BREAST

Question 1

WALLS OF THE AXILLA

Answer 1

• Anterior wall: pec. major, pec. minor and subclavius muscles.
• Posterior wall: subscapularis, lat. dorsi and teres major muscles.
• Medial wall: upper 4–5 ribs and intercostal muscles covered by serratus anterior.
• Lateral wall: bicipital groove of the humerus.
• Superiorly: outer border of first rib, superior border of scapula, and posterior border of clavicle

Question 2

tell us about the axillary artery.

Answer 2

Begins at the lateral border of the first rib as a continuation of the subclavian artery and ends at the lower border of teres major — it is divided into three parts by pec. minor:

The axillary artery:

• first part lies proximal to pec. minor and gives off one branch
  1. the superior thoracic artery
• second part lies behind the pec. minor and gives off two branches:

1. thoracoacromial trunk (clavicular, humeral, acromial, and pectoral branches)
2. lateral thoracic artery

• third part lies between the lateral border of pec. minor and medial border of teres major. It gives off three branches:

1. the subscapular artery;
2. anterior circumflex humeral artery
3. posterior circumflex humeral artery.

Question 3

What are the consequences of damaging

(i) long thoracic nerve
(ii) thoracodorsal nerve
(iii) intercostobrachial nerve

Answer 3

(i) long thoracic nerve (arises from C5-7)- winging of the scapula
(ii) thoracodorsal nerve (posterior cord of brachial plexus) - weak ADDUCTION of shoulder
(iii) intercostobrachial nerve - paraesthesia on the posteriolateral aspect of the upper arm. It is a cutaneous branch from the 2nd intercostal nerve.

Question 4

How can you identify

(i) long thoracic nerve
(ii) thoracodorsal nerve

Answer 4

(i) long thoracic nerve

• identify it high in the proximal axilla
• lies superficial to serratus anterior fascia
• at level of 4th/5th intercostal space pierces fascia to lie superficial to serratus anterior

(ii) thoracodorsal nerve

• Forms a triangle bounded by thoracodorsal nerve medially, axillary vein superiorly and subscapular vessels laterally.
• Need to identify lateral thoracic vein as 1 cm deep and inferior to this lies the thoracodorsal bundle.

Question 5

how can the axillary vein be reliably identified?

Answer 5

three main techniques can be employed to identify it.

Retrograde dissection

• identification of the angular veins draining into the thoracodorsal vein.
• The thoracodorsal vein is then followed cranially until it enters into the axillary vein.

Axillary artery

• Palpation of the axillary artery at the apex of the axilla can help locate the axillary vein.
• The vein lies anterior to the artery and posterior to the junction of the clavicle and first rib.

Pec. minor muscle

• Retraction/transaction of the pec. minor muscle will allow identification of the vein which is located posterior to the medial edge to the muscle.

Question 6

What is the clavipectoral fascia?

Answer 6

• arises from the clavicle
• encloses subclavius and pectoralis minor muscles
• lies anterior to neurovascular structures in the axilla
• pierced by lateral pectoral nerve

Question 7

What are the lymph node groups in the axilla?

Answer 7

“APICAL”

• Anterior (pectoral)
• Posterior (subscapular)
• Infraclavicular
• Apical
• Lateral

Question 8

What is the blood supply to the breast?

Answer 8

MAJOR

• perforating branches of internal thoracic (aka internal mammary)
• lateral mammary branches of lateral thoracic
• pectoral branches of thoracoacromial

MINOR

• subscapular
• intercostal (lateral) perforating

Question 9

What are the nerve roots for

long thoracic

thoracodorsal

Answer 9

thoracodorsl nerve

C 6,7,8

Long thoracic

C 567