The Shoulder (7.2) Flashcards
What are the three bones in the shoulder joint?
Clavicle, scapula and humerus
What are some features of the clavicle?
- First bone to ossify
- Among the last the fuse
- Most commonly fractured bone
- Only bony attachment of the upper extremity is via the sternoclavicular joint
- What component affects the direction of a break in the clavicle?
Ligament action pulls the fragments in specific directions (medial fragment drawn upwards)
These breaks aren’t overly benign as close to lung and brachial plexus - has been shown that fixing them surgically is a better treatment than just leaving them to recover
What type of joint is the sternoclavicular joint?
Synovial - with articular disc
Which ligament tears in a medial clavicle dislocation?
The ligament between the sternum and the clavicle
No operating on this kind of dislocation, just try and reduce it
What is the AC joint?
The acromioclavicular joint - between the clavicle and the acromium process
How many ligaments are there that attach to the coracoid process and what are they?
There are 3:
• Coracoacromial ligament, between acromium and coracoid processes (both on scapula)
• Coracoclavicular ligament -> trapezoid and conoid ligaments, attach the clavicle to the coracoid process
How can you remember the order of the coracoclavicular ligaments?
Medial to lateral:
CT scan to diagnose (conoid then trapezium)
What is an acromioclavicular separation?
This is where the coracoclavicular ligaments tear, but the AC joint is only partially damaged
What happens in an AC dislocation?
Both the AC and coracoclavicular ligaments tear, resulting in full dislocation of the distal end of the clavicle
What type of joint is the AC joint?
Synovial, but with little movement
- What is a good indication for the side to which a scapula belongs?
The direction in which the coracoid process is pointing - it will always be pointing towards the arm and is on the front/anterior side of the bone
- How are humeral head fractures treated?
Conservative management is disproportionately successful (length/alignment/rotation), use a collar and cuff.
Alternatively, surgical intervention can be used.
Where is and what are some characteristics of the glenohumeral joint?
The joint between the humeral head and the glenoid fossa/cavity
Shallow joint, stability improved by the glenoid labrum and the ligaments
Manipulated by the rotator cuff muscles amongst others
Synovial joint, ball and socket
What are the three ligaments in the glenohumeral joint?
- SGHL: superior glenoid-humeral ligament
- MGHL: medial glenoid-humeral ligament
- IGHL: inferior glenoid-humeral ligament
How do the shoulder and hip joints compare? (In one sentence)
They are opposites - hip has a more restricted range of movement but is more stable, shoulder has a larger range of movement but is less stable.
Shoulder is likened to a golfball on a golf tee
Which ribs articulate with the scapula?
Ribs 2-7
Major contributors to shoulder motion - bursas are present
What is a bursa?
Small fluid-filled sac contained within synovial joints - act as a cushion
How many muscles attach the upper limb to the axial skeleton?
17
Ones we need to know are: deltoid, rotator cuff muscles (x4) and the biceps/attachment of the biceps tendon
What is innervated by the axillary nerve?
Deltoid and teres minor (amongst others)
What happens if the axillary nerve is damaged?
Shoulder is weakened, ability to abduct is severely lessened
What are the four rotator cuff muscles?
Subscapularis, infraspinatus, supraspinatus, teres minor
What innervates supraspinatus and infraspinatus?
The suprascapular nerve
What innervates teres minor?
The axillary nerve
What innervates subscapularis?
The subscapular nerve
What acronym can be used to remember the four rotator cuff muscles/tendons?
SITS • Supraspinatus • Infraspinatus • Teres minor • Subscapularis
Where do the rotator cuff muscles attach?
- Supraspinatus, infraspinatus and teres minor attach to the greater tuberosity of the humerus
- Subscapularis attaches to the lesser tuberosity of the humerus (only one)
What is the function of the rotator cuff muscles?
- Move shoulder joint
- Provides stability (stops dislocation)
- Keeps deltoid from pulling humeral head up
Why is the biceps muscle called the biceps?
Bi - two
Ceps - cephalus, means ‘head’
The biceps has two ‘heads’, the long head and the short head - long head goes over the humeral head, short goes anteriorly, both attach to the scapula.
Where are the origins of the biceps muscle?
Long head: supraglenoid tuberosity
Short head: coracoid process
Where does the distal end of the biceps attach?
To the radius at the radial tuberosity
To which bone does brachialis attach?
The ulna
- What is the failsafe mechanism of the biceps?
There are two heads, so if one ruptured the muscle is still functional as the other remains attached - contraction still results in movement of the bone. Results in ‘popeye’ muscle
- What are some of the problems that can occur within the shoulder?
- Adhesive capsulitis (frozen shoulder)
- Impingement syndrome
- Rotator cuff tears
- Dislocation
- Arthritis
- How can age affect outcome of shoulder dislocations?
- Younger patients have a higher dislocation rate
* Older patients have a higher rate of rotator cuff tears
- How should you manage a dislocated shoulder?
Best to reduce the dislocation at time of accident, then short period of immobilisation (though external rotation splint or simple sling)
Can be managed surgically, usually after recurrent dislocations (labrum can tear and will need to be repaired).
What is the most commonly dislocated joint?
The shoulder - inherently unstable (shallow joint)
- What is adhesive capsulitis?
Aka frozen shoulder, inflammation and thickening of the shoulder capsule eventually results in hugely reduced range of movement (especially external rotation). Associated with diabetes, but often idiopathic (arises spontaneously with unknown cause).
Not self limiting (so won’t resolve itself without treatment), just stops hurting over time, doesn’t really improve.
- How can you treat adhesive capsulitis?
- Used to be conservative treatment/‘wait and see’
- Now can have glenohumeral injections
- More and more commonly manipulated under anaesthesia - only in stiff phase, and these is a slight risk of humeral fracture
Generally resolved with time (1-2 years), residual stiffness is expected. But can only get it once in each shoulder!
What is shoulder impingement?
This is where the rotator cuff tendons within the coracoacromial arch are impinged - trapped or limited mobility of tendons, or inflamed bursa within the shoulder. This affects nearby nerves and causes pain.
Association with ‘hooked’ acromion (specific shape, morphologically hooked around joint therefore increases risk of impingement)
What are the risk factors for shoulder impingement?
- Can occur at any age
- Classically involves anterior 1/3 of acromion
- Incidence does occur with age
What is the treatment for shoulder impingement?
- Usually conservative - subacromial injections and physio
- 2/3 resolve (but only 1/2 in over 60s)
- Can also have surgical decompression
What happens if a rotator cuff tendon is torn?
The patient will be unable to elevate their arm fully as only deltoid is able to work on the humerus - other abductors are compromised.
Incidence increases with age, and management is hotly debated.
What is another word for arthroscopic surgery?
Keyhole surgery
What is current treatment for damaged rotator cuff muscles?
Therapy to strengthen the remaining cuff, traditional open or mini-open repair (both arthroscopic)
How common is glenohumeral arthritis?
Least common of the major joints
What is glenohumeral arthritis?
This is joint inflammation of the shoulder, where the space between the glenoid fossa and the humeral head is greatly reduced, causing pain.
Can be secondary to trauma, chronic rotator cuff deficiency and necrosis of the humeral head (this can occur when a fracture cuts off blood supply)
How can a massive rotator cuff tear cause glenohumeral arthritis?
The rotator cuff muscles help to hold the humerus down/oppose the action of the deltoid muscle - when the rotator cuff tears, the deltoid can draw up the humerus, reducing joint space and therefore causing arthritis
What are the treatments for glenohumeral arthritis?
Conservative: injections
Operative: replacement
What position is the humeral head in relation to the transepicondylar axis of the distal humerus?
Humeral head is retroverted (tilted backwards) relative to the transepicondylar axis - joint is most unstable anteriorly, to by turning shoulder back by ~30 degrees improves stability
Where does pectoralis major insert?
To the bicipital groove and the deltoid tuberosity on the humerus (lateral to the intertubercular groove)
Where does latissimus dorsi insert?
Floor of the intertubercular groove
Where does teres major insert?
The medial lip of the intertubercular groove
How can the order of the insertions of pectoralis major, latissimus dorsi and teres major be remembered?
‘A lady between two majors’, pectoralis is the most lateral, latissimus is in the middle, teres major the most medial
What attaches to the greater tuberosity of the humerus?
Supraspinatus, infraspinatus, teres minor (C5-C6)
What attaches to the lesser tuberosity humerus?
Subscapularis - allows for internal/medial rotation and adduction
Upper (C5) and lower (C6) subscapular nerve
Patient with a Subscapularis rupture would have what findings?
- Positive Gerber lift off test (arrange hand so that it is behind the back, back of hand touching back of the person. Ask the patient to try and lift their hand from their back - if positive, patient should be unable to do this with either inability or pain as a limiting factor).
- Weak internal rotation
- Increased passive external rotation
What is the triangular space in the shoulder?
The space formed between the teres minor (superiorly), teres major (inferiorly) and long head of triceps (laterally). The scapula circumflex vessels pass through here (axillary, subscapular and scapular circumflex arteries).
What is the quadrangular space in the shoulder?
The space formed by the teres minor (superiorly), teres major (inferiorly), long head of triceps (medially) and neck of humerus (laterally). The axillary nerve and the posterior circumflex humeral artery + vein pass through here
EVERYTHING THROUGH THIS GAP EITHER HAS 4 SYLLABLES OR 4 WORDS
What provides the blood supply to the humeral head?
Anterior circumflex humeral artery
Posterior circumflex humeral artery
On the upper limb, where is the relative position of the neurovascular bundle?
Medial
What does the radial nerve supply?
Makes up the posterior cord. Innervates: • Triceps • Mobile wad • Radial portion of brachialis • Anconeus Then becomes the posterior interosseous nerve after crossing the supinator muscle.
What does the median nerve supply?
Makes up the medial/lateral cord Innervates: • Pronator teres • Flexor carpi radialis • Palmaris longus • Flexor digitorum superficialis • Flexor digitorum profundus I and II • First and second lumbrical (second and third fingers) • Thumb (thenar) Then becomes the anterior interosseous nerve supplying deep anterior muscles of the forearm
What does the ulnar nerve supply?
Makes up the medial cord
Innervates:
• Flexor carpi ulnaris
• Flexor digitorum profundus III and IV (ulnar)
• Hypothenar
• First dorsal and palmar interosseous
• Fourth and fifth fingers (3rd/4th lumbrical)
What are the ligamentous stabilisers of the elbow?
Radial and ulnar collateral ligaments
