The shoulder is a pretty complicated bit of anatomy – so much so it’s often referred to as the shoulder complex! Not just the ball and socket joint of the upper arm; we also have to think about the collar bone and shoulder blade, which come together to form the socket part of the ball and socket joint.

Collar Bone

This part is called the clavicle in proper anatomical terms. The inner part of the collar bone attaches to the breast bone, and the outer part attaches to the acromial process of the shoulder blade – here it is lashed down with strong ligaments to form the roof of the socket of our shoulders.

Our collar bones help our shoulder orientate with the front of our bodies, and hold our shoulders wide, stopping them rolling forward too far.

Shoulder Blade

The scapula is a very thin bone, so thin it is almost translucent if you were to see one by itself – which is why you won’t see many complete ones in museum exhibitions! The shoulder blade is an important place for powerful muscles of the back, chest, neck and arm to tether, so they can control your shoulder movements.

It’s movement across your back is really important for stabilising the arm in exercise where you bear weight in your arms, and also very important for gaining power in sports where you need to throw or hit.

The movement pattern of the shoulder blade is easily disrupted by pain or injury, and often needs specific rehab to get right again – it’s the cause of a lot of ongoing problems we see in clinic.

Humerus

…Or upper arm bone. The socket of the ball and socket in the shoulder isn’t very deep, so in addition to our ligaments, we need a bit of extra help to keep our arms from dislocating! That’s where the rotator cuff muscles come in. These muscles are talked about a lot, and are responsible for quite a few shoulder and arm pains. They have a very important job in terms of stabilisation, but also mobilisation – allowing our shoulders a massive range of motion. It’s in this job-sharing that they often find problems!