Posterior humeral circumflex artery

Posterior Humeral Circumflex Artery

The posterior humeral circumflex artery (PHCA) is a branch of the axillary artery, which is a major blood vessel located in the upper arm. The PHCA plays a crucial role in the blood supply to the shoulder joint and surrounding muscles. In this article, we will explore the anatomy, function, and clinical significance of the posterior humeral circumflex artery.

Anatomy

The posterior humeral circumflex artery arises from the third part of the axillary artery, which is the segment between the lower border of the pectoralis minor muscle and the lower border of the teres major muscle. It usually originates from the axillary artery along with the anterior humeral circumflex artery, forming a common trunk known as the circumflex humeral artery.

After its origin, the PHCA courses posteriorly around the surgical neck of the humerus, which is the narrow part of the bone just below the head of the humerus. It then divides into two main branches: the ascending branch and the descending branch.

The ascending branch of the posterior humeral circumflex artery runs superiorly along the posterior aspect of the surgical neck of the humerus. It gives off multiple small branches that supply the deltoid muscle, which is the main muscle responsible for shoulder abduction. These branches also provide blood to the teres major muscle and the long head of the triceps brachii muscle.

The descending branch of the PHCA descends inferiorly along the posterior aspect of the surgical neck of the humerus. It gives off branches that supply the teres minor muscle, which is one of the rotator cuff muscles involved in shoulder stabilization. Additionally, it provides blood to the posterior part of the shoulder joint capsule.

Function

The posterior humeral circumflex artery plays a crucial role in the blood supply to the shoulder joint and surrounding muscles. It provides oxygenated blood to the deltoid muscle, teres major muscle, teres minor muscle, and the long head of the triceps brachii muscle.

The blood supply from the PHCA is essential for the proper functioning of these muscles. The deltoid muscle, for example, is responsible for shoulder abduction, which is the movement of the arm away from the body. Without an adequate blood supply, these muscles may not receive enough oxygen and nutrients, leading to muscle weakness and dysfunction.

Furthermore, the posterior humeral circumflex artery supplies the posterior part of the shoulder joint capsule. This ensures that the joint receives sufficient blood flow, which is crucial for maintaining its health and integrity.

Clinical Significance

Injuries or abnormalities affecting the posterior humeral circumflex artery can have significant clinical implications. For example, a blockage or occlusion of the PHCA can lead to ischemia (lack of blood supply) in the muscles it supplies. This can result in muscle weakness, pain, and limited range of motion in the shoulder joint.

In some cases, the PHCA may be injured during surgical procedures involving the shoulder joint or the surrounding structures. Surgeons must be cautious to avoid damaging this artery to prevent complications such as excessive bleeding or compromised blood supply to the muscles and joint.

Understanding the anatomy and function of the posterior humeral circumflex artery is crucial for healthcare professionals involved in the diagnosis and treatment of shoulder-related conditions. It allows them to assess the blood supply to the shoulder joint and muscles, aiding in the management of various shoulder pathologies.

References

1. Standring, S. (Ed.). (2016). Gray's anatomy: the anatomical basis of clinical practice. Elsevier Health Sciences.

2. Drake, R. L., Vogl, W., & Mitchell, A. W. M. (2014). Gray's anatomy for students. Elsevier Health Sciences.

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