Lecture 17- Axilla and Brachial Plexus Flashcards
Axilla “armpit”
Apex: passageway for structures entering or leaving the shoulder and arm; bounded by ….. ….., ……. and superior portion of ………
1st rib
clavicle
scapula
Axilla “Armpit”
• Floor: ……. ……. and ….. of armpit
axillary fascia
skin
Axilla “armpit”
Anterior wall: pectoralis major & minor muscles, clavipectoral fascia
• Posterior wall: Subscapularis, teres major, latissimus dorsi, long head of triceps brachii muscle.
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Axilla “armpit”
• Medial wall: superior rib cage, intercostal and serratus anterior muscles.
• Lateral wall: humerus.
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Axilla Important structures in the axilla: • 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.
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Arterial supply of axilla
Brachiocephalic trunk -> ……… artery ->
…….. artery -> …….. artery -> ……./……. arteries
subclavian
axillary
brachial
radial/ulnar
Venous drainage of axilla Superficial: ....... & ...... veins Dive down to ......... vein Brachial veins surround brachial artery -> Axillary v. -> subclavian v
cephalic
basilic
axillary
Axillary lymph nodes 20-30 nodes divided into five groups: • Central nodes • Lateral (brachial, humeral) nodes • Posterior (subscapular) nodes • Anterior (pectoral) nodes • Apical (subclavian) nodes
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Brachial plexus
Neurovascular bundle in axilla=
•……. artery
•…….. vein
• Cords of brachial plexus => all bound in the …… …….
• Brachial plexus = …….. rami of spinal nerves …….
Axillary Axillary axillary sheath ventral C5-T1
Functions of nerves in the upper limb
• Motor innervation to ………
• Sensory innervation to ….. & deep structures
• Vascular tone by sympathetic vasomotor nerve fibres
• Secretomotor fibres to supply …… ……
muscles
skin
sweat glands
Brachial plexus
• 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)
Randy travis drinks cold beers
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Named nerves of the Brachial Plexus
Anterior rami of ……….
Supplies: Muscles of ……… (superficial back muscles, anterior thoracic wall muscles) All muscles of …….. …… And upper limb ….
C5-T1
shoulder
upper extremity
skin.
“C5-C6-C7 lift your arms to heaven” corresponds with which muscle?
Serratus anterior
Posterior cord nerves • Derived from posterior divisions of all 3 trunks. • (ULTRA) • Upper subscapular nerve • Lower subscapular nerve • Thoracodorsal nerve • Radial nerve • Axillary nerve
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Lateral cord nerves • Derived from the anterior divisions of the superior and middle trunks. • (LML) • Lateral pectoral nerve • Musculocutaneous nerve • Lateral root of median nerve
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Medial cord nerves • 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
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Brachial Plexus: Terminal Nerves
• 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 limb
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Axillary nerve
(C5-C6)
Deltoid muscle
Teres minor muscle
Derived from posterior cord and passes posterior to humerus
wrapping transversely across lateral aspect of humerus
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Musculocutaneous nerve (C5-C6-C7) Coracobrachialis muscle Brachialis muscle Biceps brachii muscle Derived from medial cord, pierces through coracobrachialis, travels deep to biceps brachii / superficial to brachialis then passes superficially to dermis to innervate lateral skin on forearm
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Median nerve (C5-C6-C7-C8-T1) Pronator teres muscle Flexor carpi radialis muscle Palmaris longus muscle Flexor digitorum superficialis muscle Flexor digitorum profundus muscles to thumb and index fingers Flexor pollicis longus muscle Pronator quadratus muscle Lumbricals to index and middle fingers Thenar muscles of thumb
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Cutaneous innervation
• Posterior cutaneous nerves => Branches of radial nerve.
• Lateral cutaneous nerves => Each of these nerves arise from a separate source (axillary, radial, musculocutaneous
nerves)
• Medial cutaneous nerves => Branches of the medial cord of brachial plexus.
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Arm = C5, C6, T2 Forearm = C5, C6, T1 Hand = C6, C7, C8
Thumb = C6
Middle finger = C7
Little finger = C8
Olecranon & medial epicondyle of humerus = T1
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