Anatomy of the Shoulder

Anatomy of the Shoulder

The shoulder comprises two different joints, making it very flexible and giving it a wide range of motion. Unfortunately, it is also one of the most commonly injured areas of the body. It’s also essential for everyday functions, which can make it difficult to heal when injured. The shoulder is also complex as it has many moving parts. Sometimes it can be difficult to diagnose what exactly might be causing pain or stiffness in the shoulder due to its complexity. 

Anatomy of the Shoulder Overview

There are three main parts of the shoulder: the bones, the muscles, and the other tissues. Each part works together to create a smooth range of motion and functionality. 

Shoulder Bones

The bone structure of the shoulder connects the upper arm to the torso. The bones of the shoulder are the humerus (upper arm), the clavicle or collarbone, and the scapula, which is also called the shoulder blade. The humerus and scapula connect at the glenohumeral joint, which is a ball-and-socket joint. This is the most flexible joint in the body, which is why it allows you to do so many different things. This is similar to the hip joint and makes it possible for the arm to move in many different directions. The acromioclavicular joint connects the clavicle to the shoulder blade, and it allows flexing of the shoulder, so it isn’t as flexible. There are many conditions that can affect the shoulder bones including fractures or breaks, dislocation, and arthritis. 

Shoulder Muscles

In the anatomy of the shoulder, there are three main shoulder muscles and almost 20 smaller ones. The main muscles are the trapezius muscle, the deltoid, and the pectoralis major. The trapezius muscle stretches from your neck down across your collarbone to the shoulder joint. It helps hold up your arm and supports your neck. This muscle is very wide and is the closest to the skin, and it controls the movements of the shoulder blade. The deltoid muscle covers the top of your shoulder joint and attaches to the arm bone. This muscle mostly controls arm rotation and has a distinct triangular shape. The pectoralis major is the large muscle on the front of the shoulder which stretches down to the center of the chest. Its main function is to move the arm forward and help with load bearing. The shoulder muscles can be injured through tears or breaks during exercise or other strenuous activities, which is the most common shoulder injury. 

Shoulder Tendons and Ligaments

The anatomy of the shoulder has many tendons and ligaments that hold the joints and muscles together. Because the shoulder is so complex and strong and functional, the tendons and ligaments can strain easily. Tendons connect muscles to bones, and ligaments connect bones to other bones. This means that when other injuries occur to the muscles and bones, tendons or ligaments are often injured as well. Without the tendons and ligaments, the shoulder wouldn’t be able to function properly. Avoiding injury to these connective tissues is as simple as avoiding hyperextending or straining the shoulder, or overworking it. Shoulder injuries can be difficult and even incapacitating. 

Common Shoulder Injuries

Due to the complex anatomy of the shoulder, the most common injuries to the shoulder happen most frequently doing everyday, normal activities. Some people put too much strain on their shoulders by overworking them or by doing something repetitive for too long. Athletes often cause shoulder injuries for this reason. Dislocation is also a common shoulder injury, where the glenohumeral joint pops out of its socket. This can be very painful, but it can be fixed by a doctor relatively quickly. Most of the time, the patient will not need corrective surgery. Impingement and stiffness can also occur in the shoulder where movement is impeded, meaning you may be unable to lift or move your arm in a certain way due to something not moving correctly in the shoulder. While there are many ways to injure the shoulders, there are many treatments available to help people get back to normal functionality and capability. 

Shoulder Treatment 

If you feel that you may need your shoulder examined, or you want to better understand the anatomy of the shoulder, make an appointment at your earliest convenience. Many shoulder injuries can be treated and helped, and most of them tend to worsen if left alone. Come see our team at Orthopaedic Associates of Riverdale, and we can determine which part of your shoulder may be affected and help you get appropriate treatment and care.