MSK - Clinical Arm Shoulder Flashcards
What could be injured with a stab wound to the axilla?
Artery Vein Lymph Nerves - brachial plexus Lymph nodes Biceps brachia and coracobreachialis muscle
Which is easier to tell on an X-ray anterior or posterior dislocated shoulder?
Anterior
Posterior may need CT
Why are some clavicle fractures displaced inferomedially? What is the worry with this?
Inferior due to weight of arm
Medially displaced lateral segment due to action of pectoralis major
Damage to axilla - e.g. upper brachial plexus injury and Erbs palsy
What might cause injury to the upper brachial plexus and what symptoms/clinical signs? Which nerve and roots?
Clavicle fracture or squashed baby from birth canal
Erbs palsy
C5 C6 axillary nerve
What might cause injury to the lower brachial plexus and what is the symptoms clinical signs? Which nerve(s) and roots?
Falling from a tree
Klumskis palsy - claw like a monkey - due to ulna and sometimes median damage C8-T1
How is abduction achieved of the shoulder?
First 15 degrees by supraspinatus
15- 90 by middle fibres of deltoid helped by supraspinatus
Above 90 degrees scapular needs to be rotated by trapezius and serrates anterior
What do the supra scapular nerves innervate and why is this relevant in a clavicle fracture?
Supra scapular nerves do the lateral rotator muscles
So damage to these may cause medial rotation - waiters tip
What is the arms best supinator?
Biceps brachii
What are the three muscles in the arm supplied by the musculocutaneous nerve
BBC
Brachialis
Biceps brachii
Coracobrachialis
What is the function of these three muscles BBC
Biceps brachii - supinates, flexion of arm at shoulder and elbow
Brachialis - flexion of arm at elbow
Coracobrachialis - Flexion of arm at shoulder and wear adduction as attaches to coracoid process of the scapula.
What muscle in the arm are inverted by the radial nerve?
Triceps brachii
What is the functions of triceps brachii?
Extension of the arm at the elbow
What are the two muscles in the arm innervated by the axillary nerve?
Teres minor - lateral (external) rotation of the arm at the shoulder
Deltoid - 15-90 degree abduction (middle) Posterior extension
Anterior flexion
How many deltoids are there? What do they do?
3
Anterior - flexes the arm at the shoulder
Middle - abduction of the shoulder
Posterior - extends the arm at the shoulder
What are the 4 rotator cuff muscles?
SITS
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What are the 6 intrinsic muscles of the shoulder (from scapular and/or clavicle and attach to humerus)
1) Infraspinatus
2) Supraspinatus
3) Subscapularis
4) Teres minor
5) Teres Major
6) Deltoids
What are the 4 extrinsic muscles of the shoulder?
1) Trapezius
2) Latissimus dorsi
3) Levator scapulae
4) Rhomboids - major/minor
What do the subscapular and suprascapular nerves supply?
Subscapular
- Lower - subscapularis
- Upper subsapularis and theres major
Suprascapular - infraspinatus supraspinatus
What is the resting function of the rotator cuff muscles?
Their resting tone helps pull the humeral head into the glenoid fossa
What is the glenoid fossa?
Shallow depression in the scapular where the humerus can fit
What injuries can occur with the rotator cuffs?
- Tendonitis - most commonly the supraspinatus tendon due to repetitive overhead movements.
- Rotator cuff tears - either acute or degenerative.
What are the signs that you might have a rotator cuff tear?
Impingement signs, weak internal rotation, weak external rotation and external rotation lag
What artery are you worried about in a humeral neck vs humeral shaft fracture?
Head - posterior circumflex artery (comes off radial)
Shaft - Radial - profunda brachii
What are the 5 distinguishing features of a synovial joint?
1) Articular cartilage
2) Synovial membrane
3) Synovial fluid
4) Articular (fibrous) capsule
5) Joint cavity
What are the 4 joints of the shoulder/upper limb?
Glenohumeral
Sternoclavicular
Acromioclavicular
Scapulothoracic
What type of joint is the sternoclavicular and between what bones?
Synovial
Between the clavicle and the manubrium of the sternum
What is calcific supraspinatus tendonitis? What can you get with it? Why could an Xray be normal after a few weeks?
Deposits of calcium hydroxyapatite crystals between the humeral head and the acromium
Can get impingement in subacromial space - 10/10 pain - normally resolves and gets absorbed by white cells so good give normal Xray
What is the role of the ligaments of the shoulder?
Stabilise the bones
What are the 4 major ligaments - which one prevents superior displacement of the humeral head?
Coracohumeral
Coracoacromial
Transverse humeral ligament (between two tubercles of the humerus)
Glenohumeral
The corachoachromial ligament is the corachoachromial arch that prevents superior displacement of the humeral head.
What is a ‘popeye’ arm a clinical feature of?
Long head of biceps brachii rupture
Long head goes to the supraglenoid tubercle of the scapula
Where does the short head of the biceps brachii go
To the coracoid process of the scapula
Which two muscles go through the axilla?
Biceps brachi
Coracobrachialis
What is the space between the two tubercles on the humerus called and why?
Bicipital groove as the tendon of the long head of the biceps brachii runs here.
Where does the levator scapulae originate and insert into? What’s its role?
from transverse process of C1-C14 to the medial border of the scapula.
Elevates the scapula
Which 3 muscles attach to and which tendon runs through the intertubecular groove of the humerus
Biceps brachii long arm runs through the bicipital groove
Teres major and Pectoralis major attach to either lip of the bicipital groove and the latissimus doors tendon attaches to the bicipital groove
Which muscles insert into the the greater tubercle of the humerus?
Infraspinatus
Supraspinatus
Teres minor
Which muscles inset into the less tubercle of the humerus?
Subscapularis
Where do the deltoids originate and insert into?
Originate from the scapula and the clavicle and insert in to the deltoid tuberosity of the humerus
Where does the serratus anterior originate and insert into? What is the role (2)?
From ribs 1-8 to the medial aspect of the anterior scapular.
They rotate the scapula allowing the arm to be raised over 90 degrees and it also holds the scapula against the ribcage
Name 5 muscles that move the scapula
Trapezius Latissimus dorsi Levator scapulae Rhomboids Pectoralis minor
What are the functions of the three different fibre types of the trapezius?
Upper - elevate scapula and rotate during abduction of the arm
Middle - Retract scapula (backwards towards midline)
Lower - pulls scapula interiorly e.g. if you were carrying heavy bags and your shoulders move down.
Where does the trapezius originate from and insert?
Originates from the nuchal ligament, skull and spinous processes of C1-T12
Insert into the clavicle, scapula spine, and acromion
What are the functions of the latissimus dorsi?
Extends adducts and medially rotates the arm.
Which muscle rotates the gelnoid cavity upwards? And which downwards?
Upwards - upper fibres of the trapezius
Downwards - rhomboids
What is the origin and insertion of the rhomboids? is major or minor above? What is their function?
Minor is above
Originate from C7-T5
Insert into the medial border of the scapula
Rotate and retract the scapula
