Your deltoid muscles crown your shoulder and cover the front, side, and back of the joint. They are superficial, which means they are close to the surface of your skin. The deltoid muscle resembles an inverted triangle. The tendons connect each of the three sides with bones. It was formerly called Deltoidus (plural deltoidei) and the name is still used by some anatomists. It is so named because it has the shape of the Greek capital letter delta (Δ). Deltoid is also abbreviated in slang as “delt”. Video: This video covers deltoid muscle anatomy in detail [3] Your deltoid muscles are located in your shoulder, the patella that connects your arm to the trunk of your body. Deltoid muscles help you move your arms in different directions. They also protect and stabilize your shoulder joint. Dyrna F, Kumar NS, Obopilwe E, et al.
Relationship between deltoid muscles and rotator cuff muscles during dynamic shoulder abduction: a biomechanical study of the progression of rotator cuff rupture. Am J Sports Med. 2018;46(8):1919-1926. doi:10.1177/0363546518768276 From this extended origin, the fibers converge for their introduction to the deltoid tuberosity in the center of the lateral surface of the humeral waves; The intermediate fibers run vertically, the front fibers obliquely backwards and laterally, and the rear fibers obliquely forward and laterally. The posterior deltoid muscle at the back of the shoulder also rotates the joint laterally to move the arm outward and backward. During the extension of the posterior deltoid muscle, the shoulder joint rolls downwards and inwards. Your doctor will check your symptoms and perform a physical exam. They may ask you to raise your arm forward, sideways and backwards, possibly in the face of resistance. If your deltoid muscles are working properly, your provider should be able to feel the muscle contract when you raise your arm. Like other muscles in your body, the deltoid muscles in your shoulder contain elastic fibers. These fibers make the muscles flexible, allowing them to perform many movements. The skeletal muscle is red and white, which makes them appear striped (striped or striped).
The rotator cuff is the main control unit for the shoulder area. It consists of four small muscles and tendons that support the deltoid muscles. The rotator cuff lifts the shoulder and stretches it in many uncomfortable positions. This joint is the most flexible joint in the human body because of the rotational movement it provides to the shoulder area. All the heads of the deltoid muscle work together to create the abduction of the shoulder joint. It helps to raise the front, side and back arm. Deltoid pain can affect anyone who performs repetitive aerial activities, such as house painters, swimmers, water polo players, and jugs. It is also active when carrying items such as suitcases or items to avoid subluxation/dislocation. If you are undergoing surgery or a serious deltoid muscle injury, rehabilitation usually involves an immobilizing shoulder rest to keep the arm still for at least two to three weeks. This gives the muscle enough time to heal and also prevents further injury. Most deltoid muscle diseases heal with non-surgical treatments, including: It originates from the lateral third of the collarbone and settles on the outer part of the upper arm to the deltoid tuberosity. The deltoid muscle is a major component of the wing muscles of bats and pterosaurs,[26] but in birds of the crown group it is significantly reduced, as they prefer the muscles attached to the sternum.
However, some Mesozoic flying theropods had a more developed deltoid. [27] Surgical complications specific to your deltoid muscle may include: The main function of the deltoid muscle is to move the humerus and shoulder joint at the same time. Muscle movements are called: The insertion point of the lateral deltoid muscle is located at the outer end of the scapula called the acromione process. The place where a muscle attaches to a bone is called the insertion point. Each of the three delta heads has its own insertion point. Together, they help stabilize the shoulder joint and allow for a full range of motion of the arm. This article describes the anatomy of the deltoid muscle, including the location of the heads and their different functions. It also lists various health conditions that affect the deltoid muscle and what you can do to prevent or recover from an injury. Studies have shown that there are seven neuromuscular segments to the deltoid muscle. Three of them are located in the front anatomical head of the deltoid muscle, one in the anatomical median head, and three in the back anatomical head of the deltoid muscle. [21] These neuromuscular segments are powered by smaller branches of the axillary nerve and work in coordination with other shoulder girdle muscles, including the pectoralis major and supraspinatus. [21] Your deltoid muscles play an important role in moving your arm in different directions.
They also stabilize your shoulder joint and protect it from injuries such as dislocations. People who make a lot of repetitive movements over the head, such as swimmers, jugs or mechanics, run the risk of injuring their deltoid muscles. Most deltoid muscle lesions heal with non-surgical treatments. A rotator cuff tear is a common injury in which tendons are partially or completely torn. The destabilizing effect of a tear can mechanically stress the deltoid muscle, resulting in a deltoid strain. Deltoid muscles are prone to injuries that can affect not only the muscle, but also the connective tissue called tendons, which connects muscles to bones. Underlying nerves or blood vessels can also be injured. The deltoid muscle is the main muscle of the shoulder. It consists of three heads called anterior, lateral and posterior deltoid muscle. The three heads help move the arm and stabilize the shoulder joint. Each head also has different insertion points and allows for different movements known as abduction, flexion, extension, and rotation.