ABDOMEN | PART 1

Thoracic Cage

covers all or parts of the upper abdominal organs (e.g., liver, stomach, spleen, kidneys).

• lumbar vertebrae

• the costal margin of the thoracic cage

• iliac and pubic bone elements of the pelvis.

Abdominal skeleton consists primarily of the

• skin

• superficial fascia

• deep fascia

• muscles

• transversalis fascia

• extraperitoneal fascia

• parietal peritoneum.

anterolateral abdominal wall is made up of

seven layers:

• superficial fatty layer

• deeper membranous layer.

superficial fascia is divided into two layers:

• external oblique

• internal oblique

• transversus abdominis

The abdominal wall houses three broad sheets of

muscle:

Paired rectus abdominis muscle

Form vertical straps on either side of the anterior midline

Rectus Sheath

The aponeuroses of the three sheets enclose the

rectus abdominis to form the?

External oblique aponeurosis

contains a triangular-shaped defect, the superficial inguinal ring

Spermatic cord (round ligament of the uterus)

The _ passes through superficial inguinal ring.

Inguinal ligament

The lower border of the external oblique aponeurosis forms the?

• Tendinous fibers of the internal oblique

• Transversus abdominis

They join together to form the conjoint tendon

• Anterior rami of the lower six thoracic

• First lumbar (iliohypogastric and ilioinguinal)

They supply the anterolateral abdominal wall.

T7

Epigastrium (over the xiphoid process)

T10

Umbilicus

L1

Just above the symphysis pubis.

• superior epigastric

• inferior epigastric

• deep circumflex iliac

• lower two posterior intercostal

• lumbar arteries.

The main arteries to the anterolateral abdominal wall are the:

Superficial veins

Form a network radiating from the umbilicus.

Small paraumbilical veins

connect this network through the umbilicus and along the ligamentum teres to the portal vein, forming an important portal-systemic venous anastomosis.

Anterior axillary (pectoral) group of nodes.

The lymph drainage of the skin of the anterior abdominal wall above the level of the umbilicus is upward to the

Superficial inguinal nodes

Below the level of the umbilicus, the lymph drains downward and laterally to the?

Posterior axillary group of nodes

The lymph of the skin of the back above the level of the lilac crests drains upward to the

Superficial inguinal nodes

Below the level of the iliac crests, lymph drains downward to the?

Arteries

Deep lymph vessels follow the?

Inguinal canal

Is an oblique passage through the lower anterior abdominal wall.

Spermatic cord

Males transmits the

Round ligament of the uterus

Females transmits the

• Anterior

• posterior

• superior (roof)

• Inferior (floor)

Inguinal canal has four walls:

Spermatic cord

is a bundle of structures passing through the inguinal canal to and from the testis.

It is enclosed by three concentric layers of fascia derived from the anterior abdominal wall.

Scrotum

houses the testes, epididymis, and spermatic cord. The fasciae of the abdominal wall contribute to its layers.

• vas deferens

• testicular artery

• pampiniform plexus (testicular veins)

• testicular lymph vessels

• autonomic nerves

• remains of processus vaginalis

• genital branch of the genitofemoral nerve

Components of spermatic cord

Labia majora

female homologues of the scrotum.

Superficial inguinal nodes

Lymph drainage: Scrotal skin and fascia (including tunica

vaginalis)

Lumbar nodes

Lymph drainage: testes (upward drainage)

Testis

is the male gonad, surrounded by the tunica albuginea.

• Inguinal (indirect and direct)

• Femoral

• Umbilical

• Epigastric

• Rectus abdominis separation

• Incisional

• Linea semilunaris

• lumbar

• Internal

There are several types of abdominal herniae:

• five lumbar vertebrae and their intervertebral disc

• 12th ribs

• Upper bony pelvis

Form the skeleton of the posterior wall.

• psoas major

• Quadratus lumborum

• Aponeuroses of transversus abdominis

• Iliacus

Posterior abdominal wall: The muscles include the

grid of vertical and horizontal lines

divides the abdominal wall into reference areas to describe wall regions and organ locations.

• liver,

• gallbladder

• spleen

• pancreas

• kidneys

• stomach

• colon

• appendix

• aorta.

Organs that project to landmark areas: