Trauma and orthopaedics (4): The shoulder Flashcards
the scapula
Also known as the shoulder blades. It articulates with the humerus at the glenohumeral joint, and with the clavical at the acromioclavicular joint.
- Connects the upper limb to the trunk
- Triangular, flat bone
the clavicle
The collarbone extends between the manubrium of the sternum and the acromion of the scapula.
- Long bone
- Can be palpated along its length
- In thin individuals it is visible under the skin.
- Main functions
- Attaches the upper limb to the trunk as part of the shoulder girls
- Protects the underlying neurovascular structures supplying the upper limb
- Transmits force from the upper limb to the axial skeleton
joints between the clavicle and scapula
Acromioclavicular
- Plane type synovial joint
- Located at the lateral end of the clavicle
Sternoclavicular joint
- Synovial joint between the clavicle and the manubrium of the sternum
- Only attachment of the upper limb to the axial skeleton
- Very mobile joint
- Can function more like a ball-and-socket type joint
the shoulder joint
articulating surfaces of the glenohumeral joint
- Head of the humerus with the glenoid cavity of the scapula
- Head of humerus= much larger than the glenoid fossa
- Gives wide range of movement at the cost of inherent instability
- To reduce disproportion in surfaces, the glenoid fossa is deepened by the glenoid labrum
- Fibrocartilage rim
- Head of humerus= much larger than the glenoid fossa
- Synovial joint
- Articulating surfaces covered with hyaline cartilage
stability of the glenohumeral joint
Rotator cuff muscles – surround the shoulder joint, attaching to the tuberosities of the humerus, whilst also fusing with the joint capsule. The resting tone of these muscles act to compress the humeral head into the glenoid cavity.
Glenoid labrum – a fibrocartilaginous ridge surrounding the glenoid cavity. It deepens the cavity and creates a seal with the head of humerus, reducing the risk of dislocation.
Ligaments – act to reinforce the joint capsule, and form the coraco-acromial arch.
Biceps tendon – it acts as a minor humeral head depressor, thereby contributing to stability.
synovial membrane of the shoulder joint
- Lines the inner surface of the joint capsule and produces synovial fluid to reduce friction between the articular surfaces
synovial bursa of the shoulder
Bursa
To reduce friction several synovial bursae are present- cushion between tendons and other joint structures
Subacromial -located deep to the deltoid and acromion, and superficial to the supraspinatus tendon and joint capsule. Reduces friction beneath the deltoid, promoting free motion of the rotator cuff tendons
Subscapular – located between the subscapularis tendon and the scapula. It reduces wear and tear on the tendon during movement at the shoulder joint.
Factors that contribute towards mobility of glenohumeral joint
- Type of joint- ball and socket
-
Bony surfaces- shallow glenoid cavity and large humeral head
- 1:4 disproportion in surfaces
- Commonly used analogy is gold ball and tee
- Inherent laxity of joint capsule
Factors that contribute towards stability
- Rotator cuff muscles
-
Glenoid labrum- fibrocartilaginous ridge surrounding the glenoid cavity
- Deepens the cavity and creates a seal with the head of the humerus-n reducing risk of dislocation
- Ligaments- act to reinforce the joint capsule- forms the coracoacromial arch
- Biceps tendon- acts as a minor humeral head depression
rotator cuff muscles
subscapularis
supraspinatus
infraspinatus
teres minor
arterial supply of the glenohumeral joint
anterior and posterior circumflex humeral arteries (branches of the axillary artery (branches of the suprascapular artery also contribute)
nervous supply of the glenohumeral joint
axillary, suprascapular and lateral pectoral nerve
muscle compartments of the upper limb can be divided into
intirnsic and extrinsic muscles
extrinsic muscle
Originates from the torso (trunk) and attach to the bones of the shoulder (clavicle, scapula and humerus). Located in the back- also known as the superficial back muscles.
Muscles are organised into two layers: Superficial layer and a deep layer
superficial extrinsic muscles
trapezius
latissimus dorsi
deep extrinsic muscles
levator scapulae
rhomboids
- minor
- major
intrinsic muscles
Originate from the scapula and/or clavicle and attach to the humerus. Six muscles- the deltoid, teres major, and 4 rotator cuff muscles (supraspinatus, infraspinatus, subscapularis and teres minor)
important areas found within the shoulder region
brachial plexus
axilla region
brachial plexus
The brachial plexus is a network of nerve fibres that supplies the skin and musculature of the upper limb. It begins in the root of the neck, passes through the axilla, and runs through the entire upper extremity.
The plexus is formed by the anterior rami (divisions) of cervical spinal nerves C5, C6, C7 and C8, and the first thoracic spinal nerve, T1.
Acronyms
Real Teenagers Drink Cold Beer- roots, trunks, divisions, cords, branches
Men Are Mean Really Usually- musculocutaneous, axially, median, radial, ulnar
3 Musketeers (C5, C6, C7)
2 Assassinations (C5, C6)
4 Mice (C6, C7, C8, T1)
5 Rats (C5, C6, C7, T1)
2 Unicorns (C8, T1)
axilla region
frozen should is also called
adhesive capsulitis
RF for frozen shouklder
It most commonly affects people in middle age. Diabetes is a key risk factor.
Adhesive capsulitis can be:
- Primary – occurring spontaneously without any trigger
- Secondary – occurring in response to trauma, surgery or immobilisation
pathophysiology of frozen should
inflammation and fibrosis in the joint capsule lead to adhesions (scar tissue). The adhesions bind the capsule and cause it to tighten around the joint, restrict movement in the joint
presentation iof adhesive capsulitits
3 phases
- Painful phase – shoulder pain is often the first symptom and may be worse at night
- Stiff phase – shoulder stiffness develops and affects both active and passive movement (external rotation is the most affected) – the pain settles during this phase
- Thawing phase – there is a gradual improvement in stiffness and a return to normal
can take 1-3 years before resolving
investigations for frozen shoulder
- clinical diagnosis
- x-ray normal
- US, CT or MRI show thickened joint capsule
management of frozen shoulder : conservative
- Continue using the arm but don’t exacerbate the pain
- Analgesia (e.g., NSAIDs)
- Physiotherapy
- Intra-articular steroid injections
- Hydrodilation (injecting fluid into the joint to stretch the capsule)
management of frozen shoulder : surgical
- Manipulation under anaesthesia – forcefully stretching the capsule to improve the range of motion
- Arthroscopy – keyhole surgery on the shoulder to cut the adhesions and release the shoulder
Subacromial impingement syndrome (SAIS) r
inflammation and irritation of the rotator cuff tendons as they pass through the subacromial space, resulting in pain, weakness, and reduced range of motion within the shoulder.
SAIS encompasses a range of pathology including
- rotator cuff tendinosis,
- subacromial bursitis,
- and calcific tendinitis. All these conditions result in an attrition between the coracoacromial arch and the supraspinatus tendon or subacromial bursa.
RF for SAIS
<35 years
active or in manual professions
common cause of SAIS
muscular weakness
overuse of shoulder
which cause the humerus to shift proximally towards the body
presentation of SAIS
- progressive pain of anterior superior shoulder
- exacerbated by abduction
- painful arc syndrome
- weakness/stiffness
investigations for SAIS
- clinical
- MRI imaging
conservative management of SAIS
- analgesia
- NSAIDS
- physiotherapy
- corticosteroid injections
surgical intervetion for SAIS
If SAIS persists beyond 6 months without response to conservative management, surgical intervention is recommended.
Surgical intervention is particularly useful in patients with a reduced range of movement and is most commonly arthroscopic. Current surgical techniques include:
- Surgical repair of muscular tears, most commonly the supraspinatus and long head of biceps tendon, resulting in an improvement in range of motion
- Surgical removal of the subacromial bursa, a bursectomy, increasing the subacromial space and reducing pain
- Surgical removal of a section of the acromion, an acriomioplasty, increasing the subacromial space and reducing pain
complications of SAIS
otator cuff degeneration and tear, adhesive capsulitis, cuff tear arthropathy and complex regional pain syndrome.
rotator cuff tears refers to
injury to the tendons of the rotator cuff muscles. The tendon may be partially or fully torn.
causes of rotator cuff tears
due to an acute injury (e.g., a fall onto an outstretched hand) or degenerative changes with age.
They may be related to overhead activities, such as playing tennis or overhead construction work.
The rotator cuff is made of four muscles, each with a specific action at the shoulder (mnemonic is SITS):
- S – Supraspinatus – abducts the arm
- I – Infraspinatus – externally rotates the arm
- T – Teres minor – externally rotates the arm
- S – Subscapularis–internally rotates the arm
rotator cuff muscles tear
Shoulder pain
Weakness and pain with specific movements relating to the site of the tear (e.g., abduction with a supraspinatus tear)
disruption to sleep
investigations for rotator cuff tears
X-ray not as useful
US and MRI scan
management of rotator cuff tears: non surgical option
particularly where they are at increased risk of complications from surgery
- Rest and adapted activities
- Analgesia (e.g., NSAIDs)
- Physiotherapy
management of rotator cuff tears: surgical option
if young/active/ full-thickness tears
- arthroscopic rotator cuff repair- tendon reattached to the bone during arthroscopy (keyhole surgery)
shoulder disloacation
Shoulder dislocation is where the ball of the shoulder (head of the humerus) comes entirely out of the socket (glenoid cavity of the scapula).
shoulder subluxation
partial dislocation of the shoulder. The ball does not come fully out of the socket and naturally pops back into place shortly afterwards.
types of shoulder dislocation
- anterior dislocation (most common)
- posterior
- inferior
anterior dislocation MOA
arm is forced backwards(posteriorly) whilst abducted and extended at the shoulder.
Picture someone reaching up and out to try and catch a heavy rock travelling towards them.
posterior dislocation MOA
associated with electric shocks and seizures.
TOM TIP: Exam questions might challenge you to distinguish between anterior and posterior dislocations. The answer is almost certainly an anterior dislocation unless the patient has had a seizure or an electric shock.
shoulder dislocation associated damage
-
Glenoid labrum tear
- Bankart lesions (anterior labrum)- due to repeated dislocation
- Hill- Sach lesions
- compression fractures of posterolateral part of the head of the humerus
- anterior dislocation
- Axillary nerve damage
axillary nerve damage and shoulder dislocation
he axillary nerve comes from the C5 and C6 nerve roots. Damage causes a loss of sensation in the “regimental badge” area over the lateral deltoid. It also leads to motor weakness in the deltoid and teres minor muscles.
Fractures can occur alongside shoulder dislocations, affecting the:
- Humeral head
- Greater tuberosity of the humerus
- Acromion of the scapula
- Clavicle
+ rotator cuff tears
which nevere is associated with anterior dislocations (KNOW FOR EXAM)
Axillary nerve damage
- loss of sensation in the “regimental badge” area over the lateral deltoid.
presentation of shoulder dislocation
- after acute injury
- pain- muscles go into spasms and tighten around joint
- will hold arm against side of body
- deltoid flattened, head of humerus will cause a bulge and be palpable at the front of the shoulder
what is important to assess patients with a shoulder dislocation forq
- Fractures
- Vascular damage (e.g., absent pulses, prolonged capillary refill time and pallor)
- Nerve damage (e.g., loss of sensation in the “regimental patch” area- axillary)
special test for shoulder dislocation
apprehension test
apprehension test
a special test to assess for shoulder instability, specifically in the anterior direction. It is likely to be positive after previous anterior dislocation or subluxation of the shoulder. This may be performed after recovery from any acute injuries.
The patient lies supine. The shoulder is abducted to 90 degrees, and the elbow is flexed to 90 degrees. The shoulder is then slowly externally rotated in this position while watching the patient. As the arm approaches 90 degrees of external rotation, patients with shoulder instability will become anxious and apprehensive, worried that the shoulder will dislocate. There is no pain associated with the movement, only apprehension.
investigations for shoulder dislocation
- x-ray
- MRI- looking for bankarts and hill-sachs lesion and planning for surgery
- arthroscopy- camera in shoulder to visualise structures
dislocated shoulder should be…
ASAP shoulder relocation
muscle spasm makes this harder over time, increasing risk of neurovascular injury during relocation
Acute management of a shoulder dislocation involves:
- Analgesia, muscle relaxants and sedation as appropriate
- Gas and air (e.g., Entonox) may be used, which contains a mixture of 50% nitrous oxide and 50% oxygen
- A broad arm sling can be applied to support the arm
- Closed reduction of the shoulder (after excluding fractures)- kocher method
- Dislocations associated with a fracture may require surgery
- Post-reduction x-rays
- Immobilisation for a period after relocation of the shoulder
ongoing management of shoulder dislocation
There is a high risk of recurrent dislocations, particularly in younger patients.
Physiotherapy is recommended to improve the function of the shoulder and reduce the risk of further dislocations.
Shoulder stabilisation surgery may be required to improve stability and prevent further dislocations. This may be an arthroscopic or an open procedure. Underlying structural problems are corrected, such as:
- Repairing Bankart lesions
- Tightening the shoulder capsule
- Bone graft using bone from the coracoid process to correct a bony injury to the glenoid rim (Latarjet procedure)
- Correcting Hill-Sachs lesions (Remplissage procedure)
There is a prolonged period of recovery and rehabilitation after shoulder stabilisation surgery (3 months or more).
Erbs vs Klumpke palsy
brachial plexus injurys
Erbs
- upper brachial plexus injury
- lateral traction of the neck- shoulder dystocia
- waiters tip
Klumpke
- lower brachial plexus injury
- e.g. grabbing a tree from above
- total clawing of the hand
