Shoulder Anatomy

Dr. Michael Cusick and his team specialize in orthopedic treatment, and they are well aware of the shoulder anatomy. If you have any questions, they will be more than happy to enlighten you on the subject. You can even visit our knowledgeable experts when you are having shoulder problems. Make your way to Michael C. Cusick, M.D., for exceptional orthopedic care!

Anatomy of Your Shoulder: What Makes Up the Complex Joint?

The shoulder is a highly mobile and flexible joint with fascinating, intricate details. The bones, muscles, ligaments, tendons, nerves, veins, and other parts of your shoulder come together to help it function. When the structure of your shoulder works together, you can perform many feats, tasks, and activities. Your shoulder’s anatomy has the following key components:

Bones

Your shoulder contains three bones called the humerus, scapula, and clavicle. The main joint of your shoulder, also known as the glenohumeral joint, is composed of the humerus and scapula. Here is some insight on your shoulder bones:

• Humerus: Your upper arm bone connects the shoulder to the elbow, and it is known as the humerus. It forms the ball of your shoulder joint and is the longest bone of the upper limb.
• Scapula: Then we have your scapula, which is a flat bone in a triangular shape. Your scapula is the bone that forms the shoulder blade. Most of the muscles that provide movement and stability to your joints are attached to this bone.
• Clavicle: Your collarbone, also called clavicle, is an S-shaped bone. Your scapula connects to the breastbone thanks to the clavicle. The clavicle bone is also responsible for forming two joints: the acromioclavicular joint and the sternoclavicular joint.

Soft Tissues

Your shoulder has an unbelievable amount of soft tissue, which includes the joint capsules, ligaments, bursae, tendons, and muscles. Since your shoulder complex is flexible, it requires the coordination of both static and dynamic stabilizers. They work in synchrony to make sure your shoulder’s stability is not compromised.

Our shoulder specialist understands the complex interplay between your static and dynamic components, which helps us assess and manage shoulder conditions in an effective manner.

Ligaments

Your body contains thick stands of fiber that are responsible for connecting bones to one another. Thanks to ligaments, the shoulder bones stay in place. Your shoulder ligaments include:

• Coracoclavicular Ligaments: Your collar bone connects with the shoulder blade at the coracoid process with the help of coracoclavicular ligaments.
• Acromioclavicular Ligament: The shoulder blade and collarbone also connect at the acromion process, which is possible due to the acromioclavicular ligament.
• Coracoacromial ligament: The acromion process and coracoid process also connect with the help of the coracoacromial ligament.
• Glenohumeral ligaments: The shoulder blade consists of a glenoid cavity, which is connected to the head of the arm bone. Glenohumeral ligaments are the three ligaments that connect the two bones by forming a capsule around the shoulder joint. This way, your shoulder stays stable, and the ligaments prevent dislocation.

Muscles

Your shoulder has a primary group of muscles that comprise four muscles, known as the rotator cuff. The four muscles — supraspinatus, infraspinatus, teres minor, and subscapularis — form a sleeve and provide stability to your shoulder joint. They also facilitate rotational movements.

Your shoulder also has another muscle, the deltoid muscle, which covers the shoulder. You can lift your arms and move them away from your body because of the deltoid muscle.

Tendons

Tendons, in simple terms, are fibrous connective tissue, and they attach muscles to the bones or structures. Shoulder tendons allow arm rotation and arm lifting, and they are the reason you can move the bone. Your shoulder tendons include:

• Bicep Tendons: Also called the long and short head of the bicep, tendons in your bicep connect the muscle of the upper arm to your shoulder.
• Rotator Cuff Tendons: Your shoulder also consists of a group of four tendons that are responsible for joining the head of the humerus to the deeper muscles of your rotator cuff. The shoulder is a flexible joint, and the tendons only provide it more stability as well as mobility.

Nerves

You can think of nerves like cables that are responsible for carrying messages from your brain to the muscles. The impulses between your brain and nerves help you feel sensations and direct movement. Your shoulder nerves pass through the arm and then the shoulder joint from the neck. All the nerves in your shoulder bunch up and are called the Brachial Plexus, and from this point on, they divide into individual nerves. These muscles are how your brain communicates with your muscles to move your arm!

Blood Vessels

Your blood vessels are the channels that carry blood throughout your body, including your arms and shoulders. The subclavian artery runs just below the collar bone, and it supplies oxygenated blood to your shoulder region. When it reaches the armpit area, it continues as the axillary artery. The main veins in your shoulder that carry the deoxygenated blood back to your heart for purification are the axillary vein, cephalic vein, and basilic vein.