MSK- arm Flashcards
What are the functions of the clavicle? (3)
-attatches the upper limb to the trunk -protects the underlying neuromuscular structures supplying the upper limb. -transmits force from the upper limb to the axial skeleton.
How do clavicular fractures commonly occur?
FOOSH
where is the most common point for a clavicle to fracture?
medial 2/3 and lateral 1/3
After a clavicle fracture where are the segments displaced to and why?
-lateral end is displaced inferiorly by the weight of the arm and medially by pectorals major. -medial end is displaced superiorly by the SCM.
What nerves may be damaged in a clavicular fracture and why?
The upwards movement of the medial part may damage the supra scapular nerve.
What is the common position for someone who has damaged their supra scapular nerves to present with?
The lateral rotators of the arm and shoulder are deinnervated which results in unopposed medial rotation of the upper limb- the ‘waiters tip position’
What would you be concerned about if someone presented with a scapular fracture?
Chest trauma, as scapular fractures are rare and usually indicative of severe chest trauma.
After a scapular fracture, what treatment is needed?
trick question (i’m so sneaky), The natural tone of muscles in the are hold the fragments in place, so it can be left to heal naturally.
During a surgical neck fracture of the humerus what structures are at risk?
axillary nerve and posterior circumflex artery
What happens when the axillary nerve is damaged?
paralysis of the deltoid and theres minor, weakness to the triceps, so the patient will be unable to abduct their arm. There will also be loss of sensation over the ‘regimental badge’ area.
What structures are at risk during a mid-shaft humeral fracture?
the radial nerve and profound brachii run close to the humerus in the radial groove.
What sign would be an indication of radial nerve damage?
Wrist drop. As the extensors of the wrist are deinnervated. There may also be sensory loss in the portion innervated by the radial nerve.
What are the two common fractures of the distal humerus? Give a brief description of each.
-Supraepicondylar fracture- falling on a flexed elbow, it’s a fracture spanning the the gap between the two epicondyles. It can result in damage to the blood supply to the forearm via the brachial artery. -Medial epicondylar fracture- it could cause damage to the ulnar nerve, causing ulnar claw and loss of sensation over the medial 1 and 1/2 fingers of the hand on the dorsal and palmar surfaces.
What are Volkmann’s ischaemic contractures?
uncontrolled flexion of the hands, as the flexors become fibrotic and short.
What are the four articulations of the radius?
- elbow- head of the radius with the capitulum of the humerus -proximal radioulnar joint- radial head and radial notch of the ulnar. -wrist joint- articulation between the distal end of the radius and the carpal bones -distal radioulnar joint- ulnar notch and the head of the ulna
What’s the difference between a Colles’ fracture and a Smith’s fracture?
Colles’- the most common type of radial fracture, caused by FOOSH, the distal 2cm are displaced posteriorly, causing a ‘dinner fork deformity’. Smith’s- A fracture caused by falling onto the back of the hand, the opposite of a Colles’. the distal 2cm is now placed anteriorly.
Name this fracture
Colles’ fracture
Name this fracture
Smith’s fracture
What are the two common ulnar fractures?
Montaggia’s fracture- force from behind the ulna. The proximal shaft of the ulna is fractured, and the head of the radius dislocates anteriorly at the elbow.
Galeazzi’s fracture- a fracture to the distal radius, with the ulna head dislocating at the distal radio-ulnar joint
What’s the mneumonic used to remmeber the carpal bones, and what they stand for?
Some Lovers Try Positions That They Can’t Handle
Scaphoid, Lunate, Triquetral, Pisiform, Trapezium, Trapezoid, Capitate, Hamate
name these structures:
A- Scaphoid, B-Lunate, C-Triquetral, D-Pisiform, E-Trapezium, F-Trapezoid, G-Capitate, H-Hamate
1-radius, 2-ulna, 3-metacarbal bones
How does a scaphoid fracture occur?
FOOSH
What is wrong on this x-ray?
Scaphoid fracture
What are the borders of the axilla?
**Apex **– Also known as the axillary inlet, this is formed by lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle.
Lateral wall – Formed by intertubecular groove of the humerus.
**Medial wall **– Consists of the serratus anterior and the thoracic wall (ribs and intercostal muscles).
Anterior wall – Contains the pectoralis major and the underlying pectoralis minor and the subclavius muscles.
Posterior wall – Formed by the subscapularis, teres major and latissimus dorsi.
What are the three entry’s to the axilla?
Quadrangular Space
Clavipectoral Triangle
Cervicoaxillary canal
What are the borders of the quadrangular space?
- inferior border of subscapularis (and teres minor)
- superior border of teres major
- lateral border of the long head of triceps brachii
- it’s lateral border is the surgical neck of humerus
What passes through the quadrangular space?
It allows access to the posterior arm and shoulder area, including for the axillary nerve and posterior circumflex humeral artery.
The opening in the anterior wall of the axilla is the clavipectoral triangle, but what are its borders?
- inferior border of the clavicle
- medial border of the deltoid
- superior border of pectoralis major
What enters the axilla through the clavipectoral triangle?
Cephalic vein, while the medial and lateral pectoral nerves leave.
What are the borders of the cervicoaxillary canal and where can it be found?
It’s located at the apex of the axilla. It’s bound by the 1st rib, clavicle, and superior edge of the scapula. This is how the brachial plexus enters the arm.
What are the contents of the axilla?
- Axillary artery
- Axillary vein
- Brachial plexus
- Biceps brachii and corocobrachialis
- Axillary Lymph nodes
What are the divisions of the brachial artery which can be found in the axilla? (3)
one medial to the pectoralis minor, one posterior to pectoralis minor, and one lateral to pectoralis minor. The medial and posterior parts travel in the axilla.
What lymph nodes can be found in the axilla?
pectoral, subscapular, humeral, central and apical
What is thoracic outlet syndrome?
- vessels and nerves may become compressed between the bones in the apex.
- caused by trauma or repetative motion
- It often presents with pain in the affected limb, tingling, muscle weakness and discolouration of the arm
how can a lymph node biopsy cause a winged scapula?
The axillary clearance can cause long thoracic nerve damage
Is the brachial formed of the anterior or posterior rami of C5-T1? And what does this make the fibres, afferent or efferent?
Anterior, so the fibres are efferent!
Alice Eats Dicks Alot (Anterior are Efferent e.g. movement Dorsal rami are Afferent e.g. Sensory)
What are the three trunks in the brachial plexus?
Superior, middle and inferior
What are the cords of the brachial plexus, which divisions are they made up of, and what are they named relative to?
The axillary artery
- Lateral- anterior division of the superior and middle trunks
- posterior- posterior division of all three trunks
- medial- anterior division of the inferior trunks
What are the branches of the brachial plexus (top to bottom)
MAMRU
Musculocutaneous, axillary, median, radial, and ulnar
What are the nerve roots of the musculocutaneous nerve?
C5-7
What are the nerve roots of the axilliary nerve?
C5+C6
What are the nerve roots of the Median nerve?
C6-T1
What are the nerve roots of the Radial nerve?
All roots (C5-T1)
What are the nerve roots of the ulnar nerve?
C8+T1
What is Erbs palsy?
Damage of the upper brachial plexus (C5+6). It’s usually as a result of an increased in the angle between the neck and shoulder. It produces a ‘waiters tip position’ where there is unopposed medial rotation of the arm. Paralysis of the muscles supplied by the C5+6: deltoid, biceps, and brachialis. the lateral aspect of the arm can experience a loss in sensation.
A newborn baby presents with erbs palsy, how do you predict it occured?
birth
What is hyper abduction syndrome?
compression of the cords of the brachial plexus, between the coracoid process and the pectoralis minor tendon, due to prolonged hyper abduction of the arm.
Common symptoms are numbness, parasthesia, arythemia and weakness of the hands.
Compression of the axillary vein and arteryc ause ischaemia of the arm and distension of the superficial veins.
What is Klumpke palsy?
- injury to the inferior aspect of the brachial plexus
- C8-T1
- the upper limb is suddenly pulled superiorly
- the small muscles of the hand are affected
What is a common sign of klumpke palsey?
Ulnar claw
what are the two heads of Pectoralis Major?
Sternocostal and clavicular
What are the actions of the pectoralis major?
The two heads can work independently or synergistically. Together, they act to adduct and medially rotate the humerus at the shoulder. The clavicular head also performs flexion.
What nerve innervates pec major?
Lateral and medial pectoral nerves (clavicular-C5,C6 and costal C7,8 and T1)
where does pec minor originate from?
anterior surface of ribs 3-5 and attatch to the coracoid processs
What is the role/ action of pec minor?
stabilises the scapula and is used when stretching the upper limb forward. It also assists in elevating the ribs for deep inspiration, and can depress the shoulder.
What nerve innervates pec minor ?
medial pectoral nerve (C8, T1)
Its good to remember that ‘lateral less, medial more’ so the medial nerve supplies both pecs and the lateral just pec major, as it’s bigger it has two nerves.
what is the role of the serratus anterior?
a strong protractor of the scapula and is used when punching anteriorly. the inferior part rotates the scapula, elevating the glenoid cavity so the arm can be raised above the shoulder.
what nerve innervates serratus anterior?
the long thoracic nerve (C5-7)
what is the action of the subclavius?
depresses the clavicle during movements of the arm, stopping it from dislocating at the sternoclavicular joint.
what nerve innervates the subclavius?
nerve to subclavius (C5+6)
très difficile
what type of joint is the glenohumoral joint?
ball and socket synovial joint
what it the ratio between the glenoid fossa and the head of the humerus?
4:1
What features make the shoulder joint unstable?
- disproportion in area of the surface
- lax joint capsule
what factors aid in the stability of the shoulder joint?
- rotator cuff muscles
- ligaments
- joint capsule
- deltoid
- long head of biceps and triceps
what are the three intracapsular ligaments of the shoulder?
superior, middle and inferior glenohumeral ligaments
which direction is most common fo the shoulder to dislocate in?
anteriorly
what are the three extracapsular ligaments of the shoulder?
coracoacromial, coracohumoral, coracoclavicular
what does the transverse humoral ligament do?
holds the tendon of the long head of biceps brachii in place during shoulder movement.
what is the coracoacromial arch, and what is it formed by?
- strong osseoligamentous structure formed by the coracoacromial ligamnet, acromian and coracoid process.
- it prevents upper displacement of the humerus
what are the 3 bursa of the shoulder?
- subscapular bursa
- subacromial bursa- inflammation causes painful arc syndrome (50-130degrees)
- subcorocoid bursa
Which arteries supply the shoulder joint?
anterior and posterior circumflex arteries and the suprascapular artery.
Which nerves supply the shoulder joint?
axillary, suprascapular and lateral pectoral nerve (all C5-6)
How are inferior dislocations of the shoulder usually caused, and what are they clinically called?
trauma on a full abducted arm
anterior dislocations because the humeral head dislocates anteriorly due to the pull of the powerful adductors. The humeral head lies below the coracoid process.
What are the 4 rotator cuff muscles?
SITS
supraspinatus, infraspinatus, teres minor, subscapularis
What is the action and innervation of supraspinatus?
Innitiation and first 15 degrees adbuction.
Innervated by the suprascapular nerve (C5+6)
What is the action and innervation of infraspinatus?
lateral rotation of the arm
innervated by the suprascapular nerve C5+6
what is the action and innervation of teres minor?
lateral rotation of the arm, and it’s a weak abductor.
innervated by the axillary nerve
what is the action and innervation of subscapularis?
medial rotation of the arm, and it’s a weak adductor.
innervated by the axillary artery.
what is painful arc syndrome?
Tendons rub under the CAA causing irritation and inflammation of the rotator cuff tendons and subacromial bursa.
The most common cause is are repetative overuse and degenerative changes in tendons due to age.
what are the posterior axio-appenicular muscles of the back?
(the only ones you need to know of the back)
superficial- trapezius and lattisimus dorsi
deep- levator scapulae and the rhomboids
scapulo-humeral- deltoid, teres major & 4 rotator cuff muscles
What is the innervation and action of the trapezius muscle?
superior and inferior parts rotate the scapula upwards and out, elevating the glenoid cavity.
accessory nerve
what are the heads of the trapezius and their actions? (3)
- superior- elevates the scapula e.g. shrugging
- middle part- retracts the scapula
- inferior part-depresses the scapula
where does latissimus dorsi originate from?
inferior 3/4 ribs and the last 6 thoracic vertebrae
what is the action and innervation of latissimus dorsi?
powerful adductor at the shoulder joint (climbers muscle) and also medially rotates and extends the upper arm at the shoulder joint
thoraco-dorsal nerve
what is the action and innervation of levator scapulae?
elevating the scapula and rotating it, depressing the glenoid cavity.
dorsal scapular and cervical nerves
what is the action and innervation of the rhomboids (major and minor)?
retract the scapula and also depresses the glenoid cavity by rotating the scapula
dorsal scapula nerve C5
what is the action and innervation of the deltoid?
- anterior fibres- flexion of the arm and shoulder joint
- middle fibres- adbuct the arm from 15-90 degrees
- posterior fibres- extend the arm at the shoulder joint
Axillary nerve
what is the action and innervation of teres major?
adducts the arem but also medially rotates
lower scapular nerve
what muscles flex the arm at the shoulder?
clavicular head of pec major, anterior fibres of the deltoid, choracobrachialis and biceps brachii.
What muscles extend the arm at the shoulder?
posterior fibres of the deltoid, lattisimus dorsi and teres major
What muscles abduct the arm at the shoulder and the angles?
0-20-supraspinatus
20-90- central fibres of the deltoid
>90- by rotation of the scapula- serratus anterior and trapezius.
What muscles adduct the arm at the shoulder?
pectoralis major, lattisimus dorsi and teres major
What muscles medially rotate the arm at the shoulder?
subscapularis, teres major, pec major and lat. dorsi
What muscles laterally rotate the arm at the shoulder?
infraspinatus and teres minor
what are the muscles of the anterior compartment of the arm and what are they innervated by?
BBC
biceps brachii, brachialis and coracobrachialis
Musculocutaneous nerve
where are the attatchments of the biceps brachii?
- long head- superglenoid tubercle
- short head- coracoid process
What is the actiona nd innervation of the biceps brachii?
supination of the forearm, but also flexes the arm at the elbow and shoulder
musculocutaneous nerve
how can you test the C6 spinal cord segment?
biceps tendon tap
what does the biceps tendon contribute to the cubital fossa?
gives off a connective tissue sheath wich forms the roof of the cubital fossa, called the bicipital aponeurosis.
What can be seen in the arm when the long head of the biceps tendon is ruptured?
on flexion of the elbow there is a bulge where the muscle belly is called ‘popeyes sign’. There would not be much weakness in the upper limb due to the action of the brachialis and supinator muscles.
what is the action and innervation of coracobrachialis?
flexor of the arm at the shoulder
musculocutaneous nerve
what is the action and innervation of brachialis?
flexes at the elbow
musculocutaneous nerve (a small lateral side is innervated by the radial nerve)
What muscle is contained in the posterior compartment of the arm?
Triceps brachii
what is the action and innervation of triceps brachii?
extension at the elbow
radial nerve (long head is thought to be innervated by the axillary nerve)
What are the borders of the cubital fossa?
- Lateral border - The medial border of the brachioradialis muscle
- Medial border- The lateral border of the pronator teres muscle
- Superior border- An imaginary line between the epicondyles of the humerus.
- floor -proximally by the brachialis, and distally by the supinator muscle
- roof- skin and fascia, with is reinforced by the bicipital aponeurosis. Within the roof runs the median cubital vein, which can be accessed for venepuncuture.
What are the contents of the cubital fossa?
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- Radial nerve –passing underneath the brachioradialis muscle. As is does so, the radial nerve divides into its deep and superficial branches.
- Biceps tendon
- Brachial artery - It bifurcates into the radial and ulnar arteries at the apex of the cubital fossa.
- Median nerve - Leaves the cubital between the two heads of the pronator teres.
Why is venepuncture carried out in the cubital fossa?
The median cubital vein is located superficially within the roof of the cubital fossa. It connects the basilic and cephalic veins, and can be accessed easily – this makes it a common site for venepuncture.
what two articulations are there in the elbow joint?
- trochlear notch of the ulna and the trochlear of the humerus
- head of the radius and the capitulum of the humerus
what muscles cause flexion of the elbow?
brachialis, biceps brachii and brachioradialis
what muscles cause extension at the elbow?
triceps brachii and anconeus
