Lecture 14 Flashcards
What movements occur at the shoulder?
Flexion/extension
Adduction/abduction
Medial rotation/lateral rotation
Circumduction
What are the three true bi articular (synovial) joints of the shoulder?
Sternoclavicular
Acromioclavicular
Glenohumeral
What are the two physiological (functional) joints of the shoulder?
Subdeltoid - allows supraspinatus to do abduction.
Scapulothoracic - keeps scapula sitting against rib cage.
What movements occur at the sternoclavicular joint?
Elevation/depression
Rotraction/protraction
What is the blood supply for the sternoclavicular joint?
Internal thoracic
Suprascapular
What is the shoulder complex made up of?
The pectoral girdle (manubrium of sternum, clavicle, scapula)
The humerus
What is the nerve supply to the sternoclavicular joint?
The subclavius nerve
Which has more severe consequences and why - an anterior shoulder subluxation or a posterior subluxation?
Posterior
Subclavian and carotid arteries
What is the blood supply of the acromioclavicular joint?
The suprascapular and thoracoacromial arteries.
What is the nerve supply of the acromioclavicular joint?
Supraclavicular
Lateral pectoral
Axillary
What are the intrinsic and extrinsic ligaments of the acromioclavicular joint?
Intrinsic:
Acromioclavicular
Extrinsic:
Coracoclavicular
- conoid
- trapezoid
How do the conoid and trapezoid ligaments work separately and together ?
Conoid: in the sagittal plane, stops vertical displacement of the clavicle, holds it down in place.
Trapezoid: in the transverse/horizontal plane, stops lateral displacement of the clavicle.
Together: provide stability to stop excessive rotation of the scapula and clavicle to prevent shoulder separation.
Which muscles protract the shoulder?
Serratus anterior
Pectoralis minor
Which muscles retract the shoulder?
Trapezius
Rhomboid
Which muscles elevate the shoulder?
Trapezius (upper fibres)
Levator scapulae
Which muscles depress the shoulder?
Serratus anterior (lower fibres) Pectoralis minor
Which muscles rotate the shoulder?
Serratus anterior
Pectoralis minor
Trapezius
Rhomboids
What is a grade 1 acromioclavicular dislocation?
AC ligaments are stretched but not torn.
CC ligaments are intact.
Can be fixed conservatively by immobilising the joint.
What is a grade 2 acromioclavicular dislocation?
AC ligaments torn and disrupted.
CC ligaments remain intact.
AC ligaments can be fixed.
What is a grade 3 acromioclavicular dislocation?
AC and CC ligaments are ruptured.
Wide separation of joint.
Humerus sinks inferiorly to the clavicle.
What is the blood supply of the glenohumeral joint?
Circumflex humeral arteries (anterior and posterior)
What is the nerve supply of the glenohumeral joint?
Suprascapular
Axillary
Lateral pectoral
What are the ligaments of the glenohumeral joint?
Intrinsic:
Coracohumeral
Glenohumeral (Z - superior, middle, inferior)
Extrinsic:
Coracoacromial - tight roof
Transverse humeral - holds LH of biceps tendon in bicipital groove.
Which ligament is lax to allow your arm hang by your side?
The inferior glenohumeral ligament.
What are the names of the three bursa found Im the glenohumeral joint?
Subscapular
Subacromial
Subdeltoid
Which muscles abduct the scapula?
The trapezius and serratus anterior.
Trapezius pulls the spine of the scapula upwards.
Serratus anterior pulls the spine of the scapula outwards.
When is the glenohumeral joint most like to dislocate?
When the humerus is abducted and externally rotated.
The humerus makes most contact in this position.
It gives maximal stability but is most exposed.
Dislocates anteriorly and inferiorly.
What movements do flexor musculature produce?
Flexion
Adduction
Medial rotation
Which muscles make up the flexor musculature of the shoulder joint?
Pectoralis major Deltoid Biceps Coracobrachialis Teres major Latissimus dorsi Subscapularis
Which muscles make up the extensor musculature of the shoulder joint?
Deltoid Teres major Latissimus dorsi Triceps Supraspinatus Infraspinatus Teres minor
Which muscles contribute to abduction at the shoulder joint?
Deltoid
Supraspinatus
Where is the subdeltoid physiological joint?
Between the supraspinatus tendon and the glenohumeral joint.
Deep to deltoid.
Painful arc syndrome occurs as the supraspinatus tendon doesn’t have a good blood supply (necrosis).
Where is the scapulothoracic physiological joint?
Between the serratus and the thorax.
Between the serratus and the scapula.
Scapula and humerus 1:2.
What are some rotator cuff injuries?
Frozen shoulder - adhesive capsulitis, calcification restricts movement.
Impingement of supraspinatus - during abduction.
Rotator cuff (fixator muscles) blend with capsule of joint, pull humeral head towards glenoid and compress it.
What is subacromial bursitis?
Calcification of subacromial bursa located under acromion process of the scapula.
Susceptible to irritation during shoulder abduction.
What type of dislocation of the glenohumeral joint is most common?
Anterior/inferior
Due to the force applied to the abducted and externally rotated arm.
Can be fixed.
What type of dislocation of the glenohumeral joint is least common?
Posterior. Due to electric shock or seizures. Arm adducted and internally rotated. Head of humerus is pushed behind the glenoid cavity. Can't be fixed conservatively.
