Axilla and Arm Flashcards
Which arteries anastomose in the upper arm?
-Anterior circumflex humeral artery and Posterior circumflex humeral artery
Which arteries anastomose in the posterior shoulder?
- Dorsal scapular
- Suprascapular
- Circumflex scapular
- Thoracodorsal
What two branches come off the Thyrocervical trunk?
Thyrocervical trunk comes off the subclavian artery and produces:
- Transverse cervical artery
- Superficial branch
- Dorsal scapular artery
- Suprascapular
What artery supplies the posterior shoulder from the axillary artery?
Subscapular artery
- Circumflex scapular
- Thoracodorsal artery
What forms the anterior axillary fold?
pectoralis major
What forms the posterior axillary fold?
latissimus dorsi and teres major
What is inside the axillary sheath?
THICK fascia containing:
- Axillary artery
- Axillary vein
- Distal portion of Brachial plexus
Where does the subclavian artery become the axillary artery?
lateral border of 1st rib
Where does the axillary artery become the brachial artery?
inferior border of Teres major
What divides the three portions of the axillary artery?
First part - proximal to pectoralis minor Second part - deep to pec minor Third part - distal to pec minor
What comes off the first portion of the axillary artery?
Superior thoracic artery
What does the superior thoracic artery supply?
1st and 2nd intercostal spaces
What are the two branches off of the second part of the axillary artery?
- Thoracoacromial artery
- Lateral thoracic artery
What does the thoracoacromial artery supply?
- Pectoral muscles
- Deltoid
What does the Lateral thoracic artery supply?
- Serratus anterior
- pectoral muscles
*courses with the long thoracic nerve*
What are the 3 branches of the third part of the axillary artery?
- Subscapular artery 2. Anterior circumflex humeral artery 3. Posterior circumflex humeral artery
What are the branches of the subscapular artery?
- Circumflex scapular artery 2. Thoracodorsal artery
What does the circumflex scapular artery supply?
scapular region
What does the thoracodorsal artery supply?
Latissimus dorsi
What do the anterior and posterior circumflex humeral arteries supply?
shoulder and arm
What does the posterior circumflex humeral artery travel through the quadrangular space with?
Axillary nerve and posterior circumflex humeral vein
What are the borders of the quadrangular space?
-Teres minor (superior) -Teres major (inferior) -Long head of triceps -Humerus
The union of brachial veins and basilic vein form what?
Axillary vein
Where do the brachial veins join the basilic vein?
inferior border of teres major
Where are the roots of the brachial plexus?
neck
Where are the trunks of the brachial plexus?
neck
Where are the divisions of the brachial plexus?
deep to clavicle
What spinal levels comprise the superior trunk?
C5 and C6
What spinal levels comprise the middle trunk
C7
What spinal levels comprise the inferior trunk?
C8 and T1
Anterior divisions give rise to which compartments of the arm, forearm and hand?
-Anterior compartments of the arm and forearm and palmar surface of hand
Posterior divisions give rise to what?
posterior compartments of the arm and forearm and the dorsal hand
What does the dorsal scapular nerve (C5) innervate?
- Levator scapulae 2. Rhomboid Major 3. Rhomboid Minor
What muscle does the long thoracic nerve (C5, C6, C7) innervate?
Serratus anterior
What causes a winged scapula?
lesion of the long thoracic nerve
What does the suprascapular nerve (C5, C6) innervate?
-supraspinatus -infraspinatus
Describe “army over navy”
suprascapular nerve goes under the superior transverse scapular ligament, and the suprascapular artery goes over the ligament
What does the Lateral cord give rise to?
“LMM” -musculocutaneous -median
What does the medial cord give rise to?
“MUM” -ulnar -median
What does the posterior cord give rise to?
“PAR” -axillary -radial
What does the musculocutaneous nerve innervate?
muscles of the anterior compartment of the arm
What area does the musculocutaneous provide sensory for?
near the elbow (it terminates as the lateral cutaneous nerve of the forearm which innervates the skin of the lateral forearm)
Median Nerve: motor
- anterior compartment of the forearm
- thenar
- lumbricals 2&3
What provides sensation to the mid arm?
Medial cutaneous nerve of the forearm (C8, T1)?
What provides sensory innervation to the anterior forearm and medial forearm?
Medial cutaneous nerve of the forearm (C8, T1)
What does the lateral pectoral nerve (C5, C6, C7) innervate?
Pectoralis major
What does the medial pectoral nerve innervate (C8, T1)?
Pectoralis major Pectoralis minor
What does the ulnar nerve (C7, C8, T1) innervate?
- Flexor Carpi Ulnaris
- Flexor Digitorum Profundis (digits 4&5)
- Adductor pollicis (transverse and oblique heads)
- Hypothenar (Abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi)
- lumbricals 4&5
- Interossei (dorsal and palmar)
What structures are at risk with a break of the surgical neck of the humerus?
vessels in the quadrangular space:
- Posterior circumflex humeral artery
- Posterior circumflex humeral vein
- Axillary nerve (C5, C6)
What does the axillary nerve innervate?
Axillary nerve (C5, C6) -deltoid -teres minor
What does the axillary nerve provide sensory innervation for?
skin on the lateral aspect of the shoulder
What does the radial nerve travel with on the back of the humerus?
Radial nerve (C5, C6, C7, C8, T1) travels with the deep artery and vein of the arm in the radial groove
Radial nerve: motor?
muscles of the posterior arm and forearm
Radial nerve: sensory?
skin of posterior arm, forearm and hand
What does the upper subscapular (C5, C6) nerve innervate?
subscapularis (superior part)
What does the thoracodorsal nerve (C6, C7, C8) innervate?
latissimuss dorsi
What does the lower subscapular nerve (C5, C6)
- Subscapularis (inferior part) 2. Teres major
Injury to C5-C6 is called what?
Erb’s palsy “waiter’s tip position”
What is affected in Erb’s palsy?
*ANTERIOR ARM MUSCLES Glenohumeral joint is:
- adducted
- medially rotated
- extended elbow joint
- C5, C6 dermatomes affected

What muscles are affected in Erb’s Palsy (C5, C6)?
- some rotator cuff muscles (Supraspinatus, infraspinatus, teres minor
- Deltoid
- Biceps brachii
- Brachialis
What nerve levels are affected in Klumpke’s Palsy?
C8 and T1
What does Klumpke’s Palsy affect?
Intrinsic hand muscles (ulnar and median nerves)
*CLAW HAND*
Where would someone with Klumpke’s palsy lose skin sensation?
- C8 -medial part of arm and forearm and digits 4&5
- T1 - Axilla, anteromedial portion of the arm and forearm to the wrist
What are the actions of the anterior arm?
- Flex glenohumeral joint
- Flex elbow joint
- Supinate forearm
What spinal levels/nerve are we assesing with the biceps reflex test?
- Musculocutaneous nerve
- C5-C6
What are the actions of the posterior compartment of the arm?
- Extend the glenohumeral joint
- Extend elbow joint
What spinal levels are being tested with the triceps reflex test?
- Radial nerve (C7-C8)
What is the primary supplier of blood to the posterior arm?
Deep artery of the arm