UAMS Department of Neurobiology and Developmental Sciences - Muscles of the Abdominal Region

Gross Anatomy



Muscles of the Abdominal Region - Listed Alphabetically

Muscle Origin Insertion Action Innervation Artery Notes
cremaster inguinal ligament forms thin network of muscle fascicles around the spermatic cord and testis (or around the distal portion of the round ligament of the uterus) elevates testis (not well developed in females) genital branch of the genitofemoral nerve cremasteric a., a branch of the inferior epigastric a. the cremaster m. is internal abdominal oblique muscle's contribution to the coverings of the spermatic cord and testis; the cremasteric reflex may be elicited by stroking the medial thigh (where the femoral branch of the genitofemoral n. distributes cutaneously)
dartos subcutaneous connective tissue of the scrotum and the penis (or labium majus and clitoris) skin of the scrotum and penis (or labium majus and clitoris) elevates testis (tenses the skin of the pudendal region in the female) postganglionic sympathetic nerve fibers arriving via the ilioinguinal nerve and the posterior scrotal nerve cremasteric a., posterior scrotal (labial) a. the dartos elevates the testis in response to cold (it is modified arrector pili fibers, or the goose-bump muscles)
diaphragm xiphoid process, costal margin, fascia over the quadratus lumborum and psoas major mm.(lateral & medial arcuate ligaments), vertebral bodies L1-L3 central tendon of the diaphragm pushes the abdominal viscera inferiorly, increasing the volume of the thoracic cavity (inspiration) phrenic nerve (C3-C5) musculophrenic a., superior phrenic a., inferior phrenic a. left crus attaches to the L1-L2 vertebral bodies, the right crus attaches to the L1-L3 vertebral bodies
external abdominal oblique lower 8 ribs linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest flexes and laterally bends the trunk intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves musculophrenic a., superior epigastric a., intercostal aa. 7-11, subcostal a., lumbar aa., superficial circumflex iliac a., deep circumflex iliac a., superficial epigastric a., inferior epigastric a., superficial external pudendal a. the inguinal ligament is a specialization of the external abdominal oblique aponeurosis; the external spermatic fascia is the external abdominal oblique muscle's contribution to the coverings of the testis and spermatic cord
iliacus iliac fossa and iliac crest; ala of sacrum lesser trochanter of the femur flexes the thigh; if the thigh is fixed it flexes the pelvis on the thigh femoral nerve iliolumbar a. inserts in company with the psoas major m. via the iliopsoas tendon
iliopsoas iliac fossa; bodies and transverse processes of lumbar vertebrae lesser trochanter of the femur flexes the thigh; flexes and laterally bends the lumbar vertebral column branches of the ventral primary rami of spinal nerves L2-L4; branches of the femoral nerve iliolumbar a. a combination of the iliacus and psoas major mm.
interfoveolar transversus abdominis fibers that lie superficial to the inferior epigastric vessels anterior lamina of femoral sheath, immediately distal to origin of inferior epigastric vessels compresses abdominal contents iliohypogastric and ilioinguinal nerves inferior epigastric a. an inconstant part of the transversus abdominis m. which may be replaced by a ligament (interfoveolar ligament)
internal abdominal oblique thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the inguinal ligament lower 3 or 4 ribs, linea alba, pubic crest flexes and laterally bends the trunk intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves musculophrenic a., superior epigastric a., intercostal aa. 7-11, subcostal a., lumbar aa., superficial circumflex iliac a., deep circumflex iliac a., superficial epigastric a., inferior epigastric a., superficial external pudendal a. anterior fibers of internal abdominal oblique course up and medially, perpendicular to the fibers of external abdominal oblique; the cremaster muscle and fascia is the internal abdominal oblique muscle's contribution to the coverings of the testis and spermatic cord
oblique, external abdominal lower 8 ribs linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest flexes and laterally bends the trunk intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves musculophrenic a., superior epigastric a., intercostal aa. 7-11, subcostal a., lumbar aa., superficial circumflex iliac a., deep circumflex iliac a., superficial epigastric a., inferior epigastric a., superficial external pudendal a. the inguinal ligament is a specialization of the external abdominal oblique aponeurosis; the external spermatic fascia is the external abdominal oblique muscle's contribution to the coverings of the testis and spermatic cord
oblique, internal abdominal thoracolumbar fascia, anterior 2/3 of the iliac crest, lateral 2/3 of the inguinal ligament lower 3 or 4 ribs, linea alba, pubic crest flexes and laterally bends the trunk intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves musculophrenic a., superior epigastric a., intercostal aa. 7-11, subcostal a., lumbar aa., superficial circumflex iliac a., deep circumflex iliac a., superficial epigastric a., inferior epigastric a., superficial external pudendal a. anterior fibers of internal abdominal oblique course up and medially, perpendicular to the fibers of external abdominal oblique; the cremaster muscle and fascia is the internal abdominal oblique muscle's contribution to the coverings of the testis and spermatic cord
psoas major bodies and transverse processes of lumbar vertebrae lesser trochanter of femur (with iliacus) via iliopsoas tendon flexes the thigh; flexes & laterally bends the lumbar vertebral column branches of the ventral primary rami of spinal nerves L2-L4 subcostal a., lumbar aa. the genitofemoral nerve pierces the anterior surface of the psoas major m.
psoas minor bodies of the T12 & L1 vertebrae iliopubic eminence at the line of junction of the ilium and the superior pubic ramus flexes & laterally bends the lumbar vertebral column branches of the ventral primary rams of spinal nerves L1-L2 lumbar aa. absent in 40% of cases
pyramidalis pubis, anterior to the rectus abdominis linea alba draws the linea alba inferiorly subcostal nerve subcostal a., inferior epigastric a. the pyramidalis m. is not always present
quadratus lumborum posterior part of the iliac crest and the iliolumbar ligament transverse processes of lumbar vertebrae 1-4 and the 12th rib laterally bends the trunk, fixes the 12th rib subcostal nerve and ventral primary rami of spinal nerves L1-L4 subcostal a., lumbar aa. the lateral arcuate ligament of the diaphragm crosses the anterior surface of the quadratus lumborum m.
rectus abdominis pubis and the pubic symphysis xiphoid process of the sternum and costal cartilages 5-7 flexes the trunk intercostal nerves 7-11 and subcostal nerve superior epigastric a. intercostal aa., subcostal a., inferior epigastric a. rectus sheath contains rectus abdominis and is formed by the aponeuroses of external and internal oblique and transversus abdominis mm.
transversus abdominis lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament linea alba, pubic crest and pecten of the pubis compresses the abdomen intercostal nerves 7-11, subcostal, iliohypogastric and ilioinguinal nerves musculophrenic a., superior epigastric a., intercostal aa. 7-11, subcostal a., lumbar aa., superficial circumflex iliac a., deep circumflex iliac a., superficial epigastric a., inferior epigastric a., superficial external pudendal a. transversus abdominis muscle does not contribute to the coverings of the spermatic cord and testis; transversalis fascia, the deep fascia that covers the inner surface of the transversus abdominis, forms the internal spermatic fascia


Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

The content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2009, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.
Unauthorized use is prohibited.




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