# What is the humerus?

The arm bone is called the humerus. Gray’s Anatomy (1918) describes it as follows: The humerus is the longest and largest bone of the upper extremity; it is divisible into a body and two extremities.

## What it means

- The humerus is the longest and largest bone of the upper extremity; it is divisible into a body and two extremities. Upper Extremity. —The upper extremity consists of a large rounded head joined to the body by a constricted portion called the neck, and two eminences, the greater and lesser tubercles. The Head ( caput humeri ). —The head, nearly hemispherical in form, 54 is directed upward, medialward, and a little backward, and articulates with the glenoid cavity of the scapula.
- The circumference of its articular surface is slightly constricted and is termed the anatomical neck, in contradistinction to a constriction below the tubercles called the surgical neck which is frequently the seat of fracture. Fracture of the anatomical neck rarely occurs.

## Sources

- [Gray's Anatomy of the Human Body (1918)](https://www.bartleby.com/lit-hub/anatomy-of-the-human-body/6a-3-the-humerus/)

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