Axillary Artery Function and Anatomy

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Questions and Answers

What is the main function of the axillary artery?

It provides the main blood supply to the upper limb.

Where does the axillary artery originate?

At the outer border of the first rib.

How many parts is the axillary artery divided into?

Three.

Which muscle is used to divide the axillary artery into three parts?

Pectoralis minor muscle. Signup and view all the answers

What does the first part of the axillary artery supply?

The superior thoracic artery. Signup and view all the answers

Which artery does the second part of the axillary artery supply?

Thoracoacromial artery. Signup and view all the answers

What does the lateral thoracic artery supply?

Lateral chest wall. Signup and view all the answers

What do the anterior and posterior circumflex humeral arteries supply?

Shoulder and upper arm. Signup and view all the answers

The arm is rarely completely ischemic due to a lack of anastomotic connections between branches of the subclavian and axillary arteries.

False Signup and view all the answers

What is the name of the anatomical space located in the posterior wall of the axilla?

Quadrangular Space Signup and view all the answers

What are the boundaries of the Quadrangular Space?

Superior: Inferior margin of the subscapularis muscle. Inferior: Superior margin of the teres major muscle. Medial & lateral: Margin of the long head of the triceps brachii muscle. Lateral: Surgical neck of the humerus. Signup and view all the answers

What structures pass through the Quadrangular Space?

The axillary nerve and the posterior circumflex humeral artery and vein. Signup and view all the answers

What is the name of the anatomical space found in the axilla, superior and inferior to the teres major muscle?

Triangular Interval Signup and view all the answers

What structures pass through the Triangular Interval?

The radial nerve and the profunda brachii artery. Signup and view all the answers

What is the axillary vein?

A large vein in the upper limb that drains blood from the arm, shoulder, and chest wall. Signup and view all the answers

Where does the axillary vein begin?

At the lower margin of the teres major muscle. Signup and view all the answers

What does the axillary vein become when it crosses the lateral border of the first rib?

The subclavian vein. Signup and view all the answers

What are the tributaries of the axillary vein?

The axillary vein receives tributaries corresponding to branches of the axillary artery. Signup and view all the answers

What is the basilic vein?

A superficial vein of the upper limb that drains blood from the posteromedial surface of the hand and forearm. Signup and view all the answers

What are the axillary lymph nodes?

A group of lymph nodes located in the axilla (armpit) that drains lymph from the upper limb, chest wall, and breast. Signup and view all the answers

What are the principal groups of axillary lymph nodes?

Pectoral (anterior) nodes, Subscapular (posterior) nodes, Humeral (lateral) nodes, Central nodes, and Apical nodes. Signup and view all the answers

Where are the pectoral (anterior) nodes located?

Along the medial wall of the axilla, inferior to the pectoralis minor muscle. Signup and view all the answers

What is the function of the pectoral (anterior) nodes?

To drain lymph from the anterior chest wall and breast. Signup and view all the answers

Where are the subscapular (posterior) nodes located?

Along the posterior axillary fold, near the subscapular vessels. Signup and view all the answers

What is the function of the subscapular (posterior) nodes?

To drain lymph from the posterior chest wall and scapular region. Signup and view all the answers

Where are the humeral (lateral) nodes located?

Along the lateral wall of the axilla, near the axillary vein. Signup and view all the answers

What is the function of the humeral (lateral) nodes?

To drain lymph from the upper limb, excluding the superficial lymphatic vessels. Signup and view all the answers

Where are the central nodes located?

Deep to the pectoralis minor muscle. Signup and view all the answers

What is the function of the central nodes?

To receive lymph from the pectoral, subscapular, and humeral nodes. Signup and view all the answers

Study Notes

Axillary Artery

Main Function: Provides the primary blood supply to the upper limb
Origin: Continuation of the subclavian artery, starting at the outer edge of the first rib
Division: Divided into three parts by the pectoralis minor muscle
- First Part (Proximal to Pectoralis Minor): Supplies the superior thoracic artery, which feeds the first and second intercostal spaces
- Second Part (Posterior to Pectoralis Minor): Supplies the thoracoacromial artery, branching to acromial, deltoid, pectoral, and clavicular branches, and the lateral thoracic artery (lateral chest wall)
- Third Part (Distal to Pectoralis Minor): Supplies the subscapular artery, branching into the circumflex scapular artery, thoracodorsal artery, and anterior and posterior circumflex humeral arteries (supply the shoulder and upper arm)

Ischemia Prevention in the Arm

Anastomoses: Connections exist between branches of the subclavian and axillary arteries
Network: These connections create a network around the scapula and upper humerus
Collateral Circulation: Even with artery damage, collateral blood flow ensures upper limb blood supply
Importance in Injuries: This network prevents ischemia (lack of blood flow), particularly critical in first rib fractures

Axillary Gaps (Posterior Wall)

Quadrangular Space: Bounded by superior/inferior margins of the subscapularis, teres major, and long head of the triceps brachii muscles.
- Structures passing through: axillary nerve, posterior circumflex humeral artery and vein
Triangular Interval: Bounded by superior/inferior margins of the teres major and long head of the triceps brachii muscles; lateral border by the humerus shaft -Structures passing through: radial nerve, profunda brachii artery

Axillary Vein

Origin: Begins at the lower edge of the teres major muscle
Continuation: Becomes the subclavian vein after crossing the lateral border of the first rib
Tributaries: Receives tributaries corresponding to branches of the axillary artery (e.g., cephalic vein, brachial veins)
Function: Drains blood from the arm, shoulder, chest wall, and breast

Axillary Lymph Nodes

Location: Grouped in the armpit (axilla)
Function: Drain lymph from the upper limb, chest wall, and breast
Principal Groups:
- Pectoral (Anterior): Along the medial wall, below the pectoralis minor; drains anterior chest wall and breast
- Subscapular (Posterior): Along the posterior axillary fold; drains posterior chest wall and scapular region
- Humeral (Lateral): Along the lateral wall, near the axillary vein; drains the upper limb (excluding superficial lymphatics)
- Central: Deep to the pectoralis minor, near the base of the axilla; receives lymph from the pectoral, subscapular, and humeral nodes
- Apical: At the apex of the axilla, near the first rib; receives lymph from the central nodes, draining into the subclavian lymphatic trunk

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Description

Explore the anatomy and function of the axillary artery, which is crucial for supplying blood to the upper limb. Understand its origin, divisions, and the significance of anastomoses in preventing ischemia in the arm.