• Encased in bone

• Cranial cavity → houses the brain

• Spinal cavity → houses the spinal cord

• Separated by the diaphragm

• Thoracic cavity (superior)

• Abdominopelvic cavity (inferior)

  • Subdivided into abdomen and pelvis (no physical barrier)

  • Enclosed by the abdominal wall

• Encased in bone

• houses the brain

• houses the spinal cord

• Separated by the diaphragm

superior in the ventral cavity

(a)  

inferior cavity in the ventral cavity

(a)  

• Subdivided into abdomen and pelvis (no physical barrier)

• Enclosed by the abdominal wall

purple

(a)  

orange

(a)  

pink/green

(a)  

• Embryo changes from a flat disk into a tubular structure

• tail region folds forward, moving the connecting stalk to the ventral surface → future umbilical cord site

• sides fold inward, enclosing part of the yolk sac → forms the primitive gut tube.

• Folding also creates the ___ and __

• The diaphragm forms through the coordinated growth of muscle, connective tissue, vessels, and nerves

• develops first, creating a partial separation between thoracic and abdominal cavities.

• It anchors to the front wall of the embryo, between the heart and liver

• grow inward from the sides and connect with the septum transversum

• These folds provide a scaffold for muscle and connective tissue, forming the diaphragm and its central tendon.

• The abdominopelvic cavity is divided into (a)   quadrants

• through the midline (from the xiphoid process to the pubic symphysis)

• through the umbilicus

Right upper, right lower, left upper, left lower

(a)  

Abdomen is further divided into nine regions called the (a)  

Formed by two vertical lines (midclavicular planes) and two horizontal lines (costal margin & L5/iliac tubercles

(a)  

• Right hypochondrium

• Epigastrium

• Left hypochondrium

• Right lumbar

• Umbilical

• Left lumbar

• Right iliac fossa

• Hypogastrium

• Left iliac fossa

A

(a)  

B

(a)  

C

(a)  

D

(a)  

E

(a)  

F

(a)  

G

(a)  

H

(a)  

I

(a)  

• From the thoracic cage to the pelvis

• (anterolateral abdominal wall)

• Cartilages of ribs 7–10 and the xiphoid process

• (Anterolateral abdominal wall)

• Inguinal ligament, iliac crests, pubic crests, and pubic symphysis

• (anterolateral abdominal wall)

Skin, Superficial fascia, deep fascia, muscles/aponeuroses, extraperitoneal fat, parietal peritoneum

(a)  

• Connective tissue with variable fat content

• Rich in blood vessels and nerves

• Loosely organized, no internal strength

• Dense, strong fibrous tissue

• Covers and separates muscles into groups

1

(a)  

2

(a)  

3

(a)  

4

(a)  

5

(a)  

6

(a)  

7

(a)  

8

(a)  

9

(a)  

10

(a)  

• Anterior to muscle layers and makes up the superficial fascia

• Reinforced with elastic and collagen fibers and is divided into two layers

• Contains small vessels and nerves

• Consists of a combination of fat and fibrous tissue that blends with the deep fascia

• Long vertical muscle (“six-pack”); flexes trunk and stabilizes pelvis.

• Outermost side muscle; helps bend trunk, rotate torso, and compress abdomen

• Lies under external oblique; works with it to bend, rotate, and support abdominal wall

• Deepest abdominal muscle; wraps around core like a “belt”; compresses abdomen for stability

• Runs from lumbar spine to femur; flexes hip and stabilizes spine.

• In posterior wall; helps with trunk side-bending and stabilizes the lower back

1

(a)  

2

(a)  

3

(a)  

4

(a)  

5

(a)  

5

(a)  

6

(a)  

7

(a)  

8

(a)  

9

(a)  

• Midline fibrous band running from xiphoid process to pubic symphysis; formed by fusion of abdominal muscle tendons

• Curved tendinous line on each side of the rectus abdominis; marks lateral edge of rectus sheath.

• Fibrous band from anterior superior iliac spine (ASIS) to pubic tubercle; important landmark for lower abdominal wall and inguinal canal.

• Fibrous band from anterior superior iliac spine (ASIS) to pubic tubercle; important landmark for lower abdominal wall and inguinal canal.

1

(a)  

2

(a)  

3

(a)  

• Composition

  • Lumbar vertebra

  • Posterior abdominal wall muscles

  • Diaphragm

  • Fascia

  • Lumbar plexus

  • Fat

  • Nerves

  • Blood vessels

  • Lymphatic vessels

A transparent, layered membrane in the abdomen.

(a)  

• •Covers abdominal organs; secretes a small amount of serous fluid for lubrication

• •Lines the abdominal wall

• •Supports abdominal organs (viscera).

• •Provides a pathway for blood vessels and lymph

• •The space between the visceral and parietal peritoneum

1

(a)  

2

(a)  

3

(a)  

Main and largest part of the peritoneal cavity.

(a)  

•   Extends from the diaphragm (superiorly) to the pelvic cavity (inferiorly)

• Liver, spleen, stomach, first part of the duodenum, jejunum, ileum, cecum, transverse colon, sigmoid colon, upper two-thirds of the rectum.

Subdiaphragmatic spaces

Subhepatic space (Morrison’s pouch / hepatorenal recess)

Subsplenic space

Pelvic spaces

(a)  

• Just beneath the diaphragm

• Common site for fluid/abscess collection (esp. after infection)

• Between liver & right kidney

• Lowest point when supine → fluid often accumulates here.

• Beneath the spleen

• Potential site for abscess or hemorrhage with splenic injury.

• Surround kidneys, enclosed by renal fascia & fat

• Important in infection spread or perinephric abscess