External obliques

A key muscle group involved in trunk movement, rotation, and stability.

The external obliques are a pair of muscles located on each side of the abdomen. They are the largest and the most superficial of the three flat abdominal muscles. Positioned laterally on the body, these muscles run diagonally from the lower ribs to the pelvis, aiding in twisting and bending movements.

Terminologia Anatomica

obliquus externus abdominis

System

Muscular system

Function

The primary role of the external obliques is to facilitate a range of movements in the trunk. This includes rotation of the torso, lateral flexion, and the compression of the abdominal cavity. When the external obliques contract unilaterally (one side), they enable the body to twist towards the opposite side, which is essential for many everyday activities, including sports and reaching for objects. Bilateral contraction (both sides working together) contributes to flexing the trunk forward, aiding rigorous activities such as sit-ups or lifting heavy objects. Additionally, the external obliques play a significant role in maintaining posture and stability by supporting the spine during dynamic movements and providing protection for internal organs during physical exertion.

Location

The external obliques are located in the anterolateral region of the abdomen, making them easily identifiable beneath the skin. They span from the lower ribs, specifically the fifth to the twelfth ribs, diagonally downwards to the iliac crest and the pubic bone in the pelvis. The fibers of the external obliques run downward and forward, resembling a 'hand in pocket' orientation, which is pivotal for their twisting and bending capabilities. Their location is crucial because they anchor to the thoracolumbar fascia, the connective tissue of the lower back, thereby linking to the deeper muscles of the abdomen and lumbar region, contributing to core stability.

Did You Know?

The external obliques are most active during activities that involve twisting, such as swinging a bat or playing certain sports.
Strong external obliques contribute to a flatter abdominal appearance and better overall core strength.
Injury to the external obliques can cause significant pain, affecting mobility and daily activities.
These muscles are crucial for maintaining proper body mechanics while lifting and bending.