MSK Joints of the upper limb

Question 1

What type of joint is the sternoclavicular joint?

What cartilage type is present in the sternoclavicular joint?

Answer 1

A saddle - type synovial joint between the clavicle and manubrium of the sternum
A fibrocartilaginous articular disc is present which is part of the 1st costal cartilage

Question 2

What are the 4 major ligaments of the sternoclavicular joint?

Answer 2

Anterior and posterior stenoclavicular ligaments:
Strengthen the joint capsule anteriorly and posteriorly

Interclavicular ligament:
Spans the gap of the sternal ends of each clavicle reinforcing the joint capsule superiorly

Costaclavicular ligament:
The 2 parts of this ligament (separated by bursa) bind at the 1st rib inferiorly and to the clavicle superiorly. Very strong and the main stabiliser of the joint

Question 3

What is the neurovascular supply to the sternoclavicular joint?

Answer 3

Arterial supply: internal thoracic artery and suprascapular artery
Nerve supply: medial supraclavicular nerve (C3-4) and nerve to the subclavius (C5-6)

Question 4

How mobile is the sternoclavicular joint?

How stable is the sternoclavicular joint?

Answer 4

High degree of mobility - saddle joint so can move in 2 axis
Articular disc allows free sliding allows for rotation and movement in a 3rd axis

Has to be very stable as it is the only joint connecting the upper limb to the axial skeleton

• strong joint capsule
• strong ligaments, especially costaclavicular ligament

Question 5

What is the consequence of a dislocation of the sternoclavicular joint?

Answer 5

Rare.

• Anterior dislocations most common and are caused by blow to anterior shoulder which rotates shoulder backwards
• Posterior dislocations result from force driving shoulder forwards or direct impact

Usually in young a dislocation is accompanied by a fracture through the epiphyseal growth plate of clavicle

Question 6

What type of joint is the acromioclavicular joint?

What cartilage type is present in the sternoclavicular joint?

Answer 6

Plane type synovial joint can be palpated on shoulder

Articular surfaces lined with fibrocartilage, and there is a fibrocartilage articular disc suspended from joint capsule

Question 7

What are the 3 major ligaments of the acromioclavicular joint?

Answer 7

Acromioclavicular ligament: runs from accordion to clavicle reinforcing superior part of joint capsule

Conoid ligament: runs vertical from coracoid process to conoid tubercle of clavicle
Trapezoid ligament: runs from coracoid process to trapezoid line of clavicle

Conoid and trapezoid make up the coracoclavicular ligament that is very strings and supports weight of upper limb

Question 8

What are the movements of the acromioclavicular joint?

Answer 8

Allows degree of axial rotation and anteroposterior movement (no muscles so all movement passive)

Question 9

What is the neuromuscular supply to the acromioclavicular joint?

Answer 9

Blood supply: suprascapular artery and thoraco-acromial artery
Nerve supply: suprascapular and lateral pectoral nerves

Question 10

What is the consequence of a dislocation of the acromioclavicular joint?

Answer 10

Known as ‘separated shoulder’ and is associated with soft tissue damage - Commonly occurs due to direct blow or fall an an outstretched hand

More serious if there is ligament rupture, if the coracoclavicular ligament is torn the weight of the upper limb is not supported so moves inferiorly.

Question 11

What type of joint is the glenohumeral joint?

What cartilage type is present in the glenohumeral joint?

Answer 11

A ball and socket joint

Articulating urfaces lined with hyaline cartilage

Question 12

How mobile is the glenohumeral joint?

How stable is the glenohumeral joint?

Answer 12

One of the most mobile joints of the body:

• ball and socket joint with a lax joint capsule
• shallow cavity and larger humeral head

but also one of the most unstable.:
This is because the humeral head is much larger than the glenoid fossa
- rotator cuff muscles help pull the humeral head into the glenoid fossa
- glenoid fossa is deepened by a fibrocartilage rim called the glenoid labrum
- ligaments reinforce joint capsule

Question 13

What are the major bursae present in the glenohumeral joint?

Answer 13

Subacromial bursa - inferior to deltoid and acromion and superior to supraspinatus tendon and joint capsule.

Subscapular bursa - located between subscapularis tendon and scapula

Question 14

What are the major ligaments of the glenohumeral joint?

Answer 14

Glenohumeral ligaments (superior, middle, inferior): 3 bands that runs with the joint capsule from glenoid fossa to anatomical neck of humerus. Stabilises anteriorly

Coracohumeral ligament: base of coracoid to greater tubercle of humerus. Supports superiorly

Transerve humeral ligament: Spans tubercles of humerus and holds biceps tendon in intertubecular groove
(all thickenings of the joint capsule)

The coracoacromial ligament prevents superior displacement of the humeral head

Question 15

What is the neurovascular supply to the glenohumeral joint?

Answer 15

Blood supply: posterior circumflex humeral artery and suprascapular artery

Nerve supply: axillary, suprascapular and lateral pectoral nerves (all C5-6 so erbs palsy affects shoulder)

Question 16

What is the consequence of a dislocation of the glenohumeral joint?

Answer 16

Anterior dislocations most prevalent (superior movement prevented by coraco-acromial arch)
Usually caused by excessive extension and lateral rotation
Tearing of joint capsule increased risk of future dislocations

Axillary nerve can be damaged resulting in paralysis of deltoid and loss of sensation of regimental badge area

Question 17

What is rotator cuff tendonitis?

Answer 17

Relatively common
Inflammation of the rotator cuff tendons due to overuse
Characteristic sign in the painful arc pain in the middle of abduction where the tendon comes into contact with the acromion

Question 18

What type of joint is the elbow joint?

Answer 18

Structurally a synovial joint but functionally a hinge joint

Question 19

What are the articulations involved in the elbow joint?

Answer 19

Trochlea notch of ulna and trochlea of humerus

Head of radius and capitulum of humerus

Question 20

What structures contribute to the stability of the elbow joint?

Answer 20

Radial collateral ligament: extends from lateral epicondyle to anular ligament of the radius
Ulnar collateral ligament: extends from medial epicondyle to coronoid process and olecrannon of ulna

Question 21

What are the major bursae of the elbow joint?

Answer 21

Intratendinosus bursa: within triceps tendon
Subtendinosus bursa: between olecrannon and triceps tendon
Subcutaneous bursa: between olecrannon and overlying CT

Question 22

What types of bursitis can arise at the elbow joint?

Answer 22

Subcutaneous bursitis - repetitive friction and pressure of the elbow

Subtendinosus bursitis - repeated flexion and extension. Flexion more painful as more flexion put on bursa

Question 23

What is the consequence of a dislocation of the elbow joint?

Answer 23

Most dislocations posterior
Usually occurs when child falls on hand with elbow flexed
Humerus driven through weakest part of joint capsule which is the anterior side
Ulnar collateral ligament usually torn

Question 24

What is the consequence of a supraepicondylar fracture?

Answer 24

A transverse fracture caused by falling on a flexed elbow

Can cause disruption to blood supply of forearm as swelling can affect brachial artery. This can cause volkmanns ischemic contracture (uncontrolled flexion of hand)
Also can be damage to medial, ulnar or radial nerves

Question 25

What are the 2 articulations between the radius and ulna and what type of joint are they?

Answer 25

Proximal radioulnar joint: between head of radius and radial notch of ulna
Distal radioulnar joint: between head of ulna and ulnar notch of radius

Both pivot joints responsible for pronation/supination

Question 26

What ligaments are present at the 2 radioulnar articulations?

Answer 26

Proximal radioulnar joint: The radial head is held in place by the annular radial ligament (is lined with synovial membrane to reduce friction)

Distal radioulnar joint: anterior and posterior ligaments, also a fibrocartilaginous ligaments called the articular disk (holds bones together and separates joint from wrist)

Question 27

What is the interosseous membrane and what is its function?

Answer 27

A sheet of CT connecting medial radius and lateral ulna
There are holes for the forearm vasculature

3 major functions:

• holds bones together during pronation and supination providing stability
• sites of attachment for muscles
• transfers forces from radius to ulna

Question 28

What are the 2 main types of fracture/dislocation combo of the radius and ulna?

Answer 28

Monteggias fracture - usually caused by force behind ulna
Proximal shaft of ulna fracture and radial head dislocates anteriorly at the elbow

Galeazzis fracture
A fracture to distal radius with the ulna head dislocating at the distal radio-ulnar joint

Question 29

What type of joint is the radiocarpal joint?

Answer 29

An ellipsoid type synovial joint - allows for movement in 2 axis

Question 30

What are the articulating surface of the wrist joint?

Answer 30

Proximally - Distal radius articulates with articular disk

Distally - Distal radius with proximal row of carpals except pisiform

Question 31

What is the neurovascular supply to the radiocarpal joint?

Answer 31

Blood supply: branches derives from radial and ulnar arteries
Nerve supply: branches of radial nerve, ulna nerve and median nerve

Question 32

What are the ligaments stabilising the radiocarpal joint?

Answer 32

Palmar + dorsal radiocarpal ligament - they extend from radius to both rows of carpals. They stabilise and ensure hand follows forearm during supination + pronation (respectively)

Ulnar collateral ligament - ulnar styloid process to triqutrum and pisiform. Prevents excessive lateral joint displacement

Radial collateral ligament - radial styloid process to scaphoid and trapezium. Prevents excessive lateral joint displacement

Question 33

What causes an anterior dislocation of the lunate and what are the consequences?

Answer 33

Fall on dorsiflexed wrist
Lunate forced anteriorly compressing the carpal tunnel giving symptoms of carpal tunnel syndrome
Lunate can also undergo avascular necrosis

Question 34

What is the palmar aponeurosis and what is its function?

Answer 34

It is palmar fascia that thickens in the centre of the hand (it is a continuation of the flexor retinaculum and palmaris longs tendon).

It protects underlying muscle compartments

Question 35

What is dupuytren contracture?

Answer 35

Prevents partial flexion of one or more fingers as a result of thickening of palmar fascia due to fibrosis.
Patients cannot fully extend fingers and have problems gripping objects
Treatment is surgery to relieve tension in the CT

Question 36

What are the major ligaments of the hand?

Answer 36

• The flexor retinaculum. A thick strip of CT forming the roof go the carpal tunnel and protecting structures within it. It attaches to pisiform+ hook of hamate, and to trapezium and scaphoid
• The extensor retinaculum. A thickening of dorsal fascia which keeps extensor tendons in position
• The palmar plates. Present of palmar side of each MCP and IP joint which enhance stability by preventing hyperextension
• Collateral ligaments. Medial and lateral sides of each MCP and IP joint, they are taut when fingers are flexed which limits abduction in a clenched fist. The are lax when fingers are extended allowing abduction

Question 37

What tendons are present in the hand?

Answer 37

Flexor tendons of the fingers: (of flexor digitorum profundus and flexor digitorum superficialis). Pass through carpal tunnel

Extensor tendons of the fingers: the tendons of extensor digitorum flatten as they reach metacarpals and become extensor hoods which wrap around the metacarpal.