Anatomy Tables - Abdominal Wall

Osteology

Bone Structure Description Notes
os coxae (TG6-3) one of three bones that form the pelvis paired; the os coxae forms the lateral part of the pelvis; it is formed by three fused bones: ischium, ilium & pubis; also known as the innominate bone (Latin, os = bone)
pubis (TG6-4) 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
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
pecten ridge on superior surface of the superior pubic ramus attachment point of the pectineal ligament
ilium (TG6-3) fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
iliac crest arching superior edge of 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
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; part of the iliopectineal line (Note: this is obviously not the same arcuate line as is found on the posterior aspect of the rectus sheath) (Latin, arcuate = bowed)

Muscles

Muscle Origin Insertion Action Innervation Artery Notes Image
external abdominal oblique (N249, TG5-04) 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 (N250, TG5-04) 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 and pecten 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
transversus abdominis (N251, TG5-05) lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament linea alba, pubic crest and pecten flexes and laterally bends 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. 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
rectus abdominis (N250, TG5-05) pubic crest and 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. (Latin, rectus = straight)
pyramidalis (TG5-10) pubic crest, anterior to rectus abdominis linea alba draws the linea alba inferiorly subcostal nerve subcostal a., inferior epigastric a. the pyramidalis m. is not always present
cremaster (TG5-04) 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) (Greek, cremaster = a suspender)

Joints and Ligaments

Joint Description Significance
linea alba (N249,N251,N252A,N252B, TG5-05, TG5-06) connects xiphoid with pubic symphysis & crest formed by intermingling of aponeuroses of external abdominal oblique, internal abdominal oblique, & transversus abdominis (Latin, linea alba = white line)
inguinal ligament (N250,N251, TG5-04) 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 (N251,N263, TG5-08D, TG5-09D) an extension of the medial end of 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 (Latin, lacuna = a lake or pit)
pectineal ligament (N251,N263, TG5-08D, TG5-09D) 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)
pubic symphysis (TG6-04) symphysis midline joint uniting the pubic bodies (Greek, symphysis = a growing together)
falx inguinalis the inferomedial attachment of internal abdominal oblique and transversus abdominis also known as: conjoint tendon (Latin, falx = sickle)

Nerves

Nerve Source Branches Motor Sensory Notes
intercostal n. (N254,N257, TG5-02) 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
subcostal n. (N254,N257, TG5-02) 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
iliohypogastric n. (N257,N267, TG5-02, TG5-38) 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. (N257,N267, TG5-02, TG5-38) 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
genitofemoral (TG5-02) lumbar plexus (ventral primary rami of L1-L2) genital & femoral brs. cremaster m. skin of anterior scrotum/labia majora & upper medial thigh lies on psoas major in abdomen; genital br. passes through deep inguinal ring & inguinal canal; brushing thigh elicits elevation of testis via cremasteric reflex

Arteries

Artery Source Branches Supply to Notes
epigastric, inferior (N251,N253, TG5-05, TG5-07) external iliac a. cremasteric a. lower rectus abdominis m., pyramidalis m., lower abdominal wall inferior epigastric a. anastomoses with the superior epigastric a. within the rectus abdominis m.
epigastric, superficial (N249, TG5-02) 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 (N191, TG4-08, TG5-05) 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 (TG4-39) 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
subcostal (TG4-39) descending thoracic aorta spinal br., collateral br., lateral cutaneous br. vertebrae, spinal cord; muscles, skin & fascia of the upper abdominal wall subcostal a. is equivalent to a posterior intercostal a., but is named subcostal because it courses inferior to the 12th rib

Topographic Anatomy

Structure/Space Description/Boundaries Significance
arcuate line (TG5-05, TG5-07) 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. (Latin, arcuate = bowed)
epigastric region (TG5-01) 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 (TG5-01) an area on the anterior abdominal wall lateral to the midclavicular line, superior to the transpyloric line right and left hypochondriac regions comprise 2 of 9 regions of the abdomen
hypogastric region (TG5-01) 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 (TG5-01) anterior abdominal wall lateral to midclavicular line, inferior to intertubercular line right and left inguinal regions comprise 2 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 (TG5-01) 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 (N249,N251,N252A,N252B, TG5-05, TG5-06) 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 (Latin, linea alba = white line)
lumbar region an area on the anterior abdominal wall lateral to the midclavicular line, inferior to transpyloric line, superior to intertubercular line right and left lumbar regions comprise 2 of 9 regions of the abdomen; also known as: lateral region
McBurney's point (TG5-15) 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 (TG5-01) 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, inferior left (TG5-01) a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, inferior right (TG5-01) a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, superior left (TG5-01) a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
quadrant, superior right (TG5-01) a region on the anterior abdominal wall defined by the midline and the transumbilical line one of 4 abdominal quadrants
semilunar line (TG5-01) 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 (TG5-01) 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 (TG5-01) 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 (TG5-01) 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 (Latin, umbilicus = navel)
superficial (external) inguinal ring (N387,N249,N259,N260, TG5-08A, TG5-09A) slitlike opening between the diagonal fibers of the aponeurosis of the external oblique, superolateral to the pubic tubercle exit from the inguinal canal
deep (internal) inguinal ring (TG5-08C, TG5-09C) site of an outpouching of the transversalis fascia approx. 1.25 cm superior to the middle of the inguinal ligament and lateral to the inferior epigastric a. opening into the inguinal canal
inguinal canal (N387,N249,N259,N260, TG5-08A, TG5-09A) Anterior - aponeurosis of the ext. oblique; Posterior - transversalis fascia; Roof - fibers of the int. oblique and transverse abdominis; Floor - superior surface of the inguinal ligament pathway for the spermatic cord in males and round ligament of the uterus in females

Viscera/Fascia

Organ Location Description Notes
thoracolumbar aponeurosis (fascia) (N174, TG1-13) extends laterally from the spinous processes and forms a thin covering for the deep muscles in the thoracic region and a strong, thick covering for muscles in the lumbar region forms the aponeurotic origin of latissimus dorsi (Greek, aponeurosis = a broad, flat nerve; due to the resemblance between nerves & tendons)
conjoint tendon (TG5-08D, TG5-09D) attached to pubic crest and pecten pubis the most inferior, medial tendinous fibers of the internal oblique join with the aponeurotic fibers of the deeper transverse abdominis also called the falx Inguinalis
ductus deferens (TG5-08D, TG5-09D) passes through superficial inguinal ring, inguinal canal & deep ring to reach posteroinferior surface of bladder where it joins with duct of seminal vesicle to form ejaculatory duct continuous with tail of epididymis (Latin, ductus = to lead + deferens = to carry away)
fascia, cremasteric (TG5-08B, TG5-09B) intermediate covering of spermatic cord derived from internal abdominal oblique muscle (Greek, fascia = a band + cremaster = a suspender)
fascia, external spermatic (TG5-08B, TG5-09B) outermost covering of spermatic cord derived from aponeurosis of external abdominal oblique muscle (Greek fascia = a band)
fascia, internal spermatic (TG5-08C, TG5-09C) innermost covering of spermatic cord derived from transversalis fascia
fascia lata (N249, TG3-02) deep fascia forming tubular investment of the thigh thickened laterally as iliotibial tract/band; connected to femur by lateral & medial intermuscular septa Scarpa's fascia attaches to it below inguinal ligament
crus, lateral (TG5-08C, TG5-09C) lateral border of superficial inguinal ring attaches to pubic tubercle (Latin, crus = leg)
crus, medial (TG5-08C, TG5-09C) medial border of superficial inguinal ring attaches to pubic crest (Latin, crus = leg)
rectus sheath (N249,N251,N252A,N252B, TG5-05, TG5-06, TG5-06) tough, aponeurotic, tendinous sheath of the rectus abdominis muscle (Latin, rectus = straight)
round ligament of uterus (N400, TG5-09A, TG5-09C, TG5-09D) attaches to inner aspect of labia majora, traverses superficial inguinal ring, inguinal canal & deep inguinal ring to reach lateral surface of uterus below uterine tube continuous with ovarian ligament a.k.a. ligamentum teres uteri; remnant of gubernaculum (Latin, teres = round)
scrotal ligament (TG6-31A) 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 (TG6-31A) 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 (N387, TG5-08A, TG5-08C, TG5-08D, TG5-10C) 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 comprises 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 (TG6-32B) 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 dartos scroti (TG6-32B) 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 (Greek, dartos = leather)
tunica vaginalis testis (TG6-32B) 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 (Latin, vagina = sheath)
fascia, transversalis (N251,N252,N259, TG5-07) lines majority of abdominal wall covers the deep surface of the transverse abdominis and its aponeurosis right and left sides continuous deep to the linea alba
fascia, weak (N251,N252,N259, TG5-07) located in the inguinal triangle hernias can occur here

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
superficial inguinal nodes (TG6-34) in the superficial fascia parallel to the inguinal ligament and along the terminal part of the greater saphenous v. lymphatic vessels from the superficial lower limb, superficial abdominal wall, perineum external iliac nodes; deep inguinal nodes lower abdominal wall; external genitalia; superficial parts of the lower limb superficial inguinal nodes are 12-20 in number; they become inflamed during infections of the lower limb; they may become inflamed during infections of the external genitalia

Clinical Terms

Term Definition
appendicitis inflammation (and usually infection) of the appendix, a finger-like projection of the first portion of the colon, that often causes right, lower quadrant abdominal pain, fever and loss of appetite
cholecystitis acute or chronic inflammation of the gallbladder; may necessitate a cholecystectomy or gall bladder removal, which is now usually performed laparoscopically. History may reveal pain, fever with chills and nausea with vomiting.
McBurney's point/incision McBurney's point lies 1/3rd superiomedially along the line between the right anterior superior iliac spine and the umbilicus; this point marks the usual location of the appendix within the right iliac fossa; McBurney's incision is an oblique incision over this point inferomedially directed, splitting the fibers of the external oblique aponeurosis; fibers of internal abdominal oblique and transversus abdominis muscles are then split to gain access to the appendix
median incision incisions made through the fibrous tissue of the linea alba superior and/or inferior to the umbilicus; linea alba usually only transmits small vessels and nerves, therefore these incisions are relatively harmless and bloodless; however, in some patients these incisions may be problematic as they may cut through vascularized fat; also, as it is poorly vascularized, incisions of the linea alba may result in necrosis if the incisions are not brought together well; lower median incisions are often used in female patients to access the female pelvic viscera; median incisions are generally used for exploratory procedures
paramedian incision incision through the anterior layer of the rectus sheath which is laterally retracted, and then through the posterior layer and peritoneum to enter the peritoneal cavity
subcostal incision provides access to the gallbladder and biliary tract on the right side and the spleen on the left; made parallel to the costal margin but at least 2.5 cm inferior to avoid the 7th and 8th thoracic spinal nerves
Pfannenstiel (suprapubic) incision incision made at the pubic hairline; horizontal with a slight downward convexity; used for most gynecological and obstetrical operations (e.g., for cesarean section and removal of a tubal pregnancy)
transpyloric plane at the midpoint between the suprasternal notch and the pubic symphysis, at the level of the first lumbar vertebra
paresthesia an abnormal spontaneous sensation such as burning, pricking, and numbness
periumbilical around or near the umbilicus
emesis act of vomiting
anorexia uncontrolled loss of appetite for food
auscultation the act of listening for sounds within the body, chiefly for ascertaining the condition of the lungs, heart, pleura, abdomen and other organs and for the detection of pregnancy
abdominal guarding spasm of the anterolateral abdominal muscles and a muscular rigidity usually in response to intraperitoneal inflammation or irritation
rebound tenderness when pressure is applied to an area of the abdominal wall and then suddenly removed, extreme localized pain is felt by the patient usually in response to intraperitoneal inflammation or irritation
gastroenteritis an acute inflammation of the lining of the stomach and intestines that can be initiated by food poisoning due to viral or bacterial infection resulting in nausea (+/- emesis), pain, and diarrhea (+/- blood)
peritonitis inflammation of the peritoneum
Caesarian/Cesarian section an obstetrical procedure in which an infant, instead of being born vaginally, is surgically removed from the uterus; requires both an incision into the abdominal wall and the wall of the uterus; done in ancient civilizations to save babies after the death of a full-term pregnant mother, hence, the name Caesarian, since it is believed that Caesar was born by this procedure

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.

 

 

 

Updated: 21 November 2011