Anterior Abdominal Wall

Gross Anatomy


Anterolateral Abdominal Wall; Inguinal Canal, Spermatic Cord and Testis


Anatomy Tables for Today's Topic

Bones of the Abdominal Wall
Muscles of the Abdominal Wall
Joints and Ligaments of the Abdomen
Nerves of the Abdominal Wall
Arteries of the Abdominal Wall
Topographical Anatomy of the Abdominal Wall
Viscera
Fasciae of the Abdominal Wall

Bones of the Abdominal Wall

Bone Structure Description Notes
sternum the broad flat bone forming the anterior thoracic wall it is formed by three parts: manubrium, body, xiphoid process
manubrium the superior part of the sternum manubrium means "handle", as in the handle of a sword
jugular (suprasternal) notch a notch on the superior border of the manubrium it is located between the clavicular notches which articulate with the sternal ends of the clavicles
clavicular notch a notch on the superolateral border of the manubrium it articulates with the sternal end of the clavicle
sternal angle the junction of the manubrium and body of the sternum it is an anterior projection located at the level of the costal cartilage of rib 2; an important landmark for internal thoracic anatomy
body the middle part of the sternum it articulates with the manubrium superiorly and the xiphoid process inferiorly; laterally it articulates with the costal cartilages of ribs 2-7
xiphoid process the inferior part of the sternum xiphoid means "sword shaped"; it is variable in size, shape & ossification; it articulates with the body of the sternum superiorly
pubis an angulated bone the forms the anterior part of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis; its body forms 1/5 of the acetabulum; its symphyseal surface unites with the pubis of the opposite side to form the pubic symphysis; the superior and inferior pubic rami participate in the formation of the obturator foramen
body superolateral portion of the pubis the body of the pubis forms about 1/5 of the acetabulum
pubic crest ridge on the superior border of the superior ramus attachment of rectus abdominis & pyramidalis mm.
pubic tubercle process at the lateral end of pubic crest attachment point of the medial end of the inguinal ligament
superior ramus superior "limb" that passes medially from the body of the pubis articulates with the superior ramus of the opposite side at the pubic symphysis
pecten ridge on superior surface of the superior pubic ramus attachment point of the pectineal ligament
inferior ramus inferior "limb" that passes inferolaterally from the pubic symphysis articulates with the ischial ramus to form the ischiopubic ramus; attachment site for the root of the penis (clitoris)
ilium fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
body the portion of the ilium that participates in the formation of the acetabulum the body of the ilium forms 2/5 of the acetabulum
iliac crest arching superior edge the ilium that forms the rim of the "fan" attachment for abdominal wall muscles
iliac tubercle roughened area along the outer edge of the iliac crest
anterior superior iliac spine spine at the anterior end of the iliac crest lateral attachment of the inguinal ligament
posterior superior iliac spine spine at the posterior end of the iliac crest position marked by a dimpling of the skin
arcuate line ridge running from anteroinferior to posterosuperior on the inner surface of the ilium inferior boundary of the iliac fossa; marks the plane of transition from abdominal cavity to pelvic cavity

Muscles of the Abdominal Wall - Listed Alphabetically

Muscle Origin Insertion Action Innervation Artery Notes
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
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
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
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

Joints and Ligaments of the Abdomen - Listed Alphabetically

Joint or ligament Description Notes
inguinal ligament the ligament that connects the anterior superior iliac spine with the pubic tubercle the inguinal ligament is a specialization of the inferior border of the external abdominal oblique aponeurosis; it is the site of origin for a part of the internal abdominal oblique muscle and for a part of the transversus abdominis muscle; also known as: Poupart's ligament
lacunar ligament an extension of the medial end of the inguinal ligament which connects the pubic tubercle with the pecten of the pubis the lacunar ligament is a flattened portion of the aponeurosis of the external abdominal oblique m. that projects posteriorly from the pubic tubercle; it forms the medial border of the femoral ring and the floor of the inguinal canal at the superficial inguinal ring
pectineal ligament a thickening of fascia on the pecten of the pubis the pectineal ligament looks like an extension of the lacunar ligament along the surface of the pectineal line; also known as: Cooper's ligament (note: Cooper's ligaments are also found in the breast)

Nerves of the Abdominal Wall

Nerve Source Branches Motor Sensory Notes
intercostal n. ventral primary rami of spinal nerves T1-T11 lateral & anterior cutaneous brs. intercostal muscles; abdominal wall muscles (via T7-T11); muscles of the forearm and hand (via T1) skin of the chest and abdomen anterolaterally; skin of the medial side of the upper limb (via T1-T2) intercostal n.travels below the posterior intercostal a. in the costal groove
iliohypogastric n. lumbar plexus (ventral primary ramus of spinal nerve L1) lateral and anterior cutaneous brs. muscles of the lower abdominal wall skin of the lower abdominal wall, upper hip and upper thigh iliohypogastric n. receives a contribution from T12 in approximately 50% of cases
ilioinguinal n. lumbar plexus (ventral primary ramus of spinal nerve L1) anterior cutaneous br. (also known as: anterior labial/scrotal n.) muscles of the lower abdominal wall skin of the lower abdominal wall and anterior scrotum/labium majus ilioinguinal n. courses through the inguinal canal and superficial inguinal ring
subcostal n. ventral primary ramus of T12 lateral cutaneous br., anterior cutaneous br. muscles of the abdominal wall skin of the anterolateral abdominal wall the subcostal n. is equivalent to a posterior intercostal n. found at higher thoracic levels

Arteries of the Abdominal Wall

Artery Source Branches Supply to Notes
circumflex iliac, deep external iliac a. unnamed muscular branches iliacus muscle and the lower abdominal wall deep circumflex iliac a. courses along the iliac crest on the inner surface of the abdominal wall
circumflex iliac, superficial femoral a. unnamed muscular branches superficial fascia of lower abdomen and thigh superficial circumflex iliac a. crosses the upper thigh parallel to the inguinal ligament
cremasteric inferior epigastric a. no named branches cremaster m., coverings of the spermatic cord cremasteric a. is one of the contents of the spermatic cord; it anastomoses with the testicular artery distally
epigastric, superficial femoral a. cutaneous brs. superficial fascia and skin of the lower abdominal wall superficial epigastric a. is one of three superficial arteries that arise from the femoral a. (see also: superficial circumflex iliac a. and superficial external pudendal a.)
epigastric, superior internal thoracic a. no named branches upper rectus abdominis m., upper abdominal wall superior epigastric a. is the direct continuation of the internal thoracic a.; it anastomoses with the inferior epigastric a. within the rectus abdominis m.
intercostal, posterior highest intercostal (upper 2 intercostal spaces), descending thoracic aorta (3rd-11th intercostal spaces) posterior br., spinal br., anterior br., collateral br., lateral cutaneous br. intercostal muscles, spinal cord and vertebral column, deep back muscles, skin and superficial fascia overlying the intercostal spaces posterior intercostal aa. supply the lateral and posterior portions of the intercostal space; anterior intercostal aa. supply the anterior portions of the intercostal spaces
musculophrenic internal thoracic a. anterior intercostal aa. anterior diaphragm, anterior aspects of intercostal spaces 7-10 or 11 musculophrenic a. supplies muscles that develop in the septum transversum

Topographical Anatomy of the Abdominal Wall

Structure/Space Description/Boundaries Significance
arcuate line anatomical feature on the inner surface of the abdominal wall; a fascial line in the transverse plane approximately 1/2 of the distance from the umbilicus to the pubic symphysis arcuate line is the point at which the posterior lamina of the rectus sheath ends and transversalis fascia lines the inner surface of the rectus abdominis m.
epigastric region an area on the anterior abdominal wall between the midclavicular lines, superior to the transpyloric line one of 9 regions of the abdomen
hypochondriac region an area on the anterior abdominal wall lateral to the midclavicular line, superior to the transpyloric line one of 9 regions of the abdomen; bilateral
hypogastric region an area on the anterior abdominal wall between the midclavicular lines, inferior to the intertubercular line one of 9 regions of the abdomen; also known as: pubic region
inguinal region anterior abdominal wall lateral to midclavicular line, inferior to intertubercular line one of 9 regions of the abdomen; also known as: iliac region
intercristal line an imaginary line drawn in the horizontal plane at the upper margin of the iliac crests intercristal line locates the level of the L4 vertebra; a useful landmark in spinal tap procedure
intertubercular line an imaginary line drawn in the horizontal plane at the upper margin of the iliac tubercles intertubercular line locates the level of the L5 vertebra; used with midinguinal and transpyloric lines to divide the abdominal wall into 9 regions
linea alba anatomical feature on the midline of the anterior abdominal wall; an aponeurotic band that extends from the xiphoid process to the pubic symphysis; linea alba is formed by the combined abdominal muscle aponeuroses; it is used for midline abdominal incisions to avoid major nerves or vessels
lumbar region an area on the anterior abdominal wall lateral to the midclavicular line, inferior to transpyloric line, superior to intertubercular line one of 9 regions of the abdomen; also known as: lateral region
McBurney's point a point on the anterior abdominal wall which is 1/3 of the distance along a line from the right anterior superior iliac spine to the umbilicus McBurney's point is the approximate location of the vermiform appendix; point of tenderness in appendicitis
midaxillary line an imaginary vertical line passing through the middle of the axilla used as a surface landmark for descriptive purposes
midclavicular line an imaginary vertical line passing through the midshaft of the clavicle used as a surface landmark for descriptive purposes
midinguinal line an imaginary vertical line passing through the midpoint of inguinal ligament used with the transpyloric and intertubercular lines to divide the abdomen into 9 regions
quadrant, left lower a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, right lower a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, left upper a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, right upper a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
semilunar line an anatomical feature of the anterior abdominal wall; the lateral edge of the rectus abdominis m. semilunar line is formed by the fused aponeuroses of the abdominal wall mm. at the lateral margin of the rectus sheath
transpyloric line an imaginary horizontal line 1/2 of the distance between the jugular notch and the pubic crest transpyloric line is used with the midinguinal and intertubercular lines to divide the abdominal wall into 9 regions; the fundus of the gall bladder lies at the intersection of the transpyloric line with the right 9th costal cartilage; the pylorus of the stomach is located at this plane; a horizontal plane through the transpyloric line locates the level of the L1 vertebra
transumbilical line an imaginary horizontal line through the umbilicus transumbilical line is used with the midline to divide abdomen into 4 quadrants
transverse lines anatomical features in the anterior abdominal wall; folds in the anterior abdominal wall (usually 3) transverse lines are creases that overlie the tendinous intersections in the rectus abdominis m.
umbilical region a region on the anterior abdominal wall between the midclavicular lines, inferior to the transpyloric line, superior to the intertubercular line one of 9 regions of the abdomen
umbilicus remnant of the attachment of the umbilical cord to the anterior abdominal wall umbilicus marks the approximate level of the L3/L4 intervertebral disc in non-obese individuals

Viscera

Organ/Part of Organ Location/Description Notes
ductus deferens duct of the testis ductus deferens is continuous with the tail of the epididymis; it passes through the superficial inguinal ring, inguinal canal and deep inguinal ring to reach the posteroinferior surface of the bladder where it joins with the duct of the seminal vesicle to form the ejaculatory duct
epididymis beginning of the duct system of the testis the head of the epididymis is located on the superior surface of the testis and receives sperm from the efferent ductules; the body of the epididymis lies posterolateral to the testis and is separated from the testis by the sinus of the epididymis; the tail of the epididymis is located inferiorly and is continuous with the ductus deferens; the ductus deferens ascends to pass through the abdominal wall via the inguinal canal
round ligament of the uterus a connective tissue band that attaches to the inner aspect of the labium majus and the uterus round ligament of the uterus traverses the superficial inguinal ring, inguinal canal and deep inguinal ring to reach the lateral surface of the uterus below the uterine tube; it is a remnant of the gubernaculum; it is continuous with the ovarian ligament; it holds the fundus of the uterus forward; also known as: ligamentum teres uteri
scrotal ligament band of connective tissue that attaches the inferior end of the testis to the inner aspect of the scrotal sac scrotal ligament is the remnant of the gubernaculum testis
scrotum sac of hair-covered skin containing the testis in the scrotum the fatty and membranous layers of the superficial fascia (as seen in the lower abdominal wall) are fused to form the tunica dartos scroti
spermatic cord bundle of vessels, nerves and lymphatics ensheathed in tissue layers derived from the abdominal wall; it begins at the deep inguinal ring, passes through the inguinal canal and the superficial ring to reach the testis in the scrotum spermatic cord contains the: ductus deferens, testicular a., pampiniform plexus, deferential a. & v. and genital br. of the genitofemoral n.; coverings of the cord are the: internal spermatic fascia (from the transversalis fascia), cremasteric muscle and fascia (from the internal abdominal oblique), external spermatic fascia (from the external abdominal oblique aponeurosis)
testis an endocrine and exocrine gland contained within the scrotum testis is the male gonad; its exocrine product is sperm which drain to the head of the epididymis via efferent ductules; its endocrine product is testosterone; the testis migrates into the scrotum shortly before birth; it is tethered to the scrotum inferiorly by the scrotal ligament (a remnant of the gubernaculum)
tunica albuginea, testis outer white fibrous covering of the testis tunica albuginea is a dense connective tissue capsule that is covered on its external surface by the visceral layer of the tunica vaginalis testis
tunica dartos scroti a subcutaneous layer of smooth muscle located in the scrotum fatty and membranous layers of the superficial fascia (as seen in the lower abdominal wall) are fused in the scrotum to form the tunica dartos scroti
tunica vaginalis testis a peritoneal sac located anterolateral to the testis tunica vaginalis testis has two layers: visceral and parietal; the visceral layer lies on the anterolateral surface of the testis and epididymis; the parietal layer lines the inner surface of the scrotal sac; the word "vaginalis" is derived from the Latin word for sheath

Fasciae of the Abdomen - Arranged Alphabetically

Structure Location/Description Notes
fascia, cremasteric intermediate covering layer of the spermatic cord derived from the internal abdominal oblique muscle
fascia, external spermatic outermost covering of the spermatic cord that is derived from a layer of the abdominal wall derived from the aponeurosis of the external abdominal oblique muscle
fascia, internal spermatic innermost covering of the spermatic cord derived from the transversalis fascia
fascia, transversalis the deep fascia lining the inner surface of the abdominal wall transversalis fascia covers the inner surface of the muscles of the anterior, lateral and posterior abdominal walls; where it covers the psoas mm. it is called psoas fascia; where it covers the quadratus lumborum m. it is called quadratus lumborum fascia


Other Tables of Interest:


All Anatomy Tables

Tables Organized by System Tables Organized by Region


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.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.