Moore Blue Boxes- Upper Limb

Question 1

Clavicle fracture mechanism

Answer 1

Indirect force transmitted from an outstretched hand through the bones of forearm and arm to the shoulder during a fall
May also result from a fall directly on the shoulder
The weakest parts of the clavicle are the middle and laterals thirds

Question 2

Clavicle fracture effects

Answer 2

The sternocleidomastoid muscle elevates the medial fragment of the bone. The trapezius muscle is unable to hold the lateral fragment up owing to the weight of the upper limb, so the shoulder drops. The strong coracoclavicular ligament usually prevents dislocation of the acromioclavicular joint.
The lateral fragment of the clavicle may also be pulled medially by the adductor muscles of the arm (pectoralis major)
Most often a green stick fracture in children- incomplete

Question 3

Humeral fracture- impacted

Answer 3

Commonly seen in elderly with osteoporosis.
Most often impacted fracture- one fragment driven into the spongy bone of the other fragment, so the arm can still be stable, so they can move the arm passively with little pain.
Most are of the surgical neck
Usually result from a minor fall on the hand

Question 4

Humeral fracture- avulsion

Answer 4

Avulsion fracture of the greater tubercle most commonly in middle-aged and elderly people. A small part of the tubercle is torn away. This fracture usually results from a fall on the acromion.
In younger people, an avulsion fracture usually results from a fall on the hand when the arm is abducted.
Muscles that remain attached to the humerus (especially the subscapularis) pull the limb into medial rotation

Question 5

Humeral fracture- transverse

Answer 5

Transverse fracture of the shaft- usually from direct blow to the arm. The pull of the deltoid muscle carries the proximal fragment laterally.
Indirect injury resulting from a fall on outstretched hand may produce a spiral fracture of the shaft and overriding of the oblique ends of the bone may result in foreshortening

Question 6

Humeral fracture- intercondylar

Answer 6

Results from a severe fall on the flexed elbow. The olecranon of the ulna is driven like a wedge between the medial and lateral parts of the condyle, separating one or both parts from the shaft.

Question 7

Parts of the humerus that are in direct contact with nerves:

Answer 7

Surgical neck- axillary nerve
Radial groove- radial nerve
Distal end of humerus- median nerve
Medial epicondyle- ulnar nerve

Question 8

Fracture of the radius

Answer 8

Distal end is common in adults over 50 and more frequently in women
A complete transverse fracture of the distal 2cm of the radius is called a Colles fracture, the most common fracture of the forearm. The distal fragment is often comminuted (broken into pieces)
The fracture results from forced extension of the hand, usually by trying to ease a fall by outstretching the upper limb.
Sometimes an avulsed ulnar styloid occurs.
The radial styloid process projects more distally than the ulnar styloid, so when a Colles fracture occurs, this relationship is reversed because of shortening of the radius- dinner fork deformity because the fragmented end project posteriorly (hand is shaped like a fork, not holding a fork)

Question 9

Fracture of the ulna

Answer 9

Often the styloid process is avulsed

Question 10

Most frequently fractured carpal bone

Answer 10

Scaphoid- fall on the palm when hand is abducted
Pain on the lateral side of the wrist, especially during dorsiflexion and abduction of the hand
Poor blood supply- takes 3 months to heal. Risk for avascular necrosis–> degenerative joint disease of the wrist.
Surgery to fuse the carpals- arthrodesis

Question 11

Fracture of the hamate

Answer 11

Ulnar nerve is close to the hook of the hamate, the nerve may be injured by this fracture, causing decreased grip strength of the hand. The ulnar artery may also be damaged.

Question 12

Boxer’s fracture

Answer 12

Fracture of the 5th metacarpal from punching with a closed and abducted hand- produces a flexion deformity

Question 13

Paralysis of serratus anterior

Answer 13

Injury to the long thoracic nerve, the medial border of the scapula moves laterally and posteriorly away from the thoracic wall, giving the scapula an appearance of a wing, especially when the person leans on a hand or presses the upper limb against a wall.
When the arm is raised, the medial border and inferior angle of the scapula pull markedly away from the posterior thoracic wall= winged scapula
The upper limb may also not be able to abduct above the horizontal position because the serratus anterior is unable to rotate the glenoid cavity superiorly to allow complete abduction.
Long thoracic nerve travels very superficially on the serratus anterior muscle- can be damaged in a knife wound injury in the side.

Question 14

Injury to spinal accessory nerve (CN XI)

Answer 14

Ipsilateral weakness when the shoulders are elevated/shrugged against resistance

Question 15

Injury to the thoracodorsal nerve

Answer 15

Surgery in the inferior part of the axilla puts the thoracodorsal nerve (C6-C8), supplying the latissimus dorsi, at risk. This nerve passes inferiorly along the posterior wall of the axilla, and enters the medial surface of the latissimus dorsi close to where it becomes tendinous
Vulnerable to injuries during mastectomies when the axillary tail of the Breast is removed. Also vulnerable during surgery on axillary lymph nodes, because its terminal part lies anterior to them and the subscapular artery.
Paralysis of the latissimus dorsi- unable to raise the trunk with the upper limbs*(climbing), and cannot use an axillary crutch because the shoulder is pushed superiorly by it- these are the primary activities for which active depression of the scapula is required

Question 16

Injury to the dorsal scapular nerve

Answer 16

Nerve to the rhomboids/levator scapulae- the scapula on the affected side is located farther from the midline than the normal side

Question 17

Injury to the axillary nerve

Answer 17

The deltoid atrophies when the axillary nerve (C5/6) is damaged. Because it passes inferiorly to the humeral head and winds around the surgical neck, it is usually injured when the surgical neck is fractured. It may also be damaged during glenohumeral jt dislocation and by compression from the incorrect usage of crutches.
The rounded contour of the shoulder flattens- slight hollow inferior to the acromion.
Loss of sensation over the lateral side of the proximal arm
Deltoid is also a common site for intramuscular injections- the nerve runs transversely under it

Question 18

Fracture-dislocation of the proximal humeral epiphysis

Answer 18

A direct blow or indirect injury of the shoulder of a child or adolescent may produce this because the joint capsule, reinforced by the rotator cuff muscles, is stronger than the epiphysial plate
In severe fractures, the shaft of the humerus is markedly displaced, but the humeral head remains in its normal relationship with the glenoid cavity

Question 19

Rotator cuff injuries

Answer 19

Instability of the glenohumeral joint
Trauma may rupture or tear one of the tendons of the SITS muscles- most commonly the supraspinatus.
Degenerative tendinitis of the rotator cuff is common in older people

Question 20

Arterial anastomoses around scapula

Answer 20

The importance of the collateral circulation made possible by these anastomoses becomes apparent when litigation of a lacerated subclavian or axillary artery is necessary- between 1st rib and subscapular artery
Vascular stenosis of axillary artery may result from artherosclerosis lesion that caused reduced blood flow. The direction of blood flow in the subscapular artery is reversed, enabling blood to reach the third part of the axillary artery
*surgical litigation of the axillary artery between the subscapular and deep brachial artery will cut off the blood supply to the arm because the collateral circulation is inadequate

Question 21

Aneurysm of the axillary artery

Answer 21

Enlargement* of the artery may compress the brachial plexus, causing pain and loss of sensation
Can occur in baseball pitchers and quarterbacks because of the rapid and forceful movements.

Question 22

What two nerves are at risk during axillary lymph node dissection

Answer 22

Long thoracic nerve

Thoracodorsal nerve

Question 23

Variations in the brachial plexus

Answer 23

Prefixed brachial plexus- C4-C8 roots
Postfixed brachial plexus- C6-T2 roots. The inferior trunk may be compressed by the 1st rib, producing neurovascular symptoms

Question 24

Brachial plexus injuries- superior

Answer 24

C5-C6: usually from an excessive increase in the angle between neck and shoulder (thrown from a motorcycle or horse then lands on shoulder separating it from the neck)- avulses the roots
Characteristic- waiter’s tip position. Limb hands by the side in medial rotation.
Upper brachial plexus injuries can also occur in a neonate when excessive stretching of the neck occurs during delivery
Termed “Erb’s Palsy”- deltoid, biceps and brachialis mostly. Presents with adduct shoulder, medially rotated arm, and extended elbow. The lateral aspect of the forearm also loses sensation.

Question 25

Compression of cords of brachial plexus

Answer 25

Result from prolonged hyperabduction of arm during performance of manual tasks over the head (painting a ceiling). Cords are impinged or compressed between coracoid and pectoralis minor tendon
Pain radiating down the arm, numbness and tingling, erythema (from dilation of capillaries), and hand weakness
Compression of axillary artery and vein causes ischemia of upper limb and dissension of superficial veins.

Question 26

Brachial plexus injuries- inferior parts

Answer 26

Klumpke’s palsy- less common (C8-T1)
May occur when upper limb is suddenly pulled superiorly (when a person grasps something to break a fall)
Short muscles of the hand are affected, and a claw hand results.

Question 27

Best place to compress brachial artery to control hemorrhage

Answer 27

Medial to the humerus near the middle of the arm because the arterial anastomoses around the elbow provide a functionally and surgically important collateral circulation, the brachial artery may be clamped distal to the origin of the deep artery of the arm without producing tissue damage
Ischemic compartment syndrome (Volkman’s contracture) can cause involved muscles to shorten permanently, producing a flexion deformity. Flexion of the fingers and sometimes the wrist results in loss of hand power as a result of irreversible necrosis of forearm flexors.

Question 28

Mid Humeral fracture spares:

Answer 28

When the radial nerve in the radial groove is damaged by this fracture, the triceps is not likely to be paralyzed because of the high origin of the nerves to two of its three heads.

Question 29

Musculocutaneous nerve damage

Answer 29

In the axilla- uncommon unless there is a knife wound
Paralysis of the coracobrachialis, brachialis, and biceps.
Weak flexion may occur at the glenohumeral joint owing to the injury of the nerve affecting the longhead and coracobrachialis. Consequently, flexion of the elbow joint and supination are greatly weakened, but not lost, because the brachioradialis and supinator are supplied by the radial nerve. Loss of sensation may occur on lateral surface of the forearm.

Question 30

Injury to the radial nerve

Answer 30

Injury superior to the origin of its branches to the triceps results in paralysis of triceps, brachioradialis, supinator, and extensor muscles of wrist and fingers. Loss of sensation in areas of skin by this nerve also occurs.
When the nerve is injured in the radial groove, the triceps is usually spared but only weakened by the medial head. Muscles of the posterior compartment of the forearm that are supplied by more distal branches are paralyzed- wrist drop (inability to extend the wrist and fingers at the MP joints. Wrist assumes a partially flexed position owing to unopposed tonus of flexor muscles and gravity.

Question 31

Tennis elbow

Answer 31

Elbow tendinitis is a painful condition that may follow repetitive use of the superficial extensor muscles of the forearm. Pain is felt over the lateral epicondyle and radiates down the posterior surface of the forearm. Can often feel pain when they open a door or life a glass
Repeated forceful extension and flexion of the wrist strain the attachment of the common extensor tendon, producing inflammation of the periosteum of the lateral epicondyle

Question 32

Mallet or baseball finger

Answer 32

Sudden severe tension on a long extensor tendon may avulse part of its attachment to the phalanx. The most common result of the injury is a mallet or baseball finger. This deformity results from the distal interphalangeal joint suddenly being forced into hyperflexion when, for example, a baseball is miscaught or a finger is jammed into the base pad. These actions avulse the attachment of the tendon to the base of the distal phalanx. As a result, the person cannot extend the DIP joint.

Question 33

Median nerve injury

Answer 33

Severed in the elbow region, flexion of the proximal IP joints of 1st-3rd digits is lost and flexion of the 4th and 5th digit is weakened. Flexion of the DIP joints of the 2nd and 3rd digit is also lost. Flexion of the DIP of the 4th and 5th digit is not affected (ulnar n). The ability to flex the MP of 2nd-3rd digits is affected because of the digital branches of the median nerve supplying the 1st and 2nd lumbricals. So, when the person tries to make a fist, the 2nd and 3rd digits remain partially extended (hand of benediction).
Thenar muscle function is also lost, as in carpal tunnel syndrome. When the anterior interosseous nerve is injured, the thenar muscles are unaffected, but partial paralysis of the FDP and FPL occurs. When the person attempts to make the ‘ok’ sign, opposing the tip of the thumb and index finger in a circle, a pinch posture of the hand results instead owing to the absence of flexion of the IP joint of thumb and DIP joint of the index finger.

Question 34

Pronator syndrome

Answer 34

Nerve entrapment syndrome caused by compression of the median nerve near the elbow. The nerve may be compressed between the heads of the pronator teres as a result of trauma, muscular hypertrophy, of fibrous bands. Individuals with this syndrome are first seen clinically with pain and tenderness in proximal aspect of the anterior forearm, and hypesthesia (decreased sensation) of palmar aspects of radial 3 and a half digits and adjacent palm. Symptoms often follow activities involved with repeated pronation.

Question 35

Injury of ulnar nerve at elbow and in forearm

Answer 35

Ulnar nerve injuries usually occur in 4 places- posterior to the medial epicondyle, in the cubital tunnel formed by the tendinous arch connecting the humeral and ulnar heads of the FCU, at the wrist, or in the hand.
Most commonly occurs where the nerve passes posterior to the medial epicondyle of the humerus. The injury results when the medial part of the elbow hits a hard surface, fracturing the medial epicondyle (funny bone). Any lesion superior to the medial epicondyle will produce paresthesia of the median part of the dorsum of the hand.
Compression of the nerve at the elbow (cubital tunnel syndrome) is also common
Ulnar nerve injury usually produces numbness and tingling of medial part of the palm and medial 1 and a half fingers
Injury to the nerve in the distal part of the forearm denervates most intrinsic hand muscles. Power of wrist adduction is impaired, and when an attempt is made to flex the wrist, the hand is drawn to the lateral side by the FCR (median nerve) in the absence of the balance from the FCU.
After ulnar nerve injury, the person has trouble making a fist, because in the absence of opposition, the MCP joints become hyperextended, and they cannot flex the 4th and 5th digits at the DIP when making a fist. Furthermore, the person cannot extend the IP joints when trying to straighten the fingers. This characteristic appearance of the hand, resulting from distal lesion of the ulnar nerve, is known as claw hand. The deformity results from atrophy of the interosseous muscles of the hand. The claw is produced by the unopposed action of the extensors and FDP.

Question 36

Cubital tunnel syndrome

Answer 36

The ulnar nerve may be compressed (ulnar nerve entrapment) in the cubital tunnel formed by the tendinous arch joining the humeral and ulnar heads of attachment of the FCU. The signs and symptoms are the same as the ulnar nerve lesion in the ulnar groove on posterior aspect of the medial epicondyle of the humerus.

Question 37

Injury to the radial nerve in the forearm (superficial or deep branches)

Answer 37

Mid humeral shaft fracture damage is proximal to the motor branches to the long and short extensors muscles of the wrist from the common radial nerve, and so wrist-drop is the primary manifestation.
Injury to the deep branch of the radial nerve may occur when wounds of the posterior forearm are deep/penetrating. Severance of the deep branch results in inability to extend the thumb and the MCP joints of other digits. Thus, the integrity of the deep branch may be tested by asking the person to extend the MP joints while the examiner provides resistance. The extensor digitorum tendons should be prominent on the dorsum of the hand, confirming that the extension is occurring at the MP joints rather than the IP (movements under control of other nerves). Loss of sensation does not occur because the deep branch of the radial nerve is entirely muscular and articular.
When the superficial branch of the radial nerve, a cutaneous nerve, is severed, sensory loss is usually minimal. A coin-shaped area occurs distal to the bases of the 1st and 2nd MCs, since there is considerable overlap between the median and ulnar nerves.

Question 38

Dupuytren contracture of palmar fascia

Answer 38

Progressive shortening, thickening, and fibrosis of the palmar fascia and aponeurosis. The fibrous degeneration of the longitudinal bands of the palmar aponeurosis on the medial side of the hands pull the 4th and 5th fingers into partial flexion at the MCP and PIP joints. Usually bilateral. Unknown cause. Eventually produce raised ridges in the palmar skin that extend from the proximal part of the hand to the band of the 4th and 5th fingers

Question 39

Raynaud syndrome

Answer 39

Idiopathic condition of intermittent bilateral attack seen of ischemia of the digits, marked by cyanosis and often accompanied by paresthesia and pain, characteristically brought on by cold and emotional stimuli.
The arteries of the upper limb are innervated by sympathetic nerves. Postsynaptic fibers from the sympathetic ganglia enter nerves that form the brachial plexus and are distributed to the digital arteries through branches arising from the plexus- presynaptic sympathectomy to dilate the arteries.

Question 40

Carpal tunnel syndrome

Answer 40

Results form any lesion that significantly reduces the size of the carpal tunnel or increases the size of some of the 9 structures or their coverings that pass through it. Fluid retention, infection, and excessive exercise of the fingers may cause swelling of the tendons or their synovial sheaths. The median nerve is the most sensitive structure in the tunnel. The median nerve has two terminal sensory branches that supply the skin of the hand- loss of sensation may occur in lateral 3 digits. The palmar cutaneous branch arises proximal to the carpal tunnel and does not pass through it, so the central palm remains unaffected. The nerve also has one terminal motor branch, the recurrent branch, which serves the 3 thenar muscles.
Progressive loss of coordination and strength of the thumb may occur if the cause of compression is not alleviated. Unable to oppose their thumbs or button up a shirt or gripping things like a comb. Sensory changes may progress and radiate to the forearm and axilla
Carpal tunnel release- excision of the flexor retinaculum may be necessary (medial side of the retinaculum to avoid damage to the recurrent branch)

Question 41

Ulnar canal syndrome

Answer 41

Compression of the ulnar nerve may occur at the wrist where it passes between the pisiform and the hook of the hamate. The depression between these bones is converted by the pisohamate ligament into an osseofibrous tunnel, the ulnar canal (guyon’s canal).
Manifests as hypoesthesia in the medial one and a half gainers an weakness in intrinsic muscles of the hand. Clawing of the 4th and 5th fingers (hyperextension at MP with flexion at the PIP) may occur, but unlike proximal ulnar nerve injury, their ability to flex in unaffected, and there is no radial deviation of the hand.

Question 42

Radial nerve injury in the arm and hand disability

Answer 42

Although the radial nerve supplies no muscles in the hand, radial nerve injury in the arm can produce serious hand disability. The characteristic handicap is the inability to extend the wrist resulting from paralysis of the extensor muscles of the forearm. The hand is flexed at the wrist and lies flaccid, a condition known as wrist drop. The fingers of the relaxed hand also remain in flexed position at the MP. The IP joints cant be extended weakly through the action of the lumbricals and interossei. The radial nerve only has a small area of exclude cutaneous supply- lateral part of the dorsum of the hand

Question 43

The superifical palmar arch is at the same level as

Answer 43

Distal end of the common flexor sheath

Question 44

Dislocation of the acromioclavicular joint

Answer 44

Although its extrinsic coracoclavicular ligament is strong, the AC joint itself is weak and easily injured by a direct blow. Dislocation can result from a hard fall on shoulder or an outstretched upper limb.
Often called a shoulder separation, is severe when both the AC and coracoclavicular ligaments are torn. When the CC ligaments tear, the shoulder separates from the clavicle and falls because of the weight of the upper limb. Rupture of the CC ligaments allows the fibrous layer of the joint capsule to be torn so that the acromion can pass inferior to the acromial end of the clavicle. The clavicle may move superior to this process

Question 45

Calcification supraspinatus tendinitis

Answer 45

Inflammation and calcification of the subacromial bursa result in pain, tenderness and limitation of movement of the glenohumeral. Deposition of the calcium in the supraspinatus tendon is common. This causes increased local pressure that often causes excruciating pain during abduction of the arm; the pain may radiate as far as the hand. The calcium may irritate the overlying subacromial bursa. As long as the glenohumeral joint is addicted, no pain usually results. Pain starts to occur usually during 50-130 degrees of abduction (painful arc syndrome), because during this arc, the supraspinatus tendon is in intimate contact with the inferior surface of the acromion.

Question 46

Rotator cuff injuries

Answer 46

Recurrent inflammation, especially in the avascular area of the supraspinatus tendon, is common cause of shoulder pain and results in tears of the musculotendinous rotator cuff.
Repetitive use of the RC muscles may allow the humeral head and rotator cuff to impinge on the coraco-acromial arch, producing irritation- degenerative tendinitis of the RC. To test for this, the person is asked to lower the fully abducted limb slowly and smoothly. From 90 degrees of abduction, the limb will suddenly drop to the side in an uncontrolled manner if the RC is torn.
May also occur in a sudden strain of the RC- lifting a window that is stuck
A fall on the shoulder
Often the intracapsular part of the tendon of the long head of the biceps brachii becomes frayed, leaving it adherent to the intertubercular sulcus- shoulder stiffness occurs.
The integrity of the fibrous layer is usually compromised as well, causing the articular cavity to communicate with the subacromial bursa.
If the person passively moves their arm past 15 degrees of abduction, they can usually abduct the rest of the way with the deltoid.

Question 47

Dislocation of the glenohumeral joint

Answer 47

Categorized on whether the head has descended anterior or posterior to the infraglenoid tubercle and long head of the triceps. The head of the humerus ends up lying anterior or posterior to the glenoid cavity.
Anterior discoloration most often in young adults/athletes. Usually caused by excessive extensions and lateral rotation of the humerus. The head is driven inferior-anteriorly, and the fibrous layer of the capsule and glenoid labrum may be stripped from the anterior aspect of the cavity. The strong flexor and adductor muscles pull the head anterosuperiorly when a hard blow while fully abducted occurs, causing the head into a sub coracoid position.

Question 48

Glenoid labrum tears

Answer 48

When the humeral head subluxates/instability of the shoulder
Sudden contraction of biceps or forceful subluxation of head over the labrum. Pain while throwing, especially during the acceleration phase. Pop/snap may be felt during abduction and lateral rotation of the arm.

Question 49

Adhesive capsulitis of glenohumeral joint

Answer 49

Adhesive fibrosis and scarring between the inflamed joint capsule, rotator cuff, subacromial bursa, and deltoid usually cause frozen shoulder. 40-60 years old.
Difficulty abducting the arm and can obtain an apparent abduction of up to 45 degrees by elevating and rotating the scapula.
Strain is placed on the AC joint, which may be painful during other movements.
Injuries that initiate frozen shoulder are glenohumeral dislocations, calcification supraspinatus tendinitis, partial tearing of RC, and bicipital tendinitis

Question 50

Subcutaneous Bursitis of the elbow

Answer 50

Falls on the elbow and infections from abrasions
Repeated excessive pressure and fractions as occurs during wrestling may cause bursa to become inflamed- student’s elbow.
AKA dart thrower’s elbow and miner’s elbow.

Question 51

Subtendinous bursitis of elbow

Answer 51

Excessive friction between triceps tendon and olecranon- repeated flexion and extension of forearm: assembly line jobs
Pain is most severe during flexion, because the pressure exerted on the inflamed subtendinous olecranon by the triceps tendon.

Question 52

Ulnar collateral ligament reconstruction

Answer 52

Tommy john procedure
Autologous transplant of a long tendon from the contralateral forearm or leg- palmaris longus or plantaris tendon
Tears often from over abduction of the elbow or from dislocation, (fracture of head of radius, coronoid process, or olecranon process and ulnar nerve may occur with a dislocation)

Question 53

Subluxation and dislocation of radial head

Answer 53

Incomplete dislocation of head- nursemaid’ elbow
Child is suddenly lifted/jerked by the upper limb while the forearm is pronated, which tears the distal attachment of the anular ligament, where it is loosely attached to the neck of the radius. The radial head then moves distally, partially out of socket. The proximal part of the ligament becomes trapped between the head of the radius and capitulum of humerus.
Source of pain is from pinched anular ligament.
Treat by supination and flexion of the forearm. Placed in sling to heal anular ligament

Question 54

Bankart lesion

Answer 54

Anterior inferior labral tear

Question 55

Terry Thomas sign

Answer 55

Scaphoid lunate widening >4 mm
MC carpal instability
Fluid in scapholunate ligament

Question 56

Sail sign

Answer 56

Anterior and posterior fat pad on elbow seen- effusion of elbow
Usually associated with radial head fracture

Question 57

Torus-buckle fractures

Answer 57

Children
Soft bone can bend at distal radius
Heals quickly

Question 58

Keinbock disease

Answer 58

Idiopathic avascular necrosis of the lunate