Abdomen and Pelvis Anatomy

Description

Abdominal quadrants and the positions of major viscera. Anterior view of a man

Anatomy of the female pelvis

Abdominal wall muscles

The bony and muscular structures making up the abdominopelvic ‘cavity’. The anterolateral abdominal muscles have been removed for clarity

Bones of the pelvis.

Anatomical illustration of somatic and autonomic pelvic nerves in a female pelvis (frontal view). Yellow – somatic nerves, orange – sympathetic plexus, purple – sympathetic trunk, green – PSN.

Arterial anatomy of the abdomen. The major branches of the abdominal aorta are depicted. All abdominal organs have been removed except the kidneys

General

• The abdomen and pelvis are continuous with each other
• They make up the inferior half of the torso, below the Thorax
• This region contains the vast majority of your bodies organs including digestive, endocrine, lymphatic, urinary, reproductive

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Terminology

Abdomen

• Boundaries: anterolateral and posterior abdominal walls, diaphragm, pelvic inlet
• Contents: stomach, small intestine, large intestine, vermiform appendix, pancreas, spleen, liver, gallbladder, kidneys, ureters, adrenal glands

Pelvis

• Boundaries: pelvic inlet, pelvic girdle, pelvic diaphragm
• Contents: internal genitalia, external genitalia, urinary bladder, urethra, rectum and anus

Peritoneum

• Two layered membranous sac
• Covers the abdominal wall with its parietal layer
• Lines most of the abdominal viscera with its abdominal layer

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Viscera

Gastrointestinal tract

• Esophagus
• Stomach
• Small intestine (duodenum, jejunum, ileum)
• Large intestine (cecum, colon, rectum)

Accessory organs

• Liver
• Gallbladder
• Pancreas

Genitourinary

• Kidney
• Ureter
• Bladder
• Urethra

Male Reproductive

• Prostate
• Seminal vesicles
• Vas deferens
• Testes
• Penis

Female Reproductive

• Uterus
• Ovaries
• Fallopian tubes
• Vagina

Other

• Spleen
• Suprarenal (adrenal) glands

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Muscles

Anterolateral Abdominal Wall Muscles

• External Oblique
• Internal Oblique
• Transversus Abdominis
• Rectus Abdominis
• Pyramidalis (often absent)

Posterior Abdominal Wall Muscles

• Psoas Major
• Psoas Minor (inconsistent; not always present)
• Iliacus
• Quadratus Lumborum

Pelvic Diaphragm (Floor)

• Levator Ani
  • Puborectalis
  • Pubococcygeus
  • Iliococcygeus
• Coccygeus

Urogenital Diaphragm (Deep Perineal Pouch)

• Deep transverse perineal muscle
• External urethral sphincter
• Compressor urethrae (in females)
• Sphincter urethrovaginalis (in females)

Superficial Perineal Muscles

• Ischiocavernosus
• Bulbospongiosus
• Superficial transverse perineal muscle

Other Associate Muscles

• Diaphragm
• Obturator Internus
• Piriformis

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Bones and Joints

Axial

• Lumbar Vertebrae (L1-L5)
• 9th to 12th Ribs

Bony Pelvis

• Hip Bone (Ilium, ischium, pubis)
• Sacrum
• Coccyx

Joints

• Sacroiliac Joints
• Pubic Symphysis

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Other Structures

• Linea alba
• Inguinal Ligament
• Inguinal canal
• Peritoneum
• Mesentery, omenta, and peritoneal ligaments

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Vascular Supply and Lymphatics

Major Arteries

• Celiac trunk
• Superior mesenteric artery
• Inferior mesenteric artery
• Internal iliac artery and its branches

Major Veins

• Portal vein
• Inferior vena cava (IVC)
• Internal iliac vein
• Venous plexuses

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Innervation

Abdomen

• Sympathetic (splanchnic nerves)
• Parasympathetic (vagus nerve, pelvic splanchnic)

Pelvis

• Sacral Plexus
• Autonomic: pelvic splanchnic nerves, hypogastric plexuses

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Clinical Significance

• Abdominal Pain Main
• OBGYN Main
• Urology Main
• Gastrointestinal Main
• Genitourinary Main

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See Also

• Anatomy Main

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