Anterolateral & Posterior Abdominal Walls Flashcards
Describe the layers of the anterolateral abdominal wall from Superficial to Deep.
- Skin
- Campers Fascia (Superficial Fatty layer)
- Scarpas Fascia (Deep Membranous layer)
- External Oblique m.
- Internal Oblique m.
- Transversus Abdominis m.
- Trasversalis Fascia
- Extraperitoneal fat
- Parietal Peritoneum
What 2 structures fuse to form the inguinal ligament?
What 2 structures fuse to form the “line of fusion” next to the Inguinal ligament?
External Oblique aponeurosis fuses with fascia lata of the thigh to form the Inguinal Ligament.
Scarpas fascia (membranous layer) fuses with the Fascia Lata of the thigh to form the Line of Fusion.
What is the abdominal aponeurosis?
What is it composed of?
What structure does it form?
The abdominal Aponeurosis is a broad flat tendon formed by fibers of the 3 flat abdominal muscles (which become aponeurotic at the midclavicular line). This tendonous structure forms the Rectus Sheath of the Rectus abdominis m.
What are the muscles of the Anterolateral Abdominal wall?
- External Oblique
- Internal Oblique
- Transversus Abdominis
- Rectus Abdominis
The location at which the abdominal flat muscles become aponeurotic is referred to as what?
What is the structure at which these aponeurotic structures join together on the midline?
Linea Semilunaris
Linea Alba
What is the arcuate line?
The arcuate line is the point (midway between umbilicus & pubic symphysis) at which the rectus sheath organization changes.
Above the arcuate line, the posterior rectus sheath is present & composed of TA & part of IO aponeurosis.
Below the Arcuate line, the posterior rectus sheath is absent.
What is the purpse of the Arcuate Line?
The arcuate line allows for the External Iliac a. > Inferior Epigastric a. to move into the Rectus sheath and supply the inferior portion of the Rectus Abdominis
What are the (4) major functions of the abdominal wall muscles?
- Maintenance of abdominal tone: Tensing the abdominal wall & compressing the abdominal viscera
- Stabilizing the vertebrae and reducing stresses on the spinal column
- Moving the trunk & pelvis
- Assisting in respiration
Describe the muscles associated with trunk movements
Trunk Flexion: Internal & External obliques (+ intrinsic back muscles)
Trunk Rotation: Transversus Abdominis (+ Intrinsic back muscles)
Trunk Flexion: Rectus Abdominis
How can intra-abdominal pressure be increased?
For what processes is this important for?
Abdominal muscles contract which reduces volume of the abdominal cavity, thereby increasing intra-abdominal pressure & actively compressing the abdominal viscera.
Important for:
- Defecation
- Micturition
- Vomiting
- Expulsive phase of labor
What spinal nerves innervate the dermatomes of the ALA wall?
T7-L1
What is the purpose of the Inguinal Canals?
Allows the Spermatic Cord to descend through the deep inguinal ring (Transversalis Fascia) and Superficial Inguinal ring (Ext. Oblique aponeurosis) down into the scrotum.
- Allows contents of the scrotum to communicate w/ intra-abdominal contents
- Allows blood vessels, nerves, & lymphatics to supply the scrotal contents
Describe the structure (borders & orientation) of the Inguinal Canal
Borders:
Floor: Inguinal Ligament
Posterior Wall: Transversalis Fascia (w/ lateral Deep Ring)
Anterior Wall: External Oblique Aponeurosis (w/ medial Superficial Ring)
Roof: Arching fibers of transversus abdominis & internal oblique m.
What contents travel through the spermatic cord?
- Testicular arteries
- Testicular veins
- Vas Deferens
What are the (3) Abdominal folds?
What structures run through them?
- Lateral Umbilical Fold: Inferior epigastric vessels
- Medial Umbilical Fold: Medial umbilical ligament (Obliterated umbilical arteries)
- Median Umbilical Fold: Obliterated Urachus (joined apex of fetal bladder to umbilicus)
What are the (2) Inguinal Fossa’s relative to the Umbilical folds?
What are their significance?
Medial Inguinal Fossa: Site of Direct Inguinal Hernia, between the Medial & Lateral Umbilical Folds.
AKA Inguinal/Hesselbachs triangle
Lateral Inguinal Fossa: Site of Indirect Inguinal Hernia, Lateral to the Lateral Umbilical Fold.
