Posterior Abdominal Wall And Diaphram

Front 1

Muscles of the posterior abdominal wall:

Back 1

Psoas minor
Psoas major
Iliacus
Quadratus lumborum
Diaphragm

Front 2

Psoas major Proximal attachment

Back 2

Proximal attachment is the lumbar bodies and intervertebral discs of T12 to L5;

also transverse processes of lumbar vertebrae

Front 3

Iliacus proximal attachment

Back 3

Proximal attachment is the superior 2/3 of iliac fossa

Front 4

Iliopsoas

Back 4

Psoas major and the iliacus m. merge together to form the iliopsoas m.

Iliopsoas inserts on the lesser trochanter of the femur and is a strong flexor of the hip; performs a deep bow when insertion point remains fixed

The superior portion of the psoas major muscle can laterally bend the lower vertebral column when one side acts alone; important in balancing the trunk

Front 5

Innervations of iliopsoas

Back 5

-Innervation – posas major: anterior rami L2-L4

-Innervation – iliacus m.: femoral nerve (L2 – L4)

Front 6

Psoas minor

Back 6

- Superior attachment to lateral aspect of T12 and L1 vertebral bodies

- Inferior attachment to iliopectineal eminence

- Function: balance the trunk
Innervation from L1 & L2 ventral rami

Front 7

Iliopsoas test

Back 7

- Muscle has a close relationship to abdominal organs:
Kidneys & ureters
Cecum & appendix
Pancreas
Sigmoid colon

- Intra-abdominal inflammation + psoas movement = pain

- How to test: flexion of thigh against resistance or extension of thigh while lying on unaffected side

-If there is pain then the location of sensation can be used to pinpoint the affected organ. For example, appendicitis will produce pain in the lower right quadrant

Front 8

Anterior pelvic tilt

Back 8

- Tightened iliospoas m. can cause anterior pelvic tilt because of relationship with the anterior pelvis

- Anterior tilt is countered by anterior abdominal musculature including rectus abdominis and posterior gluteus maximus and hamstring mm.

Front 9

Quadratus lumborum

Back 9

- Superior attachment: inferior border of 12th rib and transverse processes of lumbar vertebrae

- Inferior attachment: Iliac crest & iliolumbar ligament

- Lateral bending of trunk; depress rib 12

- Innervation: anterior rami of T12 – L4

Front 10

Layers of thoracolumbar fascia

Back 10

- Note anterior, middle and posterior layers of the thoracolumbar fascia and which muscles or groups of muscles they enclose.

- Lateral attachment of posterior layer to the internal oblique and transversus abdominis mm.

- Note psoas fascia and renal fascia

Front 11

Vertical deep back mm.

Back 11

between middle and posterior layers of thoracolumbar facia

Front 12

Quadratus lumborum

Back 12

between anterior and middle layers of thoracolumbar fascia

Front 13

Diaphragm

Back 13

Floor of thoracic cavity

Roof of abdominal cavity

R & L dome – Right side is higher because of the liver

Front 14

Innervation Diaphram

Back 14

- Motor (efferent) innervation is from phrenic nerve.

- Phrenic nerve also has general somatic afferent (proprioception and pain) fibers.

- On the periphery of the diaphragm GSA fibers are located within intercostal nerves and subcostal nerves.

Front 15

referred pain diaphram

Back 15

Referred pain from the diaphragm can felt in the supraclavicular and shoulder region

Front 16

Spinal cord injuries

Back 16

in the superior cervical region can paralyze the diaphragm

- If one phrenic nerve is accidentally severed during surgery or compromised due to infection then paralysis of half the diaphragm (hemi diaphragm) results and eventual muscular atrophy will ensue.

- A paralyzed hemidiaphragm cannot contract, i.e. descend, so it will be positioned higher than normal in the thorax when viewed on a chest radiograph.

- An individual can still breath in such a circumstance with half a functional diaphragm but breathing is much more difficult.

Front 17

Fibers of the diaphram

Back 17

-Muscle fibers extend peripherally to the central tendon:

- Sternal fibers
Xiphoid process
- Costal fibers
Inferior 6 costal cartilages and adjoining ribs
- Lumbar fibers
Left and right crura; medial and lateral arcuate ligs.
Left (L1-L3); Right (L1-L2)

Front 18

Arcuate ligaments

Back 18

are thickenings of fascia that serve as attachments for fibers of the diaphragm

- Lateral arcuate lig. is a superior thickening of the anterior layer of thoracolumbar fascia (around quadratus lumborum).

- Medial arcuate lig. is a superior thickening of the psoas fascia.

Front 19

Diaphragmatic apertures

Back 19

allow structures to pass from the thoracic cavity into the abdominal cavity

- Caval opening – IVC
- Esophageal hiatus – esophagus and vagal trunks
- Aortic hiatus – descending aorta and thoracic duct

Front 20

Hiatal hernia

Back 20

- Lax diaphragmatic fibers at the esophageal hiatus can cause the fundus of the stomach to herniate into the thoracic cavity within the region of posterior mediastinum.

- This will typically cause an increase in acid reflux symptoms and may require surgery.

Front 21

Superior view of diaphragm

Back 21

Greater and lesser splanchnic nerves pierce the left and right crura to reach the abdominal cavity

Sympathetic trunks and least splanchnic nerves will pass behind the medial arcuate ligament

Front 22

Diaphragm blood supply via:

Back 22

Superior phrenic arteries (from thoracic aorta)

Pericardiophrenic arteries (from internal thoracic a.)

Musculophrenic arteries (from internal thoracic a.)

Front 23

Venous drainage:

Back 23

- Pericardiophrenic & musculophrenic veins (tributaries of internal thoracic vein)

- Superior phrenic vein (tributary of the IVC)

Front 24

Diaphragm development

Back 24

- Septum transversum becomes the future central tendon.

- It grows dorsally from the ventrolateral body wall and forms a shelf between the developing heart and liver.

- The septum transversum develops in the cervical region and descends to the lower thoracic region taking the phrenic nerves (ventral rami of C3-C5) with it.

- Dorsal mesentery of the esophagus becomes the crura of the diaphragm.

- Muscular ingrowth of body wall contributes to the peripheral diaphragm.

- Pleuroperitoneal membrane (membrane that will separate pleural and peritoneal cavities) only has small contribution in neonate.

- Fusion of various components may fail resulting in congenital hernias (most common is Bochdalek’s hernia)

Front 25

Congenital diaphragmatic hernia

Back 25

- Note intestines projecting up into the abdominal cavity

- Lung on respective side can not develop or inflate due to limited space resulting in pulmonary hypoplasia

Front 26

Nerves of the posterior abdominal wall

Back 26

Ventral ramus of spinal nerve T12 = Subcostal nerve (inferior to rib 12)

Front 27

Sympathetic trunks in the lumbar region

Back 27

Lumbar splanchnic nerves

Front 28

Abdominal aorta

Back 28

Lumbar arteries (4 on each side) supply posterior abdominal wall

Bifurcates at the level of L4 into R & L common iliac arteries

Front 29

Lumbar veins drain posterior abdominal wall

Back 29

R and L iliac veins join to form the IVC

Ascending lumbar veins receive 1st and 2nd lumbar veins; 3rd and 4th drain into IVC.

Ascending lumbar veins communicate with azygous and hemiazygous veins.