Untitled Quiz

Anterior Abdominal Wall Anatomy

• Superior boundary: Diaphragm, separating respiratory and abdominal cavities
• Inferior boundary: Pelvic inlet
• Anterior structures: Skin, subcutaneous tissue, and anterior abdominal wall muscles
• Posterior structures: 5 lumbar vertebrae, intervertebral discs, psoas major, and quadratus lumborum muscles

Abdominal Cavity

• Includes structures superior to the diaphragm
• The diaphragm separates the respiratory and abdominal cavities
• The pelvic inlet is the inferior boundary of the abdominal cavity
• The abdominal cavity has layers of skin, subcutaneous tissue, and muscles
• The posterior aspect includes parts of the vertebral column, discs, psoas, and quadratus lumborum muscles

Abdominal Quadrants

• The abdomen is divided into four quadrants
• Right upper quadrant: Liver, gallbladder
• Left upper quadrant: Stomach, spleen
• Right lower quadrant: Ascending colon, anterior superior iliac spine, inguinal ligament, and pubic tubercle
• Left lower quadrant: Descending colon, sigmoid colon, and iliac spine

Regions of the Abdomen

• The abdomen is sectioned into various areas
• Vertical lines: Lateral border of rectus abdominus muscle, midpoint of inguinal ligament, mid-clavicular line
• Horizontal lines: Subcostal line (inferior margin of 10th costal cartilage), transpyloric line (tip of the 9th costal cartilage), intertubercular/interspinous line (between the two anterior superior iliac spines)
• Body regions: hypochondriac (uppermost area), lumbar (middle area, lateral to the rectus abdominis muscles), and iliac (lowermost, lateral to the rectus abdominis muscles)
• Different areas have different anatomical structures

Superficial Fascia of Anterior Abdominal Wall

• Superficial layer: Camper's fascia (fatty layer)
• Deep layer: Scarpa's fascia (membranous layer)
• Structures involved in this layer include the skin, penis, Scrotum, dartos fascia, and fascia lata

Layers of Abdominal Wall

• The abdominal wall has multiple layers and structures
• Superficial layer includes skin, Camper's fascia, and Scarpa's fascia; superficial fascia layers
• Deep layers include muscles and connective tissues; external oblique, internal oblique, transversus abdominis, and rectus abdominis muscles.
• Posterior wall of rectus abdominis sheath, external oblique, internal oblique, transversus abdominis, and transversalis fascia

Innervation

• Anterior abdominal wall: Lower 6 thoracic spinal nerves, 1st lumbar spinal nerve (iliohypogastric & ilioinguinal nerves)
• Nerves of the anterior abdominal wall: Lateral cutaneous branches of intercostal nerves, anterior cutaneous branch of T10, lateral cutaneous branch of subcostal nerve, lateral cutaneous branch of iliohypogastric nerve

Arterial Supply

• Upper extremity: Superior epigastric artery
• Lower extremity: Inferior epigastric artery
• Thoracic: Intercostal arteries
• Lumbar: Lumbar arteries

Venous Drainage

• Axillary vein drains thorax area superiorly, and femoral vein drains down.
• Drainage is also present via paraumbilical veins into the portal structures

Muscles of Anterior Abdominal Wall

• External abdominal obliques
• Internal abdominal obliques
• Transversus abdominis
• Rectus abdominis
• Cremasteric muscle
• Pyramidalis muscle

Muscles of the Abdominal Wall

• Includes muscles important to the abdominal wall
• These muscles include layers of external oblique, internal oblique, and transversus abdominis.
• The abdominal wall also contains rectus abdominis and pyramidalis muscles.

Inguinal Canal

• The inguinal canal is a passageway in the anterior abdominal wall
• Anteriorly: skin, superficial fascia, aponeurosis of external oblique muscle
• Posteriorly: medial 1/3 by conjoint tendon and transversalis fascia
• Superiorly: arched fibers of internal oblique and transversus abdominis muscle
• Inferiorly: inguinal ligament

Inguinal Region

• The inguinal region is the junction of the anterior abdominal wall and thigh; various structures and nerves pass through
• Structures include inguinal canal, deep inguinal ring, superficial inguinal ring, spermatic cord (male), round ligament of the uterus (female) and lymphatic vessel connections

Contents of Inguinal Canal

• Male: Spermatic cord (vas deferens, testicular artery, testicular vein, and autonomic nerves)
• Female: Round ligament of the uterus
• Both: Ilioinguinal nerve (sensory and motor innervation)

Abdominal Hernias

• Types : Femoral, umbilical, epigastric, and inguinal hernias (direct and indirect)
• Ventral hernias is used to refer to hernias in general, and not be confused with inguinal hernias

Deep Inguinal Ring

• Oval opening in the transversalis fascia
• Important passageway for structures and vessels in the groin
• Critical for understanding the anatomy of the groin and the structures related to reproductive organs

Pyramidalis Muscle

• Origin: Anterior surface of the pubis
• Insertion: Linea alba
• Function: Tenses the linea alba; small muscle
• Innervation: Lumbar nerve;

Contents in Rectus Sheath

• Muscle tissue and important vessels and nerves
• Important structures : rectus muscle, pyramidalis muscle, anterior rami of lower 6 thoracic spinal nerves, superior and inferior epigastric vessels, and lymphatic vessels

Arterial Supply to Abdominal Wall

• Superior epigastric artery (upper abdominal wall)
• Inferior epigastric artery (lower abdominal wall)
• Intercostal arteries (thoracic portion)
• Lumbar arteries (inferior portion)

Venous Drainage

• Upper extremity : Axillary vein
• Lower extremity : Femoral vein
• Includes smaller veins that accompany the arteries.