AXILLA

 AXILLA

 Synonymous :armpit

• Pyramidal  in shape

• Between the upper part of the arm and lateral thoracic wall

Boundaries  of axilla

Apex

Base 

4 wall( anterior ,posterior, medial and lateral )

Apex:

⁃ Facing towards the neck

⁃ Known as cervix -axillary canal

⁃ Binded in front by the clavicle , behind by the scapula and medially by the 1st rib

⁃ Axillary vessels , brachial plexus , long thoracic nerve and subclavian lymph trunk passes through this

Base:

⁃ Directed below and bounded by anterior axillary fold in front , posterior axillary fold behind and medially by the thoracic wall.

⁃ Formed by the axillary fascia.

• Anterior axillary fold : lower border of pectoralis  major

• Posterior axillary fold: lower border of latissimus dorsi in  the medial part and teres major in lateral part

CONTENT OF AXILLA

• Axillary artery and its branches 

• Axillary veins and its tributaries

• Brachial plexus cords and its branches 

• Axillary lymph nodes 

• Axillary pad of fat and occasionally

• Axillary tail of breast 

AXILLARY ARTERY 

• Begins as the continuations  of subclavian artery at the outer border of first rib

• Ends by continuing as brachial artery at the lower border of teres major muscle

• Along its it is divided by pectoralis minor muscle into three parts

Branches:

1st part   : 1. Superior thoracic artery

2nd part : 1. Thoraco- acromial artery 

                  2. lateral thoracic artery

3rd part : 1. Subscapular artery 

                 2. anterior circumflex humoural artery

                 3. posterior circumflex humoural artery

AXILLARY VEIN: 

• Continuation of basilic vein at the lower border of teres major 

• Ends and the outer border of first rib  continuing as subclavian vein

• Tributaries: cephalic vein  and the Veinus which corresponds  with the branches of axillary artery

APPLIED ANATOMY OF AXILLARY VESSELS:

• Part of the vein in front of the first part of axillary artery may get compressed by the subclavius muscles during abduction, which may effect for axillary vein thrombosis when the arm is held in prolonged abduction above the head during painting of ceiling 

AXILLARY LYMPH NODES 

• About 20 to 30 in number, 

• drain the lymphatic from ,

1. upper limb

2. Most of the mammary gland

3. cutaneous lymphatic from the trunk above the level of umbilicus.

• Divided into five groups

1. Anterior 

2. posterior 

3. lateral 

4. central 

5. epical

Anterior group

⁃ Lie along lateral thoracic vein at the lower border of pectoralis minor

⁃ Drain most of the lymphatic from the breast

⁃ In contact with the axillary Tail of Spence

Posterior group:

⁃ Lie along the subscapular vessels in posterior wall of axilla

⁃ Receives lymphatics from the trunks as far as the iliac crest