Fluid requirements are dictated by pulse, blood pressure, urine output and central venous pressure. A number of formulae are used, but in general the fluid requirement in the first 24 hours is calculated by percentage burn multiplied by body weight multiplied by 4.

There is little difference between colloid and crystalloid in the first 24 hours. Blood is usually not required in the first 24 hours.

Question 10

In hypovolaemic shock which of the following is true?
(Please select 1 option)
A narrowed pulse pressure indicates significant blood loss
Anuria (less than 17 ml/hr) occurs early
Haematocrit and haemoglobin are good indicators of estimated blood loss
Tachycardia and lowered blood pressure are early manifestations
Vasodilatation is an early response to blood loss

Answer 10

A narrowed pulse pressure indicates significant blood loss

Haemorrhage is the commonest cause of shock and post injury death in the trauma patient, and the only method of stopping on-going losses and stabilising the patient may be surgical. Therefore early surgical review is vital, along with early identification of shock itself.

Early circulatory changes are compensatory and include tachycardia and cutaneous vasoconstriction.

As the amount of blood loss increases and tissue perfusion further decreases, urine output is reduced and so eventually is the patient’s level of conciousness.

Significant reduction in blood pressure is a relatively late manifestation and a narrowed pulse pressure is an indicator of significant blood loss. Unfortunately haemoglobin and haematocrit are unreliable in estimating acute blood loss, and should not be used for diagnosing shock as they may only show minimal acute decrease in massive blood loss.

Oliguria is defined as a urine output of less than 17 ml/hr or more practically less than 400 mls in 24 hours. Oliguria only occurs when 30-40% of the circulating volume (class III haemorrhage) has been lost.

Anuria is defined as a urine output of less than 50 mls in 24 hours and only occurs when greater than 40% of the circulating volume has been lost.

Question 11

Which of the following are true of tracheostomy?
(Please select 1 option)
Bleeding should be managed by deflating the cuff and removing the tube
Cuffed tubes should be used in children under 8-years-old
It is usually required to wean from a prolonged period of mechanical ventilation
Open procedure involves division of the thyroid isthmus and vertical incision between the third, fourth and fifth tracheal rings
Removal requires a FiO2

Answer 11

It is usually required to wean from a prolonged period of mechanical ventilation

There are numerous indications for the formation of a tracheostomy.

These include:

The upper airway obstruction
To facilitate airway suction
To decrease the work of breathing and to allow weaning from mechanical ventilation.
Once the decision has been made to go ahead, a tracheostomy may be performed percutaneously or openly.

When using the open method, a midline incision is made and the thyroid isthmus divided and ligated and a vertical incision made between the second, third and fourth tracheal rings (as the formation of windows and flaps increases the risk of stenosis), and the cuff inflated.

However, in children, cuffed tubes should be avoided due to the risk of tracheal stenosis and mucosal ulceration.

Bleeding from the tracheotomy wound is also a recognised complication and best treated by not deflating the cuff or removing the tube - as they help to tamponade the bleeding - but by giving oxygen, ventilating the patient, and gaining IV access, whilst calling for help.

Criteria for the removal are that the patient is able to maintain their own airway and ventilate adequately. Indicators of this are a low inspired oxygen concentration, adequate carbon dioxide elimination, minimal sputum production and that the patient is not heavily sedated and able to co-operate!

Question 12

Which of the following is true of congenital torticollis?
(Please select 1 option)
Appears after the third month of birth
Facial asymmetry is a common presentation
Physiotherapy is ineffective in the early stages
The ear is nearer the shoulder on the normal side
Tilt and rotation of the head to the same side of swelling

Answer 12

Facial asymmetry is a common presentation

Congenital torticollis develops as a result of birth injury to the sternocleidomastoid muscle.

It can present from the second week of birth as a swelling within the sternocleidomastoid muscle.

Once the swelling subsides there is subsequent fibrosis resulting in a tilt of the head towards the affected side and rotation of the neck to the opposite side. Therefore the ear on the affected side is nearer the shoulder. Thus, congenital torticollis causes the head to tilt downwards towards the affected side and the face to turn away from the affected side.1 These are the normal actions of contraction of the muscle.

Facial asymmetry is a common clinical presentation.

In the early stages physiotherapy to lengthen the muscle is beneficial.

If the condition persists, surgical treatment in the form of division and release of the muscle at its lower end may be required.

Question 13

Regarding metastases, which of the following statements is correct?
(Please select 1 option)
Due to colon cancer are the commonest cause of bone metastases in women
Due to prostate cancer are predominately osteolytic lesions
Early in the disease process can be seen on plain radiographs
To the bone develop a pathological fracture in 10% of patients
To the bone occur in less than 5% of patients with malignant disease

Answer 13

To the bone develop a pathological fracture in 10% of patients

Bone metastases occur in up to 30% of patients with malignancy.

The commonest tumours causing bone metastases are

Breast (35%)
Prostate (30%)
Bronchus (10%)
Kidney (5%)
Thyroid (2%).
They usually present with

Bone pain
A lump
Pathological fracture
Hypercalcaemia
Cord compression.
Ten percent of patients with bone metastases will develop a pathological fracture.

Radiological changes usually occur late and bone scintigraphy is the most sensitive investigation available to detect metastatic spread.

Most metastases are osteolytic but some tumours, particularly prostate carcinoma, can cause osteosclerotic lesions.

Question 14

Which of the following regarding eponymous fractures is correct?
(Please select 1 option)
Bennett’s fracture involves the distal ulna
Colles’ fracture involves the proximal radius
Galeazzi’s fracture involves the radial shaft and dislocation of the proximal radioulnar joint
Monteggia’s fracture involves the proximal ulna and anterior dislocation of the head of the radius
Pott’s fracture is a general term applied to fractures around the knee

Answer 14

Monteggia’s fracture involves the proximal ulna and anterior dislocation of the head of the radius

A Bennett’s fracture is an intra-articular fracture of the base of the first metacarpal.

A Galeazzi’s fracture involves the radial shaft with dislocation of the distal radioulnar joint.

Monteggia’s fracture is an angulated fracture at the junction of the proximal and middle third of ulna accompanied by anterior dislocation of the radial head.

A Pott’s fracture is a general term applied to fractures around the ankle.

Question 15

Regarding osteosarcoma, which of the following statements is correct?
(Please select 1 option)
Affects the epiphyses of long bones
Can result in pulmonary metastases via haematogenous spread
Is exclusively a disease of adolescence and early adult life
Is most commonly seen around the hip
On x ray shows a ‘sunburst’ appearance due to bony involvement

Answer 15

Can result in pulmonary metastases via haematogenous spread

Osteosarcomas affect the metaphyses of long bones.

They are most commonly seen around the knee and in the proximal humerus.

They often occur in young adults but are also seen in the elderly in association with Paget’s disease. They usually present as bone pain and a palpable lump.

x Ray shows periosteal elevation (Codman’s triangle) and a ‘sunburst’ appearance due to soft tissue involvement.

Early haematogenous spread occurs and the five year survival rate is approximately 50%

Question 16

Regarding club-foot (talipes equinovarus [TEV]) deformity in a newborn, which of the following statements is true?
(Please select 1 option)
Has a higher incidence in babies delivered head first
Is more common in Chinese than other races
Is most commonly ‘postural’ in origin
Needs open reduction in most instances
Occurs in association with spina bifida cystica only if there is accompanying hydrocephalus

Answer 16

Is most commonly ‘postural’ in origin

Postural talipes is most common and can be passively corrected.

Spina bifida cystica refers to meningocoele and myelomeningocoele; these are associated with other skeletal deformities but not hydrocephalus.

It is more common in Polynesians rather than Caucasians, and not in Chinese.

Question 17

Which of the following is not associated with an acute limb compartment syndrome?
(Please select 1 option)
Absent peripheral pulses
Decreased tactile sensation
Muscular weakness
Pain relieved by passively stretching the affected muscle
Swelling

Answer 17

Pain relieved by passively stretching the affected muscle

Common symptoms of compartment syndrome include

Pain exacerbated by passively stretching the affected muscle
Reduced tactile sensation.
Weakness and swelling of the affected muscles occur.

Distal pulses disappear when intracompartmental pressure exceeds arterial pressure.

Initial treatment involves release of constricting bandages and splints, and if there is no improvement urgent fasciotomy is necessary

Question 18

In compartment syndrome in children, which of the following is correct?
(Please select 1 option)
Capillary pressure exceeds interstitial pressure
Fracture of a long bone is never present
Muscle ischaemia occurs
The usual cause is thrombophilia causing arterial occlusion
Volkmann’s ischaemic contracture occurs following fasciotomy

Answer 18

Muscle ischaemia occurs

Compartment syndrome usually develops over a period of hours. It is most often associated with crush injuries, although it may also be associated with long bone fractures.

If the interstitial pressure exceeds capillary pressure, local muscle ischaemia occurs. If this is unrecognised Volkmann’s ischaemic contracture eventually results.

It is treated by the release of constricting bandages and splints first, followed by urgent fasciotomy if there is no improvement.

Question 19

For which of the following is an urgent laparotomy performed for children with abdominal injury?
(Please select 1 option)
	 Absence of bowel sounds
	 Non-penetrating injury
	 Palpable mass
	 Refractory shock
	 Splenic rupture

Answer 19

Refractory shock

The following are indications for laparotomy:

Refractory shock
Penetrating injury, and
Definite signs of bowel perforation.
Absence of bowel sounds can be associated with peritonitis, but in the absence of other abdominal signs then peritonitis is unlikely.

A palpable mass may or may not be related to trauma and would require radiological investigations such as ultrasound scan or computerised tomography (CT). Further management would be guided by the results of the imaging.

Splenic rupture is usually managed conservatively in children (and increasingly in adults).

Nephrectomy is performed for renal pedicle injury leading to non-functioning kidney.

Question 20

Concerning the shoulder joint, which of the following is correct?
(Please select 1 option)
Posterior dislocation of the shoulder joint is the most common dislocation of this joint
Section of the nerve related to the surgical neck of the humerus would paralyse the teres minor muscle
The capsule is poorly supported superiorly
The subacromial bursa communicates with the shoulder joint cavity
The triceps tendon is intracapsular

Answer 20

Section of the nerve related to the surgical neck of the humerus would paralyse the teres minor muscle

The axillary nerve arises from the posterior cord of the brachial plexus and contains fibres derived from C5 and C6 spinal nerve roots. It passes through the quadrilateral space just below the shoulder joint.

The nerve then curves around the posterolateral surface of the humerus deep to the deltoid, dividing into anterior and posterior branches, both of which supply the deltoid muscle.

The upper lateral cutaneous nerve of the arm arises from the posterior branch and supplies the skin over the deltoid. The axillary nerve also gives a branch to supply the teres minor muscle.

The commonest dislocation of the shoulder is anterior.

Question 21

Positive criteria in diagnostic peritoneal lavage (DPL) include which of the following?
(Please select 1 option)
	 Amylase above 175 U/ml
	 Difficult traumatic entry
	 Frank blood on entering the abdomen
	 Red cell count above 10,000/ul
	 White cell count above 100/ul

Answer 21

Frank blood on entering the abdomen

If frank blood is encountered upon entering the abdomen this is a positive DPL criterion, necessitating further investigation, which in the vast majority of cases is laparotomy.

Other positive criteria include

Lavage fluid in the chest drain or urinary catheter
The presence of bile or faeces
RCC of more than 100,000/ul
WCC more than 500/ul
An amylase of more than 75 U/ml.
Today many surgeons have little experience of DPL and may cause bleeding when gaining access to the peritoneal cavity leading to false positive results.

DPL has now been largely abandoned in favour of abdominal ultrasound (FAST scan or formal emergency US). The procedure is still performed when CT or ultrasound are unavailable, or when the patient’s condition does not allow such procedures to be performed.

Question 22

Diagnostic peritoneal lavage is indicated in:
(Please select 1 option)
Abdominal gunshot wound
Explained hypotension
Peritonitis
Unexplained hypotension with abdominal distension
Wound that has penetrated the abdominal wall, but has no indication for immediate laparotomy

Answer 22

Wound that has penetrated the abdominal wall, but has no indication for immediate laparotomy This is the correct answerThis is the correct answer
The abdomen is a site of occult haemorrhage that may cause hypotension.

Diagnostic peritoneal lavage may be performed when there is

unexplained hypotension
equivocal abdominal examination (i.e. reduced level of consciousness)
mass trauma, where the number of casualties exceeds theatre facilities.
Contraindications to DPL include any indication for immediate laparotomy

abdominal gunshot wounds
frank peritonitis
hypotension with abdominal distension.
DPL has now been largely abandoned in favour of abdominal ultrasound.

The procedure is still performed when CT or ultrasound are unavailable, or when the patient’s condition does not allow such procedures to be performed.

Question 23

In the hand, which of the following statements is correct?
(Please select 1 option)
Anterior dislocation of the lunate may compress the median nerve
Digital nerves lie on the dorsum of fingers
Opposition of the thumb tests the ulnar nerve
The deep branch of the ulnar nerve supplies all the lumbricals
The thenar eminence is supplied by the ulnar nerve

Answer 23

Anterior dislocation of the lunate may compress the median nerve

The lateral two lumbricals are supplied by the median nerve, the medial two by the deep branch of the ulnar nerve.

The thenar muscles (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis and adductor pollicis) are all supplied by the median nerve, with the exception of adductor pollicis which is supplied by the deep branch of ulnar. Opposition of the thumb is therefore supplied by the median nerve.

The digital nerves run alongside the fingers. Anterior dislocation of the lunate is a common injury occurring in the carpal bones, usually as a result of falling on an outstretched hand. Unless there is prompt reduction of the dislocation, median nerve injury may occur due to compression.

Question 24

Which of the following is not true of the shoulder joint?
(Please select 1 option)
Supraspinatus is active in abduction
The nerve to serratus anterior is derived from the upper roots of the brachial plexus
The rotator cuff muscles are attached to the capsule which is deficient inferiorly
The subacromial bursa communicates with the shoulder joint
The subscapular nerve arises from the posterior cord of the brachial plexus

Answer 24

The subacromial bursa communicates with the
shoulder joint

The rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis) serve to hold the head of the humerus in the shallow glenoid cavity during movement. They are attached to the capsule of the joint.

The rotator cuff is deficient inferiorly which results in an area of potential weakness. During abduction the supraspinatus muscle fixes the humeral head against the glenoid cavity while deltoid contracts.

The subacromial bursa does not connect with the shoulder joint.

The nerve to serratus anterior, that is, the long thoracic nerve has nerve roots C5-C7.

Both the upper and lower subscapular nerves are derived from the posterior cord of the brachial plexus.

Question 25

Which of the following is not true of the shoulder joint? (Please select 1 option) Subscapularis bursa lies deep to the coraco-acromial ligament The axillary nerve passes with the posterior circumflex humeral artery in the surgical neck of the humerus The biceps tendon is intracapsular and extrasynovial The cephalic vein passes through the deltopectoral groove The long head of biceps arises from the supraglenoid tubercle

Answer 25

Subscapularis bursa lies deep to the coraco-acromial ligament It is the subacromial bursa that lies directly deep to coraco-acromial ligament. The bursa reduces friction between the supraspinatus tendon and the acromion. Degenerative change in the bursa is followed by degenerative change in the tendon and can lead to subacromial bursitis. The long head of biceps arises from the supraglenoid tubercle the short head from the coracoid process of the scapula. Biceps inserts into the posterior border of the tuberosity of the radius. The tendon of the long head of biceps crosses the humeral head within capsule of the shoulder joint. The superficial veins of the hand drain laterally into the cephalic vein (medially into basilic vein) which crosses the anatomical snuff box, ascends the arm laterally to biceps and ends by piercing the deltopectoral fascia. The axillary nerve passes with the posterior circumflex humeral artery around the surgical neck of humerus, and as such, is susceptible to injury in a fracture of the surgical neck.

Question 26

Which of the following anatomical considerations is correct? (Please select 1 option) Injury of the long thoracic nerve affects adduction The flexor digitorum superioris is the principal muscle involved in flexing the distal interphalangeal joint The median nerve is on the radial side of biceps tendon The median nerve is on the radial side of flexor carpi radialis at wrist The ulnar nerve enters the front of the forearm by crossing between the two heads of flexor carpi ulnaris (FCU)

Answer 26

The ulnar nerve enters the front of the forearm by crossing between the two heads of flexor carpi ulnaris (FCU) This is the correct answerThis is the correct answer The long thoracic nerve supplies the serratus anterior muscle which is important in rotation of the scapula during abduction of the shoulder. It is flexor digitorum profundus (FDP) that causes the distal IP joint to flex (flexor digitorum superficialis [FDS] flexes the middle phalanx and assists in flexing the proximal phalanx). The median nerve is medial to the tendon of biceps (the brachial artery lying between the two structures). At the level of the wrist, the flexor carpi radialis passes lateral to the median nerve. As the ulnar nerve crosses the medial ligament of the elbow joint it enters the front of the forearm by passing through the two heads of FCU, and continues to run between FCU and FDP.

Question 27

The scaphoid: (Please select 1 option) Articulates with the trapezium and ulna Articulates with the triquetral bone Has a narrow waist which may fracture Has a tubercle to which is attached the extensor retinaculum Is impalpable in the anatomical snuff box

Answer 27

Has a narrow waist which may fracture The scaphoid is palpated in the anatomical snuffbox. It has a narrow neck which is prone to fracture (tenderness in the ASB). Clinically it is important not to miss a fractured scaphoid as the blood supply is occasionally confined to the distal end, hence a fracture may result in avascular necrosis of the proximal fragment. The scaphoid articulates with the styloid process of radius and the trapezium, although the triquetral is medial to the lunate and hence does not articulate with the scaphoid. The extensor retinaculum is attached laterally to the distal end of radius and medially to the pisiform and hook of hamate.

Question 28

Which of the following is true concerning the wrist and hand? (Please select 1 option) Lymph from the thumb drains to the epitrochlear nodes Rupture of the tendon of flexor digitorum profundus results in an inability to flex the distal interphalangeal joint Tenderness in anatomical snuff box would signify a fractured lunate The capitate may have begun to ossify at birth Wasting of both thenar and hypothenar eminences would signify a median nerve lesion

Answer 28

Rupture of the tendon of flexor digitorum profundus results in an inability to flex the distal interphalangeal joint The lymphatic drainage of the thumb and index finger (indeed the lateral part of the hand) follow the cephalic vein and drain into the infraclavicular group of nodes. The tendon of flexor digitorum profundus (FDP) inserts into the base of the distal phalanx (the tendon of flexor digitorum superficialis [FDS] splits around FDP and inserts into the base of the middle phalanx) contraction of which causes flexion of the distal interphalangeal joint. Tenderness in the anatomical snuffbox is classically a sign of a fractured scaphoid. The capitate is the first carpal bone to ossify in the first year of life (strictly speaking the carpus is cartilaginous at birth). The remainder of the carpal bones ossify at various intervals up until 12 years when all are ossified. A median nerve lesion would result in wasting of the thenar eminence.

Question 29

Which of the following is true of humeral fractures? (Please select 1 option) Anatomical neck - damage to posterior circumflex humeral artery Medial epicondyle - sensory loss over forearm flexor muscles Mid shaft - weakness of hypothenar muscles Mid shaft - wrist drop Surgical neck - weakness of triceps

Answer 29

Mid shaft - wrist drop Medial epicondyle fractures can cause damage to the ulnar nerve which would result in sensory loss over the anterior and posterior surfaces of the medial third of the hand and medial one and a half fingers. Mid shaft fractures cause damage to the radial nerve (passing in the radial groove of the humerus) resulting in loss of extension of the wrist, that is, wrist drop and a small patch of anaesthesia over the root of the thumb. Fracture of the surgical neck of humerus damages the circumflex humeral arteries (anterior and posterior branches) in addition to the axillary nerve which causes paralysis of the deltoid and teres minor, with sensory loss over the lower part of the deltoid (regimental badge distribution).

Question 30

``` Shoulder abduction from 0° to 180° does not depend on the integrity of which of the following? (Please select 1 option) Deltoid muscle Infraspinatus muscle Spinal accessory nerve Thoracodorsal nerve Upper trunk of brachial plexus ```

Answer 30

Thoracodorsal nerve Shoulder abduction is initiated by supraspinatus (supplied by suprascapular nerve (C5, 6), that is, upper trunk of brachial plexus) which serves to hold the head of the humerus against the glenoid cavity during the movement, while subscapularis, infraspinatus and teres minor produce a downward pull on the head of the humerus against the pull of deltoid (principal abductor). The thoracodorsal nerve supplies latissimus dorsi and hence is not involved in shoulder abduction.

Question 31

``` Which of the following complications is not associated with a burn injury? (Please select 1 option) Acute renal failure Haemoglobinuria Methaemoglobinaemia Myoglobinuria Peptic ulceration ```

Answer 31

Methaemoglobinaemia A full thickness burn (or third degree burn) can result in haemoglobinuria and myoglobinuria, and is commonly encountered following a high-voltage electrical injury. In the presence of haemoglobinuria and myoglobinuria the patient may subsequently develop acute renal failure (ARF), and the use of diuretics (for example, mannitol 0.5 g/kg) may help. The development of ARF in a burned patient is associated with a high mortality. Additional complications of thermal injury include ``` Peptic ulceration (Curling's ulcer) Congestive cardiac failure Myocardial infarction Pulmonary embolism Encephalopathy Hypertension. Methaemoglobinaemia is not a known complication of a burn injury. ```

Question 32

Which of the following is true regarding intertrochanteric fractures of the femur? (Please select 1 option) Are more likely to cause avascular necrosis of the femoral head than intracapsular femoral head fractures Are treated with femoral head replacement Can be treated with dynamic hip screw (DHS) fixation Can cause the leg to be abducted Typically cause shortening and internal rotation of the leg

Answer 32

Can be treated with dynamic hip screw (DHS) fixation Intracapsular (neck of femur) fractures of the femoral neck are more likely to cause severe damage to the blood supply of the femoral head than intertrochanteric fractures. The leg is usually shortened and externally rotated. It may be adducted because intertrochanteric fractures separate abductors from adductors across the fracture line. DHS is the commonest method of fixation.

Question 33

Which of the following is true regarding supracondylar fractures of the humerus in children? (Please select 1 option) Affect the radial nerve in the majority of cases Are usually extra-articular Frequently result in compartment syndrome in the forearm Require open reduction and internal fixation in more than 50% of cases Result in hypothenar muscle wasting

Answer 33

Are usually extra-articular In children supracondylar fractures are usually extra-articular, whilst they are frequently intra-articular in adults. This type of fracture most commonly occurs around 6-7 years of age. The anterior interosseous branch of the median nerve is the most commonly affected nerve in supracondylar fractures in children. Vascular compromise (injury to the brachial artery) occurs in about 5% of children with supracondylar fractures. However, less than 1% of the children will develop compartment syndrome. Volkmann's ischaemic contracture is a recognised complication of supracondylar fractures in children. Hypothenar muscle wasting is not common with supracondylar fractures, since the hypothenar muscles are innervated by the ulnar nerve. Children with supracondylar fractures are usually treated in a plaster of Paris cast, with the elbow extended and maintaining appropriate traction. Open reduction and internal fixation is indicated in only a small proportion of children who have extensive fractures, impending vascular compromise, or where treatment with traction is not appropriate.

Question 34

Which of the following is correct regarding non-union of fractures? (Please select 1 option) A recognised cause of immobility Characterised by the absence of callus in plain radiography More common in cancellous bones than in cortical bones Rarely results from avascular necrosis Results from interposition of soft tissue between the fragments

Answer 34

Results from interposition of soft tissue between the fragments This is the correct answerThis is the correct answer Non-union is more common in cortical bones than in cancellous bones. The causes of non-union of fracture include Inadequate blood supply Avascular necrosis Acute or chronic osteomyelitis Interposition of soft tissue between the fragments Excessive shearing movements or loss of apposition between the fragments Over-distraction of the bony fragments by excessive traction Presence of foreign body or tumour in the fracture site. Rest, good nutrition, securing the fractured ends in alignment and immobility all help in healing fractures. Plain x ray of non-union of the bone may reveal closure of the medullary cavity, whilst absence of callus at the fracture site suggests delayed union.

Question 35

Which of the following is a precondition for diagnosing brain stem death? (Please select 1 option) A core temperature of greater than 32°C A senior and junior doctor to perform the tests together No output on electroencephalogram (EEG) The patient is in coma, receiving mechanical ventilation The requirement of a CT scan

Answer 35

The patient is in coma, receiving mechanical ventilation Before undertaking brain stem death testing in the comatose patient, several preconditions must be satisfied and include: The patient is in coma, receiving mechanical ventilation. The definitive cause for the coma has been diagnosed. Enough time has elapsed to ensure irreversibility. Two doctors of sufficiently senior rank perform the tests independently. The patient must have a core temperature greater than 35°C. The diagnosis of brain stem death is performed by demonstrating the absence of the following brain stem reflexes: Pupillary reflex Corneal reflex Vestibulo-ocular reflex Response to painful stimulus in the trigeminal nerve territory Gag reflex. The results should be carefully recorded in the patient's case notes, preferably on a standard form (declaration of brainstem death).

Question 36

``` A limp in a 10-year-old boy is not likely to be due to which of the following? (Please select 1 option) Osteoarthritis Perthes' disease Scoliosis Slipped capital femoral epiphysis Transient synovitis of the hip ```

Answer 36

OA Osteoarthritis is an acquired condition presenting in later life. A child with Perthes' may limp. This condition is an avascular necrosis of the femoral head. Symptoms include Stiffness Pain Limping. Slipped capital femoral epiphysis typically affects overweight boys approaching puberty. Symptoms include pain and limping, with restriction of medial rotation abduction and flexion. A child with a scoliosis may limp due to the spinal curvature. In transient synovitis of the hip, a child, usually less than 5 years of age, will develop discomfort, limited range of movement and a limp following an upper respiratory tract infection. Symptoms are mild and are self resolving.

Question 37

Which of the following is correct regarding primary blast injury? (Please select 1 option) Is common in people who are a long distance from the explosion Results in amaurosis fugax Results in crush injuries Results in hollow viscera injury only The eardrum may be perforated

Answer 37

The eardrum may be perforated This is the correct answerThis is the correct answer Injury from an explosive device results from ``` The blast wave The blast wind Fragmentation Flash burns Crush Psychological injuries. The blast wave comes from the rapidly rising air pressure resulting from the expanding sphere of hot gases (explosion). ``` Initial injury results from contusions of the underlying solid organs from the initial body compression followed by disruption of tissues at the air/tissue interface (for example, lungs). Following this, injury results from shearing forces at tissue interfaces (for example, eye) and implosion of gas filled organs (for example, intestines, middle ear). The blast wave pressure is inversely proportional to the distance cubed. Amaurosis fugax results from embolisation into the optic artery and is associated with carotid artery stenosis. Crush injuries usually result from falling masonry following the initial explosion.

Question 38

Which of the following is true of Dupuytren's contracture? (Please select 1 option) Affects the superficial fascia Is associated with long term nitrofurantoin therapy Is associated with Peyronie's disease Is less common in patients with diabetes mellitus May cause ulnar nerve compression

Answer 38

Is associated with Peyronie's disease Dupuytren's contracture is due to thickening of the palmar fascia (but is also seen in the plantar fascia and penis: Peyronie's disease) and is of unknown aetiology. The disease is commoner in association with diabetes, epilepsy (possibly drug related) and cirrhosis. Nitrofurantoin therapy is associated with respiratory fibrosis.

Question 39

Which of the following is true of Ewing's sarcoma? (Please select 1 option) Can arise from longstanding Paget's disease Commonly arises towards the end of long bones in the metaphysis Is associated with a t11:22 chromosomal translocation Is more common in adults x Rays show bone destruction and new bone formation, often with marked periosteal elevation

Answer 39

Is associated with a t11:22 chromosomal translocation Ewing's sarcoma is a malignant round-cell tumour that occurs in the diaphysis of long bones (osteosarcoma affects the metaphysis) and limb girdles, usually in children. The x ray appearance described in the choice of answers is a feature of osteosarcoma; in Ewing's sarcoma, x rays often show a large soft-tissue mass with concentric layers of new bone formation, known as 'onion-peel' sign. Paget's disease could lead to osteosarcoma in approximately 10% of patients affected for more than 10 years, but not to Ewing's sarcoma.

Question 40

Which of the following is correct concerning the knee joint? (Please select 1 option) Capsule is thick anteriorly and posteriorly but thin around the collateral ligaments Fibular collateral ligament is separated from the lateral meniscus by the semitendinosus tendon Is a synovial and a hinge joint On cross section, the lateral meniscus is deeper compared with the medial meniscus The cruciate ligaments are extracapsular

Answer 40

Is a synovial and a hinge joint The knee joint is a synovial (and a hinge) joint. The capsule of the knee joint is thin anteriorly and posteriorly but reinforced on either side by strong collateral ligaments. On the sides of the femur, the capsule attachment extends up to the epicondyles. Both the anterior and posterior cruciate ligaments are intracapsular. The medial and lateral menisci are C-shaped with their anterior and posterior horns attached to the intercondylar eminence of the tibia and their outer borders to the joint capsule. The menisci differ in size and shape, the medial being narrower though slightly larger so that its horns embrace those of the lateral meniscus. Also, the medial is attached to the medial collateral ligament and on cross section is deeper compared with the lateral meniscus. On the lateral side of the knee joint, the cord-like fibular collateral ligament descends from the lateral epicondyle of the femur to the styloid process and head of the fibula, separated from the lateral meniscus by the popliteus tendon.