Humerus

Humerus: Latin = the arm-bone.

Human skeleton back

Humerus Front

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Humerus_(PSF)

The humerus holds a significant position in the anatomy of the human body. As part of the upper limb, it connects the scapula in the shoulder to the radius and ulna in the forearm. This article delves into the structure, function, and clinical relevance of this long bone.

Introduction

The humerus is the single bone of the upper arm, playing a vital role in the skeletal system. Its anatomy provides a foundation for various muscular and ligamentous attachments, making it pivotal for movements of the shoulder and elbow.

Anatomy of the Humerus

The humerus can be broken down into three primary sections:

• Proximal end: This end features the head of the humerus, which is a rounded structure fitting into the glenoid cavity of the scapula, forming the glenohumeral (shoulder) joint. Adjacent to the head are the greater and lesser tubercles, separated by the intertubercular sulcus.
• Shaft: The cylindrical portion of the bone, it has a rough surface with various ridges and grooves serving as attachment points for muscles and ligaments.
• Distal end: This region is more complex, showcasing the capitulum and trochlea. These are important for articulating with the radius and ulna, respectively, constituting the elbow joint.

Muscular Attachments

The humerus serves as an anchor for multiple muscles, which facilitate diverse movements:

• Deltoid muscle attaches to the deltoid tuberosity on the lateral side of the shaft.
• Pectoralis major attaches at the greater tubercle.
• Teres major and Latissimus dorsi are connected to the intertubercular sulcus.
• On the posterior side, the Triceps brachii finds its origin.

These muscular attachments enable a range of motions, including flexion, extension, abduction, adduction, internal rotation, and external rotation of the shoulder.

Clinical Relevance

Understanding the anatomy of the humerus is crucial for healthcare professionals, particularly orthopedic surgeons and physiotherapists, given its vulnerability to injuries:

• Dislocation of the humeral head from the glenoid cavity.
• Impingement syndromes resulting from repetitive overhead movements.
• Entrapment neuropathies, often stemming from pressure on the nearby nerves.

Fractures and Conditions

Given its position and structure, the humerus can be susceptible to various fractures:

Proximal humeral fractures: Often associated with osteoporosis and can be complicated given the numerous muscular attachments. Mid-shaft fractures: Commonly due to direct trauma. Distal humeral fractures: Less frequent but can disrupt elbow function. Additionally, conditions such as osteoarthritis can affect the humerus, particularly at its articulating joints.

Conclusion

The humerus, while just one bone in the vast human skeletal system, holds paramount importance for the functionality of the upper limb. Its intricate anatomy and its role in biomechanical movements underline its significance in both physiological understanding and clinical practices. For aspiring medical practitioners, a comprehensive grasp of the humerus is foundational.

Also see

• Gray's anatomy (Humerus)

Gray's Anatomy

• Gray's Anatomy Contents
• Gray's Anatomy Subject Index
• About Classic Gray's Anatomy
• Note to Contributors of Gray's Anatomy
• Glossary of anatomy terms

Anatomy atlases (external)

[1] - Anatomy Atlases

Humerus Resources
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Humerus Resources
Latest articles Most recent articles Ongoing trials	Wikipedia