Axilla

Question 1

Axilla

Answer 1

• tetrahedral shaped space at junction of upper limb and thorax
• boundaries provide passage way for nerves from neck and vessels from thorax to enter upper limb

Question 2

Boundaries of axilla

Answer 2

• Apex= junction of clavicle, scapula, and 1st rib (cervicoaxillary canal)
• Base= axillary fascia
• Anterior wall= pect. major and pect. minor and clavipectoral fascia
• Posterior wall= scapula with subscapularis, teres major and lat. dorsi
• Medial wall= ribs 1-4 (5) with intercostal muscles covered by serratus anterior muscle
• Lateral boundary= junction of anterior and posterior axillary wall at inter tubercular groove

Question 3

Contents of axilla

Answer 3

1. axillary artery and branches
2. axillary vein and tributaries
3. cords and branches of brachial plexus
4. proximal long and short heads of biceps brachii and coracobrachialis muscles
5. axillary lymph nodes
6. fat
   Notes: axillary artery and veins, and cord of brachial plexus surrounded by axillary sheath (extension of prevertebral cervical fascia)

Question 4

Axillary artery

Answer 4

• continuation of subclavian artery lateral to lateral border of 1st rib
• becomes brachial artery distal to inferior border of trees major
• divided into 3 areas

Question 5

1st area of axillary artery

Answer 5

• 1 branch: supreme (highest) thoracic artery
• arises from inferior surface of axillary artery
• courses downward
• supplies 1st and 2nd anterior intercostal space

Question 6

2nd area of axillary artery

Answer 6

-2 branches

1. Thoracoacromial Artery
2. Lateral Thoracic Artery

Question 7

3rd area of axillary artery

Answer 7

• 3 branches

1. Subscapular artery
2. Anterior Circumflex humeral artery
3. posterior Circumflex humeral artery

Question 8

Thoracoacromial Artery

Answer 8

-arises posterior to pectoralis minor
- courses medially and pierces costocoracoid membrane
- short trunk and divides into 4 branches:
acromial branch
clavicular branch
deltoid branch
pectoral branch

Question 9

Lateral Thoracic Artery

Answer 9

• arises behind pectoralis minor and courses inferior parallel to lateral border
• provides branches to lateral intercostal spaces, serratus anterior, pectoralis major, pectoralis minor, mammary gland

Question 10

Supreme (highest) Thoracic Artery

Answer 10

• arises from inferior surface of axillary artery
• courses downward
• supplies 1st and 2nd anterior intercostal space

Question 11

Subscapular artery

Answer 11

• largest and most variable branch
• arises within the axilla from inferior surface of axillary artery and runs along lateral border of subscapularis muscle
• divides into:

1. Circumflex Scapular artery- courses posteriorly through triangular space; participates in scapular anastomosis
2. Thoracodorsal artery- courses with thoracodorsel nerve on anteomedial surface of latissimus dorsi (supplies this)

Question 12

Anterior Circumflex Humeral Artery

Answer 12

• arises from anterolateral surface of axillary artery in region of surgical neck
• courses laterally around neck and anastomose with posterior counterpart

Question 13

Posterior Circumflex Humeral Artery

Answer 13

• arise anteromedial aspect of axillary artery at surgical neck
• courses posterior with axillary nerve through quadrangle space to anastomose with anterior counterpart

Question 14

Axillary Vein

Answer 14

• runs with axillary artery
• distal: medial to axillary artery
• proximal: anterior and somewhat inferior to axillary artery
• formed from union of basilic and brachial veins
• tributaries named for branches of axillary artery that they parallel
• cephalic vein pierces clavipectoral fasci and joins axillary vein at superior border of pectoralis minor
• becomes subclavian when cross lateral border of 1st rib

Question 15

Superficial lymphatics of upper limb

Answer 15

• drains subcutaneous structures
• hand: drains from palmar surface dorsally and from distal proximally
• lymphatic collecting ducts follow course of major superficial veins (mostly- basilic vein)
• ends at lateral group of axillary lymph nodes
• lateral collecting ducts follow course of cephalic vein to end in apical group of axillary lymph nodes

Question 16

Deep lymphatics of upper limb

Answer 16

• drain periosteum, joint capsules, tendons, and some muscle
• collecting ducts of deep lymphatics parallel course of major arteries and drain lateral and central axillary lymph nodes

(Note: small lymph nodes can be found scattered on upper limb in superficial and deep areas along path of major vessels)

Question 17

Axillary lymph nodes

Answer 17

• 20-30 in number
• 5 groups of nodes: (infraclavicular)
  1. pectoral
  2. lateral
  3. subscapular
  4. central
  5. apical
• clinical: remove nodes- impair lymphatic drainage- limb swells (usually happens with radical great removal)

Question 18

Pectoral lymph nodes

Answer 18

• located along the lateral edge of the pectoralis minor deep to pectoralis major

Question 19

Lateral lymph nodes

Answer 19

• located along medial border of the humerus

Question 20

Subscapular lymph nodes

Answer 20

• located at junction of the trees major with latissimus dorsi

Question 21

Central lymph nodes

Answer 21

• located anterior to the tendon of the subscapularis deep to the pectoralis minor

Question 22

Apical lymph nodes

Answer 22

• located close to the cervico-axillary call superior to pectoralis minor

Question 23

lymph flow on right side of body

Answer 23

• efferent channels of apical lymph nodes drain- subclavian lymphatic trunk- right lymphatic duct- right jugulovenous angle
• right limb and right upper thorax

Question 24

lymph flow on left side of body

Answer 24

-subclavian lymph trunk drains into thoracic duct

drain rest of body not included in right lymph flow