Anterior Abdominal Wall

Front 1

Abdominal Cavity Boundaries/Contents

Back 1

- Diaphragm (4th intercostal space)
- Pelvic inlet (but continuous with pelvic cavity)

Contents:
- Peritoneal cavity
- Abdominal viscera

Front 2

Four Quadrant Dividision (key contents)

Back 2

RUQ: liver (right lobe)

LUQ: spleen, stomach, jejunum

RLQ: appendix, ileum, cecum

LLQ: Sigmoid colon, spermatic cord or uterine structures

Front 3

Nine Region Organization

Back 3

Right Hypochondriac/Epigastric/Left Hypochondriac.

Right Lumbar/Umbilical/Left lumbar

Right inguinal/pubic/left inguinal

Front 4

Superficial veins of abdomen

Back 4

- Lateral thoracic
- Thoracoepigastric
- Superficial epigastric
- Superior circumflex iliac

Blood drains along lateral thorax, flows inferiorly and converges with great saphenous vein, then combine to make femoral vein.

Front 5

Layers of Abdominal Wall

Back 5

- Skin
- Superficial fascia (fatty layer, Camper's fascia)
- Superficial fascia (membranous layer, Scarpa's fascia)
- Abdominal muscles associated with deep fascia
- Transversalis fascia
- Extraperitoneal fascia
- Parietal peritoneum

Front 6

Abdominal Muscles

Back 6

Keep abdominal viscera in cavity, protect, assist with respiration, increase intra-abdominal pressure for childbirth, urination, defecation.

Muscles:
- external oblique
- internal oblique
- transversus abdominis
- rectus abdominis
- pyramidalis

Front 7

External Oblique

Back 7

Origin: ribs 5 to 12
Insertion: lateral lip of iliac crest/linea alba
Innervation: T7-T12
Action: compress abdominal contents, flex trunk

Fibers run inferomedially, like external intercostals.

Front 8

Inguinal ligament

Back 8

Formed by lower border of external abdominal oblique aponeurosis.

Runs from anterior superior iliac spine (ASIS) to pubic tubercle (PT).

Folds under to make a canal.

Associated ligaments reinforce (lacunal ligament and pectineal ligament).

Front 9

Internal oblique

Back 9

Origin: Thoracolumbar fascia, iliac crest, 2/3 of inguinal ligament
Insertion: ribs 9-12, linea alba, pubic crest and pectineal line.
Innervation: T7 to T12 and L1
Action: compress abdominal contents, flex trunk

Fibers run superomedially (like internal intercostals).

Front 10

Transversus abdominis

Back 10

Origin: thoracolumbar fascia, iliac crest, 1/3 inguinal ligament, ribs 7-12 cartilage.
Insertion: linea alba, pubic crest, pectineal line.
Innervation: T7 to T12, L1
Action: compress abdominal contents

Fibers run transversely.

Front 11

Rectus Abdominis

Back 11

Origin: pubic crest, pubic tubercle, pubic symphysis.
Insertion: costal cartilages of ribs 5-7, xiphoid process.
Innervation: T7 to T12
Action: compress abdominal contents, flex vertebral column, tense abdominal wall.

Fibers run up and down.

Pyramidalis is small and tenses linea alba.

Front 12

Rectus Sheath

Back 12

Aponeurotic tendinous sheath formed by layering of abdominal muscles. Anterior layer of sheath covers entire anterior surface of rectus abdominis.

Posterior layer of the rectus sheath lines upper 3/4 of rectus abdominis.

So only top 3/4 of rectus is covered.

Arctuate line marks transition when all aponeuroses pass anteriorly to rectus abdominis.

Above line, 1.5/1.5 rule.
Below line, all three (internal and external oblique plus transversis) pass anterior. Only transversalis fascia is below.

Front 13

Transversalis fascia

Back 13

Continuous layer of fascia deep to transversus abdominis.
Lines abdominal cavity and pelvic cavity (where it is called endopelvic cavity).

Front 14

Extraperitoneal fascia/peritoneum

Back 14

Extraperitoneal fascia:
- aka endoabdominal fascia
- deep to transversalis fascia
- abundant around kidneys
- extends into mesenteries with vessels

Peritoneum:
- thin serous membrane
- parietal portion lines abdominal cavity, and occasionally reflects onto viscera as visceral part.
- encloses peritoneal cavity

Front 15

Innervation of anterior abdominal wall

Back 15

Skin and muscles supplied by T7-T12 and L1. Ventral rami pass inferomedially to front of body and give off cutaneous branches.

T7-T11 intecostal nerves run between internal oblique and transversus, then posterior to rectus abdominis.

T12 (subcostal nerve) does the same.

Ilioinguinal/iliohypogastric (L1) runs similar course through lumbar plexus. Courses down to genital area.

Front 16

Specific anterior abdominal wall innervation

Back 16

T7-T9 from xiphoid process to .umbilicus.
T10 around belly button
T11-L1 from umbilicus to pubic region.

L1 has thigh component, scrotal/labial component.

Front 17

Arterial Supply of Anterior Abdominal Wall

Back 17

Superficial:
- musculophrenic artery does superior wall
- superficial epigastric and superficial circumflex of iliac artery

Deep:
- superior epigsatric
- 10th/11th intercostal arteries and subcostal artery
- Inferior epigastric and deep circumflex iliac artery

Front 18

Epigastric vessels

Back 18

Superior epigastric artery (from internal thoracic) and vein.

Inferior epigastric (from external iliac slides) artery/vein.

They both (inferior and posterior) enter rectus sheath, run posteriorly. They anastomose with each other.

Front 19

Inguinal region (groin)

Back 19

Area of junction between abdominal wall and thigh. Weakened by gonal development.

Front 20

Descent of the Gonads

Back 20

Happens around week 7 of devo.
Processus vaginalis (peritoneal outpouching) forms, passes through anterior wall.

The gubernaculum extends from inferior gonad border to labioscrotal swellings, guides process.

Processus vaginalis covered with transversalis fascia, internal oblique, external oblique.

Front 21

Spermatic Cord vs Round Ligament of the Uterus

Back 21

In males:
- testes descend through inguinal canal, bring vessels ducts and nerves with them forming the spermatic cord.

In females:
- Ovaries descend into pelvic cavity, become associated with uterus. Round ligament of uterus is only remaining structure passing through inguinal canal.

Front 22

Inguinal canal

Back 22

Slit like passage extending downward and medial from part of inguinal ligament.

Begins at deep inguinal ring (internally) and continues for 4cm, ending at superficial inguinal ring.

Contains spermatic cord/round ligament of uterus and ilioinguinal nerve.

Anterior wall formed by external oblique, floor formed by inguinal ligament /lacunal ligament.
Posterior wall formed by transversalis fascia and conjoint tendon (combined insertion of transversus and internal oblique)
Roof formed by internal oblique and transversus.

Front 23

Deep Inguinal Ring

Back 23

Beginning of inguinal canal. Halfway along ligament. Beginning of the tubular evagination of transversalis fascia of spermatic cord/uterus.

Front 24

Superficial (external) inguinal ring

Back 24

End of canal. Superior to pubic tubercle. Triangle shaped opening in aponeurosis of external oblique.

Beginning of the external spermatic fascia.

Front 25

Contents of inguinal canal in male

Back 25

Deep inguinal ring, inguinal canal, spermatic cord, superficial inguinal ring.

Spermatic cord ENTERS the deep ring while ilioinguinal nerve pierces into canal through internal oblique. Still exits via superficial ring.

Front 26

Spermatic Cord contents

Back 26

Cord is group of structures passing between abdominopelvic cavity and testis.

Testicular artery surrounded by pampiniform plexus of veins.
Ductus deferens and artery.
Genital branch of genitofemoral nerve
Cremaster artery and vein plus muscle.

Front 27

Fascias enclosing spermatic cord

Back 27

Internal spermatic fascia:
- Deepest layer
- Arises from transversalis fascia
- Attached to deep ring margins

Cremasteric fascia:
- Middle layer
- associated with cremaster muscle
- arises from internal oblique

External spermatic fascia:
- Outer layer
- From external oblique
- Attaches to superficial ring

Front 28

Hydrocele

Back 28

Presence of peritoneal fluid in a persistent processus vaginalis. May or may not communicate with peritoneal cavity.

2/100 male newborns have congenital hydrocele. Residual peritoneal fluid in tunica vaginalis. NORMALLY absorbed in year one without surgery.

Can also occur due to injury or swelling of epididymis.

Front 29

Contents of inguinal canal in female

Back 29

Round ligament of uterus. Enters deep ring, exits via superficial ring. Accompanied cremasteric vessles, genital branch of genitofemoral nerve.

Also ilioinguinal nerve.

Front 30

Ilioinguinal nerve

Back 30

From L1 of lumbar plexus. Travels along posterior abdominal wall.
Innervates transversus abdominis and internal oblique (as it pierces).
DOES NOT enter canal through deep ring.

Innervates scrotum/labia and anterior thigh.

Front 31

Genitofemoral nerve

Back 31

Originates from L1/L2 (femoral from L1, genital from L2).

Travels along posterior wall. Branches into genital and femoral branches.

Genital branch enters deep ring. Exits through superficial canal.

Innervates cremasteric muscle (draws testis up when cold).

Innervates tunica vaginalis, spermatic fascia.

Front 32

Falciform ligament/ligament teres hepatis

Back 32

Remnants of fetal circulation.
Ligament teres hepatis used to be umbilical vein.

Front 33

Indirect inguinal hernia

Back 33

Congenital.
Parietal peritoneum and viscera protrude into deep ring (lateral to epigastric vessels). Travel through canal and into scrotum.

Most common abdominal hernia. Twenty times more common in men.

LATERAL TO EPIGASTRIC.

Front 34

Direct inguinal hernia

Back 34

Acquired (not congenital).
Parietal peritoneum and viscera protrude through weak area in abdominal wall of canal. Almost never enters canal. Enclosed in hernial sac formed by transversalis fascia.


MEDIAL TO EPIGASTRIC