Axilla and Brachial Plexus Flashcards Preview

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Flashcards in Axilla and Brachial Plexus Deck (22):

Define the boundaries of the axilla

Anterior: pectoralis major and minor muscles
Posterior: latissimus dorsi, teres major, long head of triceps and subscapularis
Medial: lateral thoracic wall and serratus anterior
Lateral: intertubercular groove of the humerus

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List the contents of the axilla

1. Axillary artery and the brachial plexus of nerves
2. Axillary vein and lymphatics

3. lymph nodes and the lymphatics from the upper extremity, the breast, and even the upper abdominal wall

4. Fat


What encases the axillary artery and vein and the brachial plexus?

axillary sheath


Where is the apex of the axilla?

near the clavicle and first rib


What is the floor of the axilla?

axillary skin fold


Brachial Plexus:

1. What spinal cord levels?

2. What does it innervate?

3. Mnemonic for segments?


1. C-5 to T-1

2. ALL THE INNERVATION to the upper extremity (Small exception is the intercostobrachial sensory nerve from T-2)

3. "Read That Damn Cadaver Book" = roots, trunks, divisions, cords, and branches


Name the 5 major nerve branches of the brachial
plexus and their cords:

1. musculocutaneous: lateral cord

2. median: lateral and medial cords

3. radial: posterior cord

4. axillary: posterior cord

5. ulnar: medial cord

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Name all branches of lateral cord

1. lateral pectoral nerve to the pectoralis MAJOR muscle
2. musculocutaneous nerve
3. LATERAL ROOT of the median nerve


Name all the branches of the Medial Cord

1. medial pectoral nerve to both pectoral muscles
2. medial brachial cutaneous nerve
3. medial antebrachial cutaneous nerve
4. ulnar nerve

5. MEDIAL ROOT of the median nerve


Name all the branches of the posterior cord

1. upper subscapular nerve
2. thoracodorsal nerve
3. lower subscapular nerve
4. radial nerve
5. axillary nerve


Describe the location of different parts of the brachial plexus relative to the scalene
muscles, the first rib, and the axillary artery

• Brachial plexus passes between the anterior and middle scalenes.

• Brachial plexus is superior to the first rib; cords of the brachial plexus are at or inferior to the clavicle

• The cords of the brachial plexus (lateral, posterior and medial) are named by their anatomical relation to the axillary artery

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Which nerves leave the brachial plexus proximal to the divisions AND what do they innervate?

1. long thoracic nerve (to the serratus anterior)
2, dorsal scapular nerve (to the rhomboids and some of the levator scapulae)

3. the suprascapular nerve (to supraspinatus and infraspinatus muscles)
4. the nerve to the subclavius muscle (not important)


What does the axillary nerve innervate?

deltoid and teres minor muscles


Name the arteries BEFORE and AFTER the axillary artery and at what locations the change occurs

subclavian artery becomes axillary artery at the lateral border of the first rib

axilla artery becomes the brachial artery at the inferior border of the teres major muscle


What are the locations of the three parts of the axillary artery and what branches come off of each?

First branch is proximal to the pectoralis minor: superior thoracic (not important)

Second branch is posterior to pectoralis minor: thoracoacromial and the lateral thoracic

Third branch is distal to pectoralis minor: subscapular and the anterior and posterior circumflex

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Axillary vein:

1. merger of what two veins

2. where does it end

3. anatomical position to axillary artery (what if abducted)?

1. brachial and basilic veins

2. becomes subclavian vein at the lateral border of the 1st rib

3. lies anteromedial to the axillary artery in anatomic position and anteroinferior if the arm is abducted


cephalic vein

1. where is it located?

2. What does it empty into?

1. major subcutaneous vein of the lateral upper extremity

2. empties into the axillary vein slightly lateral to the 1st rib, above the pectoralis minor

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What is the function of the lymphatic system?

Multiple one-way valves in these vessels permit flow only toward the central venous system

Lymph nodes serve to filter the fluid and are sites of immunologic activity


Where does the lymph fluid travel to and where does it drain?

Most of the lymph fluid travels to the thoracic duct, which in turn drains into the left subclavian vein


Define terms:






Lymphangitis = inflammation of lymph vessels
Lymphadenitis = inflammation of lymph nodes

Lymphadenopathy = lymph node swelling or enlargement whether or not inflamed…often a result of cancer metastases

Lymphedema = Accumulation of lymph in interstitial spaces

Chlye = lymphatic fluid from the intestines involved in fat digestion and often
appears milky


Which nerve travels on the lateral surface of the serratus anterior muscle (i.e. medial wall of the axilla)?

long thoracic