Anterior Abdominal Wall

flashcards covering key vocabulary and concepts related to the anatomy of the anterior abdominal wall and associated structures.

abdomen

region of the trunk located between the diaphragm above and the inlet of the pelvis below

abdominal wall - superior

part of the abdominal wall formed by the diaphragm

• separates abdominal cavity from thoracic cavity

abdominal wall - inferior

part of the abdominal wall that is continuous with the pelvic cavity through the pelvic inlet

abdominal wall - anterior

the part of the abdominal wall that faces the front of the body

• above = thoracic cage (lower part)

• below = muscles (rectus abdominis, internal + external oblique, transverse abdominis) + fasciae

abdominal wall - posterior

the part of the abdominal wall that faces the back of the body

• midline = lumbar vertebrae

• lateral = XII rib + posterior abdominal wall muscles (psoas major, iliacus, quadratus lumborum)

linea alba

a fibrous structure that runs vertically down the midline of the abdomen separating the rectus abdominis muscles

• formed by the aponeuroses of external oblique, internal oblique, & transversus abdominis

• origin = tip of xiphoid process

• insertion = pubic symphysis (anterior) + pubic crests on both sides (posterior)

linea semilunaris

a curved line on the lateral aspect of the abdomen that marks the lateral border of the rectus abdominis muscle

• extends from the cartilage of the IX rib → pubic tubercle

• site of union where tendons of the lateral abdominal muscles meet the rectus sheath

umbilicus

the small depression or scar on the abdomen that marks the spot where the umbilical cord was attached during fetal development

• located on the L3 / L4 vertebral level of the spine

arcuate line

line of demarcation corresponding to the free inferior margin of the posterior layer of the rectus sheath

• located deep to rectus abdominis

  • visible upon the inner surface of the abdominal wall (not seen on superficially)

inguinal ligament

a fibrous band formed by the “rolled-up” inferior edge of the external oblique aponeurosis

• extending from the anterior superior iliac spine (ASIS) → pubic tubercle

• serves as a boundary between abdomen & thigh

anterior abdominal wall - divisions

partitions to the abdominal wall created by

• 2 vertical lines

  • R & L midclavicular lines

• 2 horizontal planes

  • subcostal plane - lower points of costal margin @ 10^th costal cartilage (L3 lvl)

  • intertubercular (transtubercular) plane - between the tubercles of the iliac crests (L5 lvl)

anterior abdominal wall - regions

R hypochondrium	epigastric	L hypochondrium
R lumbar	umbilical	L lumbar
R iliac (inguinal)	hypogastric	L iliac (inguinal)

anterior abdominal wall - quadrants

formed from intersection of vertical midline (median plane) + horizontal transumbilical (L3 - L4) plane

R upper - RU

L upper - LU

R lower - RL

L lower - LL

organs - right upper quadrant (RUQ)

• liver (right lobe)

• gallbladder

• stomach (pylorus)

• duodenum (parts 1 - 3)

• pancreas (head)

• R kidney + R suprarenal gland

• ascending colon (distal)

• colon (hepatic flexure)

• transverse colon (R half)

organs - right lower quadrant (RLQ)

• cecum

• appendix

• majority of ileum

• ascending colon (proximal)

• R ureter (proximal)

• R ovary + R fallopian tube

• R spermatic cord

organs - left upper quadrant (LUQ)

• spleen

• stomach

• liver (left lobe)

• stomach (fundus + body)

• jejunum + proximal ileum

• pancreas (body + tail)

• L kidney + L suprarenal gland

• transverse colon (L half)

• colon (splenic flexure)

• superior part of the descending colon

organs - left lower quadrant (LLQ)

• distal descending colon

• sigmoid colon

• L ureter (proximal)

• L ovary + L fallopian tube

• L spermatic cord

referred pain - epigastric

region in which pain arising from foregut-derived structures are referred to

• stomach, pancreas, liver, gallbladder, esophagus, biliary apparatus, duodenum (1^st & upper half of 2^nd)

referred pain - umbilical

region in which pain arising from midgut-derived structures are referred to

• duodenum (lower half 2^nd, 3^rd, 4^th), jejunum, ileum, cecum, appendix, ascending colon, transverse colon (proximal ⅔)

referred pain - hypogastric

region in which pain arising from hindgut-derived structures are referred to

• transverse colon (distal ⅓), descending colon, sigmoid colon, rectum, anal canal (above pectinate line)

abdominal wall - layers

1. skin

2. superficial fascia

   • Camper (fatty layer)

   • Scarpa (membranous layer)

3. deep fascia

4. muscles

   • external oblique

   • internal oblique

   • transversus abdominis

5. transversalis fascia

6. extaperitoniel fat

7. parietal peritoneum

Camper’s fascia

superficial fatty layer of the superficial fascia in the abdominal wall that is continuous with the superficial fat over the rest of the body

• continues over

  • inguinal ligament to merge with the superficial fascia of the thigh

  • pubis as superficial layer of superficial perineal fascia (perineum)

• may be extreme thick (> 8 cm in obese patients)

Scarpa's fascia

deep membranous layer of the superficial fascia in the abdominal wall that is devoid of fat & firmly attached to the linea alba + pubic symphysis

• attached to the fascia lata just below the inguinal ligament → Holden’s line

• continues over the pubis as membranous fascia in perineum → Colles’ fascia

• continues as dartos fascia (or tunica dartos) in the scrotum & penis

  • responsible for wrinkling in scrotum

external oblique

superficial abdominal muscle that helps in trunk rotation, lateral flexion, & compression of the abdomen

• origin = external surface of lower 8 ribs

• insertion = iliac crest, pubic tubercle, linea alba, xiphoid process

• innervation = lower six intercostal (T7-T11), subcostal (T12), iliohypogastric (L1), ilioinguinal (L1)

• blood supply = superior & inferior epigastric

internal oblique

superficial abdominal muscle that trunk rotation, lateral flexion, & compression of the abdomen

• origin = inguinal ligament (lateral ⅔), iliac crest, thoracolumbar fascia

• insertion = lower 4 ribs, linea alba, pubic crest, pectineal line

• innervation = lower six intercostal (T7-T11), subcostal (T12), iliohypogastric (L1), ilioinguinal (L1)

• blood supply = superior & inferior epigastric, deep circumflex iliac

transversus abdominis

superficial abdominal muscle that helps in compression of the abdomen with internal oblique

• origin = lower 6 costal cartilages, thoracolumbar fascia, iliac crest, inguinal ligament (lateral ⅓)

• insertion = xiphoid process, linea alba, pubic crest, pectineal line via conjoint tendon

• innervation = lower six intercostal (T7-T11), subcostal (T12), iliohypogastric (L1), ilioinguinal (L1)

• blood supply = deep circumflex iliac, inferior epigastric

rectus abdominis

superficial abdominal muscle that helps in trunk flexion & compression of the abdomen

• origin = pubic crest, pubic symphysis

• insertion = xiphoid process, costal cartilage V - VII

• innervation = lower six intercostal (T7-T11), subcostal (T12)

• blood supply = superior & inferior epigastric

pyramidalis

small, superficial abdominal muscle that tenses linea alba

• origin = body of pubis

• insertion = linea alba

• innervation = subcostal (T12)

• blood supply = inferior epigastric artery

transversalis fascia

layer of connective tissue that forms a continuous lining of the anterior abdominopelvic cavity

• deep inguinal ring - formed by outpouching immediately above the midpoint of inguinal ligament

  • lateral opening (& deep) opening of the inguinal canal

• femoral sheath - deep to inguinal ligament that extends down into thigh

  • forms anterior wall

• PARIETAL PERITONEUM LINING = FIRST STRUCTURE EVAGINATED BY ANY ABDOMINAL HERNIA

femoral sheath

funnel-shaped sleeve of fascia deep to the inguinal ligament formed by the joining of the transversalis fascia & iliacus fascia that extends into the thigh housing the femoral vessels & lymphatics

• anterior wall = formed by transversalis fascia

• separated in 3 compartments

  1. anterior (lateral) = contains the femoral artery & femoral branch of genitofemoral nerve

  2. intermediate (venous) = contains the femoral vein

  3. posterior (lymphatic) = contains the femoral canal

• femoral nerve sits laterally NOT within it

anterior abdominal wall - nerve supply

total of 7 nerves that supply the skin

neurovascular plane

Inguinal canal

A short passage in the lower part of the anterior abdominal wall for structures like the spermatic cord in males.

Rectus sheath

An aponeurotic sheath enclosing the rectus abdominis and pyramidalis muscles.

Arcuate line

The free lower margin of the posterior wall of the rectus sheath.

Hernia

The pathological protrusion of a part of the abdominal contents through a weak point in the abdominal wall.

Inguinal ligament

A fold of tissue that extends between the pubic tubercle and the anterior superior iliac spine.

Deep inguinal ring

An oval opening in the transversalis fascia, representing the deep opening of the inguinal canal.

Superficial inguinal ring

A triangular-shaped opening in the aponeurosis of the external oblique muscle.

Lateral umbilical fold

A fold of peritoneum including the inferior epigastric artery and vein.

Medial inguinal fossa

A depression between the medial and lateral umbilical folds.

Femoral hernia

A type of hernia that occurs when abdominal contents protrude through the femoral ring.

Direct inguinal hernia

A hernia that occurs when abdominal contents protrude through the posterior wall of the inguinal canal.

Indirect inguinal hernia

A congenital hernia that occurs through the deep inguinal ring.

Umbilical hernia

A hernia that occurs at the umbilical ring, often found in infants.

Incisional hernia

A hernia that occurs at the site of a previous surgical incision.

Epigastric hernia

A small hernia occurring between the xiphoid process and the umbilicus.

Superior epigastric artery

A branch of the internal thoracic artery supplying the upper part of the abdominal wall.

Inferior epigastric artery

A branch of the external iliac artery supplying the lower part of the abdominal wall.

Neurovascular plane

The plane between the internal oblique and transversus abdominis muscles containing blood vessels and nerves.

Cutaneous lymph vessels

Lymph vessels that drain areas of the skin and superficial structures in the anterior abdominal region.

Paraumbilical veins

Veins that connect the superficial venous network to the portal vein.

Transumbilical plane

A horizontal plane that intersects the umbilicus, dividing the abdomen into upper and lower parts.

Abdominal wall defects

Congenital anomalies such as omphalocele and gastroschisis.

Rectus abdominis muscle

The muscle that runs vertically along the anterior abdominal wall.

Thoracoabdominal nerves

Nerves that innervate the anterior abdominal wall, including T7-T11.

Lumbar arteries

Arteries that supply blood to the posterior abdominal wall.

Deep circumflex iliac artery

A branch of the external iliac artery supplying the iliac region.

Intercostal arteries

Arteries supplying the ribs and intercostal spaces.

Peritoneal cavity

The space within the abdomen that houses many organs.

Spermatic cord

A structure containing nerves, blood vessels, and ductus deferens in males.

Cremaster muscle

A muscle derived from the internal oblique that surrounds the spermatic cord.

Cecum

The beginning of the large intestine, located in the right lower quadrant.

Gallbladder

An organ beneath the liver that stores bile.

Testicular artery

An artery providing blood supply to the testis.

Vas deferens

The duct that carries sperm from the testicles to the urethra.

Parietal peritoneum

The lining of the abdominal cavity.