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Anatomy, definition and function of the humerus.
Hey, everyone. It’s Matt from Kenhub! And in this tutorial, we will discuss the anatomy, definition, and function of the humerus.
The humerus is a long bone that connects the elbow to the shoulder blade. It provides a base of support for the muscles of the shoulder, the upper arm, and the lower arm.
You’ve probably heard people say that they hit their funny bone, and you’ve probably also heard people say, “Why is it called that?” and, “It hurts really bad, and it isn’t funny at all.” Well, it’s called that because what they hit is actually the humerus. So it’s a play on the word “humerous.”
Let’s discuss some of the anatomical features of the humerus. Here is the head of the humerus. The humeral head is projected medially and superiorly and articulates with the glenoid cavity of the scapula to form the glenohumeral joint (also known as the shoulder joint).
The next structure that we find on the humerus is the anatomical neck that you see now highlighted in green.
The anatomical neck is an area between the head and the greater and lesser tubercles of the humerus.
On these two images, you see two prominences known as the greater tubercle and lesser tubercle of the humerus. These areas serve as attachment points for some of the major muscles of your shoulder.
Now, we’re looking at another neck: the surgical neck of the humerus. This is a narrow area found distal to the tubercles that is a common site for fractures.
The surgical neck is in close contact with two other important structures: the axillary nerve and the posterior humeral circumflex artery.
You’re now seeing another structure highlighted known as the body of the humerus (often referred to as the shaft).
The picture here shows the lateral epicondyle of the humerus. This is a protuberance found lateral to the capitulum that gives attachment to the extensor muscles of the forearm.
And here, you now see the medial epicondyle of the humerus. This medial protuberance serves as an origin point for the flexor muscles of the forearm.
Switching from the posterior view to the anterior view, we see the capitulum of the humerus. This is a rounded projection found at the distal end of the humerus and articulates with the radius.
And last but not least, the trochlea of the humerus from the anterior view as well. The trochlea is an articular cylinder that connects with another bone known as the ulna.