Clinical Conditions

Question 1

What is thoracic outlet syndrome?

Answer 1

The apex of the axilla region is an opening between the clavicle, first rib and the scapula. In this apex, the vessels and nerves may become compressed between the bones – this is called thoracic outlet syndrome.

Common causes of TOS are trauma (e.g fractured clavicle) and repetitive actions (seen commonly in occupations that require lifting of the arms) It often presents with pain in the affected limb, (where the pain is depends on what nerves are affected), tingling, muscle weakness and discolouration.

Question 2

What nerve is possibly damaged in lymph node biopsy?

Answer 2

Approximately 75% of lymph from the breast drains into the axilla lymph nodes, so can be biopsied if breast cancer is suspected. If breast cancer is confirmed, the axillary nodes may need to be removed to prevent the cancer spreading. This is known as axillary clearance. During this procedure, the long thoracic nerve may become damaged, resulting in winged scapula.

Question 3

How is a supracondylar fracture likely to occur? What are the complications?

Answer 3

A supracondylar fracture usually occurs by falling on a flexed elbow. It is a transverse fracture, spanning between the two epicondyles.

The displaced fracture fragments may impinge and damage the contents of the cubital fossa.

Direct damage, or post-fracture swelling can cause interference to the blood supply of the forearm from the brachial artery. The resulting ischaemia can cause Volkmann’s ischaemic contracture – uncontrolled flexion of the hand, as flexors muscles become fibrotic and short.

There also can be damage to the median or radial nerves.

Question 4

What is carpal tunnel syndrome? What are the clinical features? Give tests and treatment

Answer 4

Compression of the median nerve within the carpal tunnel can cause carpal tunnel syndrome (CTS). It is the most common mononeuropathy and can be caused by thickened ligaments and tendon sheaths. Its aetiology is, however, most often idiopathic. If left untreated, CTS can cause weakness and atrophy of the thenar muscles.

Clinical features include numbness, tingling and pain in the distribution of the median nerve. The pain will usually radiate to the forearm. Symptoms are often associated with waking the patient from their sleep and being worse in the mornings.

Tests for CTS can be performed during physical examination:

Tapping the nerve in the carpal tunnel to elicit pain in median nerve distribution (Tinel’s Sign)
Holding the wrist in flexion for 60 seconds to elicit numbness/pain in median nerve distribution (Phalen’s manoeuvre)

Treatment involves the use of a splint, holding the wrist in dorsiflexion overnight to relieve symptoms. If this is unsuccessful, corticosteroid injections into the carpal tunnel can be used. In severe case, surgical decompression of the carpal tunnel may be required.

Question 5

What are the complications of scaphoid fracture?

Answer 5

In the anatomical snuffbox, the scaphoid and the radius articulate to form part of the wrist joint. In the event of a blow to the wrist (e.g falling on an outstretched hand), the scaphoid takes most of the force. If localised pain is reported in the anatomical snuffbox, a fracture of the scaphoid is the most likely cause.

The scaphoid has a unique blood supply, which runs distal to proximal. A fracture of the scaphoid can disrupt the blood supply to the proximal portion – this is an emergency. Failure to revascularise the scaphoid can lead to avascular necrosis, and future arthritis for the patient.

Question 6

How does winging of the scapula occur?

Answer 6

The serratus anterior muscle originates from ribs 1-8, and attaches the costal face of the scapula, pulling it against the ribcage. The long thoracic nerve innervates the serratus anterior.

If this nerve becomes damaged, the scapula protrudes out of the back when pushing with the arm. The long thoracic nerve can become damaged by trauma to the shoulder, repetitive movements involving the shoulder or by structures becoming inflamed and pressing on the nerve.

Question 7

What are the complications of clavicle fracture?

Answer 7

A function of the clavicle is to transmit forces from the upper limb to the axial skeleton. Thus, the clavicle is the most commonly fractured bone in the body. Fractures commonly result from a fall onto the shoulder, or onto an outstretched hand.

The most common point of fracture is the junction of the medial 2/3 and lateral 1/3. After fracture, the lateral end of the clavicle is displaced inferiorly by the weight of the arm, and medially, by the pectoralis major. The medial end is pulled superiorly, by the sternocleidomastoid muscle.

The suprascapular nerves (medial, intermedial and lateral) may be damaged by the upwards movement of the medial part of the fracture. These nerves innervate the lateral rotators of the upper limb at the shoulder – so damage results in unopposed medial rotation of the upper limb – the ‘waiters tip’ position.

Question 8

What are the complications of humerus surgical neck fractures?

Answer 8

The surgical neck of the humerus is a frequent site of fracture – usually by a direct blow to the area, or falling on an outstretched hand.

In any fracture, it is important to consider the regional anatomy; to assess any additional structures at risk of damage. In a surgical neck fracture, there are two nearby neurovascular structures – the axillary nerve and posterior circumflex artery.

Axillary nerve damage will result in paralysis to the deltoid and teres minor muscles. The patient will have difficulty performing abduction of the affected limb. The nerve also innervates the skin over the lower deltoid (regimental badge area), and sensation in this region may be impaired.

Question 9

What are the possible complications of humerus mid shaft fractures?

Answer 9

A mid-shaft fracture could easily damage the radial nerve and profunda brachii artery, as they are tightly bound in the radial groove.

The radial nerve innervates the extensors of the wrist. In the event of damage to this nerve, the extensors will be paralysed. This results in unopposed flexion of the wrist occurs, known as ‘wrist drop’.

There is also some sensory loss over the dorsal (posterior) surface of the hand, and the proximal ends of the lateral 3 and a half fingers dorsally.

Question 10

What are the possible complications of distal humerus fractures?

Answer 10

Supracondylar fractures and medial epicondyle fractures are common fracture types of the distal humerus. A supraepicondylar fracture occurs by falling on a flexed elbow. It is a transverse fracture, spanning between the two epicondyles

Direct damage, or swelling can cause interference to the blood supply of the forearm from the brachial artery. The resulting ischaemia can cause Volkmann’s ischaemic contracture – uncontrolled flexion of the hand, as flexor muscles become fibrotic and short. There also can be damage to the median, ulnar or radial nerves.

A medial epicondyle fracture could damage the ulnar nerve, a deformity known as ulnar claw is the result. There will be a loss of sensation over the medial 1 and 1/2 fingers of the hand, on both the dorsal and palmar surfaces.

Question 11

What is Monteggia’s fracture?

Answer 11

Usually caused by a force from behind the ulna. The proximal shaft of ulna is fractured, and the head of the radius dislocates anteriorly at the elbow

Question 12

What is Galeazzi’s fracture?

Answer 12

Galeazzi’s Fracture – A fracture to the distal radius, with the ulna head dislocating at the distal radio-ulnar joint.

Question 13

What is Colle’s fracture?

Answer 13

Colles’ Fracture – The most common type of radial fracture. A fall onto an outstretched hand causing a fracture of the distal radius. The structures distal to the fracture (wrist and hand) are displaced posteriorly. It produces what is known as the ‘dinner fork deformity’.

Question 14

What is Smith’s fracture?

Answer 14

Smith’s Fracture – A fracture caused by falling onto the back of the hand. It is the opposite of a Colles’ fracture, as the distal fragment is now placed anteriorly.

Question 15

What are the two common metacarpal injuries?

Answer 15

Boxer’s fracture – A fracture of the 5th metacarpal neck. It is usually caused by a clenched fist striking a hard object. The distal part of the fracture is displaced posteriorly, producing shortening of the affected finger.

Bennett’s fracture – A fracture of the 1st metacarpal base, extending into the carpometacarpal joint. It is caused by hyperabduction of the thumb.

Question 16

How is the lunate likely to be injured?

Answer 16

Hyperextension of the wrist, usually accompanied by median nerve damage.

Question 17

How may rotator cuff tendonitis occur? How would it be treated?

Answer 17

Rotator cuff tendonitis refers to inflammation of the tendons of the rotator cuff muscles. This usually occurs secondary to repetitive use of the shoulder joint.

The muscle most commonly affected is the supraspinatus. During abduction, it ‘rubs’ against the coraco-acromial arch. Over time, this causes inflammation and degenerative changes in the tendon itself.

Conservative treatment of rotator cuff tendonitis involves rest, analgesia, and physiotherapy. In more severe cases, steroid injections and surgery can be considered.

Question 18

How does wrist drop occur?

Answer 18

Wrist drop is a sign of radial nerve injury that has occurred proximal to the elbow.

There are two common characteristic sites of damage:

Axilla – injured via humeral dislocations or fractures of the proximal humerus.

Radial groove of the humerus – injured via a humeral shaft fracture.

The radial nerve innervates all muscles in the extensor compartment of the forearm. In the event of a radial nerve lesion, these muscles are paralysed. The muscles that flex the wrist are innervated by the median nerve, and thus are unaffected. The tone of the flexor muscles produces unopposed flexion at the wrist joint – wrist drop.

Question 19

What is Erb’s Palsy?

Answer 19

Erb’s palsy commonly occurs where there is excessive increase in the angle between the neck and shoulder – this stretches (or can even tear) the nerve roots, causing damage. It can occur as a result of result of a difficult birth or shoulder trauma.

Nerves affected: Nerves derived from solely C5 or C6 roots; musculocutaneous, axillary, suprascapular and nerve to subclavius.

Muscles paralysed: Supraspinatus, infraspinatus, subclavius, biceps brachii, brachialis, coracobrachialis, deltoid and teres minor.

Motor functions: The following movements are lost or greatly weakened – abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder.

Sensory functions: Loss of sensation down lateral side of arm, which covers the sensory innervation of the axillary and musculocutaneous nerves.

The affected limb hangs limply, medially rotated by the unopposed action of pectoralis major. The forearm is pronated due to the loss of biceps brachii. This is position is known as ‘waiter’s tip’, and is characteristic of Erb’s palsy.

Question 20

What is Klumpke’s palsy?

Answer 20

A lower brachial plexus injury results from excessive abduction of the arm (e.g person catching a branch as they fall from a tree). It has a much lower incidence than Erb’s palsy.

Nerves affected: Nerves derived from the T1 root – ulna and median nerves.

Muscles paralysed: All the small muscles of the hand (the flexors muscles in the forearm are supplied by the ulna and median nerves, but are innervated by different roots).

Sensory functions: Loss of sensation along medial side of arm.

The metacarpophalangeal joints are hyperextended, and the interphalangeal joints are flexed. This gives the hand a clawed appearance.

Question 21

What are clinical signs of axillary nerve damage?

Answer 21

Motor functions: Paralysis of the deltoid and teres minor muscles. This renders the patient unable to abduct the affected limb.

Sensory functions: The upper lateral cutaneous nerve of arm will be affected, resulting in loss of sensation over the regimental badge area.

Characteristic clinical signs: In long standing cases, the paralysed deltoid muscle rapidly atrophies, and the greater tuberosity can be palpated in that area.

Question 22

What are clinical signs of musculocutaneous nerve damage?

Answer 22

How it commonly occurs: An injury to the musculocutaneous nerve is relatively uncommon, as it is well protected within the axilla. The most common cause is a stab wound to the axilla region.

Motor functions: The coracobrachialis, biceps brachii and brachialis muscles are paralysed. Flexion at the shoulder is weakened, but can still occur due to the pectoralis major. Flexion at the elbow is also affected, but can still be performed because of the brachioradialis muscle. Also, supination of the affected limb is greatly weakened, but is produced by the supinator muscle.

Sensory functions: Loss of sensation over the lateral side of the forearm.

Question 23

What are the two common sites of median nerve lesions and how do they differ in presentation?

Answer 23

Damaged at the Elbow

How it commonly occurs: Supracondylar fracture of the humerus.

Motor functions: The flexors and pronators in the forearm are paralysed, with the exception of the flexor carpi ulnaris and medial half of flexor digitorum profundus. The forearm constantly supinated, and flexion is weak (often accompanied by adduction, because of the pull of the flexor carpi ulnaris).

Flexion at the thumb is also prevented, as both the longus and brevis muscles are paralysed.

The lateral two lumbricals are affected, and the patient will not be able to flex at the MCP joints or extend at IP joints of the index and middle fingers.

Sensory functions: Lack of sensation over the areas that the median nerve innervates.

Characteristic signs: The thenar eminence is wasted, due to atrophy of the thenar muscles. If patient tries to make a fist, only the little and ring fingers can flex completely. This results in a characteristic shape of the hand, known as hand of benediction.

Damaged at the Wrist

How it commonly occurs: Lacerations just proximal to the flexor retinaculum.

Motor functions: Thenar muscles paralysed, as are the lateral two lumbricals. This affects opposition of the thumb and flexion of the index and middle fingers.

Sensory functions: Same as an injury at the elbow.

Characteristic signs: Same as an injury at the elbow.

Question 24

What are the four different categories of radial nerve damage?

Answer 24

See TMA

Question 25

How do ulnar nerve injuries differ at the wrist and at the elbow?

Answer 25

Damage at elbow

How it commonly occurs: The nerve is most vulnerable to injury at the medial epicondyle, so fracture of the medial epicondyle is the most common way of damaging the ulnar nerve

Motor functions: Flexor carpi ulnaris and medial half of flexor digitorum profundus paralysed. Flexion of the wrist can still occur, but is accompanied by abduction. The interossei are paralysed, so abduction and adduction of the fingers cannot occur. Movement of the little and ring fingers is greatly reduced, due to paralysis of the medial two lumbricals.

Sensory functions: All sensory branches are affected, so there will be a loss of sensation over the areas that the ulnar nerve innervates.

Characteristic signs: Patient cannot grip paper placed between fingers.

Damaged at the Wrist

How it commonly occurs: Lacerations to the wrist

Motor functions: The interossei are paralysed, so abduction and adduction of the fingers cannot occur. Movement of the little and ring fingers is greatly reduced, due to paralysis of the medial two lumbricals. The two muscles in the forearm are unaffected

Sensory functions: The palmar branch and superficial branch are usually severed, but the dorsal branch is unaffected. Sensory loss over palmar side of medial one and a half fingers only.

Characteristic signs: Patient cannot grip paper placed between fingers. For long-term cases, a hand deformity called ‘Ulnar Claw’ develops.

Ulnar claw consists of:
Hyper-extension of the metacarpophalangeal joints of the little and ring fingers – this is because of the paralysis of the medial two lumbricals, and the now unopposed action of the extensor muscles
Flexion at the interphalangeal joints (if the lesion has occurred close to the elbow, this might not be evident, as the flexor digitorum profundus will be paralysed)