Axilla: Ch 9

Question 1

limits of the axilla

Answer 1

• apex: junction of clavicle, scapula and first rib forming cervicoaxillary canal
• base: axillary fascia
• anterior wall: pectoralis major and minor muscles and clavipectoral fascia
• posterior wall: scapula with associated musculature (subscapularis, teres major and latissimus dorsi)
• medial wall: ribs 1-4/5 with associated intercostal musculature covered by the serratus anterior muscle
• lateral boundary: junction of the anterior and posterior axillary walls at the intertubercular groove

Question 2

generalized contents of axilla

Answer 2

1. axillary artery
2. axillary vein
3. cord/branches of brachial plexus
4. portions of biceps brachii and coracobrachialis
5. axillary lymph nodes
6. fat

NOTE: the axillary artery, vein and cords of the brachial plexus are surrounded by an extension of prevertebral cervical fascia known as the axillary sheath

Question 3

axillary artery

Answer 3

know how to draw this. do it now!

Question 4

supreme/ highest thoracic artery

Answer 4

• arises on inferior surface of axillary, courses downward to supply first and second anterior intercostal spaces (medial to pectoralis minor)

Question 5

thoracoacromial a.

Answer 5

(posterior to pectoralis minor)

• arises posterior to pec. minor and courses medially and pierces the costocoracoid membrane
• possesses a short trunk and typically divides into four branches (supply clavicular, acromial, deltoid, pectoral regions)

Question 6

lateral thoracic artery

Answer 6

(posterior to pec. minor)

• arises behind the pec. minor and courses inferiorly parallel to its lateral border
• provides branches to lateral intercostal spaces, serratus anterior, pec. major/minor and mamm glands.

Question 7

subscapular artery

Answer 7

• (lateral to pec minor)
• largest and most variable branch of axillary artery
• arises within the axilla from inferior surface of axillary artery where it runs a short course along the lateral border of the subscapularis muscle -
• divides into circumflex scapular artery and thoracodorsal artery

Question 8

circumflex scapular artery

Answer 8

• courses posteriorly through the trianfular space to participiate in the scapular anastomosis

Question 9

thoracodorsal artery

Answer 9

courses with the thoracodorsal nerve on the anteromedial surface of the lat. dorsi which it supples

Question 10

anterior circumflex humeral a.

Answer 10

• (lateral to pec. minor)
• arises from anterolateral surface of axillary artery in the region of the surgical neck around which it courses laterally to anastomose with its posterior counterpart
• always smaller than the posterior

Question 11

posterior circumflex humeral a.

Answer 11

(lateral to pec. minor)

• arises on anteromedial aspect of axillary a. at the surgical neck
• courses posteriorally with the axillary nerve through the quadrangular space to anastomose with its anterior counterpart (usually larger!)

Question 12

axillary vein

Answer 12

• accompanies axillary a. along entire length
• distally lies medial to axillary a; proximally lies anterior and inferior to axillary a.
• formed by union of basilic vein with brachial veins
• at superior border of pec minor the cephalic vein pierves the clavipectoral fascia to join the axillary v.
• as axillary v. crosses the lateral border of the first rib it becomes the subclavian v.

Question 13

superficial lymphatics

Answer 13

• drain subcutaneous structures
• drain from dorsum ventrally and from distal proximally (drain ventral to dorsal)
• end in axillary lypmh nodes

Question 14

deep lymphatics

Answer 14

• drain periosteum, joint capsules, tendons and some muscles
• collecting duct s of deep lymphatics parallel the course of major arteries and drain to lateral and central axiallary lymph nodes

Question 15

pathway of axillary lymph nodes

Answer 15

• pectoral, lateral and subscapular –> central node –> apical node –> subclavian lymph trunk –> rt. lymphatic duct or thoracic duct on left side