Dissection of anterolateral abdominal wall

Composition of rectus sheath in lower abdominal wall

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Image #135-1

Dissection of anterolateral abdominal wall Composition of rectus sheath in lower abdominal wall The three flat muscles of the abdominal wall have been dissected on the right side to demonstrate the contribution of each of the formation of the sheath of the rectus muscle. The arcuate or semicircular line (18) serves as a point of reference. Below this line, which in this specimen is only moderately well defined, the aponeuroses (21) of all three muscles pass in front of the rectus muscle. Above the arcuate line a different arrangement was found. As shown at the upper limit of the dissected area, the aponeurosis of the internal oblique (3) contributes to the posterior as well as to the anterior layer of the sheath. As a consequence, the aponeurosis of the transversus pass entirely into the posterior layer of rectus sheath. Upper parts of the rectus sheath are illustrated in views 133-7 and 134-4. 1 . Sheath of rectus abdominis muscle (anterior layer) 2 . Fascia covering internal oblique muscle 3 . Area in which aponeurosis of internal oblique divides to join anterior and posterior layers of rectus sheath 4 . External oblique muscle 5 . Internal oblique muscle 6 . Transversalis fascia and peritoneum (visible through window cut in aponeuroses) 7 . Internal oblique muscle (severed at lateral margin of rectus sheath) 8 . Ascending branch deep circumflex iliac artery 9 . Transversus abdominis muscle (right pointer on aponeurosis) 10 . Iliohypogastric nerve 11 . Inguinal ligament 12 . Fascia of transversus muscle 13 . Umbilicus 14 . Linea alba 15 . Rectus abdominis muscle (divided) 16 . Sheath of rectus abdominis muscle (posterior layer) 17 . Inferior epigastric artery 18 . Arcuate line (semicircular line) 19 . Transversalis fascia 20 . Cut edge of anterior layer of rectus sheath: 21 . Upper pointer: Aponeurosis transversus muscle Middle pointer: Aponeurosis of Internal oblique muscle Lower pointer: Aponeurosis external oblique muscle 22 . Suspensory ligament of the penis