Week 10: Musculoskeletal Care - Upper limb

Question 1

How do nerves get into the Upper Limb?

Answer 1

Major artery, vein and nerves of the upper limb pass between the thorax and the limb by traveling OVER rib 1, under the clavicle, and through the axillary inlet.

Question 2

Brachial Plexus originates from cervical and thoracic spinal cord level

Answer 2

C5, C6, C7, C8, T1

Question 3

what symptoms may you present with in thoracic outlet syndrome?

Answer 3

Pain, parasthesia, pallor, diminished pulses

Question 4

__________ artery and its branches supply structures in the neck, part of the thoracic wall and entire upper limb.

Answer 4

subclavian

Question 5

The Axillary artery is the continuation of the subclavian, beginning at the lateral boarder of the _________

Answer 5

first rib

Question 6

In the ________ , the brachial artery bifurcates into the radial and ulnar arteries of the forearm.

Answer 6

elbow/cubital fossa

Question 7

In the hand, both the ulnar and radial arteries give rise to ________
arches – a superficial and a deep one, which
supply the digits.

Answer 7

palmer

Question 8

what are the three important nerves that come into close contact with the humours and why is this important?

Answer 8

nerves: axillary nerve around surgical neck, radial nerve in spiral groove posterior, ulnar nerve in medial epicondyle

Question 9

Triangle of Auscultation

Sits medial to the inferior angle of scapula. what three muscles form its border?

Answer 9

Borders:

• Trapezius
• Rhomboid major - Latissimus dorsi

Question 10

Musculocutaneous Nerve (C5-C7) what muscles does it innervate?

Answer 10

BBC nerve
Biceps Brachii
Brachialis
Coracobrachialis

Lateral Cutaneous Nerve of the Forearm Sensory ONLY

Question 11

Axillary Nerve (C5-6) what muscles does it innervate?

Answer 11

Deltoid
Teres Minor

gives off teres minor then travels through which space?
quadrangular space and then wraps around surgical neck of humorus
after motor branches, it has sensory fibres to lateral upper arm (sensory
badge area)

Question 12

The anterior compartment has a dual innervation. What two major nerves supply muscles here?

Answer 12

Median and Ulnar

Question 13

The posterior forearm is a bit more straightforward. Take a look at the muscles of the posterior compartment. i) What nerve innervates this compartment? ii) This nerve is a terminal branch off of what cord? iii) List any three of the muscles here?

Answer 13

Radial nerve
Posterior cord
Brachioradialis, ECRL, ECRB, Supinator, ECU, ED, Abductor pollicis longus, EPL, EPB, EI

Question 14

What do you notice about the emergence of the brachial plexus from the neck – where does the brachial plexus emerge between?

Answer 14

Anterior and middle scalene muscles.

Question 15

What do you notice about the vascular components? Specifically, describe the plexus’s relationship to the subclavian artery and vein

Answer 15

They course anteriorly to the plexus, with the subclavian vein being most superficial.

Question 16

What do you notice about the plexus and how it gets into the axilla – specifically how does it get past the clavicle and ribs (describe its anatomical course)

Answer 16

It courses inferior to the clavicle at around the middle of the clavicle, and courses superficial to the thoracic cavity to get to the axilla.

Question 17

the costo-clavicular space. This is a space between the clavicle and the first rib. What might happen to this area, and what structures might be affected if you wear a very heavy backpack?

Answer 17

Subclavian artery and vein (not as affected as the artery), and brachial plexus compressed – with multiple levels from C5 –T1 potentially being affected. You could have typical neurogenic symptoms like tingling or pain; and after arterial compression you could have a reduced pulse, and limb pallor.

Question 18

the shoulder joint and how the humerus articulates with the scapula. If you look directly above the articulating head of the humerus, what do you see?

Answer 18

The acromion process where it joins up with the clavicle.

Question 19

Now find the coracoid process. i) Where does it sit in relation to the clavicle? ii) What three muscles attach to this bony projection to act upon the scapula?

Answer 19

Inferior to it and points slightly lateral
Coracobrachialis
Short head of biceps brachii
Pectoralis minor

Question 20

There is a ligament that stretches from the coracoid process to the acromion process. Find the area where this ligament would be. i) What is this ligament called? ii) What type of displacement does this ligament help resist?

Answer 20

i) Coracoacromial ligament

ii) Superior displacement of the shoulder

Question 21

When the shoulder abducts what happens to the head of the humerus and the acromion process of the scapula as you try to pass a 90 degree angle?

Answer 21

The head of the humerus gets “stuck” on the acromion process, preventing further abduction.

Question 22

What must happen in order for the shoulder to abduct above a 90 degree angle? Be specific.

Answer 22

The serratus anterior and the trapezius muscle must help to upward rotate the scapula on the thoracic cage.

Question 23

Now take a look at the clavicle. What does it articulate with medially and laterally?

Answer 23

Medially: Manubrium of sternum Laterally: Acromion of the scapula

Question 24

The clavicle is the most commonly broken long bone in the body. i) What are the three functions of this bone? ii) Where along the length of the clavicle is it most commonly fractured?

Answer 24

To transmit forces from the upper limb to axial skeleton. To provide attachment for muscles.
To act as a strut holding the arm free from the trunk.
At the junction of the middle and lateral 1/3rd.

Question 25

How might a patient present if they have a fractured clavicle?

Answer 25

Patient will be supporting arm with opposite hand.
The trapezius cannot support weight of upper limb.
Lateral fragment is depressed and typically drawn medially, while proximal segment is pulled up by sternocleidomastoid.

Question 26

Identify the three carpal bones that articulate with the distal radius. Identify them from a lateral to medial position?

Answer 26

Scaphoid, lunate, triquetrum.

Question 27

Whatbonearticulateswiththefirstmetacarpal,andwhyisits distal shape so important (make sure to look at its shape!)?

Answer 27

Trapezium.

It allows great movement of the thumb upon it due to its almost round shape.

Question 28

doesthedistalulnaarticulatewith the carpal bones directly? If not, what is found between the two?

Answer 28

Fibrocartilage articular disc.

Question 29

Why is the blood supply to the scaphoid so important when you think about a fracture and possible complications?

Answer 29

Blood supply is from the radial artery, and blood vessels enter the bone primarily from its distal half and then the arterial branches comes back in a proximal direction.

You can get avascular necrosis of the proximal portion of the scaphoid bone because of disruption to the blood supply.

Question 30

borders of the anatomical snuffbox.

Answer 30

Lateral: tendons of Abductor pollicis longus and Extensor pollicis brevis. Medial: Tendon of Extensor pollicis longus.
Floor: Scaphoid

Question 31

What vein runs superficially over the anatomical snuffbox?

Answer 31

Cephalic Vein (Houseman’s Vein)

Question 32

What superficial cutaneous nerve runs superficially over the anatomical snuffbox?

Answer 32

Superficial radial nerve.

Question 33

What muscle attaches upon the radial tuberosity? What two movements does it produce?

Answer 33

Tendon of biceps brachii. Flexion of elbow and supination of the forearm.

Question 34

Where does the brachial artery lie in relation to the median nerve in the upper arm AND in the cubital fossa?

Answer 34

In the upper arm – it lies medial to the median nerve; in the cubital fossa it lies lateral to it.

Question 35

Which structure lies immediately anterior to the brachial artery and the median nerve in the cubital fossa? What is it’s purpose?

Answer 35

Bicipital aponeurosis; this structure which comprises of collagen fibres radiating from the distal part of the biceps tendon passes obliquely across the cubital fossa and merges with the fascia covering the flexor muscles in the medial side of the forearm. It provides some protection to the brachial artery & the median nerve

Question 36

list the boundaries below (medial, lateral, superior, and roof) of the cubital fossa

Answer 36

Medially: Pronator teres
Laterally: Brachioradialis
Superiorly: Imaginary Line between medial and lateral epicondyles of humerus
Roof: Aponeurosis of biceps brachii tendon

Question 37

What important venous structure lies superficial to the cubital fossa and why is it important clinically?

Answer 37

Median cubital vein

Used for blood draw/IV access

Question 38

Where in the elbow region can you normally palpate the ulnar nerve against the humerus? How might this anatomical position lead to compression?

Answer 38

The ulnar nerve at the elbow passes behind the medial epicondyle of the humerus. It lies in close proximity to the bone surface (& grooving it). It enters the forearm passing through a structure called the “cubital tunnel” formed by the tendinous arch joining the humeral and ulnar heads of the attachment of flexor carpi ulnaris. Here the nerve could get compressed to produce symptoms/signs of the “cubital tunnel syndrome”.

Question 39

In the event of bleeding from a large vessel in the upper limb as a result of a mid-humeral shaft fracture, how would you differentiate whether an artery or a vein has been ruptured?

Answer 39

Subclavian artery: may show pulsatile release of blood from an open wound, but damage to such a major artery the patient would most likely be unconscious and dying!

Subclavian vein: Non-pulsatile, patient conscious, haematoma forming if not an open wound

Question 40

Whydoesbursitisoccur?

Answer 40

Excess wear and tear or trauma can result in inflammation and swelling of the bursa. The olecranon bursa is subject to wear when leaning on your elbows.

Bursitis can also result from gout, infection or rheumatoid arthritis.

Question 41

Describe the anatomical structure of the elbow joint

Answer 41

The elbow is formed by the trochlea notch of the elbow articulating with the trochlea of the humerus, and the radial head articulating with the capitulum of the humerus. The olecranon is the protuberance of bone located on the posterior surface of the proximal ulna. The subcutaneous olecranon bursa sits under the skin over the bony olecranon.

Question 42

In injuries of the shoulder joint, the humerus may fracture at its “surgical neck”. Where is the “anatomical neck” of the humerus and give one clinical significance of it?

Answer 42

The anatomical neck is formed by the groove circumscribing and separating the head from the greater and lesser tubercles.
Significance:
• The articular capsule of the joint is attached nearby.
• The anatomical neck also marks the region of the epiphyseal growth
plate during the growth in length of the humerus.

Question 43

Describe in the upper limb where you would you feel for the THREE main arterial pulses (and what artery are you feeling)?

Answer 43

In the cubital fossa (brachial pulse), at the wrist (radial pulse between flexor carpi radialis & brachioradialis & ulnar pulse above the flexor retinaculum)

Question 44

What is the most common way in which a shoulder dislocates? (Anterior or Posterior AND Superior or Inferior) and why?

Answer 44

Anterior and inferior
It is more inherently unstable in the anterior/inferior direction. You have many muscles, joints, tendons which help to strengthen the joint capsule in all the other directions, except this one.

Question 45

The rotator cuff is a very important muscle group that helps to strengthen the shoulder joint and prevent dislocation. What are the four rotator cuff muscles, and for each, describe their major action?

Answer 45

Supraspinatus – first 15 degrees of abduction of the arm Infraspinatus – External rotation of arm
Teres minor – External rotation of arm
Subscapularis – Internal rotation of arm

Question 46

The coracoacromial ligament has not been damaged in your patient, but is a very important ligament of the shoulder joint which helps give the joint stability. i) What two bony structures does this ligament stretch between? ii) This ligament overlies what bony aspect of the humerus? Iii) What type of displacement does this ligament prevent? iv) Why is this ligament important when you consider ‘Painful Arc’ syndrome?

Answer 46

i) Acromion and the Coracoid process of the scapula
ii) It overlies the humeral head
iii) It prevents upper displacement
iv) The supraspinatus tendon travels on top of the humeral head and under the coracoacromial arch (which in part is made up of the ligament). It can start to rub under this ligament and become inflamed and painful as the shoulder abducts (supraspinatus tendonitis). You can also have a subacromial bursitis in this area, as it sits in the tight space right under the ligament.

Question 47

The surgical neck of the humerus is different than the anatomical neck. What key bony region does the anatomical neck mark?

Answer 47

Region of epiphyseal growth plate.

Question 48

Mid-humeral shaft facture Which important nervous and vascular structures pass along the posterior humerus at the fracture point? Which bony feature of the humerus can normally be used to landmark their location?

Answer 48

The radial nerve and profunda brachii artery are at risk of damage
The nerve passes through the spiral groove of the humerus. The spiral groove runs inferolaterally around the posterior humerus. It is ~6.5cm in length and can be centred on the deltoid tuberosity

Question 49

Mid-humeral shaft facture. Identify the muscles that have likely lost their innervation following this injury (include in your description a discussion of what movements will be affected)?

Answer 49

Radial nerve injury in the spiral groove can lead to partial loss of triceps innervation, and total loss of innervation of the posterior compartment of the forearm.
Integrative Term 6 Workbook Session Ten: Musculoskeletal Care – Upper Limb
190
Issues include:
- Weakened elbow extension
- Loss of wrist extension (wrist drop) - Weak thumb abduction
- Lack of digit extension

Question 50

Mid-humeral shaft facture. In light of the nerve this patient has likely damaged, what cord levels are you concerned with her having deficits in?
Explain why supination of the forearm is still possible in her damaged limb?

Explain why your patient is still likely able to extend her elbow (even though it would be painful)?

Answer 50

C5, 6, 7, 8, T1 (Radial nerve cord levels).

Supination is brought about by two muscles, supinator (radial nerve innervated and therefore paralyzed) and biceps brachii (musculocutaneous nerve innervated and therefore working).

Triceps is innervated by the radial nerve at different levels. Spiral groove injury can lead to a loss of part of triceps innervation, but in general the muscle works well as it receives innervation prior to the spiral groove.

Question 51

Mid-humeral shaft facture. Which area of skin on the distal upper limb could you use to test the cutaneous portions of the nerve at risk of damage in this injury?

Considering the patient’s safety what is the best way to assess damage to the nerves you think are at risk of damage—specifically, how would you assess the damage (motor and sensory damage) to these nerves?

Answer 51

Skin covering the 1st dorsal interosseous muscle on the dorsal surface of the hand (radial nerve territory).

(All testing should involve minimal movement and ideally distal to the injury). Sensory: test peripheral innervation (hand and forearm) of the radial nerve. Motor: Definitely no testing. Will cause more damage and pain!

Question 52

Three posterior forearm muscles that go to the wrist:

Answer 52

ECRL, ECRB, ECU

Question 53

Three posterior forearm muscles that go to the thumb:

Answer 53

EPB, EPL, AbPL.

Question 54

Colles’ Fracture. With this fracture, is the wrist dorsally or ventrally displaced?

Answer 54

Dorsally – you can see the wrist has ridden dorsally over top of the distal fractured end of the forearm. This is often called a “Dinner Fork Deformity”

Question 55

Most of these types of fractures are sustained secondarily after falling on an outstretched hand, aka a FOOSH injury. What anatomical position of the wrist does one often assume when they fall in this manner?

Why is it that the distal radius, not the ulna, is typically affected in this type of a fall?

Answer 55

Pronated forearm, wrist in dorsiflexion (extension of the wrist).

The wrist joint is an articulation between the distal end of the radius, an articular disc overlying the distal ulna and the wrist (scaphoid, lunate and triquetrum bones). Thus, the ulna does not directly articulate with the bones of the wrist, thus does not receive the same forces the radius does upon falling.

Question 56

Colles’ Fracture. What other condition do individuals who sustain this type of fracture often have (a condition that increases the chance of fracture)?

Answer 56

Osteoporosis: The fracture is particularly common in patients with osteoporosis and as such, they are most frequently seen in elderly women. The relationship between Colles’ fractures and osteoporosis is strong enough that when an older male patient presents with a Colles’ fracture, he should be investigated for osteoporosis because his risk of a hip fracture is also elevated.

Question 57

What type of joint is the wrist? Identify the four major movements that the wrist is capable of

Answer 57

Synovial condyloid joint.

Flexion, extension, adduction (ulnar deviation), abduction (radial deviation).

Question 58

A professional piano player comes to you complaining of tingling, numbness and some motor weakness in his hands. You take a history and discover that he practices for up to 8 hours every day. You look at his hands and notice that the thenar eminence on both of his hands looks flat, almost deflated. What nerve, which innervates the thenar muscles, is likely affected?

Answer 58

Median nerve (specifically the recurrent branch of the median nerve).

Question 59

Considering his tingling, numbness and wasted thenar muscle groups, what condition do you think this pianist is suffering from? Define and describe the condition?

Answer 59

Carpal tunnel syndrome.
Synovial condyloid joint.
Flexion, extension, adduction (ulnar deviation), abduction (radial deviation).
It is an entrapment syndrome caused by pressure on the median nerve within the carpal tunnel. The aetiology of this condition is often obscure, though in some instances the nerve injury may be a direct effect of increased pressure on the median nerve caused by overuse, swelling of the tendons and tendon sheaths (e.g., rheumatoid arthritis), and cysts arising from the carpal joints.

Question 60

Following conservative management for carpel tunnel, the pianist still complains of symptoms. Surgery is now indicated. Which structure is divided in surgery for relief in this case?

Answer 60

Flexor retinaculum.

Question 61

You consider damage your patient might have to other structures in the hand and you consider the Ulnar nerve. However, you notice that he does not present with a classic “claw hand”. With damage of the ulnar nerve at the wrist, why would clawing be pronounced in the fourth and fifth digit?

Answer 61

This is because of the paralysis of the 3rd and 4th lumbrical muscles acting on the 4th (ring finger) and 5th (little finger) digits; these two lumbricals are supplied by the ulnar nerve. The lumbrical muscles flex the digits at the metacarpophalangeal joints (MPJ) and extend the digits at the interphalangeal joints (IPJ) via the dorsal digital expansion.
Paralysis of the lumbricals will result in the MCPJoints becoming hyperextended and the IPJoints becoming flexed; this deformity is obvious because the first and second lumbricals (acting on the index & middle fingers) supplied by the median nerve are not paralysed.

Question 62

Besides repetitive movements (as is the case with your piano- practicing patient), what are other causes of carpel tunnel syndrome?

Answer 62

Carpal tunnel syndrome can be caused by anything that occupies space in the carpal tunnel. Ganglion cyst, Giant cell tumour, Neuroma, Lipoma, Soft tissue thickening, Fluid retention (for example, during pregnancy).
Associated conditions include hypothyroidism.