Axilla & Brachial Plexus Flashcards
Boundaries of Axilla
- Superiorly by the clavicle, the scapula, and the 1st rib
- Inferiorly by the skin at the lower borders of the pectoralis major and the teres
major/latissimus dorsi - Anteriorly by pectoral muscles
- Posteriorly by the subscapularis
- Medially by the serratus anterior
- Laterally by the humerus
Contents of Axilla
B. Contents
- Brachial plexus
- Axillary fat and fascia
- Axillary vessels and branches
- Axillary lymph nodes
What roots does the BP come from
C5, C6, C7, T1
How are spinal roots named as they come out of vertebrae?
C1 - C7 come out above respective vertebrae
C8 comes out above T1, there is no C8 vertebrae
T1 and onward come out below respective vertebrae
What are the segments of the Brachial Plexus
“Real teachers drink cold beer”
Roots, trunks, divisions, cords, branches
Anterior Rami of C5-8 & T1
What is another name for the middle subscapular nerve?
Thoracodorsal nerve
What artery does the radial nerve travel with?
Deep brachial or profundi brachial artery
Damage to what nerve results in carpal tunnel?
Median Nerve
What nerves come from the lateral cord?
DS - dorsal scapular SUBc - subclavius SUP - suprascapular LP - lateral pectoral LT - long thoracic - from roots of C6-7
What nerves come from the posterior cord?
L - lower subscapular
M - middle subscapular - also known as the thoracodorsal which goes to the lat
U - upper subscapular
What nerves come from the medial cord?
MAC - medial antibrachial cutaneous
MBC - medial brachial cutaneous
MP - medial pectoral
What nerves come from the “M/W”?
MAR-MU M - musculocutaneous A - axillary R - radial M - medial U - ulnar
What does the musculocutaneous nerve pierce?
Corachobrachealis.
Also innervates brachealis, and biceps.
What does median nerve do in upper arm?
Nothing
Branches of the axillary artery?
Screw The Lawyer, Save A Patient S - Superior thoracic T - thoracic acromial L - lateral thoracic S - subscapular - largest branch A - anterior circumflex humeral P - posterior circumflex humeral
Where do dorsal ramii go?
To the true back muscles
Where does the subscapular nerve pass?
Under the transverse scapular ligament. Army over…navy under
What provides sensation to the thumb?
C6 root
What other nerve does C5 contribute to?
Phrenic Nerve
Where do the trunks of the BP lie?
Between the scalene muscles medial to the midpoint of the clavicle
Where do the BP divisions Lie?
Posterior to clavicle MP adjacent to third part of subclavian artery and beginning of axillary artery
Where do the BP cords lie?
Extend laterally from clavicle midpoint to inferomedial aspect of coracoid process on the scapula
Erb’s Palsy
Upper trunk injury
Effects suprascapular, musculocutaneous, and axillary nerves
Lose ability to laterally rotate leaving you in tip taking position
Klumpke’s Palsy
Lower trunk injury - also called “TOTAL PAW”
If you pull on a babies are in general or in trying to deliver you can rip the lower trunk
“Klumpke the Monkey” - Makes your fingers permanently flexed
Ulnar Claw
Caused by distal ulnar lesion paralyzing two medial lumbricals
Pope’s blessing / Benedictine sign
Looks same as Ulnar Claw but only evident when making fist
Due to median nerve injury paralyzing lateral 2 lumbricals and weakening FDS
MARMU mnemonic
3 Musketeers assassinated 5 rats, 5 mice, and 2 Unicorns