Axilla and Brachial Plexus Flashcards
Anterior boundary of the axilla
pectoralis major and minor
Posterior border of the axilla
scapula, latissimus dorsi, teres major
Medial boundary of the axilla
ribs 1-4 and intercostal spaces
Lateral border of the axilla
intertubercular groove of the humerus
Base of the axilla
skin and fascia of arm
Apex of axilla
convergence of clavicle, scapula and rib 1
Contents of Axilla
Axillary Artery
Axillary Vein
Lymphatics
Brachial Plexus
Where does the axillary artery come from?
Aorta-> brachiocephalic trunk->subclavian artery-> becomes axillary artery
Where does the axillary artery begin? Where does it end?
it begins at the lateral border of the 1st rib and ends at the inferior border of teres major, then the axillary artery is continuous with the brachial artery
Where is part 1 of the axillary artery located?
between the lateral border of the first rib and the medial border of pectoralis minor
Where is the second part of the axillary artery?
posterior to pectoralis minor
where is the third part of the axillary artery?
it extends from the lateral border of pec minor to the inferior border of teres major
What is the 1st branch of the axillary artery?
superior thoracic artery
what are the second branches of the axillary artery?
Thoracoacromial trunk
Lateral thoracic arteries
What are the third branches of the axillary artery?
Subscapular artery
Anterior humeral circumflex
Posterior humeral circumflex
Where is the axillary vein formed?
at the inferior border of the teres major muscle by the union of the
brachial veins and
the basilic vein
What does the Brachial plexus innervate?
the entire upper extremity
what forms the brachial plexus?
ventral rami of spinal nerves, C5 C6 C7 C8 T1
anterior and posterior roots form a
mixed spinal nerve
what does each spinal nerve innervate?
a segment of skin and a specific muscle
What does each spinal nerve give rise to?
anterior and posterior RAMI
Where does the dorsal ramus go?
to deep back muscles/skin
Where does the Ventral ramus go?
to trunk/limbs
which rami form the brachial plexus?
C5 C6 C7 C8 T1
What are the roots of brachial plexus?
the ventral rami of the spinal cord
What are the trunks of the brachial plexus?
Comination of roots forms the Superior Middle Inferior trunks
What are the divisions of the brachial plexus?
Each trunk divides into
anterior
posterior divisions
What are the Terminal Branches of the brachial plexus?
Two nerves from each cord Musculocutaneous Median (from 2 cords) Ulnar Radial Axillary
Where do Supraclavicular branches come off of?
Roots or Trunks
Level of Dorsal scapular nerve?
C5
Level of Long thoracic nerve?
C5-7
Level of suprascapular nerve?
C5 and C6
Nerve to Subclavius level?
C5 C6
Where do infraclavicular branches come off of?
Cords
What infraclavicular branch comes from the LATERAL cord?
Lateral pectoral nerve
What Infraclavicular branches comes off of the MEDIAL cord?
Medial pectoral nerve, medial brachial cutaneous nerve
medial antebrachial cutaneous nerve
What Infraclavicular branches come off of the POSTERIOR cord?
Upper subscapular nerve
Lower subscapular nerve
Thoracodorsal nerve
What does the long thoracic nerve innervate?
serratus anterior
what does the dorsal scapular nerve innervate?
rhomboid major
rhomboid minor
levator scapulae
what does the suprascapular nerve innervate?
supraspinatus
infraspinatus
What does the nerve to subclavius innervate?
subclavius
what does the lateral pectoral nerve innervate?
pec major
What does the medial pectoral nerve innervate?
pec major and minor
what does the Upper Subscapular nerve innervate?
subscapularis
what does the lower subscapular nerve innervate?
subscapularis and teres major
what does the thoracodorsal nerve innervate
latissmus dorsi
What does the terminal axillary branch innervate?
deltoid and teres minor
what does the terminal Musculocutaneous branch innervate?
biceps brachii
brachialis
coracobrachialis
What do the Median nerves and branches innervate?
Most muscles in anterior FOREARM
Lumbricles 1 and 2, and thenar intrinsic muscles of the HAND
what does the Ulnar nerve inervate?
muscles of anterior forearm and HAND
Flexor carpi Ulnaris
Flexor Digitorum Profundus of forearm
and ALL REMAINING INTRINSIC MUSCLES OF THE HAND
What do the Radial nerves and branches innervate?
All POSTERIOR compartment muscles of arm and forearm, NO MUSCLES IN HAND