Abdominal Wall Flashcards
Rectus abdominis Origin (lateral and medial head)
Lateral Head: Crest of pubis to pubic tubercle
Medial Head: Anterior region of pubic symphysis
Rectus abdominis insertion
Cartilages of ribs 5-7, xiphoid process of sternum
Rectus abdominis innervation
Intercostal n. T5-T12
Rectus abdominis action
flexes trunk, compresses abdomen, stabilizes pelvis
External oblique origin
ribs 5 to 12
external oblique insertion
linea alba, pubic tubercle, anterior iliac crest
External oblique innervation
Intercostal n. T7-T12
External and Internal Oblique Action
Unilateral: bends trunk to same side, rotates trunk to opposite side
Bilateral: Flexes trunk, compresses abdomen, stabilizes pelvis
Internal oblique origin
Thoracolumbar fascia (deep), iliac crest, anterior superior iliac spine, iliopsoas fascia
Internal oblique insertion
Ribs 10-12 (lower borders), linea alba
Internal oblique and transversus abdominis innervation
Intercostal n. T7-T12
iliohypogastric n.
ilioinguinal
Transversus abdominis origin
costal cartilage 7-12, thoracolumbar fascia (deep), iliac crest, anterior superior iliac spine, iliopsoas fascia
Transversus abdominis insertion
linea alba, pubic crest
Transversus abdominis action
Unilateral: Rotates trunk to same side
Bilateral: compresses abdomen
Psoas major superficial layer origin
T12-L4 vertebral bodies and associated intervertebral disks
Psoas major deep layer origin
L1-L5
Psoas major, minor, and iliacus common insertion
Lesser trochanter of femur, joint insertion as iliopsoas muscle
Psoas Major innervation
Direct branches from lumbar plexus L2-L4
Psoas Major action
Hip Joint: Flexion and external rotation of lumbar spine (with femur fixed)
Unilateral: Contraction bends trunk laterally
Bilateral: Contraction raises trunk from supine position
Psoas minor origin
T12, L1 vertebrae and intervertebral disk
Psoas minor innervation
Direct branches from lumbar plexus L2-L4
Iliacus origin
iliac fossa
iliacus innervation
Femoral n. L2-L4
Quadratus lumborum origin
Iliac crest and iliolumbar ligament
Quadratus lumborum insertion
12th rib, transverse processes of L1-L4 vertebrae
Quadratus lumborum innervation
T12, L1-L4 spinal n.
Quadratus lumborum action
Unilateral: bends trunk to same side
Bilateral: Bearing down and expiration, stabilizes 12th rib
diaphragm costal part origin
ribs 7-12 (inner surface; lower margin of costal arch)
Diaphragm lumbar part origin
Medial part: L1-L3 vertebral bodies, intervertebral disks, and anterior longitudinal ligament as right and left crura
Lateral part: lateral and medial arcuate ligaments
Diaphragm sternal part origin
Xiphoid process (posterior surface)
Diaphragm insertion
Central tendon
Diaphragm innervation
Phrenic n. C3,4,5
Diaphragm action
Main muscle in respiration; aids in compressing abdominal viscera
Superficial transverse perineal origin
Ischial ramus
Superficial transverse perineal insertion
Perineal body
Superficial transverse perineal action
holds the pelvic organs in place, closes the urethra
External anal sphincter origin/ insertion
encircles anus (runs posteriorly from perineal body to anococcygeal ligament
External anal sphincter action
closes anus
External urethral sphincter origin/insertion
encircles urethra (division of deep transverse perineal muscle)
External urethral sphincter action
closes urethra
Bulbospongiosus origin/insertion
Runs anteriorly from perineal body to clitoris or penile raphe
Bulbospongiosus action
females: compresses greater vestibular gland
males: assists in erection
Ischiocavernous origin
Ischial ramus
Ischiocavernous insertion
Crus of clitoris or penis
Ischiocavernous action
Maintains erection by squeezing blood into corpus cavernosum of clitoris or penis
Superficial/Deep transverse perineal, external anal/urethral sphincter, bulbospongiosus, and ischiocavernous innervation
Pudendal n. S2-S4
Iliacus action
Flexes thigh and stabilizes hip joint; acts w/ psoas major
Psoas minor action
weak trunk flexor
Psoas minor insertion
Pecten pubis, iliopubic ramus, iliac fascia, lowermost fibers may reach inguinal ligament
