Axilla and Brachial plexus Flashcards
What are the 3 borders of the axillary inlet (entrance of axilla)?
Lateral margin of rib1
Clavicle
Superior margin of scapula
What is the lateral wall of the axilla?
The bicipital groove of the humerus
What is the medial wall of the axilla?
Serratus anterior
Thoracic wall
What innervates serrates anterior?
Long thoracic nerve
What does the intercostobrachial nerve innervate?
The skin on the upper, medial and posterior arm.
It is a lateral branch of the second intercostal nerve.
What is the anterior border of the axilla?
Pectoralis major + minor
Subclavius
Clavipectoral fascia
What does the lower margin of pectoralis major form?
The anterior axillary fold
Which part of the anterior wall of axilla also makes up the floor of the axilla?
The clavipectoral fascia
It encloses the pectoralis and subclavius muscles.
What is the posterior wall of the axilla?
Subscapularis
Teres major
Latissimus dorsi
Long head of triceps
Which 2 muscles of the posterior wall make up the posterior axillary fold?
Teres major
Latissimus dorsi
Is the skin of the armpit the base of the axilla?
Yes! it is not the same as the skin of the arm.
Name the 4 gateways of the axilla on the posterior wall
Suprascapular foramen
Quadrangular space
Triangular space
Triangular interval
What is the suprascapular foramen on the axilla formed by?
The suprascapular notch and superior transverse scapular ligament
Does the suprascapular nerve pass through the suprascapular foramen?
Yes, it passes through the suprascapular foramen
Does the suprascapular artery pass through the suprascapular foramen?
No, the suprascapular artery passes above the suprascapular foramen
What is the quadrangular space of the axilla formed by?
The surgical neck of humerus
Inferior margin of teres minor
Superior margin of teres major
Lateral margin of long head of triceps
What 2 structure pass around the quadrangular space?
Axillary nerve
Posterior humeral circumflex artery
What is the triangular space of the axilla formed by?
Medial margin of long head of triceps
Superior margin of teres major
Inferior margin of teres minor
What passes through the triangular space of the axilla?
Circumflex scapular artery
Circumflex scapular vein
What is the triangular interval in the axilla formed by?
Lateral margin of triceps
Shaft of humerus
Inferior margin of teres major
What 2 structures pass through the triangular interval of the axilla?
Radial nerve
Deep artery of the arm
(close under groove of humerus)
What can happen to the teres minor and deltoid when there is swelling on the quadrangular space?
Weakness and atrophy can occur due to the axillary nerve being affected by the swelling
What is the contents of the axilla?
Axillary artery
Axillary vein
Brachial plexus
Biceps brachii
Coracobrachialis
Axillary lymph nodes
What does the subclavian artery become when it crosses the first rib boundary?
It becomes the axillary artery
What does the axillary artery become at the inferior margin of teres major?
It becomes the brachial artery
How many parts are there of the axillary artery within the axilla?
3
What divides the 3 parts if the axillary artery from each other?
The pectoralis minor is anterior to the second part, so the proximal part is more proximal then the third part.
How many branches come off the first part of the axillary artery?
1 branch
How many branches come off the second part of the axillary artery?
2 branches
How many branches come off the third part of the axillary artery?
3 branches
What is the name of the artery coming off the first part of the axillary artery?
Superior thoracic artery
What does the superior thoracic artery supply?
Upper medial and anterior axillary walls
Whats are the names of the branches coming off the second part of the axillary artery?
Thoracoacromial artery
Lateral thoracic artery
What does the thoracoacromial artery supply?
Clavicular, acromial, deltoid, pectoral branches (anterior axillary wall)
What does the lateral thoracic artery supply?
Pectoralis minor, serratus anterior, lateral thoracic wall (anterior and lateral thoracic walls)
Which rises first from the second part of axillary artery - thoracoacromial or lateral thoracic?
Thoracoacromial rises first
What 3 branches come off the third part of the axillary artery?
Subscapular artery
Anterior humeral circumflex artery
Posterior humeral circumflex artery
What arteries does the subscapular artery give rise to?
Circumflex scapular artery
Thoracodorsal artery
Does the circumflex scapular artery pass through the triangular spaces and infraspinous fossa?
Yes, this is obvious by how I worded this
What branches does the circumflex scapular artery anastomose with for the shoulder anastomoses?
Subscapular artery
Dorsal scapular artery
What does the thoracodorsal artery supply?
Posterior axillary walls and latissimus dorsi along the inferior angle
What space does the posterior humeral circumflex artery pass through?
The quadrangular space
What 4 branches does the posterior humeral circumflex artery anastomose with?
Anterior humeral circumflex artery
Branches of profound brachii
Subscapular
Thoracoacromial
Which 2 arteries anastomose with the circumflex scapular artery?
Subscapular artery
Transverse cervical artery
What are the 2 main branches of the axillary vein in the arm?
Cephalic vein
Basilic vein
Which is more medial, the axillary artery or axillary vein?
The axillary vein is more medial
Which vein is more medial, the basilica vein or cephalic vein?
The basilic vein is more medial, the cephalic vein is more lateral
In which groove does the cephalic vein lie?
The deltopectoral groove
How do the subclavian artery and vein divide at the anterior scalene muscle?
The subclavian vein moves in front, the subclavian artery moves behind the anterior scalene muscle
What is the origin of the biceps?
The long head - supraglenoid tubercle
The short head - coracoid process
What is the insertion of the biceps?
The radial tuberosity of the forearm
What innervates the biceps?
Musculocutaneous nerve
What is the action of the biceps?
Strong flexor of the forearm, flexor of arm
Which other muscles are on the anterior surface of the arm?
Coracobrachialis
Brachialis (deep to the biceps)
List the 5 groups of axillary lymph nodes found in the axilla
Lateral
Subscapular
Pectoral
Central
Apical
What is an important clinical indication oft he axillary process of the mammary gland?
The axillary process may enter the axilla, which has to be considered with regards to breast cancer
Define the word plexus
Connection of more than one spinal nerve rot to a peripheral nerve
Which rami does the brachial plexus involve ?
Ventral rami of C5-T1
What colour are sympathetic rami?
Grey
What is the function of the brachial plexus?
Somatic plexus that provides somatic motor and sensory innervation to whole of upper limb - apart from trapezius and patch of skin near axilla
Is there any parasympathetic innervation to the upper limb?
Nope!
Where is the brachial plexus found?
It runs between scalene anterior and medius, behind the sternocaleidomastoid and subclavian artery
What are the 5 nerve roots involved in the brachial plexus?
C5-T1
Which 2 nerve roots combine to form the superior trunk?
C5+C6
Which 2 nerve roots combine to form the inferior trunk?
C8+T1
Which nerve root forms the middle trunk?
C7
Where are the roots of the brachial plexus found?
Between the anterior and mid scalene muscle
Where are the roots of the brachial plexus found?
Between the anterior and mid scalene muscle
Where are the trunks of the brachial plexus found?
At the first rib
Where are the division of the brachial plexus found?
First part of the axillary artery
Where are the cords of the brachial plexus found?
Second part of the axillary artery
Where are the terminal ends of the brachial plexus found?
Third part of the axillary artery
Where are the terminal ends of the brachial plexus found?
Third part of the axillary artery
Name the 3 nerves that rise from the roots of the brachial plexus
Long thoracic nerve
Dorsal scapular nerve
Contribution to the phrenic nerve
What does the dorsal scapular nerve innervate?
Rhomboids major and minor
Part of elevator scapulae
What does the long thoracic nerve innervate?
Serrates anterior
What 2 nerves rise from the superior trunk of brachial plexus?
Suprascapular nerve
Nerve to subclavius
Do any new nerves rise from the divisions?
No
The anterior parts of which trunks come together to from the lateral cord?
The superior and middle trunk
The posterior parts of which trunks come together to form the posterior cord?
Superior, middle and inferior trunks
The anterior part of which trunk comes to form the medial cord?
Inferior trunk
How many nerves rise form the lateral cord?
1
What is the name of the nerve that rises from the lateral cord of brachial plexus?
Lateral pectoral nerve
What does the lateral pectoral nerve innervate?
Pectorals major
How many new nerves rise from the medial cord?
3
Name the three nerves that rise from the medial cord of the brachial plexus
Medial pectoral nerve
Medial brachial cutaneous nerve
Medial ante brachial cutaneous nerve
What does the medial pectoral nerve innervate?
Pectoralis major and minor
What does the medial brachial cutaneous nerve innervate?
Skin on medial side of detail part of arm
What does the medial ante brachial cutaneous nerve innervate?
Skin on medial part of forearm
How many new nerves rise from the posterior cord of brachial plexus?
4
Name the 4 new nerves rising from the posterior cord
Axillary nerve
Superior sub scapular nerve
Thoracodorsal nerve
Inferior sub scapular nerve
What does the axillary nerve innervate?
Deltoid
Teres minor
Skin of upper lateral part of arm
What does the superior sub scapular nerve innervate?
Subscapularis
What does the throacodorsal nerve innervate?
Latissimus dorsi
What does the inferior sub scapular nerve innervate?
Subscapularis
Teres major
How many terminal nerves of the brachial plexus are there?
4
Name the 4 terminal nerves of the brachial plexus?
Musculocutaneous nerve
Median nerve
Radial nerve
Ulnar nerve
Which cord gives rise to the musculocutaneous nerve?
The lateral cord
Which cord gives rise to the median nerve?
Lateral and medial cord
Which cord gives rise to the radial nerve?
The posterior cord
Which cord gives rise to the ulnar nerve?
The medial cord
What does the musculocutaneous nerve C5-7 innervate?
Motor to all anterior muscles of arm, skin and lateral forearm
What does the median nerve C6-T1 innervate?
Motor to most flexors forearm
Thenar muscles
2 lateral lumbrical muscles
Skin over lateral palmar side of hand
What does the radial nerve C5-T1 innervate?
Motor to all posterior muscles of arm and forearm
Skin of posterior arm and forearm
Dorsolateral hand
What does the ulnar nerve C8-T1 innervate?
Motor to the muscle in hand the median nerve does not innervate
Most intrinsic muscle of the hand
Skin of medial palmar surface of hand
What are the 2 muscles on the forearm that the median nerve does not innervate?
Flexor carpi ulnaris
Medial half of flexor digitorum profundus
Define a dermatome
Area of skin supplied by single spinal cord level
Define a peripheral nerve
Nerve that can have contributions from multiple spinal levels
What test can check the C7 median nerve dermatome?
Pinching pad of index finger
Do dermatomes overlap?
Some places can have lots of overlap, some places have very minimal overlap
Which dermatomes are found on the anterior of the arm?
C3
C4
C5
C6
C7
Which dermatomes are found on the posterior side of the arm?
C8
T1
T2
What test can check the C5 dermatome?
Upper lateral arm
What test can check the C6 dermatome?
Pad of the tumb
What test can check the C8 dermatome?
Pad of little finger
What test can check the T1 dermatome?
Medial elbow
What is the area on the lower deltoid called which has sensory innervation from the axillary nerve?
“Regimental badge”
What branch of the axillary nerve gives sensory innervation to the lower deltoid “regimental badge”?
Upper lateral cutaneous nerve of arm
Which nerve gives sensory innervation to the lateral part of the upper arm below deltoid?
Inferior lateral cutaneous nerve of arm, branch of radial nerve
What nerve gives sensory innervation to the middle anterior line and medial part of forearm of the upper arm?
Medial cutaneous nerve of forearm, branch of medial cord
What nerve (not from brachial plexus) gives sensory innervation to the medial part of upper arm?
Intercostobrachial nerve T2
What nerve gives sensory innervation to the lateral part of the upper forearm?
Lateral cutaneous nerve of forearm, branch of musculocutaneous nerve
What nerve gives sensory innervation to posterior fold of axilla?
Posterior cutaneous nerve of arm, branch of radial nerve
What nerve gives sensory innervation to the posterior medial half of hand and half of the first 3 digits?
Superficial branch of radial nerve
What nerve gives sensory innervation to half of the first 3 digits and quarter of the 4th digit on the posterior surface of the hand?
Median nerve
What nerve gives sensory innervation to the posterior lateral half of hand and 3 quarters of the 4th digit and whole last digit on the posterior surface of the hand?
Ulnar nerve
What nerve gives sensory innervation to the posterior middle of arm and forearm>
Posterior cutaneous nerve of forearm, branch of radial nerve
What nerve gives sensory innervation to the anterior surface of hand from second half of the thumb half of the 4th digit?
Median nerve
What nerve gives sensory innervation to the anterior surface of the hand from the second half of 4th digit to the end of last digit?
Ulnar nerve
What nerve gives innervation to the first half of thumb on the anterior surface of hand?
Superficial branches of the radial nerve
Which nerve roots are damaged in Erb-Duchenne palsy?
C5+6
Which nerves are affected by Erb-Duchenne Palsy?
Suprascapular, axillary, dorsal scapular, musculocutaneous and some radial
What is the presentation of Erb-Duchenne palsy and which specific muscles are affected?
No supraspinatus and deltoid - no abduction of the arm
No infraspinatus and teres minor - only medial rotation of the arm
No biceps - no flexion, arm permanently pronated
No finger extensors - permanently bent fingers ‘waiters tip’
Which nerve roots are damaged in Klumpke’s palsy?
C8+T1
Which nerve is damaged in Klumpke’s palsy?
Ulnar nerve
What is the presentation of Klumpke’s palsy?
Claw hand - damage to intrinsic hand muscles
Name 2 causes of Erb-Duchenne palsy?
Traumatic fall onto shoulder
Childbirth
Name 1 cause of Klumpke’s palsy?
Hyperabduction of arm
Name 3 situations which can cause damage to the radial nerve (posterior cord)
Fracture of humerus
Saturday night palsy
Improper use of crutches
Name 3 situations which can cause damage to the radial nerve (posterior cord)
Fracture of humerus
Saturday night palsy
Improper use of crutches
What is the presentation of damage to the radial nerve?
Wrist drop - loss of extensors in the arm and forearm
Loss of sensation of posterior forearm
Which muscles are affected in damage to the median nerve?
Finger and wrist flexors, thenar muscles, 1st+2nd lumbricals
