What are some anterior abdominal wall surface landmarks?
Surface features: linea alba (medial border of rectus sheath), semilunar line (lateral border of rectus sheath), umbilicus, inguinal ligament (junction between abdomen and thigh)
What is the Abdominal cavity and location
The major part of the abdominopelvic cavity
Located beetween the diaphragm and the pelvic inlet
Separated from throacic cavity by thoracic diaphragm
Continuous inferiorly with the pelvic cavity
Under cover of the thoracic cage superiorly
Supported and par
Boundaries of anetrolateral abdominal wall
superiorly: caritlages of ribs 7-10 and xiphoid process of sternum
inferiorly: inguinal ligament and superior margins of pelvic gridle (ilicac crests, pubic crests, pubic symphysis)
Clinicians refer to nine regions of the abdominal cavity to descibe the location of abdominal organs, pains or pathologies
The nine regions are delineated by 4 planes:
2 sagittal (vertical) and 2 transverse (horizontal)
2 sagittal planes are usually the midclavicular planes that pass from midpoint of clavicles to the midinguinal points
Transverse planes intersect palpable structure
4 quadrants of the abdominal cavity (right and left upper and lower quadrants)
Defined by two readily defined planes
1) transverse - transumbilical plane
2) vertical median plane
Can you identify which organs are in which quadrants of the abdominal?
What is Mcburney Point?
Gridiron (muscle-splitting) incisions are often used for an appendectomy
Oblique McBurney incision is made at the McBurney point, approximately 2.5 cm superomedial to the ASIS on the spinoumbilical line
What are lines of langer?
Tension lines in the skin, the predominant direction of the collage fiber bundles in the dermis
Parallel Incisions have less tendency to gape than those crossing them
What are the layers of the anterolateral abdominal wall (superficial to deep)
Skin
Camper Fasica (superficial fatty layer of subcutaneous tissue)
Scarpa Fascia (deep membranous layer of subcut. tissue)
Aponeuros. External Oblique (Investing deep fascia, superfical)
External Oblique
Aponeuros of Internal Oblique (Invesitng deep fasc
Differentiate between fascia in upper abdomen from lower abdomen
The superficial fascia (sub cutaneous) layer is modified in the lower abdomen to include a superficial fatty layer and a deep membranous layer.
The superficial fatty layer is specialized, particularly in males for lipid sotrage
Deep membranous layer for c
What is the clinical significance of endoabdominal fascia (transversalis)?
In surgery, this enable the establishment of an extraperitoneal space that allows anterior access to retroperiteneal structures (kidneys, ureters and bodies of lumbar vertebra) without entering the peritoneal cavity
What is another name for deep membranous layer?
Scarpa Fascia
This layer continues inferiorly into the perineal region as the superficial perineal fascia (COLLES Fascia), but not into the thighs
What is another name for superficial fatty layer of subcutaneous tissue?
Camper Fascia
How many bilaterally paired muscles are there in the anterolateral abdominal wall?
5 total
3 flat muscles
(external obliq., internal obliq., and transverse abdominal)
2 vertical muscles (found within rectus sheath)
(rectus abdominus and pyramidalis)
What is the direction of the fibers of the external oblique?
Unlike the other two flat muscles, external oblique DOES NOT originate from____?
(Think Hands in Pocket)
posteriorly from Thoracolumbar fasica
Its posteriormost fibers have a free edge where they span bw its costal origin and the iliac crest
What is the direction of the fibers of the internal oblique?
(Think direction of fingers when placed over chest)
What are the functions and actions of Anterolateral Abdominal Muscles?
Form a strong expandable support for wall
Protect viscera from injury
Compress the abdominal contents to maintain or increase the intra-abdominal pressure, oppose the diaphragm (increased intra-abdominal pressure facilitates expulsion)..elevate diaphragm
What is the rectus sheath
the strong, incomplete fibrous compartment of the rectus abodminus and pyramidalis.
also found in the sheath are the superior and inferior epigastric arteries and veins, lymphatic vessels, T7-T12 nerves
What is the significance of the arcuate line?
The rectus sheath is a tough, tendinous sheath over the rectus abdominis muscle. It covers the entire anterior surface of the rectus abdominis. However, on the posterior side of the muscle, the sheath is incomplete-- it ends inferiorly at the arcuate line
What is Linea alba
runs vertically the entire length of the anterior abdominal wall and separates the bilateral rectus sheath
Contains the umbilical ring
Summary points of muscles
3 (flat horizontal), 2 vertical muscles
Fibers of aponeuroses interlace in the midline, forming the Linea Alba, and continue into the contralateral muscles
Three layers of flat, bilateral digastric muscles encircle the trunk, forming oblique and and trans
What is the innervation of Anterolateral Abdominal Wall?
Multi-segmental innervation. Rami pass separately to the muscles without uniting
VPR of T7 - L1
T7-T11 = Thoracoabdominal Nerves (Distal inf. intercostals n)
Lateral Thoracic cutaneous branches (T7-T9 or T10)
Subcostal nerve - T12
Ilihypogastric and ilioi
T10 Dermatome
L1 Dermatome
Umbilicus
inguinal fold
What is the Blood supply of the anterolateral abdominal wall? what are they branches of?
Blood supply is provided by the lower intercostal arteries (from thoracic aorta) and the superior/inferior epigastric arteries (branches of internal thoracic and external iliac, respectively).
Superior Epigastric Artery
Direct continuation of the Internal Thoracic Artery
Enters rectus sheath superiorly through its posterior layer
Supplies superior part of the rectus abdominis and anastomoses with the inferior epigastric artery in the umbilical region
Inferior Epigastric Artery
Arises from External Iliac Artery, just superior to the inguinal ligament
Runs superiorly in the transversalis fascia to enter the rectus sheath below the arcuate line
Enters the lower rectus abdominis and anastomoses with superior epigastric artery
10th and 11th posterior intercostal arteries
Arise from Thoracic Aorta
Between internal oblique and transverse abdominal
Supplies superficial and deep abdominal wall of lateral region
Where do superficial lymphatic vessels drain to?
Superficial (unpaired) vessels (superior to umbilicus) drain the superficial fascia to the axillary lymph nodes
Superficial vessels (inferior to umbilicus) drain to inguinal lymph nodes
Describe venous drainage in abdominal wall
Pattern of superficial venous drainage is more vertical than transverse (circumferential)
Thoracoepigastric vein, formed of anastomosing tributaties of the lateral thoracic (axillary) and superficial epigastric (femoral) veins, is capable of providing col
Summary of vessels
Skin and subcutaneous tissue of ab wall drain superiorly (to SVC) via Internal thoracic vein meidally and the lateral thoracic vein laterally
Inferiorly (to the IVC) wia the superficial and inferior epigastric veins
Cutaneous veins surrounding the umbilic
Priamry features of internal suface of the anterolateral abdominal wall
Peritoneal folds overylying structures radiating form the umbilical ring and the peritoneal fossae
Central 3 umbilical peritoneal folds (median, medial) cover remnants of embryological structures
Lateral folds cover inferior epigastric vessels***
Transiti
What is the Peritoneum
Continuous serous membrane that lines the ab cavity (parietal) and the contained viscera such as stomach and intestines (visceral)
What layers would be incised when approaching the appendix from McBurney's point.
Following incision of the skin and subcutaneous tissue, the external oblique aponeurosis is incised along the lines of its fibers
Obening is then made in same way in internal oblique and transverse abdominal muscles, thus avoiding nerve supply
Iliohypogas
Which abdominal muscles are capable of tensing the thoraco-lumbar fascia? What does this achieve?
Transverse Abdominal and Internal Oblique
Compression and support of abdominal viscera for respiration
What is cut when entering the abdomen in the midline, and what are the clinical implications of this incision.
relatively bloodless and avoids major nerves
cut through fibrous tissue of the Linea alba, superior and/or inferior to umbilicus
What is in each quadrant?
Whats in each section?
What are the major skeletal landmarks of abdominalpelvic cavity?
ribs, sternum, infrasternal angle and costal margin
iliac crests, anterior superior iliac spines, and posterior superior iliac spines: These structures mark points in the inferior portion of the abdomen.
pubic crests and pubic tubercle: These structures m
What does the superficial inguinal ring transmit in the female? In the male?
Both: ilioinguinal nerve
Female: round ligament of the uterus
Male: spermatic cord, covered by cremaster muscle and fascia, and internal spermatic fascia
At what level (relative to the umbilicus) do you find the arcuate line?
The arcuate line is a transverse line halfway between umbilicus and pubic symphysis