Case scenario questions upper limb

Question 1

A young cyclist is involved in a road traffic collision. He is complaining of pain in his right shoulder region – he is unable to abduct his right arm and lateral rotation is weakened. He has decreased sensation over the upper outer deltoid. Which nerve has he damaged?

Answer 1

The axillary nerve.
Supplies the deltoid and teres minor muscles, along with an area of sensation over the outer deltoid known as the regimental badge area. The deltoid is an important muscle of abduction innervated by the axillary nerve. The latter also supplies teres minor muscle which laterally rotates the arm. Since the nerve supply to infraspinatus is intact, lateral rotation is only weakened.

Question 2

A 29 year old pregnant woman presents to her GP complaining of pain and tingling in her fingers. On questioning, the GP determines that, in fact, it is only the palmar surface of the thumb and lateral 2.5 fingers that are the problem. The pain is causing her to wake during the night and she is having difficulty buttoning up her blouse.

Carpel tunnel syndrome is diagnosed. Which nerve has been affected in this syndrome?

Answer 2

The median nerve.
Supplies sensation to the palmar surface of the lateral 3 and ½ digits. The palmar cutaneous branch of the median nerve supplying the central palm area passes superior to the flexor retinaculum (roof of the carpal tunnel); therefore, sensations in the central palm will be preserved.

Question 3

A 25 year old man crashed his car. He was not wearing a seat belt, hit the steering wheel and subsequently developed a haemothorax. A large calibre chest drain was inserted just posterior to the mid-axillary line in the 4th intercostal space. Whilst rehabilitating it was noticed that his right scapula protruded from his thorax whilst exercising with the physiotherapists. Which nerve has been damaged during the insertion of the chest drain?

Answer 3

The long thoracic nerve (C5-C7).

Supplies the serratus anterior muscle which protracts and holds the scapula against the thoracic wall.

Question 4

A 20 year old heroin addict falls into a deep sleep for 6 hours on an arm chair. When he wakes up he finds one of his arms is weak in extension of his wrist and fingers and there is an area of pins and needles on the posterolateral aspect of the forearm and hand. Which nerve has been compressed against the arm of the chair?

Answer 4

The radial nerve.
Continuation of the posterior cord of the brachial plexus. The radial nerve soon travels in the radial or spiral groove on the posterior surface of the humerus. It is vulnerable to injury here as it can get compressed against the hard surface of the bone.

Question 5

You are a GP and a 70 year old lady has come in to have her blood pressure checked. Over which artery do you place your stethoscope to listen for the Korotkov sounds?

Answer 5

The brachial artery.
Commences as a continuation of the axillary artery (at the inferior border of teres major). It ends just under the bicipital aponeurosis in the cubital fossa where it divides into the radial and ulnar arteries.

Question 6

A surgeon is performing a carpel tunnel decompression in day case theatre and decides to extend the incision distally. A heavy pulsatile bleed ensues. Which structure has been injured?

Answer 6

The superficial palmar arch.
The main terminal of the ulnar artery in the hand. Although lying more distal than the deep palmar arch, it is more superficial (hence the name) and is more vulnerable to injury. However, anastomoses mean that bleeding is profuse when injury occurs.

Question 7

Before taking an arterial blood gas sample at the wrist Allen’s test is performed. Pressure is applied firmly to the wrist lateral to the tendon of flexor carpi radialis and just lateral to the tendon of flexor carpi ulnaris. The hand goes white. The pressure point lateral to flexor carpi ulnaris is released and the hand goes pink. Patency in which artery has been proved?

Answer 7

The ulnar artery.
Both the radial and ulnar arteries are occluded in this test. The ulnar artery is palpated, and in this case occluded, just lateral to the tendon of flexor carpi ulnaris.

Question 8

A 75 year old man was admitted to Accident and Emergency following a fall onto his right arm. He complained of pain in the right shoulder and inability to move the arm. An x-ray revealed a fracture around the neck of the humerus. What is at risk of damage?

Answer 8

The anterior and posterior circumflex humeral arteries. Surround the surgical neck of the humerus as does the axillary nerve. Damage to the arteries can present as a haematoma of the axilla.

Question 9

An elderly lady was having a central line inserted in theatre. The anaesthetist inserted the needle under her right clavicle. Shortly afterwards she became very breathless and hypotensive. A chest x-ray revealed a large right haemothorax. Which vein has most likely been damaged?

Answer 9

The subclavian vein.
Continuation of the axillary vein. It commences at the lateral border of the first rib and ends when it joins the internal jugular vein to form the brachiocephalic vein. Incorrect needle insertion may lead to damage to the pleura and lung collapse (pneumothorax). In this case, blood has entered the pleural space, causing a haemothorax.

Question 10

A medical student is trying to take blood from a patient with poor veins. In despair, the student blindly inserts the needle over the radial border of the forearm, at the level of the distal radius to search for which common named vein?

Answer 10

The cephalic vein.
Commences at the lateral side of the dorsal venous arch of the hand and continues subcutaneously in the lateral forearm and arm, finally joining the terminal part of the axillary vein after passing through the deltopectoral triangle.

Question 11

A cancer patient with central venous catheterization, complains of pain and discomfort in his right armpit and shoulder. On examination his upper limb and hand are slightly swollen and he says his arm feels heavy and uncomfortable. On Doppler ultrasound, the subclavian vein was patent. Which vein has most likely thrombosed?

Answer 11

The axillary vein.
The long term use of the central venous line has lead to platelet aggregation and the formation of a venous thrombosis. Pain is localised in the armpit (axilla) and shoulder and so, the most likely vein affected is the axillary vein. This would be confirmed with ultrasound.

Question 12

A young girl tripped and fell putting her left arm through a glass door. She sustained a deep laceration to the medial and anterior aspect of her left upper arm 3 – 4 cm above the medial epicondyle. When she attended Accident and Emergency she was noted to have blood continually oozing from the wound. Which vein has most likely been lacerated?

Answer 12

The basilic vein
Commences at the medial border of the wrist draining blood from the dorsal venous arch of the hand. It passes subcutaneously up the medial forearm. At the cubital fossa it receives blood from the median cubital vein as it enters the arm. It is subcutaneous for a short period (here at the site of injury) before piercing the fascia. It joins venae comitantes of the axillary artery (deep veins) to form the axillary vein.

Question 13

A jockey has fallen from his horse at speed. You examine his arm and can find no pulses from the axilla downwards. Which fracture has caused this arterial injury?

Answer 13

Clavicular fracture.
The arterial blood supply to the upper limb comes from the subclavian artery which can be found posterior to the clavicle. The clavicle usually fractures at a point 2/3 from the sternum and 1/3 from the acromion; the fracture ends may overlap or project backwards causing damage. During clavicular fractures, the structures immediately posterior to the clavicle are vulnerable to injury (the subclavian vein, subclavian artery and divisions of the brachial plexus).

Question 14

A 25 year old was standing on a table when the table gave way and the patient fell backwards. He put his arms out behind him to break his fall. He fell on his outstretched right hand. He attends Accident and Emergency with severe pain in his right shoulder, a prominent acromion, and loss of sensation over the regimental badge area. What is the likely diagnosis?

Answer 14

Anterior dislocation of the humeral head.
Loss of angulation of the shoulder, as seen by the prominent acromion, indicates a disruption of the shoulder joint. The most common dislocation, fitting with this history, is an anterior dislocation of the humeral head from the glenoid fossa. Loss of sensation over the regimental badge area indicates damage to the axillary nerve. The axillary nerve wraps around the surgical neck of the humerus and would be stretched in such an injury.

Question 15

A 16 year old girl falls on an outstretched hand whilst playing netball. She is complaining of pain in her right wrist and has tenderness to palpation in a small area on the lateral dorsal aspect of her wrist and tenderness and telescoping of her right thumb. Which is the most likely fracture?

Answer 15

Scaphoid fracture.
The clinician has palpated the anatomical snuff box and elicited pain. This indicates a scaphoid fracture; the scaphoid is palpable in this area.

Question 16

An 86 year old man missed a step as he was alighting a bus. He landed on the kerb on his left arm. When you examine him you notice he is unable to extend his left wrist and there is swelling in the arm. Which fracture is likely to cause these signs?

Answer 16

Mid shaft humeral fracture.
The swelling in the arm and the history is suggestive of a midshaft humeral fracture, which this is. What may confuse is the inability to extend at the wrist. The radial nerve lies in the radial groove of the humerus and as such is vulnerable to injury in this fracture. Since the radial nerve supplies the extensor muscles of the wrist, this movement will be compromised due to the nerve lesion.

Question 17

An elderly man, who suffers from osteoarthritis, has been complaining of pain in the right shoulder. On examination, you find that he can easily hold his arm up when abducted to 90º, but that he awkwardly leans to the right hand side when trying to initiate abduction. Which muscle tendon has been ruptured?

Answer 17

Supraspinatus.
The first 15 degrees of initiation of abduction of the upper limb is due to the action of supraspinatus. A rupture of this tendon will lead to the symptoms and signs presented. Osteoarthritis in the joint can lead to the development of osteophytes. These bony projections may irritate locale tendons causing tendonitis.

Question 18

A 19 year old female present to Accident and Emergency having been in a road traffic collision the previous day. She was sat at the traffic lights in the driver’s seat when she was hit from behind by a van. She was shaken but had no pain at the time. She now has posterior pain and tenderness above the spine of each scapula. You diagnose her with whiplash. Which muscle will be most tender on this palpation?

Answer 18

Trapezius.
A shunt from behind in her car, will force the lady’s head into flexion. No vertebral damage was done in this case, but soft tissues injury to the trapezius will happen, giving her the symptoms of whiplash which usually present worse the subsequent day. Posterior longitudinal ligamental damage can also occur on the vertebral column.

Question 19

An 18 year old student regularly attends the gym to do weightlifting. One day he is lifting a heavy weight in front of him with his elbows flexed. He suddenly experiences pain and weakness in his left anterior upper arm and drops the weight. He notices a bulge at the distal end of his upper arm and at the elbow. The tendon of which muscle has ruptured?

Answer 19

Biceps brachii.
Putting such force through a muscle and its tendon on a regular basis can lead to tendonitis which may in turn lead to tendon rupture. In this case, a proximal tendon of biceps brachii has ruptured (usually the long head) leading to the muscle noticeably bunching up in the distal arm. As the short head is usually intact, there may only be a 10% loss of power and no loss of function overall.

Question 20

After a difficult birth, a child is shown to have Erb’s palsy (damage to the C5 spinal root). Lateral rotation has been weakened. Which is the principle lateral rotator at the shoulder?

Answer 20

Infraspinatus.
Supplied by the suprascapular nerve. This nerve has its spinal roots from C5 and C6 and so may be lesioned in this injury. Teres minor also laterally rotates and its nerve supply, the axillary nerve, also has C5 and C6 roots. So you can have some credit for this. However, it is not such a large muscle as infraspinatus and therefore not the principle lateral rotator.

Question 21

A professional cyclist consults his GP complaining of tingling in his right ring and little fingers after long bike rides. On examination the GP notes slight clawing of the ring and little fingers and notes weakness on flexion of these fingers at the metacarpal phalangeal joint. He diagnosed ulnar nerve compression at the hook of hamate. Which muscles have been affected to cause the weakness of flexion at the metacarpophalangeal joint of his medial two digits?

Answer 21

Lumbricals 3 and 4.
Since the nerve injury has occurred near the wrist, we are only looking for muscles distal to this which may be compromised. Flexion at the mcp joint is by the lumbricals (in this case 3rd and 4th lumbricals). They may be assisted by the interosseous muscles.

Question 22

A 20 year old university student is practicing for a cricket match. While catching a cricket ball, the ball hits the tip of the left middle finger on the dorsal aspect, causing hyperflexion at the distal interphalangeal joint. He is now unable to extend at this joint.
The muscle whose tendon is most likely to have been damaged is…

Answer 22

Extensor digitorum.

The only extensor muscle to the middle finger distal phalanx.

Question 23

A 21 year old girl was pruning a tree. She slipped on the ladder and the saw cut the back of her proximal thumb on the right. She found she was unable to extend her thumb, and the posterior (or medial) border of her anatomical snuff box wasn’t there. Which tendon has been severed?

Answer 23

Extensor pollicis brevis and longus.
The tendon of extensor pollicis longus forms the medial border of the anatomical snuff box; the lateral border is formed by the 2 tendons of abductor pollicis longus and extensor pollicis brevis.

Question 24

A 45 year old woman recently underwent a carpal tunnel release operation for carpal tunnel syndrome of the left hand. Following the operation she complained of weakened flexion of the thumb. The tendon of which muscle may have been damaged?

Answer 24

Flexor pollicis longus.
There are 9 tendons passing through the carpal tunnel. These include 4 tendons form flexor digitorum superficialis, 4 tendons from flexor digitorum profundus and one tendon from flexor pollicis longus. This latter tendon is the only one which goes to the thumb and surgical damage to it would account for the presentation.