L11 Clinical Anatomy of Upper Limb

Question 1

What needs to be identified and released to allow insertion of a shoulder replacement?

Answer 1

1. anterior inter-nervous plane: b/w deltoid and pectoralis major
   
   • cephalic vein lies there - deltoid and pectoralis major get pushed apart
2. coracoid process: fasica underneath is incised
3. subscapularis: gets cut
4. humeral head and glenoid

Question 2

What are things to look out for when operating around the shoulder joint?

Answer 2

• brachial plexus → not caught in retractors
• musculocutaneous nerve → not streched when coracobrachialis is cut away

Question 3

rotator cuff injuries

Answer 3

• usually supraspinatous gets torn (due to spur of acromium causing inflammation)
• continued wear: infraspinatous and subscapularis gets torn

Question 4

What procedures can be done when inflammation caused by acromium occurs?

Answer 4

• open acromiosplasty → older procedure
• athroscopic acromioplasty → more common

Question 5

What kind of procedures can be done when the clavicle is fractured?

Answer 5

• pin inserted into hollowed out clavicle bones
• pin and plate: be wary of pin lengths

Question 6

When fixing the clavicle, what are some structures that may be endangered?

Answer 6

• axillary artery/subclavian artery
• axillary vein/subclavian vein
• brachial plexus

Question 7

arcuate artery

Answer 7

• branch of anterior humeral circumflex artery
• branches via greater tuberosity
• supplies humeral head

Question 8

If blood vessels to the humeral head are damaged, what could occur?

Answer 8

1. bone in humeral head will necrose, avascular necrosis
2. cartilage will then also die
3. joint becomes arthritic

Question 9

How much of the proximal humerus does the anterior circumflex artery provide blood supply to?

Answer 9

3/4 of proximal humerus

Question 10

How much of the proximal humerus does the posterior circumflex artery provide blood supply to?

Answer 10

1/4 → 1/3 of proximal humerus

Question 11

How does the parts of fractures affect the rate of avascular necrosis?

Answer 11

• 3-part: 12-25%
• 4-part: 21-75%
• Valgus (lateral displacement) 4-part: 8-26%

Question 12

What are some predictors of ischemia in the humeral head?

Answer 12

• metaphyseal head extension (calcar) < 8mm
• loss of integrity of medial higne
• fracture pattern (anatomical neck) → more fracture pattern = worse

Question 13

SLAP tear and grades of SLAP tears

Answer 13

• Superior Labral Anterior Posterior lesion
• I: little damage to biceps insertion
• II: torn off insertion - can be sewn back
• III: labrum flaps and causes catching in shoulder
• IV: tears running into biceps tendon

Question 14

What can occur due to a torn glenoid labrum? What can be the consequence of this?

Answer 14

• cysts can occur
• can cause impingement of supraspinatous nerve
• impingement syndrome
  
  • weakness of supraspinatous and infraspinatous

Question 15

What are the grades of AC joint dislocation?

Answer 15

• I: sprained ligaments
• II: conoid and trapezoid ligaments aren’t torn

above: can be healed by physiotherapy

• III: tear of ligaments but displacement is small → can be healed with physiotherapy, however 20% of grade III displacements need surgery
• IV & V: tear of ligaments with greater (V: and greater) displacement → requires surgery
• VI: distal clavicle displaced behind tendon of biceps and coracobrachialis - not common though

Question 16

What are some procedures that can be done to fix AC joint dislocations?

Answer 16

• tightrope fixation surgery - liable to breakage, but allows for mobility
• bosworth screw - old method and rigid - breaks easily as AC joint is meant to be mobile
• lateral clavicular plate: attached under acromium (could affect subacromial space - SITS), is usually removed after ligaments are healed

Question 17

What are some treatments for fractures of the clavicle in the lateral third?

Answer 17

similar to AC joint dislocation treatment (physio or in worse cases, surgery with lateral clavicular plate)

Question 18

When repairing distal biceps tendon tears, what structures are at risk of being endangered?

Answer 18

posterior interosseous nerve (branch of radial nerve) - goes round the two heads of supinator

Question 19

When placing a plate along the whole length of the humerus, what structures may be damaged?

Answer 19

• axillary nerve (near the head)
• radial nerve (runs across the shaft of the humerus)
  
  • plate needs to be placed under the radial nerve
  • if plate is placed over, can cause wrist drop due to damage
• ulnar nerve (elbow)

Question 20

Holstein Lewis humeral fracture

Answer 20

• fracture at where radial nerve crosses through lateral intermuscular septum
• radial nerve at danger of getting trapped in the fracture

Question 21

What can cause damage to the axillary nerve?

Answer 21

• dislocated shoulder
• proximal humeral fracture

Question 22

If the axillary nerve is damaged, what are the consequences?

Answer 22

• if stretched → axillary nerve palsy
  
  • numbness at deltoid insertion
  • deltoid palsy
• if prolonged injury → 2° deltoid wasting

Question 23

Hilton’s Law

Answer 23

Nerve that supplies muscles that move a joint also innervates articular branches of said joint and the skin overlying the insertion of the muscle

Question 24

Hill-Sach’s deformity

Answer 24

• shoulder dislocation → humeral head hits edge of glenoid → Hill-Sachs impaction fracture (can include bleeding in joint)

Question 25

What can be done when a Hill-Sach’s impaction fracture occurs? Or when a more severe shoulder dislocation occurs?

Answer 25

• arthroscopic repair
  
  1. detach ligaments (usually anterior and inferior glenohumeral ligament - which attach to glenoid via glenoid labrum)
  2. then repair arthroscopically - stops shoulder dislocation
• with recurrent shoulder dislocation - mini open procedure
  
  • similar to shoulder replacement surgery

Question 26

What can be done to manage humeral head defects?

Answer 26

based on severity of damage

• 20-30%: engaging lesion Bristow or Laterjet
• 33%: osteochondral allograft - transfer infraspinatous rotational osteotomy
• >40%: arthroplasty

Done by surgery via internervous plane b/w teres minor and infraspinatous

• injury usually at the back of the humeral head (posterior)

Question 27

What can be a consequence of plating the distal radius? How can this complication be fixed?

Answer 27

• screws may rupture extensor pollicis longus
• can be repaired with extensor indicis

Question 28

De Quervain’s tenosynovitis

Answer 28

• occurs in 1st compartment when extensor pollicis brevis and abductor pollicis longus get inflammed via 1st compartment tunnel
• pain with the Finkelstein test - pressing the thumb into the palm and getting the patient to counter it
• fixed with surgery on radial styloid

Question 29

How to fix radius and ulna midshaft fracture

Answer 29

• radius: Henry’s approach ⇒ incision b/w radial styloid and lateral epicondyle (of humerus) → find internervous plane b/w brachioradialis and forearm flexor (flexor carpi radialis) and reflect → find pronator teres and attach plate
  
  • warning! be aware of radial artery - it runs in the same plane
• ulna: find internervous plane b/w flexor carpi ulnaris and extensor carpi ulnaris