Largest Muscle in the Human Body: What Is It and How Is It Measured?

There are about 600 muscles in the human body that guide both voluntary and involuntary movements. Several muscles can be considered the largest, depending on whether they are measured in mass or surface area.

(Photo: Unsplash/ Alan Calvert)

Largest Muscle by Mass

Gluteus maximus holds the record for being the largest muscle in the human body by mass. Also known as the "glute muscle," the gluteus maximus runs diagonally across from the top center of the pelvis to the thigh bone or femur.

According to a morphological analysis of adult cadavers, the glute muscles account for almost 12% to 13% of the total weight of all the leg muscles. Aside from being the largest muscle by mass, gluteus maximus is also regarded as one of the strongest muscles in the human body.

The human gluteus maximus is bigger than that of apes and monkeys in terms of overall body sizes. Some experts believe its great size may have resulted from an evolutionary adaptation to certain activities requiring a bipedal position.

This muscle is responsible for the movement of the hip and thigh. It is used when a person stands up from a sitting position, when climbing stairs, or when staying in an erect position. Because of these functions, the gluteus maximus needs to be powerful enough to move the weight of the entire upper body.

The size of the gluteus maximus can be increased by training in sports that require ample glute power, such as sprinting. A study on muscle morphology reveals that the absolute volume of elite sprinters' glute muscles is about 45% greater than that of sub-elite sprinters.

Largest Muscle by Surface Area

In terms of surface area, the latissimus dorsi is regarded as the largest muscle in the human body. Also known as the "lats," they are the two triangle-shaped muscles on each side of the spine. These broad, flat muscles are found on top of the other muscles of the mid- and lower back.

According to a 2022 study, an average adult possesses latissimus dorsi, which measures about 7 inches (18 centimeters) wide and 14 inches (36 centimeters) long. On the other hand, it only measures half an inch (1.3 centimeters) thick.

The primary function of this muscle is the movement of the upper extremities in collaboration with the teres major and pectoralis major. These muscles work together to adduct, rotate, and extend the arm at the glenohumeral joint.

While the lats are active in moving the upper extremities, it is also considered an accessory respiration muscle. Scientists are still investigating the role of this muscle in trunk movement due to its broad attachment to various vertebral spinous processes and the thoracolumbar fascia.

Latissimus dorsi is also a climbing muscle, raising the trunk upwards with the arms fixed above the head. It also plays an important role in chopping, swimming, and rowing. It is also active in violent expiration since it is attached to the ribs. When a person coughs or sneezes, this muscle can be felt pressing inward as it compresses the abdomen and the thorax.