Abdominal Wall Anatomy PDF

# Paroi Abdominale ## Introduction The abdominal wall is divided into two parts: - Anterior and lateral: musculo-aponeurotic - Posterior: osteo-muscular The anterior and lateral wall contains the large muscles of the abdomen: - Rectus muscle medially - The internal oblique muscle, the external ob...

# Paroi Abdominale ## Introduction The abdominal wall is divided into two parts: - Anterior and lateral: musculo-aponeurotic - Posterior: osteo-muscular The anterior and lateral wall contains the large muscles of the abdomen: - Rectus muscle medially - The internal oblique muscle, the external oblique muscle, and the transverse muscle This wall is in direct contact with the digestive viscera A musculo-aponeurotic tunnel is located at its lower part (inguinal canal) The posterior wall mainly relates to the urinary system, the large blood vessels, and the abdominal nerve plexuses ## Paroi Antero-Latérale (Plan cutanée) - **Superior:** xiphoid process and 7th costal cartilage - **Inferior:** iliac crest, inguinal ligament, and pubis The anterior and lateral wall is divided into 9 regions: epigastric, umbilical, hypogastric, hypochondriac, lateral, and inguinal regions ## Paroi Antero-Latérale (Muscles) ### Rectus muscle - Pair and ventral muscle, located in an aponeurotic sheath: rectus sheath - **Origin:** anterior surface of ribs 5-6, costal cartilages 6-7, and xiphoid process - **Course:** vertical with 3-4 tendinous intersections - **Insertion:** crest of the pubis - **Innervation:** intercostal nerves 6-11, and subcostal nerve ### Pyramidal muscle - Pair and triangular muscle, located anterior to the inferior part of the rectus muscle - **Course:** extends from the linea alba to the crest of the pubis - **Innervation:** subcostal nerve ### External oblique muscle - Superficial muscle, originating from the external surfaces of ribs 6-12 - **Course:** flat muscle with oblique fibers inferiorly and medially - **Insertion:** - Posterior: iliac crest - Anterior: participates in forming the rectus sheath - Inferior: forms two pillars: - **Lateral:** inserts onto the inguinal ligament - **Medial:** inserts onto the pubis - **Innervation:** intercostal nerves 6-11, and subcostal nerve ### Internal oblique muscle - Located against the internal surface of the external oblique muscle - **Origin:** thoracolumbar fascia, iliac crest, and inguinal ligament - **Course:** fan-shaped ending - **Superior:** external surface of ribs 10-12 and the 10th costal cartilage - **Anterior:** participates in forming the rectus sheath - **Inferior:** joins the transverse abdominal muscle forming the **conjoint tendon** (which attaches to the pubic crest) - **Innervation:** intercostal nerves 10-11, subcostal nerve, and iliohypogastric nerve ### Transverse abdominal muscle - Deepest of the anterior and lateral abdominal muscles - **Origin:** anterior 2/3 of iliac crest - **Course:** transverse fibers - **Insertion:** participates in forming the rectus sheath - **Innervation:** intercostal nerves 7 - 11, subcostal nerve, iliohypogastric nerve, and ilioinguinal nerve ### Cremaster muscle - Originates from the internal oblique muscle, consisting of two bundles: - **Lateral:** originating from the internal oblique muscle - **Medial:** originating from the pubis - **Innervation:** genitofemoral nerve (cremasteric reflex L2,L3) ## Paroi Antero-Latérale (Fascias) ### Rectus sheath - A fibrous sheath encompassing the rectus and pyramidal muscles, composed of: - 2 laminae (posterior and anterior) in its superior 2/3 - 1 anterior lamina in its inferior 1/3 - The large abdominal muscles (external oblique, internal oblique, and transverse) participate in its formation ### Linea alba - Marks the midline meeting point of the rectus sheaths - Extends from the xiphoid process to the pubic symphysis - The functional efficiency of the abdominal muscles depends on its solidity ### Umbilicus - Abdominal depression located just below the middle of the linea alba ### Transversalis fascia - Located deep to the transverse abdominal muscle and the rectus sheaths - **Superior:** continuous with the diaphramatic fascia - **Inferior:** attaches to the iliac crests, the inguinal ligament - **Posterior:** attaches to the anterior lamina of the thoracolumbar fascia ## Canal inguinal - Oblique canal 5 cm long, located above the inguinal ligament. - Has 4 walls: anterior, posterior, superior, and inferior, and 2 openings (superficial and deep). - Contains the spermatic cord (in men) and the round ligament of the uterus (in women). ### Walls - **Anterior:** skin, superficial abdominal fascia, lateral pillar of the external oblique muscle, and the lateral 1/3 of the internal and transverse muscles - **Posterior:** medial pillar and transversalis fascia - **Superior:** inferior border of the internal and transverse muscles. - **Inferior:** inguinal ligament. ### Openings - **Superficial:** medial, bordered by the medial and lateral pillars of the external oblique muscle. - **Deep:** lateral, formed by an invagination of the transversalis fascia. This opening lies above the inguinal ligament and below the inferior border of the transverse muscle. ## Paroi Postérieure - **Superior:** T12 vertebra and the 12th rib. - **Inferior:** iliac crests. ### Superficial layer - **Components:** posterior lamina of the thoracolumbar fascia, latissimus dorsi muscle, and the external oblique muscle. ### Middle layer - **Components:** erector spinae muscles, internal oblique muscle, and the serratus posterior inferior muscle. ### Deep layer - **Components:** transverse abdominal muscle, the costo-lumbar ligament, quadratus lumborum muscle (enclosed by the middle and anterior laminae of the thoracolumbar fascia), and the psoas muscle. - **Innervation:** thoracolumbar fascia. ## Intérêt clinique - **Abdominal hernias:** tears in the abdominal wall that occur at weak points, which can involve viscera and their strangulation. - **Inguinal hernias:** occur above the inguinal ligament, in contrast to femoral hernias (below the ligament), due to weakness in those areas or congenital malformations. - **Omphalocele:** congenital malformation due to non-closure of the abdominal wall, leading to externalization of the viscera. ## Terminologie | **New anatomical nomenclature** | **Old anatomical nomenclature** | |---|---| | Inguinal ligament | Crural arch |