Upper Extremity: Axilla and Brachial Plexus Flashcards

1
Q

Axilla

A
  • Passageway from neck to upper limb

- Begins at cervico-axillary canal (clavicle, 1st rib, superior scapula)

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2
Q

Boundaries of axilla

A
  • Apex (superior): cervico-axillary canal
  • Base (inferior,floor): axillary fascia
  • Anterior: pectoralis major and minor
  • Posterior: latissimus dorsi, teres major, subscapularis
  • Medial: thoracic wall (ribs 1-5, intercostal muscles, serratus anterior)
  • Lateral: intertubercular sulcus of the humerus
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3
Q

Content of axilla

A
  • Axillary artery/vein
  • Cords and branches of the brachial plexus
  • Lymphatics and axillary lymph nodes
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4
Q

Axillary sheath surrounds

A
  • Axillary vessels

- Brachial plexus cords

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5
Q

Subclavian branches that contribute to the scapular region

A
  • Dorsal scapular
  • Branch from either transverse cervical or subclavian directly
  • Suprascapular
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6
Q

3 parts of the axillary artery

A
  • Part 1: outer border of rib 1 up to pectoralis minor
  • Part 2: posterior to pectoralis minor
  • Part 3: outer edge of pectoralis minor to inferior edge of teres major
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7
Q

Branches of axillary artery 1st part

A
  • Superior thoracic artery (Highest or supreme thoracic artery)
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8
Q

Branches of axillary artery 2nd part

A
  • Thoracoacromial artery
  • Acromial branch
  • Clavicular branch
  • Pectoral branch
  • Deltoid branch (accompanies cephalic vein)
  • Lateral thoracic artery
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9
Q

Branches of axillary artery 3rd part

A
  • Subscapular artery
  • Anterior circumflex humeral artery
  • Posterior circumflex humeral artery
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10
Q

Subscapular artery branches

A
  • Circumflex scapular artery

- Thoracodorsal artery

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11
Q

Anterior circumflex humeral artery

A
  • Supplies surgical neck/humeral head/GH joint
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12
Q

Posterior circumflex humeral artery

A
  • Supplies surgical neck/humeral head/GH joint

- Can anastomosis with profunda brachii artery

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13
Q

Arterial anastosomes around the scapula

A
  • Provide alternate means of blood supply

- Occlusion/ligation of subclavian or axillary arteries

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14
Q

Arteries involved with collateral circulation around scapula

A
  • Transverse cervical
  • Descending scapular (dorsal scapular)
  • Suprascapular
  • Subscapular and circumflex scapular
  • Branches from posterior intercostals (2-7)
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15
Q

Axillary lymph nodes

A
  • Anterior (pectoral)
  • Posterior (subscapular)
  • Lateral (humeral)
  • Central
  • Apical
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16
Q

Anterior (pectoral) axillary lymph nodes

A
  • Located around the lateral thoracic vessels/pec minor
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17
Q

Posterior (subscapular) axillary lymph nodes

A
  • Located along posterior axillary fold and subscapular vessels
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18
Q

Lateral (humeral) axillary lymph nodes

A
  • Located along lateral wall of axilla, medial and posterior to axillary vein
  • Receive most lymph from upper extremity except that which parallels the cephalic vein
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19
Q

Central axillary lymph nodes

A
  • Located deep to pec minor

- Receives lymph from anterior, posterior, and lateral axillary nodes

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20
Q

Apical axillary lymph nodes

A
  • Located at the apex of axilla

- Lymph directly from pectoral region and lateral upper extremity

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21
Q

Apical node pathway

A

Apical nodes –> subclavian lymphatic trunk –> right lymphatic duct (right) and thoracic duct (left)

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22
Q

Brachial plexus

A
  • Origin of the nerves of the upper limb
  • Most branches arise in the axilla (not all)
  • Formed by anterior rami of C5 – T1 (sometimes C4 and T2 may contribute)
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23
Q

Brachial trunks (superior, middle, and inferior trunks)

A
  • Each divides into an anterior and posterior division at the cervico-axillary canal
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24
Q

Superior trunk of brachial plexus

A
  • Union of C5,6 roots (anterior rami)
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25
Q

Middle trunk of brachial plexus

A
  • C7 root
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26
Q

Inferior trunk of brachial plexus

A
  • Union of C8,T1
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27
Q

Anterior divisions from superior and middle trunk

A
  • Unite to form the lateral cord
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28
Q

Anterior division from the inferior trunk

A
  • Forms the medial cord
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29
Q

Posterior divisions from all 3 trunks

A
  • Unite to form the posterior cord
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30
Q

Roots (ventral rami)

A
  • Pass between anterior and middle scalene muscles

- Receive sympathetic fibers from middle and inferior cervical (stellate) ganglia

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31
Q

Supraclavicular/infraclavicular branches

A
  • Some branches arise from the roots and upper trunk
  • No branches from the divisions
  • Most branches arise from the cords
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32
Q

Branches from roots (ventral rami)

A
  • Dorsal scapular (C5, sometimes C4)

- Long thoracic (C5-7)

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33
Q

Branches from trunks

A
  • Nerve to subclavius (C5,6)

- Suprascapular (C5,6)

34
Q

Lateral branches from cords

A
  • Lateral pectoral (C5-7)

- Musculocutaneous (C5-7)

35
Q

Medial branches from cords

A
  • Medial pectoral (C8,T1)
  • Medial cutaneous nerve of arm (C8,T1)
  • Medial cutaneous nerve of forearm (C8,T1)
  • Ulnar nerve (C8,T1; often C7)
36
Q

Lateral and medial branches from cords

A
  • Median nerve (C5-T1)
37
Q

Posterior branches from cords

A
  • Upper and lower subscapular (C5,6)
  • Thoracodorsal (C6-8)
  • Axillary (C5,6)
  • Radial (C5-T1)
38
Q

Dorsal scapular nerve (C5, sometimes C4 contributes)

A
  • Branches off ventral rami of C5 posteriorly, pierces middle scalene
  • Descends along medial scapular border along with dorsal scapular artery
  • Supplies levator scapulae and rhomboids (deep to these muscles)
39
Q

Long thoracic nerve

A
  • Branches off C5-7 ventral rami
  • Passes through cervico-axillary canal
  • Descends along serratus anterior around the mid-axillary line
  • Supplies serratus anterior
  • Injury can cause winging of the scapula
40
Q

Suprascapular nerve

A
  • Derived from upper trunk (C5,6)
  • Traverses posterior triangle of the neck
  • Passes through suprascapular foramen, below transverse scapular ligament
  • Suprascapular vessels pass above ligament
  • Innervates supraspinatus, infraspinatus, and shoulder joint
41
Q

Lateral pectoral nerve (C5-7)

A
  • Originates from the lateral cord
  • Pierces through clavipectoral fascia
  • Innervates pectoralis major primarily
  • Innervates shoulder joint
42
Q

Medial pectoral nerve (C8,T1)

A
  • Originates from medial cord pierces pectoralis minor, enters deep surface of pectoralis major
  • Innervates pectoralis minor and major (sternocostal part)
43
Q

Musculocutaneous nerve (C5-7)

A
  • Terminal branch of lateral cord
  • Pierces coracobrachialis
  • Descends into the arm between biceps brachii and brachialis
  • Becomes lateral cutaneous nerve of the forearm
44
Q

Musculocutaneous nerve (C5-7) motor innervation

A
  • Arm anterior compartment
  • Coracobrachialis
  • Biceps brachii
  • Brachialis
45
Q

Musculocutaneous nerve (C5-7) sensory innervation

A
  • Lateral forearm
46
Q

Medial cutaneous nerve of arm

A
  • Originates from medial cord (C8,T1)
  • Very small
  • Supplies skin on medial side arm
47
Q

Medial cutaneous nerve of forearm

A
  • Originates from medial cord (C8,T1)
  • Pierces deep fascia and becomes superficial with basilic vein
  • Supplies skin over biceps, anterior and medial forearm
48
Q

Ulnar nerve

A
  • Terminal branch of medial cord (C8,T1; often C7)
  • Descend into the arm on the medial side
  • Posterior to medial epicondyle
  • Travels along medial forearm into the hand
49
Q

Ulnar nerve motor innervation

A
  • 1 ½ anterior forearm compartment muscles

- Every hand muscle not innervated by median

50
Q

Ulnar nerve sensory innervation

A
  • Hand medial to midline of 4th digit
51
Q

Median nerve

A
  • Derived from the lateral and medial cord
  • Descends into arm next to the brachial artery
  • Passes through cubital fossa to enter the forearm
52
Q

Median nerve lateral root

A
  • (C5-7): terminal branch of lateral cord
53
Q

Median nerve medial root

A
  • (C8,T1): terminal branch of medial cord
54
Q

Median nerve motor innervation

A
  • Anterior forearm compartment (except 1 ½ muscles)

- 5 intrinsic hand muscles

55
Q

Median nerve sensory innervation

A
  • Lateral hand, lateral to midline of 4th digit
56
Q

Superior (upper) and Inferior (lower) Subscapular Nerves

A
  • Originate from the posterior cord (mostly C5,6)
  • Both supply subscapularis
  • Lower subscapular nerve also supplies teres major
57
Q

Thoracodorsal nerve

A
  • Originates from the posterior cord (C6-8)
  • Arises between the subscapular nerves
  • Travels along axillary wall
  • Innervates latissimus dorsi
58
Q

Axillary nerve

A
  • Terminal branch of posterior cord (C5,6)
  • Exits axilla through quadrangular space along with
  • Posterior humeral circumflex artery
59
Q

Axillary nerve motor innervation

A
  • Deltoid muscle

- Teres minor muscle

60
Q

Axillary nerve sensory innervation

A
  • Superior/lateral arm (superior lateral cutaneous nerve of arm)
  • Shoulder joint
61
Q

Injuries to axillary nerve

A
  • Surgical neck fracture

- Inferior shoulder dislocation

62
Q

Radial nerve

A
  • Terminal branch of posterior cord (C5-T1)
  • Passes through triangular interval
  • Travels with deep artery of the arm
  • Radial groove (between med and lat heads of triceps)
  • Enters anterior elbow region and branches (cover later)
63
Q

Radial nerve motor innervation

A
  • Posterior compartment muscles of arm and forearm
64
Q

Radial nerve sensory innervation

A
  • Inferolateral arm
  • Posterior arm and forearm
  • Dorsum of hand, lateral to midline of 4th digit
65
Q

Brachial plexus injuries

A
  • Stretching, compression that affects the integrity of the brachial plexus
  • Thoracic outlet syndrome
  • Trauma
66
Q

Common trauma injuries to brachial plexus

A
  • Pentrating trauma in the posterior triangle of the neck or axilla
67
Q

Sensory symptoms of brachial plexus injury

A
  • Anesthesia

- Paresthesia

68
Q

Motor symptoms of brachial plexus injury

A
  • Paralysis

- Incomplete paralysis (paresis or weakness)

69
Q

Upper plexus injury causes

A
  • Shoulder depression and lateral flexion head toward opposite side
70
Q

Lower plexus injury causes

A
  • Arm abduction and distraction away from the body
71
Q

Erb-Duchenne’s Palsy (Upper plexus injuries) causes

A
  • Caused by an injury that draws the head away from the shoulder (birth trauma, sports, etc)
72
Q

Nerves damaged in Erb-Duchenne’s Palsy (Upper plexus injuries)

A
  • C5,6 ventral rami are damaged (or upper trunk)

- C5,6 contributes to suprascapular nerve, axillary nerve, musculocutaneous nerve

73
Q

Effects of Erb-Duchenne’s Palsy (Upper plexus injuries)

A
  • Results in medial rotation of the upper limb (Waiter’s tip deformity)
74
Q

Waiter’s tip deformity

A
  • Arm/forearm hangs down by the side in a position of extension, pronation, and internal rotation
  • Wrist is flexed
75
Q

Motor functions lost in Waiter’s tip deformity from Erb-Duchenne’s Palsy (Upper plexus injuries)

A
  • Arm lateral rotation
  • Shoulder abduction and flexion
  • Elbow flexion
  • Supination
76
Q

Sensory functions lost in Waiter’s tip deformity from Erb-Duchenne’s Palsy (Upper plexus injuries)

A
  • Lateral shoulder, arm, forearm, thumb
77
Q

Dejerine-Klumpke palsy (Lower type plexus injuries)

A
  • C8,T1 ventral rami are effected

- Injury most commonly occurs when the arm is pulled upwards

78
Q

Dejerine-Klumpke palsy (Lower type plexus injuries) innervation issues

A
  • Loss of innervation to intrinsic hand muscle

- Causes claw hand deformity

79
Q

Claw hand deformity

A
  • Hyperextension of metacarpophalangeal joint

- Flexion of interphalangeal joints

80
Q

Sensory functions lost in Dejerine-Klumpke palsy (Lower type plexus injuries)

A
  • Medial side of forearm, hand and 5th digit