Shoulder Flashcards
Movements of the scapula
Elevation, depression, abduction, adduction, lateral rotation, medial rotation
Sternoclavicular joint
- Articular disc divides into two synovial cavities—allows flat joint to act like a ball-and-socket joint
Acromioclavicular joint
- Allows for axial rotation and anteroposterior movement
Glenohumoral joint
- Highly mobile, shallow ball-and-socket joint
- Flexion/extension, abduction/adduction, medial+lateral rotation, circumduction
Scapulothroacic “joint”
- Allows for elevation/depression, protraction/retraction, rotation
Subclavius muscle
- Innervated by nerve to subclavius
- Depression
Pectoralis minor
- Innervated by medial pectoral nerve
- Depresses scapula, elevates rib
Serratus anterior
- Innervated by long thoracic nerve
- Abducts scapula, elevates ribs
Trapezius
- Innervated by accesory nerve (CN XI)
- Superior: elevates scapula, upward rotation of scapula
- Middle: retracts scapula
- Inferior: depresses scapula, upward rotation of scapula
Rhomboid major and minor
- Innervated by dorsal scapular nerve
- Adducts scapula, downward rotation of scapula, fix scapula to thoracic wall
Levator scapulae
- Innervated by dorsal scapular nerve and cervical (C3, C4) nerves
- Elevates scapula, rotates glenoid cavity inferiorly by rotating scapula
Ligaments stabalizing glenohumoral joint
Superior, middle, and inferior glenohumeral ligaments
Rotator cuff muscles that stabalize glenohumoral joint
Supraspinatus, infraspinatus, teres minor, and subscapularis
Supraspinatus holds head of humerous in the glenoid cavity
Danger of glenohumoral dislocation
Disruption of quadrangular space and risk of injuring the axillary nerve and posterior circumflex humeral vessels
Test for spinal accesory nerve lesion
Weakness in turning the head to the opposite side against resistance
Ipsilateral weakness when shoulders are shrugged against resistance
Test for long thoracic nerve lesoin
Observation: winged scapula when arm is raised
Abduction of the arm against resistance
Test for axillary nerve lesion
Observation: deltoid atrophy
Abduction of the arm against resistance
Test sensation over the lateral aspect of the proximal arm
Rotator cuff muscles and their innervation
Supraspinatus - abducts the arm, innervated by the suprascapular nerve
Infraspinatus - externally rotates the arm, innervated by the suprascapular nerve
Teres minor - externally rotates and weakly adducts the arm, innervated by the axillary nerve
Subscapularis - the only rotator cuff muscle that arises from the anterior aspect of the scapula, innervated by the subscapular nerves
Location and function of subacromial bursa
Between the supraspinatus tendon and the coracoacromial ligament
Functions to allow the deltoid muscle to move smoothly over the fibrous capsule of the shoulder joint
Symptoms and likely cause of rotator cuff injury
Rupture or tear of the supraspinatus tendon is the most common injury
Symptoms:
- Dull ache deep in shoulder
- Disturbed sleep if lying on affected shoulder
- Arm weakness
“Frozen Shoulder”
Adhesive fibrosis and scarring of the joint capsule, rotator cuff muscles, subacromial bursa, and deltoid muscle
“Shoulder separation”
Dislocation of the acromioclavicular joint (two joint surfaces lose all contact)
In severe dislocation, there is tearing of the acromioclavicular (AC) ligament and coracoclavicular ligament
Clavicular fracture (site, presentation, at-risk structures)
The most common clavicular fracture is a midclavicular fracture
Clavicle fractures are fairly common (5% of all adult fractures) and fairly “easy” to do (only 8 lbs of pressure required to break)
Clavicle fractures most often occur following a direct blow to the shoulder.
Symptoms:
- Sagging of the shoulder downward and forward
- Inability to lift the arm because of pain
- A grinding sensation when you try to raise the arm
- A deformity or “bump” over the break
- Bruising, swelling, and/or tenderness over the collarbone
At-risk areas
- The subclavius muscle protects underlying neurovascular structures
- Major neurovascular structures at risk in clavicular fracture include:
- Lateral cord of brachial plexus
- Lateral pectoral nerve
- Axillary artery
- Axillary vein
C3 dermatome
C4 dermatome
C5 dermatome
Test upper lateral arm
C6 dermatome
Test pad of thumb
C7 dermatome
Test pad of index or middle finger
C8 dermatome
Test pad of little finger
T1 dermatome
Test medial aspect of elbow
T2 dermatome
Cutaneous innervation of axillary nerve
Cutaneous innervation of radial nerve
Cutaneous innervation of musculo-cutaneous nerve
Cutaneous innervation of ulnar nerve
Cutanious innervation of median nerve
