Axilla and Pectoral Region

Question 1

Arterial supply of breast tissue

Answer 1

-Mammary branches from anterior intercostal thoracic, lateral thoracic, and internal thoracic arteries

Question 2

Venous drainage of breast tissue

Answer 2

• To axillary vein via lateral thoracic veins and medial mammary veins
• Some to internal thoracic vein via anterior intercostal vein

Question 3

Innervation of breast tissue

Answer 3

• Mainly anterior and lateral branches of the 4th-6th intercostal nerves
• Some from supraclavicular nerve branches as well as branches of other intercostal nerves

Question 4

Superficial fascia

Answer 4

• Platysma

- Innervated by the supraclavicular nerves (platysma) and anterior and lateral branches of intercostal nerves

Question 5

Deltopectoral (clavipectoral) triangle

Answer 5

• Borders formed from the deltoid, pectoralis major, middle 1/3 of clavicle
• Contains cephalic vein, deltopectoral lymph nodes, and deltoid branch of thoracoacromial artery (from axillary artery)

Question 6

Clavipectoral fascia

Answer 6

• Invests subclavius and pectoralis minor
• Attaches to clavicle and anterior thoracic wall
• Cephalic vein, thoracoacromial artery, and lateral pectoral nerves pierce it
• Becomes suspensory ligament of axilla

Question 7

Pectoralis major

Answer 7

• Action: Adducts and medially rotates humerus, draws scapula anteriorly and inferiorly (via clavicle); clavicular portion flexes humerus, sternal portion can extend humerus while it is in this flexed position
• Blood supply: Pectoral branches of thoracoacromial arterial trunk
• Innervation: Lateral and medial pectoral nerves (C5, C6 clavicular portion, C7, C8, T1 sternocostal portion)

Question 8

Pectoralis minor

Answer 8

• Action: Stabilizes scapula by pulling it anteriorly and inferiorly and inferiorly against posterior thoracic wall
• Blood supply: Pectoral branches of thoracoacromial arterial trunk
• Innervation: Medial pectoral nerve (C8, T1) it is usually pierced by this nerve

Question 9

Subclavius

Answer 9

• Action: Anchor and depress clavicle
• Blood supply: Clavicular branches pf thoracoacromial arterial trunk
• Innervation: “Nerve to subclavius” (C5, C6)

Question 10

Serratus anterior

Answer 10

• Action: Protracts scapula, rotates scapula, holds scapula against thorax
• Blood supply: Lateral thoracic artery
• Innervation: Long thoracic nerve (C5, C6, C7)

Question 11

Boundaries of the Axilla: Base

Answer 11

• Skin and superficial fascia
• Anterior axillary fold (pectoralis major)
• Posterior axillary fold (latissimus dorsi, teres major)
• Chest wall (serratus anterior)

Question 12

Boundaries of the Axilla: Anterior Wall

Answer 12

• Clavicle
• Subclavius
• Pectoralis major
• Pectoralis minor

Question 13

Boundaries of the Axilla: Posterior Wall

Answer 13

• Scapula
• Subscapularis
• Latissimus dorsi
• Teres major

Question 14

Boundaries of the Axilla: Lateral Structures

Answer 14

• Intertubercular sulcus (bicipital groove)
• Tendon of long head of biceps
• Coracobrachialis tendon

Question 15

Contents of the Axilla

Answer 15

-Axillary vein, axillary artery, brachial plexus (axillary sheath)