Human Anatomy Vol 1

BONES AND JOINTS OF THORAX

Figs 13.31 a to c: Position of diaphragm. (a) Sitting, (b) stand-
ing, and (c) lying down

Mnemonics

• One joint between sternum and xiphoid
  process-primary cartilaginous.


• Sternum forms^2 joints with clavicles of the
  2 sides, saddle type of synovial joint


• It articulates with 1st-7th costal cartilages on
  each side forming a total of^14 joints-plane
  synovial except 1st chondrosternal which is
  synchondrosis.
  A typical thoracic vertebra forms following joints:


• Body of one vertebrae with body of vertebra
  above and body of vertebra below-secondary
  cartilaginous joint (2 joints).


• Lower larger part of head of corresponding rib
  for the demifacet along the upper border of the
  body on each side (2 joints).


• Upper smaller part of head of a lower rib for
  the demifacet along the lower border of the body
  on each side (2 joints).


• Superior articular processes on each side with
  the inferior articular processes of the vertebra
  above (2 joints).


• Inferior articular processes on each side with the
  superior articular processes of the vertebra
  below (2 joints).


• Transverse process of the vertebra with the
  articular part of the tubercle of the rib on each
  side (2 joints).


• Body of the vertebra with the pedicle of the
  vertebra on each side. These are primary
  cartilaginous joints (2 joints).
  Thus there are 14 joints which a typical thoracic
  aertebra mnkes.
  2 secondary cartilaginous joints
  2 primary cartilaginous joints
  L0 plane joints of synovial variety
  The rib are arched bones. loints formed by n typical rib
  aTe:


• Posterior end or head of a typical rib articulates
  with two adjacent vertebrae, corresponding one
  and one above it and the intervening
  intervertebral disc.


• The articular part of the tubercle articulates with
  transverse process of corresponding vertebra


• The anterior part of the shaft of rib continues as
  the costal cartilage. It is primary cartilaginous
  joint.


• A costal cartilage forms plane synovial joint with
  the side of sternum.
  Respiratory movements produced by movements
  of thoracoabdominal diaphragm are called
  "abdominal respiration".
  Respiratory movements produced by movements
  of intercostal muscles is called "*roracic respira-
  tion".

Structures in costal groove VAN from above

downwards

Posterior intercostal vein

Posterior intercostal artery

lntercostal nerve

Structures on neck of lst rib, VAN from medial to

lateral side

Posterior intercostal vein

Superior intercostal artery

'l st thoracic nerve

Vertebrae: Recognising a Thoracic from Lumbar

o Presence of costal facets on the sides of the body

and transverse process

. Shape of the vertebral body

• Thoracic is heart-shaped body (since your heart
  is in your thorax).


• Lumbar is kidney/bean shaped body (since
  kidneys are in lumbar area)
  . Spine is long and oblique

Sternum forms joints with its own parts:

• One manubriosternal joint-secondary carti-
  laginous.


• Three joints between sternebrae-primary
  cartilaginous.