Anterior Abdominal Wall Flashcards
Bony Landmarks of the Anterior Abdominal Wall (8)
1) Ribs and Costal Cartilages
2) Transverse processes
3) Ilium and Iliac Crest
4) Pubic Symphysis and Rami
5) Pubic Tubercle
6) Pecten Pubis
7) Anterior superior/inferior iliac spines
8) Greater and Lesser pelvis (lesser below pelvic inlet)
9 Regions of Abdominal Wall
1) Right hypochondrium
2) Right Flank (lateral region)
3) Right Inguinal (groin)
4) Epigastric
5) Umbilical
6) Pubic
7) Left hypochondriac
8) Left Flank (lateral region)
9) Left inguinal (groin)
4 Quadrants of the Abdominal Wall
1) Right Upper Quadrant
2) Left Upper Quadrant
3) Right Lower Quadrant
4) Left Lower Quadrant
Organs in Right Upper Quadrant (10)
1) Liver: right lobe
2) Gallbladder
3) Stomach: pylorus
4) Duodenum: parts 1-3
5) Pancreatic head
6) Right Suprarenal gland
7) Right Kidney
8) Right Colic (hepatic) flexure
9) Ascending Colon: superior part
10) Transverse Colon: right half
Organs in Left Upper Quadrant (10)
1) Liver: left lobe
2) Spleen
3) Stomach
4) Jejunum and proximal ileum
5) Pancreas: body and tail
6) Left Kidney
7) Left Suprarenal gland
8) Left Colic (splenic)
9) Transverse colon: left half
10) Descending Colon: superior part
Organs in Right Lower Quadrant (9)
1) Cecum
2) Appendix
3) Most of ileum
4) Ascending Colon: inferior part
5) Right Ovary
6) Right Uterine Tube
7) Right Ureter: abdominal part
8) Uterus
9) Urinary Bladder
Organs in Left Lower Quadrant (8)
1) Sigmoid Colon
2) Descending Colon: inferior part
3) Left ovary
4) Left Uterine tube
5) Left Ureter: abdominal part
6) Left spermatic cord: abdominal part
7) Uterus
8) Urinary Bladder
Transverse planes/ Organs (4)
1) Transpyloric Plane
2) Subcostal Plane
3) Transtubercle Plane
4) Interspinous Plane
Transpyloric Plane
- L1 Level
- level of gall bladder fundus, pylorus, pancreatic neck, SMA origin, hepatic portal vein, root of transverse mesocolon, hila of kidneys
Subcostal Plane
- passes inferior border 10th costal cartilage
- level of transverse colon
Transtubercle Plane
- between iliac tubercles
- level of iliocecal junction
Interspinous Plane
- between ASIS
- level of appendix, sigmoid colon
Abdominopelvic Cavities
- location
- lining
- abdomen and pelvis
- between thoracic and diaphragm and pelvic diaphragm
- 4th intercostal space
- abdomen separate from pelvis by imaginary border of pelvic inlet
- greater pelvis (above pelvic inlet)
- walls mostly bone, muscle, and CT
- Lined by peritoneum
Anteriolateral Abdominal Wall
- boundaries
- Outer layer
- mostly muscle and aponeurosis
- boundaries
- Upper 7-10 Costal cartilage
- lower inguinal ligament and pelvic bones
Outer Layer
- skin, camper’s fascia, scarpa’s fascia
- aponeurosis- tough, thick bc of several layers ( rectus sheath)
Camper’s and Scarpa’s Fascia
- integument
- Camper’s Fascia: fatty layer of superficial fascia
- Scarpa’s Fascia: membranous underlying CT layer of superficial fascia
- continuous with Colle’s fascia of perineum but fused with fascia lata of lower limb
- fluid cannot go from abdominal wall into leg but could flow into or out of superficial perineum
External Oblique Muscle
- location
- direction
- OIAN
- runs in downward medial direction (inferiormedially)
- interdigitates with serratus anterior
Origin: outer surface of lower 6 ribs
Insertion- aponeurosis and linea alba, anterior iliac crest and pubic tubercle
- makes opening of superficial inguinal canal
Innervation: Ventral Rami of T7-12 of intercostal nerves
Action: compress abdomen and increase intra-abdominal pressure; move trunk and retain posture
Internal Oblique Muscle
- direction
- OIAN
- Runs 90 degrees from external oblique muscle (superomedially and horizontally)
Origin: iliac crest, thoracolumbar fascia
Insertion: lower 10-12 ribs, aponeurosis, linea alba and pubic crest, inguinal falx
- some fibers follow spermatic cord and make cremasteric muscle
- aponeurosis splits to encompass rectus muscle
Innervation: T7-T12 and L1
Action: compresses and supports viscera, lateral flexes and rotates
Transversus Abdominus Muscle
- direction
- OIAN
- Runs tranverso-medially except for some running toward pubic crest ( contribute to conjoint tendon)
- innermost of the 3 layers
Origin: lower 7-12 costal cartilages, thoracolumbar fascia, iliac crest, upper inguinal ligament
Insertion: linea alba, pecten pubis, pubic crest
- aponeurosis contributes to rectus sheath
Innervation: T7-L1
Action: compresses and supports visceral
Rectus Abdominus Muscle
- OIAN
- two muscles
- paired muscle of anterior abdominal wall; wider at top than bottom
Origin: pubic symphysis and pubic crest
Insertion: xiphoid process and outer surface of 5-7th intercostal cartilage
-tendinous insertions form part of rectus sheath at umbilical, xiphoid, and midway levels
Innervation: ventral rami of T7-T12
Action: flexes abdomen and compresses it
Linea semilunaris- lateral border of rectus abdominis m.
Pyramidis m- missing in 20%
Rectus Sheath
- content
- Description of EO, IO, TA
- arcuate line definition
- made of fascia and aponeurosis of muscles encompassing RA
- EO aponeurosis is always anterior
- IO aponeurosis splits in upper 3/4s but all anterior in lower 1/2
- TA aponeurosis is posterior except in lower 1/4
Arcuate line
- sharp transition where all EO, IO, TA aponeuroses become anterior to RA m.
- so below line, the rectus abdominis is in contact with transversalis fascia
Thoraco-abdominal Nerve
T7-T11 continuation of intercostal n - sensory and motor innervation - run between TA and IO m. - lateral thoracic cutaneous branches of thoracic spinal nerve T7-T9 or 10
Subcostal Nerve
T12
run along inferior 12th rib
- motor
- sensory is superior to iliac crest
Iliohypogastic Nerve
L1
runs between 2nd and 3rd layer
- motor to IO and TA
- sensory bifurcate to upper inguinal and hypogastric region
Ilioinguinal Nerve
L1
- motor lower IO and TA
- sensory to lower inguinal
- anterior scotum/labia, near medial thigh
