Anatomy Tables - Inguinal Region

Osteology

Bone Structure Description Notes
ilium (N486, TG3-05, TG3-05) fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
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
cremaster (N260,N387,N390, TG5-10B, TG6-31) 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) (Latin, cremaster = a suspender)
dartos (TG5-04, TG5-05) 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) (Greek, dartos = leather)
external abdominal oblique (TG5-04, TG5-05) 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 (TG5-04, TG5-05) 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
rectus abdominis (TG5-05) 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 (TG4-08, TG4-09) 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 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

Joints and Ligaments

Joint or ligament Description Notes
linea alba (TG5-04) 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 (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 (TG5-08) 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 = lake)
pectineal ligament (TG5-08) 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)
falx inguinalis (TG5-08) represents inferomedial attachment of transversus abdominis with some fibers of internal abdominal oblique also known as: conjoint tendon (Latin, falx = sickle)

Nerves

Nerve Source Branches Motor Sensory Notes
ilioinguinal n. (TG5-08, TG5-09, TG5-10) 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 (TG5-08) 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 (N255,N262,N260, TG5-05, TG5-07A) 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.
cremasteric (TG6-31) 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 (Latin, cremaster = suspender)
testicular (TG6-31) abdominal aorta ureteric brs. testis, epididymis, lower part of the ductus deferens, ureter near its midpoint testicular a. is one of the contents of the spermatic cord; the origin of the testicular a. from the aorta at the L2 vertebral level indicates the embryonic level of origin of the testis prior to its descent

Veins

Vein Tributaries Drains Into Regions Drained Notes
pampiniform venous plexus (TG6-31) no named tributaries becomes the testicular vein at the deep inguinal ring testis, epididymis, ductus deferens pampiniform venous plexus surrounds the testicular a. to cool arterial blood before it reaches the testis (Latin, pampinus = a tendril + forma = shape, thus the vine-like structure of the pampiniform plexus of veins)

Topographic Anatomy

Structure/Space Boundaries/Description Significance
superficial (external) inguinal ring (TG5-10) slitlike opening between the diagonal fibers of the ext. oblique, superolateral to the pubic tubercle; bounded by medial and lateral crura exit from the inguinal canal
deep (internal) inguinal ring (TG5-09) 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 (N260, TG5-10A, TG5-10B, TG5-11A) 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
inguinal region (TG5-08) anterior abdominal wall lateral to midclavicular line, inferior to intertubercular line 1 of 9 regions of abdomen
inguinal triangle (N259, TG5-07) bounded by the rectus abdominis medially, the inferior epigastric vessels laterally, and the inguinal ligament inferiorly the weak fascia, where direct hernias occur, is located in the inferior portion of this triangle
linea alba (TG5-04) 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)
lateral inguinal fossa (N253,N259, TG5-07) shallow depression on the inner aspect of the abdominal wall lateral to the lateral umbilical fold an indirect inguinal hernia passes through the anterior abdominal wall in this fossa (Latin, fossa = trench or ditch)
lateral umbilical (epigastric) fold peritoneal fold overlying the inferior epigastric vessels an indirect inguinal hernia passes through the anterior abdominal wall lateral to this fold; a direct inguinal hernia passes through the anterior abdominal wall medial to this fold
medial inguinal fossa (N253,N259, TG5-07) shallow depression on the inner aspect of the abdominal wall between the medial inguinal fold and the lateral umbilical fold a direct inguinal hernia passes through the anterior abdominal wall in this fossa; it passes through a subdivision called the inguinal triangle (Latin, fossa = trench or ditch)
medial umbilical fold (N253, TG5-07) peritoneal fold overlying the medial umbilical ligament medial umbilical ligament is the obliterated umbilical a.
median umbilical fold (N253, TG5-07) peritoneal fold overlying the median umbilical ligament (remnant of urachus) median umbilical ligament is the remnant of the urachus
supravesical fossa (N253, N259, TG5-07) between the median and medial umbilical folds, formed as the peritoneum reflects from the anterior abdominal wall onto the bladder potential sites for rare external supravesical hernias (Latin, fossa = trench or ditch)

Viscera

Organ Location Description Notes
ductus deferens (N387, N262, TG5-08, TG5-08D, TG5-10B, TG5-10C) 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 (Latin, ductus = to lead + deferens = to carry away)
extraperitoneal connective tissue abdominal region separates the transversalis fascia and parietal peritoneum
fascia, cremasteric (N260, N387, N390, TG5-10B, TG6-31) intermediate covering of spermatic cord derived from internal abdominal oblique muscle (Latin, cremaster = suspender)
fascia, external spermatic (N260, N387, N390, TG5-10B, TG6-31) outermost covering of spermatic cord derived from aponeurosis of external abdominal oblique muscle
fascia, internal spermatic (N260, N387, N390, TG5-10B, TG6-31) innermost covering of spermatic cord derived from transversalis fascia
fascia, transversalis (TG5-08) 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 located in the inguinal triangle hernias can occur here
parietal peritoneum (N348, N331, TG5-42, N349, TG5-43) lines the internal surface of the abdominopelvic wall invests organs (Latin, parietal = wall)
round ligament of the uterus (TG 5-09) 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 (N387, N262, TG5-08, TG5-08D, TG5-10B, 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 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 (TG6-31) 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 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 (Latin, tunica = a coat + dartos = leather)
tunica vaginalis testis (TG6-32C) 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 (Latin, tunica = a coat)

Lymphatics

Structure Location Afferents from Efferents to Regions drained Notes
inguinal nodes, superficial (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
umbilical hernia an abnormal protrusion of abdominal contents into a defect in the umbilical area; common in the newborn, but usually resolves by age two (Latin, hernia = to rupture)
direct/indirect inguinal hernia protrusion of parietal peritoneum and viscera such as the small intestine, or part of them, through a normal or abnormal opening from the cavity in which they belong. Most hernias are reducible, meaning that they can be returned to their normal place in the abdominal cavity by appropiate manipulation. Approximately 90% of abdominal hernias are in the inguinal region. An indirect (congenital) inguinal hernia is the most common type, leaves the abdominal cavity lateral to the inferior epigastric vessels and enters the deep inguinal ring, enters a hernial sac formed by a persistent processus vaginalis, goes through the entire inguinal canal, exits through the superficial inguinal ring and commonly enters the scrotum. However, a direct inguinal hernia leaves the abdominal cavity medial to the inferior epigastric artery, protrudes through the posterior wall of the inguinal canal, has a hernial sac formed by the transversalis fascia, lies outside the tunica vaginalis, does not traverse the entire inguinal canal, protrudes through the inguinal triangle, emerges through or around the conjoint tendon to reach the superficial inguinal ring, gains a covering of external spermatic fascia, and almost never enters the scrotum (Latin, hernia = to rupture)
incisional hernia protrusion of omentum (a fold of peritoneum) or an organ through a surgical incision. If the muscular and aponeurotic layers of the abdomen do not heal properly, an incisional hernia can result. Infection, bowel obstruction, and obesity are predisposing factors to incisional hernias (Latin, hernia = to rupture)
herniorrhaphy surgical repair of a hernia; can be done under local or general anaesthesia; may be performed using a conventional incision or using a fiberoptic laparoscope
strangulation, gangrene strangulation involves stopping blood flow by constriction or compression; as, a strangulated hernia; gangrene is death of tissue, usually in considerable mass and generally associated with loss of vascular (nutritive) supply and followed by bacterial invasion and putrefaction
reduction correction of a fracture, dislocation or hernia
cremasteric reflex elicited by lightly stroking the skin on the medial aspect of the superior part of the thigh with an application stick or tongue depressor; this area of skin is supplied by the femoral branch of the genitofemoral nerve; the elevation of the testes is on the same side as the stroking (Latin, cremaster = suspender)
cryptorchidism failure of one or both testes to descend into the scrotum; occurs in 3% of full-term and in 30% of pre-mature infants; the importance of this condition is its potential for developing malignancy
hydrocele an accumulation of serous fluid in a sac-like cavity adjacent to the testis, a swelling due to the accumulation of serous fluid in the tunica vaginalis of the testis or in the spermatic cord (Greek, hydro = water + -cele = hernia)

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: 30 November 2011