Put your head on my shoulder…ow. Sound familiar? I want to take you on a journey of the shoulder and see what is inside and what can go wrong.
First we will have to look at the anatomy to better understand what is happening with the bones, ligaments, tendons, and cartilage.
First we can see the scapula or wing blade is a wide broad bone with a lot of space for muscle attachments. The ball and socket itself is a shallow cup that is not constrained at all and which relies on ligaments to hold it in place versus a rigid bony surrounding.
The acromion is above the humerus and can be a source of impingement where it can dig into the muscles of the rotator cuff which lie below it. This can occur after age 40 and is rare before that. The clavicle forms a joint with the acromion which can give weightlifters problems. It can sometimes break down and sometimes have arthritis in it. Arthritis is when the joint cushion wears down over time.
Ligaments hold the bones together. The clavicle has several ligament that keep it place and the glenohumeral joint or shoulder joint also has ligaments that make up the capsule. If the ligaments tear then the shoulder can become loose or unstable resulting in a dislocation.
The muscles of the shoulder attach to the bones with tendons which are a gritty material at the end of the muscle. The tendons actually grow into the bone and are subject to tearing in life as wear and tear accumulates. This is what happens with a rotator cuff tear. Each muscle around the shoulder is responsible for certain motions like elevation to the side or rotating in and out. Other muscle like biceps and triceps are responsible for moving the elbow and forearm in space.
The labrum is a fibrocartilaginous structure that acts as a shock absorber cushion for the joint. It can act as a suction cup like device holding the humeral head or ball in place. It acts as a stabilizer because the ligaments attach to the labrum which then attaches to the glenoid or cup. It can tear more easily as an athlete gets older and the tissue dehydrates compared to softer more spongy tissue that is seen into adolescence and early adulthood