External Oblique Muscles, Lateral View

Description

Seen in lateral profile, the external oblique forms the superficial anterolateral abdominal wall, arising by serrated digitations from ribs 5 through 12 and interlocking superiorly with the slips of serratus anterior and posteriorly with latissimus dorsi. Its inferomedial fibres sweep toward the linea alba as a broad aponeurosis, while the posterior border approaches the iliac crest and transitions toward the thoracolumbar fascia near the lumbar region. Inferiorly, the aponeurosis rolls to form the inguinal ligament between the anterior superior iliac spine and pubic tubercle, with the superficial inguinal ring positioned just superolateral to the pubic crest. A lateral view clarifies fibre direction and the layered handoff from muscle belly to aponeurosis, which is the key to understanding abdominal wall incisions and hernia anatomy. This is the plane surgeons exploit in oblique and transverse approaches to the flank and lower abdomen, and it is also where weakness or disruption of the external oblique aponeurosis and inguinal canal coverings relates to inguinal hernia patterns and postoperative fascial pain. Palpation landmarks matter. The iliac crest, costal margin, and ASIS guide both clinical examination and safe port placement. Ideal for gross anatomy teaching on the trunk, surgical anatomy chapters on the inguinal region, and physiotherapy materials explaining trunk rotation and side-bending mechanics with correct fibre orientation. It also fits radiology and sports medicine content discussing abdominal wall strains and aponeurotic injuries at the costal attachments or along the inguinal ligament. Anatomical accuracy verified by SciePro's Medical Advisory Board.