Abdominal Wall

Question 1

Anterolateral (3) vs. Anterior Abdominal Wall (2)

Answer 1

Anterolateral:
-External obliques (EO)
-Internal obliques (IO)
-Transversus abdominis

Anterior:
-Rectus abdominis
-Rectus sheath

Question 2

External Oblique

Answer 2

O: Ribs 5-12
I: Iliac crest and pubis
A: Bilateral= flexion of trunk, Unilateral= contralateral rotation of trunk

*fibres run inferior and medially (hands in pockets)

Question 3

Internal Oblique

Answer 3

O: inguinal ligament, iliac crest, lumbodorsal fascia
I: Ribs 10-12
A: Bilateral= abdominal compression, Unilateral= ipsilateral rotation

*fibres run superior and medially (hands in armpits)

Question 4

Transversus Abdominis

Answer 4

O: Costal margin, iliac crest, inguinal ligament and thoracolumbar fascia
I: Linea alba, xiphoid process, pubis symphysis
A: Rotation and flexion of trunk

Question 5

Rectus Abdominis

Answer 5

O: Pubic bone
I: Xiphoid process, ribs 5-7
A: Trunk flexion, aids in pelvic stability

Question 6

Rectus Sheath

Answer 6

Surrounds rectus abdominis anteriorly and posteriorly

Formed by:
-EO aponeurosis
-IO aponeurosis
-Transversus abdominus aponeurosis

*Layers dependent on location (arcuate line, between umbilicus and pubis)

Question 7

Rectus Sheath- Above Arcuate Line

Answer 7

Anterior Rectus Sheath:
-EO aponeurosis
-1/2 IO aponeurosis

Posterior Rectus Sheath:
-1/2 IO aponeurosis
-Transversus abdominis aponeurosis

Question 8

Rectus Sheath- Below Arcuate Line

Answer 8

Anterior Rectus Sheath:
-EO aponeurosis
-IO aponeurosis
-Transversus abdominis aponeurosis

Transversalis Fascia:
-In direct contact with rectus abdominis

Question 9

Posterior Abdominal Wall (4)

Answer 9

1. Psoas minor
2. Quadratus lumborum
3. Psoas major
4. Iliacus

Question 10

Psoas Minor

Answer 10

O: Lateral aspect of T12 and L1
I: Iliopectineal line
A: assists in trunk flexion

Question 11

Psoas Major

Answer 11

O: Transverse processes T12-L5
I: Lesser trochanter
A: Flexion of the hip

Question 12

Quadratus Lumborum

Answer 12

O: Iliac crest
I: Transverse processes of L1-L5, rib 12
A: Bilateral= extension of trunk, Unilateral= lateral flexion of trunk

Question 13

Iliacus

Answer 13

O: Iliac fossa
I: Lesser trochanter
A: Flexion and external rotation of hip

Question 14

Inguinal Region

Answer 14

Surface Anatomy:
-Left and right of the hypogastric region

Key Structures:
-Inguinal ligament
-Inguinal canal

Question 15

Inguinal Ligament

Answer 15

Bony Attachments:
-ASIS
-Pubis

Functions:
-Anchors abdominal muscles
-Supports soft tissues of the groin

Question 16

Inguinal Canal

Answer 16

Location:
-Lower anterior abdominal wall (4cm)
-Extends from deep inguinal ring -> superficial inguinal ring

Deep inguinal ring: evagination in transversalis fascia

Superficial inguinal ring: opening in external oblique aponeurosis

Question 17

Inguinal Canal- Borders

Answer 17

Anterior wall: external oblique aponeurosis
Posterior wall: transversalis fascia
Inferior (floor): inguinal ligament
Superior (roof): fibres of transversus abdominis and internal oblique

Question 18

Inguinal Canal Males vs. Females

Answer 18

Males:
-Spermatic cord
-Gonadal vessels (testicular a. and v.)
-Ilioinguinal nerve
-Lymphatics

Females:
-Round ligament of the uterus
-Ilioinguinal nerve
-Lymphatics

Question 19

Innervation of Abdominal Wall

Answer 19

Sensory:
-Dermatomes

Motor:
-Thoracoabdominal nerves
-Subcostal nerve
-Lumbar plexus

Question 20

Sensory Innervation

Answer 20

Dermatomes:
-Cutaneous/skin innervation
-Arranged in inferiorly sloping parallel rows around the abdomen
-Clinically relevant dermatomes= T10 (umbilical) and L1 (inguinal)

*T10 at belly butTEN

Question 21

Motor Innervation

Answer 21

To abdominal muscles:
-Thoracoabdominal nerves (T7-T11)
-Subcostal nerve (T12)
-Lumbar plexus (L1) *iliohypogastric nerve, ilioinguinal nerve

Question 22

Lumbar Plexus

Answer 22

Location: posterior abdominal wall
-Lumbar spinal nerves L1-L4
-Innervation mainly to the lower limb

Iliohypogastric nerve (L1)
Ilioinguinal nerve (L1)
Genitofemoral nerve (L1, L2)
Lateral femoral cutaneous nerve (L2, L3)
Femoral nerve (L2-L4)
Obturator nerve (L2-L4)
Lumbosacral trunk (L4, L5)

Question 23

Lymphatic Drainage- Superficial (2)

Answer 23

Drains cutaneous and subcutaneous structures

Above the umbilicus:
-Axillary nodes

Below the umbilicus:
-Superficial inguinal nodes

Question 24

Lymphatic Drainage- Deep (4)

Answer 24

Deep drainage below the umbilicus:
1. Superficial inguinal nodes
2. Deep inguinal nodes
3. Common iliac nodes
4. Lumbar nodes

Question 25

Lymphatic Drainage- Return to Venous Circulation

Answer 25

Left abdomen and right abdomen below the umbilicus:
-Cisterna Chyli
-Axillary nodes (left)
-Thoracic duct

Right abdomen above the umbilicus:
-Axillary nodes (right)
-Right lymphatic duct