Diaphragm

Cone-shaped partition between thorax and abdomen

Chief muscle of inspiration

Pathway for spread of disease between thorax and abdomen

http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/dissector/muscles/images/dph.jpg
Components 

Musculotendinous sheet

• Central tendon

  • Central tendon is a broad sheet of decussating tendinous fibers Pericardium is firmly attached to the upper surface of central tendon

• Muscle fibers

  • Right and left leaflets

  • Two parts - crural and costal 

  • Vertebral:crura from bodies of L1, 2 (left), L1-3(right). Lumbar diaphragm (posterior portion), muscle fibers are long
    Costal: med and lat arcuate ligs, inner aspect of lower six ribs .
    Sternal: two slips from post aspect of xiphoid 

    Insertion:  Muscle fibers insert into central tendon

    • Crural: From - L1,2,3 and the medial and lateral arcuate ligaments. To - Central tendon. 
      Function: normally it displaces abdominal contents only. 

    • Costal: From - lower 6 ribs. To - Central tendon. 
      Function: normally it displaces abdominal contents and elevates and expands lower rib
      cage. The extent of each depends on abdominal and thoracic compliance. 
      

Nerve supply

Phrenic Nerve (motor) (C3, 4, 5).

Sensory: Phrenic, intercostals(6-12) and upper two lumbar N roots 

Action

Inspiration and assists in raising intra-abdominal pressure

Chief muscle of inspiration

Optimal position at the beginning of inspiration is important for efficient diaphragmatic function

Radiological recognition

• Actual position of the diaphragm is infered

• Visualized only when inner aspect is marginated by intraperitoneal  fat,  fatty liver or outer aspect by lung

• The left hemidiaphragmatic dome relates to the contiguous mass of the left side of heart

Defects

Triangular spaces between muscle fibers arising from sternum and those arising from 7th rib constitute weak area in the diaphragm (the foramina of  Morgagni.

Deficiencies in the origin of the muscles from the posterolateral rib cage similarly creates the foramina of Bochdalek

5. Following upper abdominal surgery: 

A.There is no alteration in the function of the diaphragm
in most patients 
B.There is often severe impairment of diaphragm
function which can significantly impair patients with
COPD 
C.Theophylline may help improve diaphragm function 

a is false

Paralysis

• Etiology

  • Interruption of phrenic nerve due to malignancy

  • Idiopathic

    • always on right

    • usually males

  • Cardiovascular surgery/Cardioplegia

• Radiological findings

  • Elevated hemi diaphragm

  • Paradoxical motion (inward movement of the
    abdomen ) with inspiration during inspiration and sniffing

  • Mediastinal swing during respiration

• Pulmonary funsction

  • Decrease in  the vital capacity  and NIF 

  • Significant change in upright versus
    supine vital capacity 

• Symptoms

  • Dyspnea on effort

  • Dramatic orthopnea

• Physical examination

  • Place flat portion of one hand in infraclavicular region and the other below costal margin. Note the
    contribution of intercostals and diaphragm in expanding the chest. Make a similar assessment of the
    other side. 

  • Infracostal Movement: 
    Apply both your palms along infracostal region and note the symmetrical downward displacement of
    hands with deep inspiration. There is symmetrical outward movement of epigastrium with inspiration. In
    diaphragmatic paralysis there will be ipsilateral inspiratory retraction of epigastrium (Paradoxical
    movement). This results in see-saw movement of epigastrium during respiration. 

  • Tidal Percussion: 
    Percuss diaphragmatic position with deep inspiration and expiration and assess the depth of mobility. 

  • Orthopnea: 
    Diaphragm assumes 80% function for inspiration in supine position. Hence if the diaphragm is paralysed,
    significant compromise occurs and patients become very short of breath. 
    

Impaired function due to position of diaphragm

• Hyperinflation in COPD

• Massive pleural effusion

• Tension Pneumothorax

In these conditions the diaphragm is pushed down and is either horizontal or concave upwards. With contraction of muscles there is no significant downward movement of diaphragm and it can be paradoxical when it is concave upwards.

Diaphragm paralysis is associated with the following: 

A.No change in the vital capacity or NIF, upright versus
supine 
B.Abdominal paradox, inward movement of the
abdomen with inspiration 
C.Recent cardiac surgery 
D.Rapid development of orthopnea when becoming
supine 
A is false

Eventeration

• Failure of muscular development

• Thin membranous sheet attached to normal muscle at points of origin

• Almost exclusively on left

• Roentgenologic signs similar to paralysis

• Asymptomatic in adults

• In neonates respiratory CV and GI distress requiring surgery

Diaphragmatic hernias

• Esophageal hiatus

  • Mass in the posteroinferior mediastinum

  • Containing a fluid level

  • Incarceration and volvulus are the complications

• Foramen of Bochdalek

  • 80-90% occur on left side

  • Pleuro-peritoneal hiatus

  • Ipsilateral diaphragm is partly or completely obscured

  • multiple radiolucencies seen in hemi thorax

  • heart and mediastinum shifted to opposite side

  • ipsilateral lung compression

  • complete absence of intestinal gas within abdomen

• Foramen of Morgagni

  • retrosternal or parasternal

  • cleft bounded by diaphragmatic muscle fibers originating from sternum medially and from the seventh costal cartilage laterally

  • most hernias on right

  • peritoneal sac present

  • omentum is the most common content

  • smooth well defined opacity in the right cardio-phrenic angle

  • transverse colon is situated high in the abdomen with a peak situated anteriorly and superiorly

• Traumatic rupture