Abdomen - Lecture 1 Flashcards
Superior Border of the Abdominal Cavity?
Diaphragm
Inferior Border of the Abdominal Cavity?
Continuous with the Pelvic Cavity
Posterior Border of the Abdominal Cavity?
Vertebral Column and Abdominal Wall
Lateral and Anterior Border of the Abdominal Cavity?
Abdominal Wall with ribs in Superior Portion
Because of the dome shape of the diaphragm…
Many abdominal organs (stomach, spleen, liver) are protected by thoracic wall and diaphragm.
Orientation of Abdomen and Pelvis
Abdomen- vertical
Pelvis- diagonal tilt backwards
What is the Serous Membrane of the Abdomen?
Peritoneum (has a visceral and parietal layer) and continues into the pelvis
Mesentery
Double layer of Peritoneum that folds over onto itself and suspends organs in the abdominal cavity by anchoring them to the POSTERIOR Abdominal Wall
4 Quadrants of the Abdominal Cavity (Clinically preferred)
Right Upper, Left Upper, Right Lower, Left Lower
SS Abdomen 1
Planes that make the 4 Quadrants of the Abdominal Cavity (Clinically preferred)
Horizontal/Transumbilical Plane (ventrally it goes through the umbilicus and dorsally passes between L3 and L4) Vertical Plane (from Xiphoid Process to Pubic Symphysis) (SS Abdomen 1)
9 regions of the Abdominal Cavity (Anatomist preferred)
- Right Hypochondrium
- Epigastric Region
- Left Hypochondrium
- Right Flank (Lumbar)
- Umbilical
- Left Flank (Lumbar)
- Right Groin (Inguinal)
- Pubic
- Left Groin (Inguinal)
(SS Abdomen 2)
Planes that demarcate the 9 Abdominal Cavity Regions
Subcostal Plane (Horizontal; lower border of Rib 10 Costal Cartilage and L3) Intertubercular Plane (Horizontal; connects tubercles of Iliac Crests) Midclavicular Planes (Vertical; go from midpoint of clavicles to the a point between pubic symphysis and anterior superior iliac spine) (SS Abdomen 2)
Components of Abdominal Wall
- Bony Components
- Muscular Components (Majority)
- Fascial Components
Bony Components of Abdominal Wall
- Lumbar Vertebrae
- Upper wings of Pelvic Bones
- Costal Margin
- Floating Ribs (11 and 12)
Muscular Components of Abdominal Wall
- Anteriorly: Rectus Abdominus
- Laterally: External Oblique, Internal Oblique, and Transversus Abdominis
- Posteriorly: Quadratus Lumborum and Iliopsoas
(SS Abdomen 3)
Quadratus Lumborum
Bilateral (either side of the Lumbar Vertebrae) flat muscle that makes up a good amount of posterior abdominal wall; kidney sits on part of this
(SS Abdomen 3)
Iliopsoas
Hip flexors; combination of the muscles Iliacus and Psoas Major since they have a common origin
(SS Abdomen 3)
Superficial Fascia layers of Abdominal Cavity
Above Arcuate Line:
Camper’s Fascia
Below Umbilicus:
1. Camper’s Fascia (most superficial fatty layer)
2. Scarpa’s Fascia (deeper membranous layer
Campers Fascia
Most Superficial fatty, protective layer of Abdominal Cavity Superficial Fascia
Scarpas Fascia
- Deepest Layer of Abdominal Cavity Superficial Fascia below the Umbilicus
- MEMBRANOUS
- Fuses with Fascia Lata in the thigh
- Becomes Colles Fascia in the Perinuem
- Becomes Dartos Fascia in the Penis/Scrotum
Dartos Muscle
A Smooth Muscle continuation of the deep layer of Superficial Fascia present in the Penis and Scrotum
Side Note: Scarpas- in the Abdomen below the Umbilicus
Colles- in Perinem
Dartos- Penis and Scrotum
External Oblique
- Most SUPERFICIAL of Lateral Muscles Abdominal Cavity
- Hands in pockets Orientation (Inferomedial)
- Aponeurosis (thick flat tendinous insertion that attaches to Linea Alba (midline)
- Twists
- Compresses Abdomen (supports abdominal components and posture)
Aponeurosis
Thick flat membranous insertion of an Abdominal muscle such as the Internal or External Oblique or Transversus Abdominus that attaches to the Linea Alba (midline)
Inguinal Ligament
- Formed by External Ligament Aponeurosis
2. Originates from ASIS (Anterior Superior Iliac Spine) and Inserts at Pubic Tubercle
Internal Oblique
- Deep to External Oblique
- Same Plane as Rectus Abdominus
- Fibers run Superomedially (OPPOSITE of hands in pockets)
- Ends at Linea Alba (midline)
- Compresses Abdomen & Twists
Linea Alba
Midline of Abdominal Cavity that runs from Xiphoid Process down to Pubic Symphysis
Rectus Abdominus
- Long, flat, vertical muscle
- Bilateral; each pair separated at Linea Alba
- Origin: Pubic Crest (Symphysis and Tubercle)
- Insertion: Costal Margin
- 4 or 5 Tendinous Intersections perpendicular to muscle fibers (prevent over-contraction)
- Enclosed in Rectus Sheath (Aponeurosis of abdominal wall muscles and Transversalis Fascia)
- Compresses Abdomen and Flexes Trunk
Rectus Sheath
Aponeurosis of the abdominal muscles that surround the Rectus Abdominus.
ABOVE Arcuate Line:
- Anterior Side: External Oblique, Internal Oblique
- Posterior Side: Internal Oblique and Transversus Abdominus
BELOW Arcuate Line:
- Anterior Side: External Oblique, Internal Oblique, and Transversus Abdominus
- Posterior Side: Transversalis Fascia
Transversus Abdominus
- Deepest Abdominal Muscle
- Fibers run horizontally
- Insertion at Linea Alba
- Compresses Abdomen
Deep Fascia Layers of Abdominal Cavity
- Transversalis Fascia
2. Extraperitoneal Fascia
Transversalis Fascia
- Deep to Transversus Abdominus
- Continuous Layer of Deep Fascia that lines Abdominal and Pelvic Cavities
- Continuous with Inferior Diaphragm Surface and Posterior Muscles
- Superficial to Peritoneum
- Direct Contact with Rectus Abdominus posteriorly below Arcuate Line
ABOVE Arcuate Line the Rectus Abdominus is surrounded by…
Rectus Abdominus surrounded by:
- Anterior Rectus Sheath (Internal and External Oblique Aponeuroses)
- Posterior Rectus Sheath (Internal Oblique and Transversus Abdominus Aponeuroses)
BELOW Arcuate Line the Rectus Abdominus is surrounded by…
Rectus Abdominus surrounded by:
- Anterior Rectus Sheath (Internal and External Oblique AND Transversus Abdominus Aponeuroses)
- Transversalis Fascia
Extraperitoneal Fascia
- Deep to Transversalis Fascia separating it from Peritoneum
- Lines Abdominal and Pelvic Cavities
- Abundant on Posterior Wall
- Houses the Vasculature
- Organs in Extraperitoneal Fascia are Retroperitoneal