BIOMECHANICS OF THORAX

1. BIOMECHANICS OF THORAX
PRESENTED BY-
RAMANDEEP KAUR SAINI(MPT1)

2. THORAX-GENERAL STRUCTURES
• THE RIBS-laterally
• THORACIC VERTEBRE-posteriorly
• STERNUM-anteriorly
• Provides a stable base for the muscles
attachments of UL,head,neck,Vertebral column
and pelvis.
• Protection of lungs, heart, viscera
• Ventilation

3. • The rib cage is a closed
chain that involves
many joints and
muscles.
• Superior border-Jugular
notch ,1st
costocartilages,1st rib
and 1st thoracic
vertebra.
• Inferior border-xiphoid
process,costocartilages
of 7 -10ribs,inferior
portion of 11th and 12th
ribs and 12th thoracic
vertebra.

4. Manubrium
• Jugular (suprasternal) notch
• Articulation with rib 1 & 2
• Clavicular Articular facets
• Sternal Angle – 2 nd rib
Body of sternum
• Articulates w/ribs 2-7
• Xiphisternal joint
Xiphoid process
• Cartilage-calcifies through time.
• Partial attachment of many muscles
THE STERNUM-

5. THE RIBS-
12 pairs
• 7 True ribs-direct attachment to sternum
• 5 False ribs-indirect or no attachment to sternum
• Floating ribs- 11th and 12th no ventral
attachment.
Typical Ribs
• Ribs # 2-9
Atypical Ribs
• Ribs #1, 10,11,12
 Ribs are placed obliquely, upper less oblique than
lower.
 Length increases from Ist to 7th and gradually
decreases from 8th to 12th .
Reinforce thoracic cage

7. THE THORACIC VERTEBRA-

8. ARTICULATIONS OF THE RIB CAGE-
 The articulations that join the bones of the
rib cage are:
 Manubriosternal (MS),
Xiphisternal (XS),
Costovertebral (CV),
 Costotransverse (CT),
 Costochondral (CC),
Chondrosternal (CS), and the
Interchondral.

9. Manubriosternal and Xiphisternal Joint-
• The manubrium and the body of the sternum
articulate at MS joint. Also known as the
sternal angle or the angle of Louis.
Synchondrosis type joint.
• Ossification of the MS joint occurs in elderly
persons.
• The xiphoid process joins the inferior aspect
of the sternal body at the XS joint.
• The XS joint is also a synchondrosis that
tends to ossify by 40 to 50 years of age.

10. Costovertebral joint-
• The typical CV joint is a synovial joint, 2 through 9.
• Formed by head of the rib, two adjacent vertebral
bodies, and the interposed intervertebral disk.
• Ribs 2 to 9 have typical CV joints, as heads of these
ribs have 2 articular facets, or so-called
demifacets.
• The demifacets are separated by ridge called crest.
• Small, oval, and slightly convex demifacets of the
ribs are called the superior and inferior
costovertebral facets.
• Adjacent thoracic vertebrae have facets
corresponding to those of the heads of 2-9 ribs
that articulates with them.

11. LIGAMENTS OF CV JOINT-
• Typical CV joint is divided into two
cavities by the interosseous or intra-
articular ligament.
• The radiate ligament has three bands:
• superior band, attached to the
superior vertebra
• intermediate band, attached to the
intervertebral disc; and the
• inferior band, attached to the inferior
vertebra.

12. • The atypical CV joints of ribs 1 and 10,11 & 12 are more mobile
because the rib head articulates with only one vertebra.
• Interosseous ligament is absent in these joints; therefore, have only
one cavity.
• The radiate ligament is present in these joints, with the superior
band still attaching to the superior vertebra.
• Both rotation and gliding motions occur at all of the CV joints

13. Costotransverse Joint-
• The CT joint is a synovial joint. formed by costal
tubercle of rib with costal facet on transverse
process of the corresponding vertebra.
• 10 pairs of CT joints articulates T1 through T10
with the rib of same number.
• CT joints on T1-T6 have slightly concave costal
facets on the transverse processes and slightly
convex costal tubercles on the corresponding
ribs. This allows slight rotation movements.
• At the CT joints of T7 through T10, both articular
surfaces are flat and gliding motions
predominate.
• Ribs 11 and 12 do not articulate with their
respective transverse processes of T11 or T12

14. LIGAMENTS-
• The CT joint is surrounded by a thin, fibrous capsule.
• Three major ligaments support the CT joint capsule .
• Lateral costotransverse ligament-a short, stout band
located between the lateral portion of the costal
tubercle and the tip of the corresponding transverse
process.
• costotransverse ligament- composed of short fibers
that run with in the costotransverse foramen between
the neck of the rib posteriorly and the transverse
process at the same level.
• superior costotransverse ligament-runs from the crest
of the neck of the rib to the inferior border of the
cranial transverse process.

15. COSTOCHONDRAL JOINT AND CHONDROSTERNAL JOINT-
• CC joints are formed by articulation of the 1st
through 10th ribs anterolaterally with the costal
cartilages.
• Synchondroses type.
• The CC joints have no ligamentous support.
• CS joints are formed by the articulation of costal
cartilages of ribs 1 to 7 anteriorly with the sternum.
• Rib 1 attaches to the lateral facet of the manubrium.
• Rib 2 is attached via two demifacets at the
manubriosternal junction,
• Ribs 3 through 7 articulate with the lateral facets of
the sternal body. The CS joints of the 1st, 6th, and 7th
ribs are synchondroses.
• The CS joints of ribs 2 to 5 are synovial joints.

17. LIGAMENTS OF CS JOINT-
• Ligamentous support for the capsule
includes
• anterior and posterior radiate costosternal
ligaments.
• The sternocostal ligament is an
intraarticular ligament, that divides the
two demifacets of the 2 nd CS joint.
• The CS joints may ossify with aging.
• The costoxiphoid ligament connects the
anterior and posterior surfaces of the
seventh costal cartilage to the front and
back of the xiphoid process.

18. Interchondral joint-
• The 7th to 10th costal cartilages articulate with
cartilage above them to form interchondral joints.
• For 8th through 10th ribs,articulation is indirectly
with sternum.
• Interchondral joints are synovial joints and are
supported by a capsule and interchondral ligaments.
• The interchondral articulations,tend to become
fibrous and fuse with age.

19. KINEMATICS-
Movement of rib cage is a combination of geometry governed by-
• Angle of the articulation
• Movement of Manubriosternum
• Elasticity of the Costal Cartilage

20. • There is a single axis of motion for the 1st to
10th ribs through the center of the CV and CT
joints.
• For upper ribs axis lies close to frontal
plane(frontal axis) allowing motion
predominantly in sagittal plane.
• For lower ribs axis is nearly in sagittal
plane(sagittal axis) allowing motion
predominantly in the frontal plane.
• The axis of motion for the 11th and 12th ribs
lies close to frontal plane.

21. • During inspiration, the ribs elevate.
• In upper ribs, most of movement occurs at
anterior aspect of the rib,nearly frontal axis at the
vertebrae.
• The movement of ribs pushes the sternum
ventrally and superiorly.
• Less movement occurs at manubrium because
first rib is shortest and less mobile.
• The motion of upper ribs and sternum has
greatest effect by increasing anteroposterior (A-P)
diameter of thorax.
• This combined rib and sternal motion has been
termed as “pumphandle” motion.

22. • Elevation of the lower ribs occurs nearly at sagittal
axis.
• Lower ribs have more angled shape and an indirect
attachment anteriorly to sternum.
• These factors allow the lower ribs more motion at
the lateral aspect of the rib cage.
• Elevation of the lower ribs has greater effect to
increase the transverse diameter of the lower thorax.
• This motion has been termed the “bucket handle”
motion of the thorax.
• The orientation of the axes of motion from cephalad
to caudal is shifting gradually therefore, the
intermediate ribs perform both types of motion.
• The 11th and 12th ribs do not participate in closed-
chain motion of the thorax

23. MUSCLES OF VENTILATION-
• Primary muscles are recruited for quite ventilation-
• Diaphragm
• Intercostals (Parasternals)
• Scalene
• These muscle promote inspiration
• There is no muscle for expiration as it is a passive process.

24. • Diaphragm-
• Accounts for 70-80% of inspiration during quite
breathing
• Circular set of muscles arises from: Sternum, Costal
cartilage, Ribs and Vertebral bodies.
• Inserts into central tendon.
• Diaphragm muscular portions-dorsal segments arise
from vertebral bodies(crural fibers)
• Ventral segments arise from sternum and ribs (costal
fibres)

25. • During tidal breathing,the costal fibres contract
,causing a descent in the dome of diaphragm.The
abdominal contents are compressed and increase
intra abdominal pressure.
• Futher deep inhalation,the abdomen compressed
acts to stabilize the central tendon.
• With continued contraction of costal fibres,the
lower ribs are lifted and rotated outwardly in bucket
handle motion.
• There is increase in thoracic szie and resultant
decreased intrapulmonary pressure.
• When active muscle contraction ceases, the domes
of diaphragm returns to resting position.The
thoracic volume decreases and intrapulmonary
pressure increases and exhalation occurs.

26. Intercostal muscles-(External & internal)
• INTERNAL INTERCOSTAL- arise from a ridge on the
inner surfaces of ribs 1-11
• Inserts-sup. Border of the rib below.
• Lies deep to the external intercostal muscles and runs
caudally & posteriorly to the angle of the
ribs(posterior intercostal membrane).
• Active during exhalation.
• EXTERNAL INTERCOSTAL -arise from inferior orders
of ribs 1-11
• Inserts-superior border of the rib below.
• Runs caudally and anteriorly at an oblique angle to
the internal intercostal muscles.(anterior intercostal
membrane)
• Active during inspiration

27. Scalene muscles-
• Arises from transverse process of C3 to
C7 and descends to the upper borders
of 1st rib(SA,SM) and 2nd rib (SP).
• Lifts the first 2 ribs and sternum in
pump handle movement of upper rib
cage.
• Activity begins at onset of inspiration
and increases as gets closer to Total
lung capacity.
• Stabilizer of the rib cage

28. ACCESSORY MUSCLES-
• Attaches the rib cage to shoulder girdle, head, verterbral column, or pelvis.
• Assist with inspiration or expiration in situation of stress.
• Accessory muscles of inspiration-increases thoracic diameter moving ribcage upward
and outward.
• Expiration-moves diaphragm upwards and thorax downward and inward.
• Sternocleidomastoid and trapezius -pulls rib cage superiorly expanding in pump handle
motion during end of a maximal inspiration.
• Pectoralis major, minor and subclavius -helps to raise the upper chest for inspiration
• Levatores costarum -runs from transverse process of C7-T11 to posterior external
surface of the next lower rib.Assist with elevation of upper ribs.

29. • Abdominal muscles-(Transversus abdominis,
internal and external oblique abdominis,rectus
abdominis)-
• Assist with forced expiration but during periods of
increased ventilator needs assists in both.
• Significant role during inspiration-the increased abdominal
pressure created by lowering the diaphragm is countered
by tension in abdominal muscles by effectively stabilizing
central tendon for expanding lateral chest wall
• Also prepares respiratory system for next inspiration by
optimizing the length tension relationship of the
diaphragm muscle fibres by pushing it cranially during
forced exhalation.

30. • Transverses thoracis -runs deep to the parasternal muscles
originating from the the posterior surface of the caudal half of the
sternum
• Insert-inner surface of the costal cartilages of rib 3-7
• Recruited along with abdominal muscles to pull the rib cage caudally
• Primarily expiratory muscle when it is active as in talking,coughing or
laughing or in forced exhalation into functional residual capacity.

31. PATHOLOGICAL CHANGES IN COPD-
• Damage to airway and destruction of alveolar
walls
• elastic recoil property diminished
• air trapping and hyperinflation
• alters lung volumes and capacities leading barrel
shape chest with flattening of diaphragm at rest
• shortening ,decreased available range of
contraction
• pull the lower rib cage inward

32. RECENT ADVANCES-
• A narrative review-Thoracic ultrasound: Potential new tool for physiotherapists in
respiratory management.
• AUTHORS-Aymeric Le Neindre ,Silvia Mongodi, François Philippart, Bélaïd
Bouhemad.
• PUBLISHED-Journal of critical care,2016

33. • Physiotherapists currently lack accurate, reliable, sensitive, and valid
measurements for patient monitoring and assessments of the indications
and effectiveness of chest physiotherapy.
• Basics of lung US-simple machine with a micro-convex probe of
frequency 2-4Mhz.
• Longitudinal and transverse view
• Modes- B mode(brightness, real time)2D,M mode (motion)

34. EFFECT OF MULLIGAN’S MOBILIZATION WITH MOVEMENT ON
THORACIC EXPANSION IN COPD PATIENTS-
• PUBLISED-Original Research Paper- Physiotherapy of GLOBAL JOURNAL
FOR RESEARCH Analysis,April 2018
• AUTHORS-Dr.Poonam Patil, Viraj Dighe
• The sample design- 30 subjects with age group 50 to 70 years male and
female included diagnosed with COPD were treated by using mulligans
MWM.
• The study was concluded by pre and post assessment where the subjects
were treated for 3 days a week.

35. • Pre treatment assessment- incentive spirometer and inch tape
measurement of chest expansion. The treatment procedure of
Mulligan’s mobilization with movement was performed for intercostal
spaces and costochondral joints.
• Post treatment assessment was done respectively. The statistical
analysis was done by using instat by paired t-test using pre and post
interventional data and the results were compared.

36. Conclusion: From the above conducted study it concluded that a subject with mulligan’s
mobilization with movement on COPD patients has significant improvement clinically and
statistically which improved chest expansion and spirometry score.
Further studies can be done in order to determine the long term effect of this program and
evaluate this COPD Rehabilitation regimen.