Anatomy - Umbilical hernia repair, open, preperitoneal umbilical mesh plasty (“PUMP”-Repair)

1. Anterior Abdominal MusclesM. rectus abdominis: straight abdominal muscle within the rectus sheath with 3-4 tendinous transverse stripes (Intersectiones tendineae), which are fused with the anterior leaf of the rectus sheath.
M. pyramidalis: originates from the upper pubic ramus and radiates into the linea alba, lies ventral to the M. rectus abdominis in its own sheath in the anterior leaf of the rectus sheath.

2. Layer Structure of the Anterior Abdominal WallRectus Sheath: encloses the M. rectus abdominis; above the midpoint between the umbilicus and symphysis, a distinction is made between an anterior and a posterior leaf; the posterior leaf ends here in the form of the linea arcuata; above this line, the M. obliquus externus abdominis radiates into the anterior leaf of the rectus sheath, the M. obliquus internus abdominis into the anterior and posterior leaf, and the M. transversus abdominis into the posterior leaf.
Linea semilunaris: transition zone between the aponeuroses of the lateral abdominal muscles and the lateral edge of the rectus sheath.
Linea alba: approximately 1 cm wide taut connective tissue strip between the right and left rectus sheath, extends from the sternum to the symphysis.
Fascia transversalis: above the linea arcuata, it covers the posterior leaf of the rectus sheath internally, below the linea it lies directly on the M. rectus abdominis.

3. Internal Relief of the Abdominal WallPlica umbilicalis mediana: median peritoneal fold that runs from the umbilicus to the urinary bladder, within the fold is the Lig. umbilicale medianum (connective tissue strand = urachus remnant).
Plica umbilicalis medialis: paired peritoneal fold, contains on both sides the Lig. umbilicale mediale = obliterated remnant of the bilateral umbilical artery, A. umbilicalis.
Plica umbilicalis lateralis: paired peritoneal fold, beneath it lies on both sides the A. epigastrica inferior with two accompanying veins each.

4. Conduction Pathwaysa) ArteriesA. epigastrica superior: continuation of the A. thoracica interna, anastomoses at umbilical level with the A. epigastrica inferior.
A. epigastrica inferior: arises from the A. iliaca externa and runs like the aforementioned artery on the dorsal surface of the M. rectus abdominis in the rectus sheath.
A. epigastrica superficialis: originates from the A. femoralis and distributes after crossing the inguinal ligament in the subcutaneous tissue of the anterior abdominal wall.
Aa. intercostales posteriores VI – XI and A. subcostalis: originate from the thoracic aorta; their terminal segments run obliquely downward between M. obliquus internus abdominis and M. transversus abdominis and extend from lateral to the rectus sheath, where they anastomose with A. epigastrica superior et inferior.

b) VeinsVv. epigastricae superiores: accompany the artery of the same name; anastomose with branches of the V. epigastrica inferior and drain into the Vv. thoracicae internae.
V. epigastrica inferior: branches into accompanying veins of the A. epigastrica inferior and drains into the V. iliaca externa.
V. epigastrica superficialis: runs parallel to the artery of the same name (see above).

c) Lymphatic VesselsSuperficial Lymphatic Vessels: above the umbilicus, they drain to the axillary lymph nodes (Nodi lymphatici axillaris), below to the inguinal lymph nodes, Nodi lymphatici inguinales.
Deep Lymphatic Vessels: generally run parallel to the blood vessels; reach the Nodi lymphatici parasternales, lumbales, and iliaci externi.

d) NervesNn. intercostales VI – XII: as Rr. ventrales of the Nn. thoracici VI – XII; they enter the abdominal wall behind the costal cartilages between M. obliquus internus abdominis and M. transversus abdominis; motor branches supply the anterior and lateral abdominal muscles, the sensory branches the abdominal skin.
N. iliohypogastricus, N. ilioinguinalis and N. genitofemoralis: participate in the motor and sensory innervation of the lower abdominal region and genitals.

Umbilical region: (1) Umbilical ring, (2) Collagen fiber layer, (3) Round ligament of the liver, (4) Umbilical scar, (5) Linea alba, (6) Tendinous intersection of the rectus abdominis muscle, (7) Rectus abdominis muscle (translucent), (8) Anterior cutaneous branches.

The navel or umbilicus refers to the remnant of the umbilical cord attachment, which remains as a scar at the level of the body's center after birth.

At the navel, three layers are distinguished:

• superficial layer consisting of skin and subcutis
• middle, aponeurotic layer
• deep layer of preperitoneal connective tissue and peritoneum.

1. Superficial Layer
The relatively delicate umbilical skin in adults is only movable cranially against the umbilical ring; otherwise, it is firmly anchored everywhere to a underlying taut connective tissue plate. Within the umbilical ring, the subcutis is very delicately developed and is only traversed by sparse vessels and nerves.

2. Middle Layer
The middle, aponeurotic layer consists of a taut connective tissue meshwork that is traversed by the obliterated embryonic vascular remnants as well as by the remnant strand of the urachus and closes the umbilical opening. At the edges of the umbilical opening, the connective tissue plate is fused with the umbilical ring, into which tendon bands from the rectus sheath radiate. The closure of the umbilical opening by the tough connective tissue plate is completed by the end of the second year of life.

3. Deep Layer
In the deep layer of the umbilical plate, there is usually a circumscribed fat pad up to the size of a palm, which is traversed by radial connective tissue strands and is divided by a total of five peritoneal folds, the so-called umbilical plicae, which extend from lateral caudal to cranial towards the umbilicus:

• one median umbilical fold, contains the obliterated urachus
• two medial umbilical folds, contain the obliterated umbilical arteries
• two lateral umbilical folds, house the inferior epigastric vessels.

Towards the abdominal cavity, the umbilical region is covered by the transversalis fascia and by the peritoneum fused with it. The peritoneum is reinforced in the umbilical region by the umbilical fascia, which is built up from taut connective tissue. The fascia spans dorsal to the umbilical vein, is anchored laterally in the posterior leaf of the rectus sheath, and ends caudally at the level of the middle of the umbilical ring. Cranially, it extends about 5 cm beyond the umbilicus, with its fibers converging towards the linea alba and attaching to it.

Between the transversalis fascia and the linea alba, there is a canal that is only filled with loose connective tissue (umbilical canal) and which can form the path for umbilical hernias.