Anatomy Tables for Today's TopicBones 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 inferior boundary of the iliac fossa;

anteroinferior to posterosuperior on the inner surface of the ilium

marks the plane of transition from abdominal cavity to pelvic cavity

Muscles of the Abdominal Wall - Listed Alphabetically

Muscle OriginInsertio

nAction 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.,

anterior fibers of internal abdominal oblique course up and medially, perpendicular to the fibers of external abdominal oblique; the cremaster muscle and

superficial external pudendal a.

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.,

transversus abdominis muscle does not contribute to the coverings of the spermatic cord and testis; transversalis fascia, the deep fascia that covers the inner

superficial external pudendal a.

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

lateral & anterior cutaneous brs.

intercostal muscles; abdominal wall muscles

skin of the chest and abdomen anterolaterally; skin of the medial

intercostal n.travels below the posterior intercostal a. in

nerves T1-T11

(via T7-T11); muscles of the forearm and hand (via T1)

side of the upper limb (via T1-T2)

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

used with the transpyloric and intertubercular lines to divide the

ligament 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

spermatic cord contains the: ductus deferens, testicular a., pampiniform plexus, deferential a. & v. and genital br.

begins at the deep inguinal ring, passes through the inguinal canal and the superficial ring to reach the testis in the scrotum

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