Today I would like to chat with you about one of the most important landmark of our body: the Acromion (Scapula bone).
The acromion is a flat process of the scapula which extends laterally from the spine of the scapula over the shoulder joint. It articulates with the clavicle to form the acromioclavicular joint.
HOW CAN I RECOGNISE IT?
The shape of the acromion is very simple: it’s a rectangle located on top of the shoulder area. From the following images you can easily identify it - it doesn’t matter how muscular or skinny you are, this landmark is most of the time visible. Being able to read and to replicate this deformation into our digital rigs and models will really make the difference! From the following references, you can see how the acromion literally divide the medial deltoid (Acromial Part of the deltoid) and the trapezius (Transverse Part of the trapezius)
THE MOST COMMON ERROR: The most common error which can affect the quality of our animRig and MuscleRig is to not properly place the Acromion - this mistake will, as a consequence, put us on the wrong path during the placement of the shoulder joint (Most of the time lower than it should be) Understanding the shape of the scapula and the relative proximity of the Acromion to the skin will allow us to put the right fundamental for our muscles placement - keep in mind that 17 muscles are attached to the scapula! So we definitely need to get it right since the beginning. Let's analyze this x-ray, as you can see the acromion is quite close to the skin and the humerus (which connects to the frame of the body via the glenoid fossa of the scapula).
After you find the correct acromion position you will place more precisely the shoulder pivot joint. Have a look at this additional x-ray reference:
On the left, we have a standard shoulder x-ray and on the right, we have a dislocated shoulder x-ray. This two references are here just to show and prove how crucial is to start analyzing your model and properly place the scapula, it will become automatic overtime to put the shoulder in the right spot without dislocating your Rigs :) CONCLUSION: I hope this insight gave you enough explanations and examples that will allow you to properly identify and understand the importance of this landmark. I’m sure your digital sculpture, animRig, MuscleRig and even your shotSculpt can benefit from what you learned today! Develop your observation skills on daily basis will bring you to the next level! ROCK ON and keep up the good work!