Axilla & Brachial Plexus Flashcards
What makes up the anterior wall of the axilla?
Pectoralis Major and Minor
What makes up the posterior wall of the axilla?
Latissimus Dorsi, Teres Major, and subscapularis
What makes up the medial wall of the axilla?
Serratus anterior
What makes up the lateral wall of the axilla?
Intertubercular sulcus of humerus
What makes up the base of the axilla?
Skin and fascia of armpit
What is contained within the axilla?
Fat & connective tissue, axillary v & lymphatics (outside sheath), cutaneous nerves, axillary sheath (axillary a & brachial plexus)
What are the five principal lymph node groups?
Humeral (lateral), pectoral (anterior), subscapular (posterior) drain to central node, which drains to apical node
What branch comes off the first part of axillary artery?
Superior thoracic artery
What branches come off the second part of axillary artery?
Thoracoacromial and lateral thoracic aa
What branches come off the third part of axillary artery?
Subscapular, anterior, and posterior circumflex humeral aa
Where do the rami of the brachial plexus emerge? How many are there?
5 emerge in upper neck
Where do the trunks of the brachial plexus form? How many are there?
3 form in lower neck
Where do the divisions of the brachial plexus split? How many are there?
6 split off behind clavicle
Where do the cords of the brachial plexus form? How many are there?
3 form in the axillary region
Where do the branches of the brachial plexus split? How many are there?
5 split off in upper arm
What muscle does musculocutaneous n pass through?
Corachobrachialis
What muscles does musculocutaneous n enter?
Biceps brachii and brachialis
What kind of innervation is musculocutaneous n providing?
Motor and sensory
What does median nerve innervate?
Most of the anterior forearm, 3 thenar eminence mm, and first 2 lumbricals in hand
Where does ulnar nerve run?
Behind medial epicondyle
What does ulnar nerve innervate?
Most of the mm of the hand, FCU m, and ulnar half of FDP m in forearm
Where does axillary nerve run?
Circles behind humerus in quadrangular space
What does axillary nerve innervate?
Deltoid and teres minor mm
Where does radial nerve run?
Passes posterior to humerus in radial groove and within triangular interval
What does radial nerve innervate?
All muscles in both regions & half of brachial is m
What nerves make up the upper plexus?
Dorsal scapular nerve, long thoracic nerve, and supra scapular nerve
Where does dorsal scapular nerve originate? What does it innervate?
C5; rhomboid & levator scapulae mm
Where does long thoracic nerve originate? What does it innervate?
C5-C7; serratus anterior
Where does suprascapular nerve originate? What does it innervate?
C5-C6; supraspinatus & infraspinatus
What are the pectoral nerves?
Lateral and medial pectoral nn
Where does lateral pectoral n originate? What does it innervate?
C5-C7; pectoralis major m
Where does medial pectoral n originate? What does it innervate?
C8-T1; pectoralis major & minor mm
What nerves make up the lower plexus?
Upper subscapular, thoracodorsal, and lower subscapular nn
Where does upper subscapular n originate? What does it innervate?
C5-C6; subscapularis m
Where does thoracodorsal n originate? What does it innervate?
C6-C8; latissimus dorsi m
Where does lower subscapular n originate? What does it innervate?
C5-C6; subscapularis and teres major mm
What additional nerves are in the brachial plexus?
Nerve to subclavius, medial brachial cutaneous n, medial antibrachial cutaneous n
Where does nerve to subclavius originate? What does it innervate?
C5-C6; subclavius m
Where does medial brachial cutaneous n originate? What does it innervate?
C8-T1; sensory to medial arm
Where does medial anti brachial cutaneous n originate? What does it innervate?
C8-T1; sensory to medial forearm
No nerves come directly off of which part of the brachial plexus?
Divisions
