21 External Oblique Muscle OriginFleshy digitations from the lower 8 ribs
22 External Oblique Muscle XiphoidProcessInsertionThe muscle is inserted by fleshy fibers as well as aponeurosis, as follows:A- Fleshy fibers:Outer lip of the iliac crestB- Aponeurosis:Medial part → linea alba from xiphoid process to symphysis pubisLateral part → folded upwards & backwards upon itself to form the inguinal ligament (ASIS → pubic tubercle)Symphysis Pubis
23 External Oblique Muscle Direction of fibersDownwardForwardsMedially
26 Internal Oblique Muscle OriginAnterior 2/3 of the intermediate line of the iliac crestThe lateral 2/3 of the inguinal ligamentLumbar fasciaInsertionLower 6 costal cartilagesXiphoid processLinea AlbaPubic crest
27 Internal Oblique Muscle Direction of fibersUpwardsForwardsMediallyNerve SupplyT7-T12Iliohypogastric n.Ilioinguinal n.
35 Rectus Abdominis Muscle The muscle is divided into segments by tendinous intersections, Which indicate that the muscle arises from a number of myotomes, fused togetherSurgical Importance1- Segmental nerve supply.2- Hematoma of rectus m. is localized2- In paramedian incision displace m.laterally (n. supply comes from lateral)
36 It is a landmark of linea alba intraoperative Pyramidalis MuscleIt is a landmark of linea alba intraoperative
37 Actions of Anterior Abdominal Wall Muscles They assist in raising the intra-bdominal pressure (so, they help in vomiting, cough, delivery, etc….)Keep the abdominal viscera in position.Rectus abdominis flexes the trunk, while the 2 oblique muscles bend the trunk laterally.Act as accessory expiratory muscles.Lower midline & paramedian incisions.