Abdominal Wall Flashcards
Anterolateral (3) vs. Anterior Abdominal Wall (2)
Anterolateral:
-External obliques (EO)
-Internal obliques (IO)
-Transversus abdominis
Anterior:
-Rectus abdominis
-Rectus sheath
External Oblique
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)
Internal Oblique
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)
Transversus Abdominis
O: Costal margin, iliac crest, inguinal ligament and thoracolumbar fascia
I: Linea alba, xiphoid process, pubis symphysis
A: Rotation and flexion of trunk
Rectus Abdominis
O: Pubic bone
I: Xiphoid process, ribs 5-7
A: Trunk flexion, aids in pelvic stability
Rectus Sheath
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)
Rectus Sheath- Above Arcuate Line
Anterior Rectus Sheath:
-EO aponeurosis
-1/2 IO aponeurosis
Posterior Rectus Sheath:
-1/2 IO aponeurosis
-Transversus abdominis aponeurosis
Rectus Sheath- Below Arcuate Line
Anterior Rectus Sheath:
-EO aponeurosis
-IO aponeurosis
-Transversus abdominis aponeurosis
Transversalis Fascia:
-In direct contact with rectus abdominis
Posterior Abdominal Wall (4)
- Psoas minor
- Quadratus lumborum
- Psoas major
- Iliacus
Psoas Minor
O: Lateral aspect of T12 and L1
I: Iliopectineal line
A: assists in trunk flexion
Psoas Major
O: Transverse processes T12-L5
I: Lesser trochanter
A: Flexion of the hip
Quadratus Lumborum
O: Iliac crest
I: Transverse processes of L1-L5, rib 12
A: Bilateral= extension of trunk, Unilateral= lateral flexion of trunk
Iliacus
O: Iliac fossa
I: Lesser trochanter
A: Flexion and external rotation of hip
Inguinal Region
Surface Anatomy:
-Left and right of the hypogastric region
Key Structures:
-Inguinal ligament
-Inguinal canal
Inguinal Ligament
Bony Attachments:
-ASIS
-Pubis
Functions:
-Anchors abdominal muscles
-Supports soft tissues of the groin
Inguinal Canal
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
Inguinal Canal- Borders
Anterior wall: external oblique aponeurosis
Posterior wall: transversalis fascia
Inferior (floor): inguinal ligament
Superior (roof): fibres of transversus abdominis and internal oblique
Inguinal Canal Males vs. Females
Males:
-Spermatic cord
-Gonadal vessels (testicular a. and v.)
-Ilioinguinal nerve
-Lymphatics
Females:
-Round ligament of the uterus
-Ilioinguinal nerve
-Lymphatics
Innervation of Abdominal Wall
Sensory:
-Dermatomes
Motor:
-Thoracoabdominal nerves
-Subcostal nerve
-Lumbar plexus
Sensory Innervation
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
Motor Innervation
To abdominal muscles:
-Thoracoabdominal nerves (T7-T11)
-Subcostal nerve (T12)
-Lumbar plexus (L1) *iliohypogastric nerve, ilioinguinal nerve
Lumbar Plexus
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)
Lymphatic Drainage- Superficial (2)
Drains cutaneous and subcutaneous structures
Above the umbilicus:
-Axillary nodes
Below the umbilicus:
-Superficial inguinal nodes
Lymphatic Drainage- Deep (4)
Deep drainage below the umbilicus:
1. Superficial inguinal nodes
2. Deep inguinal nodes
3. Common iliac nodes
4. Lumbar nodes
Lymphatic Drainage- Return to Venous Circulation
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
