Bones of the shoulder – a guide for artists
One of the best ways to understand complex things is to break them down into a collection of simple things. I always struggled with sculpting and drawing shoulders – without an understanding of what was going on below the muscles it was impossible to place the bony landmarks correctly, or recognise when I had missed the mark.
In this post I want to go over the bones of the shoulder: the clavicle, scapula and humerus, and look at how they fit together. In part II we will look at how they move together and hopefully demystify this tricky part of the body. (If you are familiar with these bones feel free to skip ahead to part II where we talk about joints and movements of the shoulder).
Bones
Still with me? Great!
Like I said; first we will have a look at the bones of the shoulder girdle. Once we get to know them, we will see how they move together.
The clavicle
The clavicular bones start in the pit of the neck where they articulate with the sternum (the bone on the front of the ribcage, not defined in the image).
When seen from the front the clavicle are almost straight, but from any other angle each clavicle looks like an elongated ‘S‘.
From above both clavicle together look like an archer’s bow, or an upside down coat hanger.
From the sternum the first 2/3rds of the clavicle are cylindrical. This will be important later, so I’m going to say it again: one end of the clavicle is cylindrical. The last 1/3rd of it flattens and widens to attach to the acromion process of the scapula. Don’t worry we will meet him next.
Scapula (shoulder blade)
The scapula is a flat, slightly concave, triangular bone that spends its time sliding over the ribs. It is about the same size as the dome at the back of the head, or about the same size and shape as a slightly cupped hand.
From above, its most prominent feature – seen here almost touching the clavicle – is the large flat protrusion known as the acromion process (it’s not made of chrome but if you imagine it being shiny it might help you remember the name).
We met him in the last section. As you can see, he articulates with the end of the clavicle. He also provides a bony landmark for the shoulder.
From the back, following from the acromion we can see a ridge that travels from one side of the scapula to the other (crest of the spine). It’s this ridge that gives us one of the main bony landmarks of the back and allows us to track the position and rotation of the scapula through the skin.
From the front we can see a finger-like projection called the coracoid process. We don’t need to worry about this fellow right now but in case you are curious he is the attachment point for some of the muscles in the arm (short head of the bicep and the coracobrachialis).
The slightly concave surface below him is the glenoid cavity (I just call him Glen). We do care about Glen; he is the socket part of the ball and socket joint of the arm.
Humerus
Which brings us to the humerus.
Looking at the humerus we can see how its domed head makes up the ball part of our ball and socket joint. There are tubercles and other interesting things on the humerus but for now all we need to know is, it’s got a roundy bit!
Great, now that we are familiar with the bones let’s have a look at how they work together in part II joints and movements of the shoulder.
References
Goldfinger, Elliot – Human Anatomy for Artists: The Elements of Form. Oxford University Press Inc (2011)
Hogarth, Burne – Dynamic Anatomy: Revised and Expanded Edition. Watson-Guptill Publications (2003)
Neumann, Donald A. – Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. Mosby Elsevier (2010) p.132-135
Netter, Frank H. – Atlas of Human Anatomy, Professional Edition. Elsevier (2018)
Zarins, Uldis – Anatomy For Sculptors: Understanding the Human Figure. Anatomy Next, Inc. (2014)
Dzian / 21 August 2021 7:34
Thank you so much! Aspiring storyboard artist here and your 3D animations are so helpful in visualizing the shoulders in motion!
pearse / 22 August 2021 2:50
Hey Dzian!
Thanks so much for your comment, it’s very rewarding to know people are finding the animations useful. Glad to be a part of your artistic journey.