Anatomy Bones and Muscles · MU Pleven

34. The diaphragm

Explains the diaphragm's origins from sternal, costal and lumbar parts, including the crura and arcuate ligaments, its central tendon insertion, innervation and blood supply. Covers the three major openings with their vertebral levels and structures passing through them, its role in inspiration and forced expulsive acts, and a table comparing quiet and forced inspiration and expiration with the muscles involved.

Inside: 7 sections · 6 labelled pictures · 1 table · 11 flashcards · 3 min

Topic 32 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 7 sections, about 217 words (3 min of reading), with 11 flashcards.

In this note

  1. DIAPHRAGM
  2. Structure:
  3. Innervation:
  4. Blood Supply:
  5. Major openings of diaphragm:
  6. Functions:
  7. RESPIRATION

DIAPHRAGM

T8 - L3

  • The diaphragm is the primary muscle for inspiration.

Structure:

Origin:

The diaphragm has 3 origins:

  1. 1. Sternal part
  • ↳ From back of xiphoid process.
  1. 2. Costal part:
  • ↳ From Internal surfaces of lower costal cartilages & ribs 7-10
  1. 3. Lumbar part:
  • A) right crus: anterolateral surface of first 3 lumbar vertebrae and IVDs. L1 - L3
  • B) left crus: anterolateral surface of first 2 lumbar vertebrae and IVD. L1 - L2
  • C) medial arcuate lig.: from body of vertebra to front of transverse process.
  • D) lateral arcuate lig.: from transverse process to 12ᵗʰ rib.

* There is also the median arcuate ligament. Connecting the medial margins of the 2 crura.

Insertion : Central tendon of diaphragm.

  • Has 2 surfaces . thoracic & abdominal

Innervation:

Phrenic nerves (C3-C5)

Blood Supply:

  • Subcostal art.
  • Sup. & Inf. phrenic arts.

Major openings of diaphragm:

  1. 1. Vena Caval
  • At the level of T8 to the right
  • It gives passage for:
  • IVC
  • Branches of right phrenic nerve.
  1. 2. Esophageal hiatus:
  • At the level of T10 to the left
  • passage for:
  • esophagus
  • Ant. & post. vagal trunks
  1. 3. Aortic
  • At the level of T12 in the midline.
  • passage for:
  • Aorta
  • Thoracic duct.

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