Biomechanics of the Thorax

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Top Contributors - Sonal Joshi and Manisha Shrestha  

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Introduction[edit | edit source]

Biomechanics is the study of forces and their effects when applied to human body. To understand the biomechanics of thorax we will need to study the basic anatomy, joint articulations, muscles associated in the thorax along with kinematics of the rib cage.

The thorax is formed by the thoracic vertebrae ,the ribs and the sternum. It has two main functions,

  1. Providing anchor for muscle attachments
  2. Role of ventilation

Structure of Thorax[edit | edit source]

This is the cornerstone of understanding function and thus biomechanics of thorax.

Rib Cage[edit | edit source]

Anatomy[edit | edit source]

The rib cage is a system of various bones and muscle. Bones involved are sternum, 12 pairs of Ribs, 12 Thoracic vertebrae.

The borders of ribcage consist of:

- Anterior border: sternum

- Lateral border: Ribs

- Posterior border: Thoracic vertebrae

- Superior border: Jugular notch of sternum, superior borders of costocartilages, first rib and its connecting vertebrae

- Inferior border: xiphoid process, costocartilages of 6 to 10th ribs, inferior portion of 11th & 12th ribs and 12th thoracic vertebrae

Refer the Thoracic Anatomy for further details of Thoracic vertebrae & the joint which they form.

Articulations[edit | edit source]
Joint Bones involved in the joint articulation Special features
Manubriosternal Manubrium and superior part of body of Sternum - Synchondrosis type of joint

- Also called Angle of Louis

Xiphisternal Xiphoid process and inferior part of body of Sternum - Synchondrosis type of joint

- Ossifies by 40 to 50 yrs. of age

Typical Costovertebral - Synovial type of joint

Function of Thorax[edit | edit source]

Kinematics[edit | edit source]

Muscles involved in Rib Cage[edit | edit source]

Primary Muscles[edit | edit source]
  • Diaphragm
  • Intercoastal muscles
  • Scalene
Accessory Muscles[edit | edit source]
  • Sternocleidomastoid
  • Trapezius
  • Pectoralis major
  • Pectoralis minor
  • Subclavius
  • Levatores costarum
  • Serratus posterior superior
  • Serratus posterior inferior
  • Abdominal muscles
  • Transverse thoracis

Developmental Differences with Age[edit | edit source]

Pathological Changes[edit | edit source]

References[edit | edit source]

Original Editor - [[User:Manisha Shrestha|Manisha Shrestha] Top Contributors - Sonal Joshi and Manisha Shrestha