Muscles & Structures of the Abdominal Wall/Pelvis Flashcards
External oblique
Action
- Compresses and supports abdominal viscera
- flexes and rotates the trunk
External oblique
Innervation
Thoracoabdominal nn. T7–T11 and subcostal n.
External oblique
Blood supply
Superior and inferior epigastric a.a
Internal oblique
Innervation
Thoracoabdominal nn. T7–T11, subcostal n., and L1
Internal oblique
Blood supply
Superior and inferior epigastric a.a., deep circumflex iliac a.a.
Transversus abdominus
Action
- Compresses and supports abdominal viscera
- flexes and rotates the trunk
Transversus abdominus
Innervation
Thoracolumbar nn. T7-T11, subcostal n., and L1
Transversus abdominus
Blood supply
Deep circumflex iliac and inferior epigastric a.a.
Rectus abdominis
Origin
Xiphoid process, costal cartilages 5–7
Rectus abdominis
Insertion
Pubic symphysis, and pubic crest
Rectus abdominis
Action
Flexes trunk, assists in pelvic tilt, and compresses abdominal viscera
Rectus abdominis
Innervation
Thoracoabdominal nn. T7–T11 and subcostal n.
Rectus abdominis
Blood supply
Superior and inferior epigastric a.a.
Transverse mesocolon attachments
- Attaches transverse colon to the anterior surface of the duodenum and pancreas (along the posterior abdominal wall)
- Left end: phrenicocolic ligament, which attaches the left colic flexure to the diaphragm
Psoas major
Origin
Lumbar vertebrae (bodies, intervertebral discs, and transverse processes)
Psoas major
Insertion
Lesser trochanter of the femur
Psoas major
Action
Flexes the thigh and extends the vertebral column
Psoas major
Innervation
L1–L4 (anterior rami)
Psoas major
Blood supply
Lumbar branches of iliolumbar artery
Psoas minor
Origin
Lateral surface of T12 and L1
Psoas minor
Insertion
Iliopubic eminence and arcuate line of the ilium
Psoas minor
Action
Tilts pelvis posteriorly
Psoas minor
Innervation
L1–L2 (anterior rami)
Psoas minor
Blood supply
Lumbar branch of iliolumbar artery
Iliacus
Origin
Iliac fossa
Iliacus
Insertion
Lesser trochanter of the femur
Iliacus
Action
Flexes the thigh
Iliacus
Innervation
Femoral n.
Iliacus
Blood supply
Iliac branches of iliolumbar artery
Quadratus lumborum
Origin
12th rib and lumbar transverse processes
Quadratus lumborum
Insertion
Iliolumbar ligament and iliac crest
Quadratus lumborum
Action
Flexes vertebral column laterally and anchors the rib cage during respiration
Quadratus lumborum
Innervation
T12–L4 (anterior rami)
Quadratus lumborum
Blood supply
Iliolumbar artery
Superficial inguinal canal borders
Anterior: External oblique aponeurosis
Posterior: Conjoined tendon and transversus abdominus aponeurosis
Superior: Internal oblique and transverus abdominus aponeuroses
Inferior: Inguinal ligament and lacunar ligament
Lumbar plexus nerves (roots)
- Ilio-inguinal nerve (L1)
- Iliohypogastric nerve (L1)
- Lateral cutaneous nerve of thigh (L2, L3)
- Femoral nerve (L2-L4)
- Genitofemoral nerve (L1, L2)
- Obturator nerve (L2-L4)
- Lumbosacral trunk (L4, L5)
Ilioinguinal nerve course
From L1
- Enter the abdomen posterior to the medial arcuate ligaments
- Run between the transversus abdominis and internal oblique
Ilioinguinal nerve
area it supplies
Supply the skin of the suprapubic and inguinal regions.
Iliohypogastric nerve course
L1
- Runs above ilioinguinal n.
- Enter the abdomen posterior to the medial arcuate ligaments
- Run between the transversus abdominis and internal oblique
Iliohypogastric nerve (area it supplies)
Supply the skin of the suprapubic and inguinal regions
Lateral cutaneous nerve of the thigh nerve course
L2, L3
- Enters the thigh posterior to the inguinal ligament, just medial to the anterior superior iliac spine
Lateral cutaneous nerve of the thigh (area it supplies)
- Skin on the anterolateral surface of the thigh
Femoral nerve course
Emerges from the lateral border of the psoas
Femoral nerve (area it supplies)
Innervates the iliacus muscle and the extensor muscles of the knee
Genitofemoral nerve course
L1, L2
- Pierces the anterior surface of the psoas major muscle
Obturator nerve course
L2-L4
- Emerges from the medial border of the psoas