The shoulder stands out as the body’s most flexible joint, offering an extensive range of motion. Comprising the humeral head and the shoulder blade, it serves as the vital connection between the arm and the torso.
As humans evolved from a four-legged to a bipedal gait, the positioning of the shoulder blade on the rib cage underwent a significant transformation. The migration of the shoulder blade, along with the entire upper extremity, shifted it backward and downward. This fundamental alteration in biomechanics greatly enhanced the joint’s range of motion. This controlled range of motion enables humans to execute precise and powerful movements with their upper limbs. It paved the way for activities such as crafting and accurately hurling tools like spears during hunting, achieving impressive levels of acceleration and precision.
This evolutionary development conferred a substantial advantage upon humans compared to other species. While primates like chimpanzees possess greater raw strength, they cannot match the precision and swiftness of human throwing abilities. This proficiency in hunting likely played a pivotal role in our ongoing evolution.
However, the remarkable mobility of the shoulder also renders it susceptible to wear, tear, and injury. In daily life, at work, and especially during sports, this potent yet vulnerable joint endures exceptionally high levels of strain.
The most common shoulder injuries are:
- Dislocation of the acromioclavicular joint (AC)
- Shoulder dislocation
- Collarbone fracture
- Humeral head fracture
- Torn long biceps tendon
- Tendon rupture
The most common degenerative conditions of the shoulder are:
- Calcium deposits (calcific tendinitis)
- Acute and chronic inflammation of the capsule (“frozen shoulder”)
- Tears in the rotator cuff
- Nerve compression syndrome
Range of treatments: The shoulder
- Rotator cuff
- Calcified shoulder
- Shoulder instability
- Biceps tendon tears
- Frozen shoulder
- AC joint