ANATOMY

External Oblique Muscle is located on the lateral and anterior side of the Abdomen. It is wide, thin and Quadrilateral in shape. The muscular portion occupies the sides and its Aponeurosis (layers of flat tendons) occupies the anterior of the Abdomen. Due to Subcutaneous Fat (layer of subcutaneous tissues containing Adipocytes) and its small size the muscle is not visible in most humans especially females. The origin for the External Oblique muscle is from eight digitations (division into finger like parts), each of these digitations is from the external surface and inferior sides of the Fifth to Twelfth Ribs.

Five above digitations increase in size from above to downward and are present in the processes of Serratus Anterior Muscle. The last three reduce in size from above to downward and are in the processes of Latissimus Dorsi Muscle. These attachments allow the fibers to proceed in different directions.

Inguinal ligament is formed by the Aponeurosis of External Oblique Muscle. Inguinal Canal is also contributed by this muscle.

INNERVATION

External Oblique Muscle is innervated by five lower Intercostal Nerves and Subcostal Nerves. It also receives nerve supply from Iliohypogastric and Ilioinguinal Nerves.

BLOOD SUPPLY

External Oblique Muscle receives its blood supply from the following.

• Lower Intercostal and subcostal Arteries

• Superior and Inferior Epigastric Arteries

• Deep Circumflex Iliac Arteries

• Posterior Lumbar Arteries

FUNCTION

Important functions of External Oblique Muscle are as follows.

• Maintenance of Abdominal Tone

• Vomiting by compressing the abdominal contents

• Flexion and rotation of turn

• Help in forced expiration

CLINICAL SIGNIFICANCE

The common injury to the External Oblique Muscle is Side Strain. It is typical cricket injury and happens commonly in Bowlers. The symptoms of the injury include tightness and slight pain in lower ribs region.