The posterior abdominal wall Flashcards
What are the bones of the posterior abdominal wall?
Lumbar vertebrae
Ribs 11/12
Ilia
Sacrum
What are muscles of the posterior abdominal wall?
Diaphragm
Quadratus lumborum
Iliacus
Psoas
What is the diaphragm anchored by?
Crura (left and right crus)
Purpose of the central tendon of the diaphragm
to not crush the structures that pass through the hiatus
What are the levels of the structures that pass through the hiatus?
IVC - T8
Oesophagus - T10
Aorta - T12
Location of the quadratus lumborum
- Post to kidneys
- Superficially to the psoas major
Attachments of quadratus lumborum
- It originates from the iliac crest and iliolumbar ligament
- The fibres travel superomedially, inserting onto the transverse processes of L1-L4 and the inferior border of the 12th rib
What are the actions carried out by the quadratus lumborum?
- Extension and lateral flexion of the vertebral column
- It also fixes the 12th rib during inspiration, so that the contraction of diaphragm is not wasted
What is the innervation of the quadratus lumborum?
Anterior rami of T12-L4 nerves
Location of the psoas major
The psoas major is located near the midline of the posterior abdominal wall, immediately lateral to the lumbar vertebrae
What are the attachments of the psoas major?
Originates from the transverse processes and vertebral bodies of T12-L5.
It then moves inferiorly and laterally, running deep to the inguinal ligament, and attaching to the lesser trochanter of the femur
What are the actions of psoas major?
Flexion of the thigh at the hip lateral flexion of the vertebral column
What is the innervation of the psoas major?
Anterior rami of L1-L3 nerves
Location of psoas minor
Is only present in 60% of the population. It is located anterior to the psoas major
Attachments of psoas minor
Originates from the vertebral bodies of T12 and L1 and attaches to a ridge on the superior ramus of the pubic bone, known as the pectineal line
What are the actions of the psoas minor?
Flexion of the vertebral column
What is the innervation of the psoas minor?
Anterior rami of the L1 spinal nerve
Location of the iliacus
The iliacus muscle is a fan shaped muscle that is situated inferiorly on the posterior abdominal wall
It combines with the psoas major to form the iliopsoas - the major flexor of the thigh
What are the actions of the iliacus?
Flexion of the thigh at the hip joint
What is the innervation of the iliacus?
Femoral nerve (L2 - L4)
What is the vein/artery that supplies the diaphragm?
Sup and inf phrenic
What is the vein/artery that supplies the quadratus lumborum?
Lumbar
Vein/artery for iliopsoas
Lumbar
Innervation of diaphragm
Phrenic (C3-5)
Intercostal (T5-11)
Subcostal (T12)
Innervation of quadratus lumborum
Lumbar (T12-L4)
Innervation of iliopsoas
Femoral (L2-L4)
What are the three midline vessels of the aorta?
Coeliac, SMA and IMA
What are the paired parietal branches of the aorta?
Inferior phrenics, lumbars and middle sacral
Examples of paired visceral branches of the aorta?
Renal and gonadal
Where is an aneurysm more common in the aorta?
More common below renal arteries
What can occlusion of the aortic bifurcation cause?
Claudication and impotence
What does the somatic innervation in the abdomen innervate?
Somatic - Muscles of anterior/posterior abdominal wall, joints (eg intervertebral), skin etc
What does the autonomic innervation in the abdomen innervate?
Autonomic - In segmented structures (blood vessels in muscle, sweat glands in skin etc)
- In viscera, aka splanchnic (peristalsis of stomach, heart rate etc)
Where do the somatic nerves for the abdomen originate from?
Lumbar plexus (L1-L4) - motor and sensory
Sacral plexus
Where does the autonomic sympathetic nerve supply originate from?
Segmented – Sympathetic chain (paravertebral)
Viscera – Celiac, sup and inf mesenteric (prevertebral)
Where does the autonomic parasympathetic nerve supply originate from?
vagus; pelvic splanchnic
Where do the nerves for the prevertebral ganglia originate from?
Nerves originate in spinal cord and project to these ganglia bypassing the symp chain and from these to the viscera –> Splanchnic nerves
What part of the spinal cord does the greater splanchnic nerve originate from?
T5-T9
What part of the spinal cord does the lesser splanchnic nerve originate from?
T10-T11
What part of the spinal cord does the least splanchnic nerve originate from?
T12
What are the two types of abdominopelvic splanchnic nerves?
Lower thoracic splanchnic nerves
Lumbar splanchnic nerves
What nerves are part of the lower thoracic splanchnic nerves?
Greater, lesser and least thoracic splanchnic nerves.
What ganglia and plexuses do the lower thoracic splanchnic nerves pass through?
They pass through the diaphragm to send fibers to the celiac, aorticorenal, and superior mesenteric ganglia and plexuses
Where do the lumbar splanchnic nerves start?
These nerves start at the abdominal sympathetic trunk
What plexuses do the lumbar splanchnic nerves go through?
Join the intermesenteric, inferior mesenteric, and superior hypogastric plexuses
What are the suprarenals innervated by?
Suprarenals are innervated by greater, lesser and least splanchnic nerve from the celiac and aorticorenal ganglia
Kidneys innervated mostly by fibres from the least splanchnic nerve
What are the three types of abdominal pain?
Somatic, visceral and referred
Where does the somatic abdominal pain arise from
Skin, fascia, muscle and parietal peritoneum
What is the character of somatic abdominal pain
Precisely localised and severe
Where does visceral abdominal pain arise from
Abdominal organs, mesenteries and visceral peritoneum
What are the causes of visceral abdominal pain?
Stretching viscus or mesentery, impaired blood supply to viscus and chemical damage to viscus
Describe the character of visceral abdominal pain
Dull and poorly localised
Pain is referred to midline(embryology)
Colic pain is a form of visceral pain
What is referred pain?
Describes pain at a location other than site of origin stimulus but supplied by same or adjacent segments of the spinal cord
What is the level that visceral pain arise from for the stomach?
T5-T9
What is the level that visceral pain arise from for the appendix?
T10
What is the level that visceral pain arise from for the gall bladder?
T7-9; but with parietal peritoneum involvement C3,4
What are the nerves that pain signals from pleura or peritoneum of diaphragm or anterior abdominal wall reach the CNS via?
Central part diaphragm - phrenic C3-5
Peripheral diaphragm - intercostals T7-11
Anterior abdominal wall - T7-12 and L1