MSK Bones of the upper limb

Question 1

What muscle(s) originate from the coracoid process of the scapula?

Answer 1

Short head of biceps brachii
Pectoralis minor
Coracobrachialis

Question 2

What muscle(s) originate from the supraglenoid tubercle of the scapula?

Answer 2

Long head of biceps brachii

Question 3

What muscle(s) originate from the infraglenoid tubercle of the scapula?

Answer 3

Long head of triceps brachii

Question 4

How are scapula fractures treated?

Answer 4

Uncommon - indicative of severe chest trauma

Does not require much intervention as tone of surrounding muscles holds scapula together well.

Question 5

What causes winging of the scapula?

Answer 5

The serratus anterior attaches to costal face of scapula and pulls it against the ribcage. Serratus anterior is innervated by the long thoracic nerve, if the nerve is damaged the scapula protrudes when the arms are pushed against a wall.

Question 6

List the muscles that attach to the shaft of the clavicle?

Answer 6

• deltoid
• trapezius
• subclavius
• pec maj

Question 7

Which ligaments attach to the lateral end of the clavicle? And what are the bony landmarks they attach to?

Answer 7

Conoid tubercle - conoid ligament attaches (medial part of the coracoclavicular ligament)
Trapezoid line - trapezoid ligament attaches (lateral end of coracoclavicular ligament)

(function of the coracoclavicular ligament is to suspend weight of upper limb)

Question 8

What is the most common site of fractures to the clavicle?
What position does the fractured clavicle undertake?
What are some possible complications?

Answer 8

Most commonly fractured bone in body
Most common point of fracture is the junction between medial 2/3 and lateral 1/3

Lateral end displaced inferiorly and medially by weight of the arm and pec major
Medial end pulled superiorly by sternocleidomastoid muscle

The supra scapular nerves (medial, intermedial, lateral) may be damaged by upwards movement of the medial part of fracture. These nerves innervate lateral rotators so damage results in medial rotation of upper limb - ‘waiters tip’ position

Question 9

Which muscle(s) attach to the greater tubercle of the humerus?

Answer 9

3 of the rotator cuffs: (the 3 at the back as the greater tubercle is at the back)

• infraspinatus
• supraspinatus
• teres minor

Question 10

Which muscle(s) attach to the less tubercle of the humerus?

Answer 10

The remaining rotator cuff - subscapularis

Question 11

What runs through the intertubecular sulcus?

Answer 11

Tendon of the long head of biceps brachii

Tendons of pec major, teres maj, latissimus dorsi attach to lips of the intertubecular sulcus

Question 12

What damages can occur from fractures to the surgical neck of the humerus?

Answer 12

Vulnerable structures -

1. Axillary nerve, paralysis of deltoid and teres minor, loss of sensory of regimental badge area (patient unable to abduct arm)
2. Posterior circumflex artery

Question 13

What are the bony landmarks of the humeral shaft?

Answer 13

Deltoid tuberosity - deltoid attaches

Radial groove - posterior surface of humerus, radial nerve and profound brachii artery lie in this groove

Question 14

List the muscles that attach anteriorly and posteriorly to the shaft of the humerus?

Answer 14

Anteriorly:
Coracobrachialis
Brachialis
Brachioradialis
Deltoid

Posteriorly:
Medial and lateral heads of triceps

Question 15

What are the complications of a mid-shaft fracture to the humerus?

Answer 15

Radial nerve and profunda brachii artery could easily be damaged

Radial nerve innervates wrist extensors - damage results in wrist drop (unopposed flexion), also sensory loss to dorsal surface of hand and proximal ends of lateral 3 1/2 fingers

Question 16

What are the names of the bony landmarks on the humerus that articulate with the ulna and radius?

Answer 16

The trochlea articulates with the ulna

The capitulum articulates with the radius

Question 17

What are the 3 depressions at the distal humerus and what is their function?

Answer 17

Coranoid fossa - above trochlea, accommodates coranoid process of the ulna when elbow flexed
Radial fossa - above capitulum, accommodates radius when flexed
Olecranon fossa - posterior, accommodates olecranon process of ulna when extended

Question 18

Where does the ulnar nerve pass into the forearm?

Answer 18

Posterior side of the medial epicondyle of the humerus

Question 19

What are the common fracture sites at the distal humerus?

What are the possible complications?

Answer 19

Common fractures are supracondylar (fall on a flexed elbow, fracture between two epicondyles) and medial epicondlye fractures.

Damage or swelling can cause interference of the blood supply to the forearm from the brachial artery - volkmanns ischaemic contracture.

A medial epicondyle fracture could damage the ulnar nerve - forms ‘ulnar claw’ - little and ring fingers flexed, with loss of sensation

Question 20

Describe the locations of the bony landmarks at the proximal ulna, and their functions

Answer 20

Olecranon - a bony prominence palpated as the ‘tip of the elbow’, triceps brachii attaches

Coronoid process - projects outwards anteriorly

Trochlear notch - wrench shaped, made up of the olecranon and coronoid process

Radial notch - lateral surface of trochlear notch, articulates with head of radius

Tuberosity of ulna - roughening distal to coronoid process where the brachialis attaches

Question 21

What are the 3 surfaces and 3 borders of the shaft of the ulna? and their attachments

Answer 21

3 surfaces:
Anterior - pronator quadratus attaches
Posterior - many muscles attach e.g. carpi flexors, indices extensors
Medial

3 borders:
Posterior
Interosseous - site of attachment of interosseous membrane
Anterior

Question 22

What bony landmarks are at the distal end of the ulna?

Answer 22

Much smaller in diameter than proximal
There is a distal projection called the styloid process which articulates with the ulnar notch of the radius to form the distal radio-ulnar joint

Question 23

What are the most common fractures to the ulna?

Answer 23

(Usually the radius also fractures)

The shaft is most likely to fracture, and muscle tone pulls the proximal ulna posteriorly

Less common - olecranon process can fracture if patients falls on flexed elbow, and the triceps brachii can pull a fragment proximally

Classical fractures:
Monteggias fracture - from force behind the ulna, proximal ulna fractures and head of radius dislocates from elbow
Galeazzis fracture - fracture to distal radius with the ulna dislocating at the distal radio-ulnar joint

Question 24

What are the articulations of the radius?

Answer 24

• articulates at the elbow with capitulum of the humerus
• articulates at proximal radio-ulnar joint with the radial notch
• articulates at the distal radio-ulnar joint with the ulna notch
• articulates at the wrist with scaphoid and lunate

Question 25

What are the important bony landmarks at the proximal end of the radius?

Answer 25

The radial head - disc shaped with concave articulating surface, involved in proximal radio-ulnar joint

The radial neck - narrow area between the head and tuberosity

The radial tuberosity - a bony projection which is the attachment of biceps brachii

Question 26

Describe the shape of the radial shaft and its attachments

Answer 26

The radial shaft is triangular in shape and expands in diameter as it moves distally

The middle and lateral surface is the attachment of the pronator teres muscle

Question 27

What are the important bony landmarks at the distal end of the radius?

Answer 27

Styloid process - a distal projection in which brachioradialis attaches
Ulnar notch - on medial surface for articulating with the head of the ulnar
Two facets on distal surface for articulation with scaphoid and lunate

Question 28

What is a colles and smiths fracture?

Answer 28

Colles fracture (most common) is a fracture of the distal radius due to a fall on an outstretched hand. The wrist and hand are displaced posteriorly forming a 'dinner fork' deformity
Smiths fracture is a fracture due to falling on the back of the hand, the distal fragment is displaced anteriorly

Question 29

Describe how a fracture of the radial head occurs?

Answer 29

A fall on an outstretched hand causes the radial head to be forced into the capitulum, causing it to fracture

Question 30

List the carpal bones in order

Answer 30

Left hand
Trapezium trapezius capitate hamate (has a hook)
Scaphoid lunate triquetrum pisiform (sesamoid in flexor carpi ulnaris tendon)

Question 31

What are the causes and complications of a lunate fracture?

Answer 31

Fail on an outstretched hand causing hyperextension of the wrist
Can have some median nerve damage

Question 32

Describe the general shape of the metacarpals

Answer 32

Each metacarpal has a base, shaft and head
They articulate proximally with the carpals and distally with the proximal phalanges
The medial and lateral surfaces are concave allowing for attachment of the interossei muscles

Question 33

What are the names of the common fractures to the metacarpals?

Answer 33

Boxers fracture: fracture of 5th metacarpal neck and the distal part is displaced posteriorly, shortening the finger
Caused by clenched fist hitting hard object

Bennets fracture: fracture of 1st metacarpal base extending to the carpometacarpal joint
Caused by hyperabduction of thumb