This document discusses nerve blocks of the anterior abdominal wall including the transverse abdominis plane (TAP) block, rectus sheath block, and ilioinguinal/iliohypogastric nerve block. It describes the relevant anatomy, including the nerves innervating the abdominal wall muscles and skin, and techniques for administering each type of block. Potential complications are also outlined. The goal of these nerve blocks is to provide postoperative analgesia for surgeries of the lower abdominal wall and groin by interrupting nerve pathways.

1. Nerves of the abdominal wall
nerve block
University of Gondar
College of medicine and health science
department of anesthesia
Misganaw M
1

2. INTRODUCTION
 A significant, component of pain experienced after abdominal
surgery.
 Regional block of the anterior abdominal wall can significantly
help with intraoperative and postoperative analgesia.
 The key to understanding nerve block of the abdominal wall is
understanding and application of anatomy.
 The anterior abdominal wall described as area surrounded by
costal margin, xiphiod process, inguinal ligament, pelvic bone
and midaxillary line 2

3. Anatomy of anterolateral
abdominal wall
 The lateral and anterior abdominal wall consists of subcutaneous
tissue, the external oblique muscle, the internal oblique muscle, and
the transverses abdominis muscle
 innervation of the anterolateral abdominal wall
arises from the anterior rami of spinal nerves T7 to L1.
 These include the intercostal nerves (T7-T11), the
subcostal nerve (T12), and the iliohypogastric and
ilioinguinal nerves (L1). 3

4. MUSCLES OF ANTERIOR ABDOMINAL
WALL
 External oblique
 Internal oblique
 Transvers abdominus
 Rectus abdominal
 Pyramidal
 Knowing the origin and innervation of each muscle is
important for adequate nerve block.
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5. TAP BLOCK
 The aim of a TAP block is to deposit local anesthetic in the
plane between the internal oblique and transverses abdominis
muscles targeting the spinal nerves in this plane.
 The innervation to abdominal skin, muscles and parietal
peritoneum will be interrupted.
 If surgery traverses the peritoneal cavity, dull visceral pain
(from spasm or inflammation following surgical insult) will still
be experienced. 5

6. ANATOMY CONT..
 TAP block can be used for any surgery involving the lower
abdominal wall. This includes
 bowel surgery,
 Caesarean section,
 Appendectomy
 Prostatectomy
 hernia repair, umbilical surgery and gynecological
surgery.
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7. TAP CONT.…
 A single injection can be used, or a catheter inserted
for several days of analgesic benefit.
 The principal of the block is to deposit local anaesthetic
into the tissue plane between the internal oblique and the
transverses abdominis.
 The block takes up to 30 minutes to be effective .
 Intravenous opioid is required for skin incision and the early
operative period as the block becomes established
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8.  Adequate volume is more important than using strong
concentrations of local anaesthetic.
 The maximal safe dose of the chosen agent must
be strictly adhered to.
Dose

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9. LANDMARK TECHNIQUE
 The landmark technique, described by McDonnell et al,
accesses the transverses abdominis plane via the lumbar
triangle of petit.
 This is a surface landmark bound by the external oblique
muscle anteriorly, the latissimus dorsi muscle posteriorly and
the iliac crest inferiorly
 complications
 Block failure
 ……………
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10. RECTUS SHEATH NERVE BLOCK
 The rectus sheath encloses the rectus abdominis muscle
and is formed by the aponeuroses of the three flat abdominal
muscles.
 These aponeuroses join in the lateral border of the
rectus muscle in the point called linea semilunaris.
 Medial to the semilunaris, the aponeuroses split with some
fbres passing anterior to the rectus muscle and some
posterior.
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11. ANATOMY
 The external oblique aponeurosis and the anterior
layer of the internal oblique aponeurosis form the
anterior wall of the rectus sheath.
 The transverses abdominis aponeurosis and the posterior
layer of the internal oblique aponeurosis form the posterior wall
of the sheath.
 In the midline the aponeuroses from both sides join
to form the linea alba.
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12. ANATOMY CONT.…
 The anterior cutaneous branch of the ventral rami of the
inferior six thoracic nerves (T7-T12) run anteriorly
through the posterior of the rectus muscle to give off
sensory branches to the paraumbilical skin.
 The anterior layer of the rectus sheath is firmly attached to
the rectus abdominis muscle forming intersections.
 The rectus sheath is loosely attached posteriorly, forming a
potential space.
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13.  Local anaesthetic can spread caudad and cephalad in the
plane between the rectus muscle and
the posterior rectus sheath.
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14. TECHNIQUES
 Landmark technique
 Ultrasound
 dose…
complications
 Intraperitoneal injection,
 visceral damage,
 vascular puncture (it is possible to identify the inferior
epigastric vessel in larger children with Doppler). 14

15. ILIOINGUINAL/ILIOHYPOGASTRIC NERVE
BLOCK (ILNB)
 The ilioinguinal/iliohypogastric nerve block (ILNB) provides
excellent analgesia after
 inguinal hernia repair,
 hydrocele repair and orchidopexy.
 Pfannenstile incision
 It does not abolish visceral pain due to peritoneal
traction or manipulation of the spermatic cord during
inguinal hernia repair or orchidopexy. 15

16. ANATOMY
 The iliohypogastric (T12, L1) and ilioinguinal (L1) nerves
are terminal branches of the lumbar plexus.
 The iliohypogastric nerve supplies the gluteal region and the
skin over the pubic symphysis.
 The ilioinguinal nerve supplies the area of the skin beneath
that supplied by the iliohypogastric nerve and the anterior
scrotum.
 The nerves emerge at the lateral border of psoas major and
pass anterior to quadratus lumborum.
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17.  They pierce the lumbar fascia at the lateral border of
quadratus lumborum and run in the plane between the
internal oblique muscle and transverses abdominis
muscles.
 The iliohypogastric nerve pierces (again) the internal
oblique and runs under the external oblique superior to
the inguinal canal .
 The ilioinguinal nerve continues in the inguinal canal.
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18. TECHNIQUE
 Landmark
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19.  dose
Use a volume of up to 0.5ml.kg-1 0.25% bupivacaine for
the landmark technique.

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20. COMPLICATIONS
 The most common complication is block failure (more
common using the landmark technique).
 Transient femoral nerve palsy with transient quadriceps paresis
may be seen if the injection is too deep.
 Visceral perforation
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21. 
 any question
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