G: Axilla & Brachial Plexus Flashcards
What are the borders of the axilla?
Anterior - pec major and minor
Posterior - Lat. dorsi, teres major, and subscapularis
Medial - serratus anterior
Lateral - intertubercular sulcus of humerus
Base - Skin of armpit
What are the contents of the axilla?
Fat and connective tissue
Axillary vain and lymphatics
Cutaneous nerves
Axillary sheath - axillary artery and brachial plexus
What are the 5 groups of nodes in the axilla?
- Pectoral (anterior)
- Subscapular (posterior)
- Humeral (lateral)
- Central
- Apical
Which lymph nodes receive lymph from all of the axillary nodes and the proximal cephalic vain nodes?
Apical nodes
Which dermatome serves the cutaneous lateral arm?
C5
Which dermatome serves the cutaneous anterior arm, lateroanterior forearm and thumb?
C6
Which dermatome innervates cutaneous palm and middle three digits?
C7
Which dermatome serves cutaneous pinky and posteriomedial forearm?
C8
Which dermatome innervates medial elbow and forearm?
T1
Which dermatome innervates medial arm and axilla?
T2
Where is the axillary sheath in relation to the axilla?
Travels down center of the axilla, continues to medial of arm
What is contained within the axillary sheath?
Axillary artery, nerves, veins, lymphatics
Which is more anterior: axillary artery or axillary vein?
Axillary vein
Where does the subclavian artery transition to the axillary artery?
Lateral border of 1st rib
Where does the axillary artery transition to the brachial artery?
Inferior border of the teres major
What are the borders of the 1st part of the axillary artery?
1st rib -> pec minor
How many branches come from the 1st part of the axillary artery?
One: Superior thoracic artery
What are the borders of the 2nd part of the axillary artery?
The borders of pec minor. Whole 2nd part is deep to pec minor
How many branches does the 2nd part of the axillary artery give off?
Two.
Thoracoacromial and lateral thoracic
What are the borders of the 3rd part of the axillary artery?
Pec minor and teres major
How many branches does the 3rd part of the axillary artery give off?
Three.
Subscapular, anterior circumflex humeral, and posterior circumflex humeral.
What upper limb muscle is not innervated by the brachial plexus?
Trapezius muscle (CN XI)
What is the general organization of the brachial plexus from proximal to distal?
Read The Damn Cadaver Book
Rami (5) -> Trunks (3) -> Divisions (6) -> Cords (3) -> Branches (5)
T/F: Roots, trunks and divisions are typically before the clavicle. Cords and branches are found distal to the clavicle.
TRUE
Which rami form which trunks?
Upper trunk: C5 and C6
Middle trunk: C7
Lower trunk: C8 and T1
Each trunk splits into an _______ and ________ division.
Anterior; posterior
The lateral cord contains which divisions?
Anterior from upper and middle (C5-C7)
Which divisions make up the posterior chord?
All three posterior divisions (C5-T1)
Which divisions contribute to the medial cord?
Anterior of lower trunk (C8 and T1)
What are the five major terminal branches of the brachial plexus and what are their contributing chords and dermatomes?
- Musculocutaneous: lateral chord (C5-C7)
- Median: Lateral and medial (C5-T1)
- Axillary: posterior (C5 and C6)
- Radial: posterior (C5-T1)
- Ulnar: medial (C8-T1)
Which terminal branches of the brachial plexus form the “M” shape?
Musculocutaneous, Median, Ulnar
Which terminal branches of the brachial plexus form the “Y” shape?
Axillary and radial nerves
Which is the major nerve of the anterior arm? What does it innervate?
Musculocutaneous (C5-C7); coracobrachialis, biceps, and half of brachialis
Which is the major nerve of the anterior forearm? What does it innervate?
Median nerve (C5-T1); most of anterior forearm
Which nerve is the major nerve of the hand? What does it innervate?
Ulnar nerve (C8-T1); muscles of hand, flexor carpi ulnaris, flexor digitorum profundus
Which major terminal branch of the brachial plexus circles around the humerus and goes through the quadrangular space? What does it innervate?
Axillary nerve (C5-C6); deltoid and teres minor
Which nerve is the major nerve of the posterior arm and forearm? What does it innervate?
Radial nerve (C5-T1); all posterior muscles and half brachialis
What are the three upper plexus nerves? What do they innervate?
- Dorsal Scapular n. (C5) - rhomboid and levator scapulae
- Long thoracic n. (C5-C7) - serratus anterior
- Suprascapular n. (C5-C6) - supraspinatus and infraspinatus
What are the two pectoral nerves and what do they innervate?
- Lateral pectoral n. (C5-C7) - pectoralis major
2. Medial pectoral n. (C8-T1) - pectoralis major and minor
What are the three lower plexus nerves and what do they innervate?
- Upper subscapular n. (C5-C6) - subscapularis
- Thoracodorsal n. (C6-C8) - latissimus dorsi
- Lower subscapular n. (C5-C6) - subscapularis and teres major
The __________ is an additional brachial plexus nerve that innervates the subclavius muscle.
Nerve to subclavius (C5-C6)
The two cutaneous nerves from the medial cord of the brachial plexus are the ________ (medial arm) and ________ (medial forearm).
Medial brachial cutaneous n.
Medial antibrachial cutaneous n.
