The diaphragm is a dome shaped muscle that forms the partition between the thoracic and abdominal cavities. It has three parts that arise from the sternum, ribs, and lumbar vertebrae. Its central tendon inserts below the pericardium in a trilobar shape. The diaphragm receives motor innervation from the phrenic nerve and sensory innervation from lower thoracic nerves. During respiration, the diaphragm contracts to increase the volume of the thoracic cavity.

1. DIAPHRAGM

2. INTRODUCTION
• DEFINITION
The diaphragm is a dome shaped muscle
forming the partition between the thoracic and
abdominal cavities.
- Diaphragm is a chief
muscle in respiration

3. STRUCTURES OF DIAPHRAGM

4. ORIGIN
The muscle fibers are grouped into three parts;
- The sternal part arises by two fleshy slips from the back of
the xiphoid process.
- The costal part arises from the inner surfaces of the
cartilages.
- The lumbar part arises from the medial and lateral
lumbocostal arches.

5. INSERTION
• The central tendon of the diaphragm lies below the
pericardium
• The tendon is trilobar in shape,made up of three
leaflets
- middle leaflets is triangular in shape and directed
towards xiphoid process
- right and left leaflets are tongue shaped and
curved laterally and backward

7. OPENINGS OF DIAPHRAGM

9. RELATIONS
• SUPERIORLY
- Pleurae, covering lungs
- Pericardium, covering heart
• INFERIORLY
-Peritonium , liver
- fundus of the stomach
- spleen , kidneys and suprarenals

10. NERVE SUPPLY
• MOTOR
- The phrenic nerves are the sole motor nerves to
the diaphragm
[ventral rami C3 C4 C5]
• SENSORY
- The phrenic nerves are sensory to the central part,
and the lower six thoracic nerves are sensory to the
peripheral part of diaphragm.

12. DEVELOPMENT of
diaphragm
• Diaphragm develops from the following sources-
- Septum transversum forms the central tendon
-Pleuroperitoneal membranes form the dorsal paired
portion
- Lateral thoracic wall contributes to circumferential
portion of the diaphragm
- Dorsal mesentery of esophagus forms the dorsal
unpaired portion

14. CLINICAL ANATOMY
 HICCOUGH OR HICCUP- This is due to the
spasmodic contraction of the diaphragm
a. peripheral, due to local irritation of diaphragm
or its nerve
b. central, due to irritation of the hiccough center in
medulla.
 SHOULDER TIP PAIN- This is because irritation of
the diaphragm may cause referred pain in the shoulder
because the phrenic nerve and supraclavicular nerves have
the same root values[C3,C4,C5]

15.  DIAPHRAGMATIC HERNIA
The types of hernia are
- congenital hernia
• Retrosternal hernia
• Posteriolateral hernia
• Posterior hernia
• Central hernia
-acquired hernia
• Traumatic hernia
• Hiatal hernia

17. Paralysis of the Diaphragm
• Diaphragmatic paralysis is due to an interruption in its
nervous supply. This can occur in the phrenic nerve,
cervical spinal cord, or the brainstem. It is most often
due to a lesion of the phrenic nerve:
• Mechanical trauma: ligation or damage to the nerve
during surgery.
• Compression: due to a tumour within the chest cavity.
• Myopathies: such as myasthenia gravis.
• Neuropathies: such diabetic neuropathy.

18. • Paralysis of the diaphragm produces a paradoxical
movement. The affected side of the diaphragm
moves upwards during inspiration, and downwards
during expiration.
• A unilateral diaphragmatic paralysis is usually
asymptomatic and is most often an incidental
finding on x-ray. If both sides are paralysed, the
patient may experience poor exercise tolerance,
orthopnoea and fatigue.
• Lung function tests will show a restrictive deficit.

20. • Clinical Relevance: Subphrenic Abscesses
• The subphrenic recesses are potential spaces in the
supracolic compartment of the greater sac. They are
located between the diaphragm and the liver. There are
left and right subphrenic spaces, separated by the
falciform ligament of the liver.
• Subphrenic abscesses refer to an accumulation of pus
in the left or right subphrenic space. They are more
common on the right side due to the increased
frequency of appendicitis and ruptured duodenal
ulcers (pus from the appendix can track up to the
subphrenic space via the right paracolic gutter).