Shoulder anatomy and conditions Flashcards
What is the function of the glenoid labrum?
Increases capture of the humeral head
What does the trapezius muscle do? What are it’s origins and insertions?
Elevates/depresses the scapula. Origins on thoracic vertebrae/occipital bone, inserts onto spine of scapula
What are the rotator cuff muscles and their function?
Supraspinatus- abduction Infraspinatus- external rotation Teres minor- external rotation Subscapularis- internal rotation Overall- stabilise the shoulder girdle
Three of the rotator cuff muscles share an insertion. What is this, and which muscle is the exception to this?
Greater tubercle of humerus Subscapularis inserts onto lesser tubercle of humerus
Where does the deltoid muscle attach and what is its function?
Attaches to the deltoid tuberosity on the lateral aspect of the humerus
What are the origins of the long arm and short arm of biceps brachii, and what is their common insertion?
Short- coracoid process Long- labrum/glenoid
What is impingement?
Compression of the rotator cuff tendons within the tight subacromial space. Possible causes: inferior acromial osteophyte, bursitis, hooked acromion, rotator cuff tear, tendonitis
What signs are seen upon clinical examination in impingement?
Painful arc Pain on Hawkins-Kennedy test
How is impingement managed?
Initially- most settle with NSAIDs, physio, steroid injections Refractory- may require subacromial decompression surgery
How do rotator cuff tears typically happen in a) younger people b) older people
a) traumatic- e.g. shoulder disclocation b) minimal trauma- usually due to underlying degenerate changes in tendon. Typical history is of a sudden jerk followed by shoulder pain and weakness
How can rotator cuff tears be managed?
Controversial: - physio can help strengthen other muscles to compensate - surgicalrepair of the muscle may fail due to underlying tendon disease
What may be the result of chronic rotator cuff insufficiency?
Osteoarthritis of the glenohumeral joint
Describe the typically history of adhesive capsulitis.
Takes place over about 18-24 months- pain followed by stiffness, followed by gradual “thawing” of the stiffness
What is the principal clinical sign in adhesive capsulitis?
Loss of external rotation
What other diseases are associated with adhesive capsulitis?
Diabetes Hypercholesterolaemia Dupuytren’s disease
How is adhesive capsulitis managed?
Conservative- analgesics and physio Once pain has settled- can relieve stiffness by manipulation under anaesthetic (MUA) or capsular release (tears the capsule)
What are the two main patterns of shoulder instability?
Traumatic (e.g. past dislocation which doesn’t stabilize, predisposing to subluxation/dislocation with minimal force) Atraumatic- people with generalised ligamentous laxity (Ehler’s-Danlos, Marfan’s)
How does a dislocated shoulder appear?
Loss of roundness of the shoulder and loss of symmetry
How is shoulder dislocation managed?
Closed reduction under sedation/anaesthesia, followed by imaging to confirm the reduction. Patient is placed in a sling for two weeks, followed by physiotherapy. Delayed presentation may require open reduction with internal fixation
Approximately what percentage of patients suffering a shoulder dislocation under the age of 20 will present with a further dislocation at some point?
Around 80%
How does damage to the axillary nerve in shoulder dislocation often present?
Loss of sensation in the “regimental badge” area
What is the typical mechanism of injury in a proximal humeral fracture?
Fall onto outstretched hand in osteoporotic patient
What is the typical fracture appearance in a proximal humeral fracture?
Fracture of surgical neck of femur, with medial displacement of the shaft due to pull of pectoralis muscles
How are a) marginally displaced and b) displaced proximal humeral fractures treated?
a) conservatively with a sling, anelgesia b) ORIF
