Lecture 18: Axilla & Brachial Plexus Flashcards
Name some of the important structures in the axilla?
5
Axillary artery • Axillary vein(s) • Axillary lymph nodes • Brachial plexus of nerves • Pectoralis minor muscle • Biceps brachii muscle • Coracobrachialis muscle • Axillary tail of female breast
Parts of the axilla (pits) Floor? Apex Anterior wall Posterior wall Medial wall Lateral wall
Floor: axillary fascia and skin of armpit
• Apex: passageway for structures entering or leaving the shoulder and arm; bounded by 1st rib, clavicle and superior portion of scapula.
• Anterior wall: pectoralis major & minor muscles, clavipectoral fascia
• Posterior wall: Subscapularis, teres major, latissimus dorsi, long head of triceps brachii muscle.
• Medial wall: superior rib cage, intercostal and serratus anterior muscles.
• Lateral wall: humerus.
Superior thoracic aperture slide 6
Transverse section through right shoulder joint label in slide 7 and 8
H
What is the arterial supply of the axilla? 9
Venous drainage of axilla? 10
Arterial supply: brachiocephalic trunk ➡subclavian artery➡ axilla ray artery ➡brachial artery ➡ radial/ulnar arteries
Venous drainage of axilla:
Cephalic and basilic veins➡ axillary vein ➡ subclavian v
Lymphatic drainage of upper limb 11
Axillary lymph nodes, Name them slide 12
Lymphatic drainage:
- most is draining up to apical/axillary nodes
- heaps on hands coz we cut their often
- lymph nodes will filter the fluid and trap pathogens,
- surround blood vessels picking up leaking fluid
20-30 nodes divided into five groups: • Central nodes • Lateral (brachial, humeral) nodes • Posterior (subscapular) nodes • Anterior (pectoral) nodes • Apical (subclavian) nodes Don't have to know them all
Whats contained in the brachial plexus? Brachial plexus
Neurovascular bundle is going to be wrapped up with axillary artery, vein and cords of the brachial plexus, all bound in axillary sheath.
Brachial plexus= ventral rami of spinal nerves of C5-T1
Label the brachial plexus on slide 15,16,17
Brachial plexus comes out between anterior and middle scalene
Functions of the nerves in the upper limb
- motor innervation to muscles
- sensory innervation to skin and deep structures
- vascular tone by ymlathetic vase motor nerve fibres
- secretomotor fibres to supply sweat glands.
The brachial plexus has \_\_ roots - \_\_\_trunks \_\_\_divsions \_\_\_cords \_\_\_terminal branches Know slide 21 won't have to draw it- she wants us to know 5 terminal branches, basically whole next slide
5 roots (ventral rami)
• 3 trunks
• 6 divisions (3 anterior, 3 posterior)
• 3 cords (named for their relationship to the axillary artery)
• 5 large terminal branches (M, A, R, M, U)
Mneominic to remember brachial plexus:
Randy Travis Drinks Cold Beers
Roots Trunks Divisons Cords Branches
Know the shit out of slides 23, 31, 32, 34
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35
Posterior cord nerves
Derived from posterior divisions of all 3 trunks. • (ULTRA) • Upper subscapular nerve • Lower subscapular nerve • Thoracodorsal nerve • Radial nerve • Axillary nerve
36
Lateral cord nerves
➡ Name them
Derived from the anterior divisions of the superior and middle trunks. • (LML) • Lateral pectoral nerve • Musculocutaneous nerve • Lateral root of median nerve
Medial cord nerves
37
Derived from the anterior division of the inferior trunk. • (M4U) • Medial pectoral nerve • Medial cutaneous nerve of arm • Medial cutaneous nerve of forearm • Medial root of the median nerve • Ulnar nerve
5 terminal branches of the brachial plexus picture slide 38.
Name them all and what they innervate
Axillary —innervates the deltoid, teres minor, and skin and joint capsule of the shoulder
- Musculocutaneous —innervates the anterior arm muscles and skin of lateral forearm
- Median —innervates the skin, most flexors and pronators in the forearm, and thenar muscles
- Ulnar —supplies the flexor carpi ulnaris, medial half of flexor digitorum profundus, most intrinsic muscles of the hand, and skin of medial aspect of hand
- Radial —innervates essentially all extensor muscles, supinators, and posterior skin of lim
Axiallary nerve 40 and 41
Level
What it innervates?
Derived from?
(C5-C6)
Deltoid muscle Teres minor muscle
Derived from posterior cord and passes posterior to humerus wrapping transversely across lateral aspect of humerus
