Label The Arteries Of The Upper Limb

Labeling the Arteries of the Upper Limb: A Comprehensive Guide

The arterial supply of the upper limb is a complex network crucial for delivering oxygenated blood to the muscles, bones, and tissues of the arm, forearm, and hand. Understanding this intricate system is essential for medical professionals, students, and anyone interested in human anatomy. This comprehensive guide will navigate you through the arteries of the upper limb, providing detailed descriptions and aiding in accurate labeling. We'll explore their origins, branching patterns, and clinical significance.

The Subclavian Artery: The Starting Point

The journey begins with the subclavian artery, which is different on the right and left sides. The right subclavian artery originates from the brachiocephalic trunk, while the left subclavian artery branches directly from the aortic arch. Both arteries pass superior to the first rib, transitioning into the axillary artery at the lateral border of the first rib.

Branches of the Subclavian Artery:

Before becoming the axillary artery, the subclavian artery gives off several significant branches:

Vertebral artery: A crucial artery supplying the brain and spinal cord. It ascends through the transverse foramina of the cervical vertebrae.
Internal thoracic artery (internal mammary artery): Supplies the anterior chest wall, including the pericardium and diaphragm.
Thyrocervical trunk: This short trunk further branches into the inferior thyroid artery (supplies the thyroid gland), suprascapular artery (supplies the scapula), and transverse cervical artery (supplies the muscles of the neck and scapula).
Dorsal scapular artery: Supplies muscles of the scapula, often arising directly from the subclavian artery or the thyrocervical trunk.

The Axillary Artery: A Key Artery of the Shoulder

The axillary artery, a continuation of the subclavian artery, courses through the axilla (armpit). It's divided into three parts based on its relationship to the pectoralis minor muscle:

Part 1 (First Part): Lies medial to the pectoralis minor. Its only branch is the superior thoracic artery, which supplies the upper pectoral muscles and nearby structures.
Part 2 (Second Part): Lies posterior to the pectoralis minor. It gives rise to two significant branches: the thoracoacromial artery (supplies the pectoral muscles, deltoid, and acromion) and the lateral thoracic artery (supplies the serratus anterior muscle and breast tissue).
Part 3 (Third Part): Lies lateral to the pectoralis minor. This part gives rise to the subscapular artery, the largest branch of the axillary artery. The subscapular artery further branches into the circumflex scapular artery (supplies the posterior scapula) and the thoracodorsal artery (supplies the latissimus dorsi muscle). Additionally, the posterior humeral circumflex artery and the anterior humeral circumflex artery arise from Part 3, supplying the head of the humerus and the surrounding muscles.

The Brachial Artery: The Major Artery of the Arm

The brachial artery is a direct continuation of the axillary artery, beginning at the inferior border of the teres major muscle. It runs along the medial aspect of the arm, deep to the biceps brachii muscle. The brachial artery is clinically significant as a common site for obtaining blood pressure measurements and arterial blood gas samples.

Branches of the Brachial Artery:

The brachial artery has several branches, including:

Deep brachial artery (profunda brachii artery): A significant artery accompanying the radial nerve in the posterior compartment of the arm. It supplies the posterior muscles of the arm and contributes to the anastomoses around the elbow.
Superior ulnar collateral artery: Supplies the muscles around the elbow joint.
Inferior ulnar collateral artery: Also contributes to the blood supply around the elbow joint.
Nutrient artery of the humerus: Supplies the bone marrow and inner layers of the humerus.

The Radial and Ulnar Arteries: Arteries of the Forearm

At the distal end of the humerus, near the elbow joint, the brachial artery bifurcates into the radial artery and the ulnar artery. These two arteries form an extensive network of anastomoses in the forearm and hand, ensuring collateral circulation even if one artery is compromised.

Radial Artery:

The radial artery is located on the lateral side of the forearm. It's easily palpable at the wrist, making it a convenient site for assessing the pulse. Its branches include:

Radial recurrent artery: Supplies the muscles around the elbow joint.
Superficial palmar arch: A significant contributor to the blood supply of the hand.
Deep palmar arch: Contributes significantly to the hand’s blood supply, often connecting with the deep branch of the ulnar artery.

Ulnar Artery:

The ulnar artery, located on the medial side of the forearm, is also a major artery. Its branches include:

Common interosseous artery: Divides into the anterior and posterior interosseous arteries, supplying the deep muscles of the forearm.
Anterior ulnar recurrent artery: Supplies the muscles around the elbow joint.
Posterior ulnar recurrent artery: Also supplies the muscles around the elbow joint.
Deep palmar arch: Contributes to the hand’s blood supply, frequently anastomosing with the radial artery's deep branch.
Superficial palmar arch: Contributes to the hand's blood supply, commonly arising from the ulnar artery's superficial branch.

Arterial Supply of the Hand: The Palmar Arches

The intricate network of arteries in the hand is crucial for its fine motor functions and sensitivity. The arterial supply of the hand is primarily derived from the deep and superficial palmar arches.

Superficial Palmar Arch:

Primarily formed by the ulnar artery, with a contribution from the superficial palmar branch of the radial artery, the superficial palmar arch gives rise to the common palmar digital arteries, which further divide into proper palmar digital arteries supplying the fingers.

Deep Palmar Arch:

The deep palmar arch, primarily formed by the deep branch of the radial artery with a contribution from the deep palmar branch of the ulnar artery, runs deep to the superficial palmar arch. This arch supplies the thenar muscles and contributes to the blood supply of the fingers.

Clinical Significance: Conditions Affecting the Upper Limb Arteries

Understanding the anatomy of the upper limb arteries is crucial for diagnosing and managing various clinical conditions. These include:

Thoracic Outlet Syndrome: Compression of the neurovascular bundle (including the subclavian artery) in the thoracic outlet can lead to pain, numbness, and weakness in the arm and hand.
Aneurysms: Abnormal dilations in the arteries can occur anywhere in the upper limb, potentially leading to rupture and significant bleeding.
Emboli: Blood clots can travel from other parts of the body and lodge in the arteries of the upper limb, causing ischemia (reduced blood flow) and potentially limb-threatening complications.
Raynaud's phenomenon: This condition causes episodic vasospasm in the arteries of the fingers and toes, leading to discoloration and pain.
Trauma: Injuries to the upper limb can damage arteries, requiring prompt surgical repair.

Conclusion: Mastering the Arterial Network

The arterial supply of the upper limb is a complex yet fascinating network essential for the proper function of the arm, forearm, and hand. This detailed guide offers a comprehensive overview, enabling better understanding and accurate labeling of the arteries. Mastering this knowledge is invaluable for healthcare professionals and anyone interested in human anatomy, paving the way for improved patient care and a deeper appreciation of the human body's intricate vascular system. Remember to always consult reliable anatomical resources for further study and detailed visualization. Continued study and practice will refine your ability to identify and label these vital arteries accurately. The detailed understanding of this network opens the door to a deeper understanding of the complex interplay between structure and function within the human body.