Anatomy of Abdominal wall by Shehryar Ahmad

Abdominal wall Anatomy

1. Structure of the Anterior Abdominal Wall Shehryar Ahmad Lecturer : NIHMS

2. The anterior abdominal wall is made up of : Skin Superficial fascia Deep fascia Muscles Extraperitoneal fascia Parietal peritoneum

3. 1. Skin The skin is loosely attached to the underlying structures except at the umbilicus , where it is tethered to the scar tissue. The umbilicus is a scar representing the site of attachment of the umbilical cord in the fetus; it is situated in the linea alba

4. 2. Superficial Fascia The superficial fascia is divided into: Superficial fatty layer (fascia of Camper) Deep membranous layer ( Scarpa's fascia)

5. SuperFacial Fascia The super facial fascia is divided into superfascial fatty layer (fascia of camper) and a deep membranous layer ( scarpas fascia ). The fatty layer is continuous with the superficial fat over the rest of the body and may be extremely thick [8 cm] or more in obese patients.

6. The membranous layer is thin and fades out laterally and above, where it becomes continuous with the superficial fascia of the back and the thorax, respectively.

7. 3. Deep Fascia It lies immediately deep to the membranous layer of superficial fascia.

8. 4. Muscles The muscles of the anterior abdominal wall consist of three broad thin sheets. From exterior to interior they are the External oblique Internal oblique Transversus abdominis

9. On either side of the midline anteriorly is, in addition, a wide vertical muscle, the rectus abdominis .

10. A. External Oblique Origen : the outer surfaces of the lower eight ribs and fans out to be Insertion : the xiphoid process, the linea alba, the pubic crest, the pubic tubercle, and the anterior half of the iliac crest Most of the fibers are inserted by means of a broad aponeurosis .

11. A triangular-shaped defect in the external oblique aponeurosis lies immediately above and medial to the pubic tubercle. This is known as the superficial inguinal ring

12. The spermatic cord passes through this opening and carries the external spermatic fascia (or the external covering of the round ligament of the uterus) from the margins of the ring.

13. Between the anterior superior iliac spine and the pubic tubercle, the lower border of the aponeurosis is folded backward on itself, forming the inguinal ligament .

14. B. Internal Oblique Origin : lumbar fascia, the anterior two thirds of the iliac crest, and the lateral two thirds of the inguinal ligament. Insertion : the lower borders of the lower three ribs and their costal cartilages, the xiphoid process, the linea alba, and the symphysis pubis.

15. C. Transversus Origin : the deep surface of the lower six costal cartilages, the lumbar fascia, the anterior two thirds of the iliac crest, and the lateral third of the inguinal ligament. Insertion : the xiphoid process, the linea alba, and the symphysis pubis.

16. D. Rectus Abdominis The rectus abdominis is a long strap muscle that extends along the whole length of the anterior abdominal wall. It is broader above and lies close to the midline, being separated from its fellow by the linea alba.

17. The rectus abdominis muscle is divided into distinct segments by three transverse tendinous intersections : One at the level of the xiphoid process, One at the level of the umbilicus One halfway between these two

18. Aponeuroses Aponeuroses a flat sheet or ribbon of tendonlike material that anchors a  muscle  or connects it with the part that the muscle moves. The aponeurosis is composed of dense fibrous  connective tissue  containing fibroblasts (collagen-secreting spindle-shaped cells) and bundles of collagenous fibres in ordered arrays. Aponeuroses are structurally similar to tendons and ligaments. As the aponeuroses of the three sheets pass forward, they enclose the rectus abdominis to form the rectus sheath .

19. Rectus sheath The rectus sheath is a long fibrous sheaththat encloses the rectus abdominis muscle and pyramidalis muscle. It is formed by aponeurosis of three lateral abdominal muscles .

20. Fascia Transversalis The fascia transversalis is a thin layer of fascia that lines the transversus abdominis muscle.

21. 5. Extraperitoneal Fat The extraperitoneal fat is a thin layer of connective tissue that contains a variable amount of fat and lies between the fascia transversalis and the parietal peritoneum .

22. 6. Parietal Peritoneum The walls of the abdomen are lined with parietal peritoneum . This is a thin serous membrane and is continuous below with the parietal peritoneum lining the pelvis.

23. Thanks