Pelvic Region Anatomy

Questions and Answers

Which of the following structures forms the anterior wall of the pelvic cavity?

Piriformis muscle and obturator internus muscle

Sacrum and coccyx

Pubic symphysis and bodies of pubic bones (correct)

Levator ani muscle and coccygeus muscle

Through which foramen do the piriformis muscle and other structures leave the pelvis?

Greater sciatic foramen (correct)

Obturator foramen

Lesser sciatic foramen

Sacral hiatus

What is the name of the muscular structure that forms the inferior wall of the pelvic cavity?

Pelvic diaphragm (correct)

Urogenital diaphragm

Levator ani muscle

Obturator internus muscle

Which of the following structures does not form the lateral wall of the pelvic cavity?

Coccyx Signup and view all the answers

What is the name of the line that divides the pelvis into two parts?

Linea terminalis Signup and view all the answers

What is the name of the space between the inlet and outlet of the pelvis?

Pelvic cavity Signup and view all the answers

What forms the lower part of the abdominal cavity?

Greater pelvis Signup and view all the answers

Which of the following structures leaves the pelvis through the lesser sciatic foramen?

Tendon of obturator internus muscle Signup and view all the answers

What is the anterior angle of the pelvic outlet bounded by?

Inferior border of pubic symphysis Signup and view all the answers

What is the posterior angle of the pelvic outlet bounded by?

Apex of coccyx Signup and view all the answers

What is the anterolateral border of the pelvic outlet bounded by?

Ischiopubic ramus Signup and view all the answers

What is the posterolateral border of the pelvic outlet bounded by?

Sacrotuberous ligament Signup and view all the answers

What is the name of the region that encloses the pelvic cavity and perineum?

Lesser pelvis Signup and view all the answers

Which of the following arteries is a visceral branch of the abdominal aorta?

Ovarian artery Signup and view all the answers

Which ligament is equivalent to the anterior longitudinal ligament?

Anterior SC ligament Signup and view all the answers

Which of the following arteries supplies the prostate?

Inferior vesical artery Signup and view all the answers

Which of the following foramina communicates the pelvic cavity with the gluteal region?

Greater sciatic foramina Signup and view all the answers

Which ligament is equivalent to the ligamentum flavum?

Superficial posterior SC ligament Signup and view all the answers

Which of the following arteries enters the gluteal region through the greater sciatic foramen?

Internal pudendal artery Signup and view all the answers

Which of the following arteries is replaced by the vaginal artery in females?

Inferior vesical artery Signup and view all the answers

Which of the following ligaments is equivalent to the intertransverse ligament?

Lateral SC ligament Signup and view all the answers

What is the main characteristic of the pelvic cavity in females?

It is more cylindrical than in males Signup and view all the answers

What is the function of the puborectalis muscle?

It provides sphincteric action to the pelvic cavity Signup and view all the answers

What nerve supplies the pelvic diaphragm?

Ventral rami S2-S4 Signup and view all the answers

What is the function of the sacrotuberous ligament?

It moves the base of the sacrum Signup and view all the answers

What ligament provides immediate posterior strength to the sacroiliac joint?

Interosseous sacroiliac ligament Signup and view all the answers

What is the primary function of the pelvic diaphragm?

It prevents prolapse of pelvic viscera Signup and view all the answers

What is the characteristic of the pelvic bone in females?

It is thinner and lighter than in males Signup and view all the answers

What is the nerve supply of the sacroiliac joint?

Inferior gluteal nerve and dorsal rami S1-S2 Signup and view all the answers

Which of the following arteries enters the gluteal region through the greater sciatic foramen inferior to the piriformis muscle?

Internal iliac artery Signup and view all the answers

Which of the following vessels communicates with the internal vertebral venous plexus?

Pelvic veins Signup and view all the answers

Which of the following nerves supplies the skin of the medial leg and foot?

Saphenous nerve of femoral nerve Signup and view all the answers

Which of the following plexuses is the main autonomic plexus of the pelvis?

Inferior hypogastric plexus Signup and view all the answers

Which of the following arteries is the largest branch of the internal iliac artery?

Superior gluteal artery Signup and view all the answers

Which of the following nerves forms the sacral plexus?

Part of ventral rami of L4 and ventral rami of L5-S4 Signup and view all the answers

Which of the following arteries supplies the psoas major and quadratus lumborum?

Iliolumbar artery Signup and view all the answers

What forms the posterior wall of the pelvic cavity?

Sacrum and coccyx Signup and view all the answers

What structures make up the pelvic diaphragm?

Levator ani muscle and coccygeus muscle Signup and view all the answers

Which of the following muscles leaves the pelvis via the greater sciatic foramina?

Piriformis muscle Signup and view all the answers

What forms the lateral wall of the pelvic cavity?

Hip bone inferior to the pelvic brim Signup and view all the answers

Which of the following structures forms the inferior wall of the pelvic cavity?

Pelvic diaphragm Signup and view all the answers

What is the name of the line that splits the pelvis into two parts?

Pelvic brim Signup and view all the answers

What is the region superior to the pelvic brim?

Greater pelvis Signup and view all the answers

The pelvic inlet is bound superiorly by which structure?

Pelvic brim Signup and view all the answers

What is the function of the lesser pelvis?

Encloses the pelvic cavity and perineum Signup and view all the answers

What is the posterior angle of the pelvic outlet bounded by?

Apex of the coccyx Signup and view all the answers

What is the anterolateral border of the pelvic outlet bounded by?

Ischiopubic ramus Signup and view all the answers

What is the contents of the lesser pelvis?

Pelvic cavity and perineum Signup and view all the answers

What is the characteristic of the sciatic notch in females?

Wider Signup and view all the answers

What is the function of the pelvic diaphragm?

Prevents prolapse of pelvic viscera Signup and view all the answers

Which ligament provides immediate posterior strength to the sacroiliac joint?

Interosseous SI ligament Signup and view all the answers

What is the nerve supply of the sacroiliac joint?

Dorsal rami S1 and S2, and superior gluteal nerve Signup and view all the answers

What is the primary action of the puborectalis muscle?

Sphincteric action Signup and view all the answers

Which muscles form the pelvic diaphragm?

Levator ani muscle and coccygeus muscle Signup and view all the answers

What is the characteristic of the pelvic bone in females?

Thinner and lighter Signup and view all the answers

What divides the lesser pelvis into two parts?

Pelvic diaphragm Signup and view all the answers

Which artery is a parietal branch of the abdominal aorta?

Medial sacral artery Signup and view all the answers

What is the equivalent of the posterior longitudinal ligament in the sacrococcygeal joint?

Deep posterior SC ligament Signup and view all the answers

Which artery leaves the pelvis through the greater sciatic foramen and enters the gluteal region?

Internal pudendal artery Signup and view all the answers

What is the function of the umbilical artery in the fetus?

Carries oxygenated blood from the placenta to the fetus Signup and view all the answers

Which artery is a terminal branch of the inferior mesenteric artery?

Superior rectal artery Signup and view all the answers

Which ligament is equivalent to the ligamentum flavum in the sacrococcygeal joint?

Superficial posterior SC ligament Signup and view all the answers

What is the function of the middle rectal artery?

Supplies the lower rectum Signup and view all the answers

Which artery is present in males but replaced by the vaginal artery in females?

Inferior vesical artery Signup and view all the answers

Which of the following arteries supplies the uterus and uterine tube?

Uterine artery Signup and view all the answers

What is the function of the posterior trunk of the internal iliac artery?

Supplies the lower back and pelvis Signup and view all the answers

Which of the following nerves forms the sacral plexus?

Ventral rami of L4-S4 Signup and view all the answers

What is the main autonomic plexus of the pelvis?

Inferior hypogastric plexus Signup and view all the answers

Which of the following arteries is the largest branch of the internal iliac artery?

Superior gluteal artery Signup and view all the answers

Which of the following nerves supplies the skin of the medial leg and foot?

Saphenous nerve Signup and view all the answers

What is the function of the pelvic splanchnic nerves?

Motor and sensory to pelvic organs Signup and view all the answers

Study Notes

Pelvic Region Anatomy

The pelvis is divided into two parts by the pelvic brim (also known as linea terminalis), which consists of:
- Sacral promontory
- Arcuate line
- Pectineal line
- Pubic crest
- Superior border of pubic symphysis
The greater pelvis (or false pelvis) is the superior part of the pelvis, located above the pelvic brim, and forms the lower part of the abdominal cavity.
The lesser pelvis (or true pelvis) is the inferior part of the pelvis, located below the pelvic brim, and encloses the pelvic cavity and perineum.
The pelvic cavity is the space between the pelvic inlet and outlet, bounded by:
- Anterior wall: pubic symphysis and bodies of pubic bones
- Posterior wall: sacrum, coccyx, and piriformis muscle
- Lateral walls: hip bone inferior to the pelvic brim, obturator membrane, and internus muscle
The pelvic diaphragm is a muscular structure that divides the lesser pelvis into two parts:
- Pelvic cavity (superior to the pelvic diaphragm)
- Perineum (inferior to the pelvic diaphragm)
The pelvic diaphragm is formed by:
- Levator ani muscle (with three parts: puborectalis, pubococcygeus, and iliococcygeus)
- Coccygeus muscle (also known as ischiococcygeus muscle)
Gender differences:
- Female pelvic bones are thinner, lighter, and have less prominent muscular markings
- The female pelvic cavity is more cylindrical, with a greater distance between the ischial spines and tuberosities
- The female greater sciatic notch is wider, and the subpubic angle is wider

Sacroiliac (SI) Joint

The SI joint is a synovial joint that connects the sacrum and ilium bones.
Nerve supply: ventral rami S2-S4, superior gluteal nerve, and dorsal rami S1-S2
Ligaments:
- Ventral SI ligament (small anterior strength to the SI joint)
- Interosseous SI ligament (major strength and stability to the SI joint)
- Dorsal sacroiliac ligament (posterior to the interosseous SI ligament)
- Sacrotuberous ligament (connects the PSIS, sacrum, and coccyx to the ischial tuberosity)
- Sacrospinous ligament (connects the lower sacrum and coccyx to the ischial spine)

Sacrococcygeal (SC) Joint

The SC joint is a cartilaginous joint connected by a small fibrocartilaginous disc.
Reinforced by:
- Anterior SC ligament (equivalent to the ALL)
- Deep posterior SC ligament (equivalent to the PLL)
- Superficial posterior SC ligament (equivalent to the ligamentum flavum)
- Lateral SC ligament (equivalent to the intertransverse ligament)

Pelvic Cavity Arteries

Ovarian artery (visceral branch of the abdominal aorta)
Medial sacral artery (parietal branch of the abdominal aorta)
Superior rectal artery (terminal branch of the inferior mesenteric artery)
Internal iliac artery:
- Anterior trunk:
  - Umbilical artery (with a proximal part that gives off superior vesical arteries)
  - Obturator artery (leaves through the obturator canal)
  - Inferior vesical artery (present in males, replaced by the vaginal artery in females)
  - Middle rectal artery (supplies the lower rectum)
  - Internal pudendal artery (enters the gluteal region through the greater sciatic foramen)
  - Inferior gluteal artery (enters the gluteal region through the greater sciatic foramen)
  - Uterine artery (supplies the uterus, uterine tube, upper vagina, and ovaries)
  - Vaginal artery (supplies the vagina and adjacent bladder and rectum)
- Posterior trunk:
  - Iliolumbar artery (iliac branch supplies the iliacus muscle and ilium, and lumbar branch supplies the psoas major, quadratus lumborum, and cauda equina)
  - Lateral sacral arteries (superior and inferior branches supply the sacrum and sacral canal)
  - Superior gluteal artery (the largest branch of the internal iliac artery, enters the gluteal region through the greater sciatic foramen)

Sacral Plexus

The sacral plexus is formed by:
- Part of the ventral rami of L4
- Ventral rami of L5-S4
Supplies:
- Muscles and skin of the gluteal region, posterior thigh, entire leg and foot, and perineum
- Skin of the medial leg and foot is supplied by the saphenous nerve of the femoral nerve

Autonomic Plexus of the Pelvis

The inferior hypogastric plexus is the main autonomic plexus, providing motor and sensory innervation to pelvic organs.
Formed by:
- Hypogastric and pelvic splanchnic nerves
- Small contribution from sacral splanchnic nerves

Pelvic Region Anatomy

The pelvis is divided into two parts by the pelvic brim (also known as linea terminalis), which consists of:
- Sacral promontory
- Arcuate line
- Pectineal line
- Pubic crest
- Superior border of pubic symphysis
The greater pelvis (or false pelvis) is the superior part of the pelvis, located above the pelvic brim, and forms the lower part of the abdominal cavity.
The lesser pelvis (or true pelvis) is the inferior part of the pelvis, located below the pelvic brim, and encloses the pelvic cavity and perineum.
The pelvic cavity is the space between the pelvic inlet and outlet, bounded by:
- Anterior wall: pubic symphysis and bodies of pubic bones
- Posterior wall: sacrum, coccyx, and piriformis muscle
- Lateral walls: hip bone inferior to the pelvic brim, obturator membrane, and internus muscle
The pelvic diaphragm is a muscular structure that divides the lesser pelvis into two parts:
- Pelvic cavity (superior to the pelvic diaphragm)
- Perineum (inferior to the pelvic diaphragm)
The pelvic diaphragm is formed by:
- Levator ani muscle (with three parts: puborectalis, pubococcygeus, and iliococcygeus)
- Coccygeus muscle (also known as ischiococcygeus muscle)
Gender differences:
- Female pelvic bones are thinner, lighter, and have less prominent muscular markings
- The female pelvic cavity is more cylindrical, with a greater distance between the ischial spines and tuberosities
- The female greater sciatic notch is wider, and the subpubic angle is wider

Sacroiliac (SI) Joint

The SI joint is a synovial joint that connects the sacrum and ilium bones.
Nerve supply: ventral rami S2-S4, superior gluteal nerve, and dorsal rami S1-S2
Ligaments:
- Ventral SI ligament (small anterior strength to the SI joint)
- Interosseous SI ligament (major strength and stability to the SI joint)
- Dorsal sacroiliac ligament (posterior to the interosseous SI ligament)
- Sacrotuberous ligament (connects the PSIS, sacrum, and coccyx to the ischial tuberosity)
- Sacrospinous ligament (connects the lower sacrum and coccyx to the ischial spine)

Sacrococcygeal (SC) Joint

The SC joint is a cartilaginous joint connected by a small fibrocartilaginous disc.
Reinforced by:
- Anterior SC ligament (equivalent to the ALL)
- Deep posterior SC ligament (equivalent to the PLL)
- Superficial posterior SC ligament (equivalent to the ligamentum flavum)
- Lateral SC ligament (equivalent to the intertransverse ligament)

Pelvic Cavity Arteries

Ovarian artery (visceral branch of the abdominal aorta)
Medial sacral artery (parietal branch of the abdominal aorta)
Superior rectal artery (terminal branch of the inferior mesenteric artery)
Internal iliac artery:
- Anterior trunk:
  - Umbilical artery (with a proximal part that gives off superior vesical arteries)
  - Obturator artery (leaves through the obturator canal)
  - Inferior vesical artery (present in males, replaced by the vaginal artery in females)
  - Middle rectal artery (supplies the lower rectum)
  - Internal pudendal artery (enters the gluteal region through the greater sciatic foramen)
  - Inferior gluteal artery (enters the gluteal region through the greater sciatic foramen)
  - Uterine artery (supplies the uterus, uterine tube, upper vagina, and ovaries)
  - Vaginal artery (supplies the vagina and adjacent bladder and rectum)
- Posterior trunk:
  - Iliolumbar artery (iliac branch supplies the iliacus muscle and ilium, and lumbar branch supplies the psoas major, quadratus lumborum, and cauda equina)
  - Lateral sacral arteries (superior and inferior branches supply the sacrum and sacral canal)
  - Superior gluteal artery (the largest branch of the internal iliac artery, enters the gluteal region through the greater sciatic foramen)

Sacral Plexus

The sacral plexus is formed by:
- Part of the ventral rami of L4
- Ventral rami of L5-S4
Supplies:
- Muscles and skin of the gluteal region, posterior thigh, entire leg and foot, and perineum
- Skin of the medial leg and foot is supplied by the saphenous nerve of the femoral nerve

Autonomic Plexus of the Pelvis

The inferior hypogastric plexus is the main autonomic plexus, providing motor and sensory innervation to pelvic organs.
Formed by:
- Hypogastric and pelvic splanchnic nerves
- Small contribution from sacral splanchnic nerves

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Description

Learn about the anatomy of the pelvic region, including the pelvis, its components, and boundaries. This quiz covers the pelvic brim, linea terminalis, and more.