BIOMECHA OF THORAC AND RIB CAGE.pptx
- 1. 1
- 2. BIOMECHANICS OF THORAX AND CHEST WALL 2
- 3. Most important functions of the thorax and chest wall : Ventilation of lungs Protection of heart, lungs and viscera 3
- 4. Ventilatory mechanism in humans has three parts The ribcage The ventilatory muscles The abdomen 4
- 5. 5 Ribcage
- 6. Truncated cone shaped Articulations of ribcage Manubriosternum Xiphisternum Costovertebral Costotransverse Costochondral Costosternal Interchondral 6
- 7. 7 Manubriosternal and xiphisternal joints - manibriumsternum xiphisternum Synchondrosis variety of cartilaginous joints
- 8. 8 Sternal angle/angle of Louis corresponds to T4-T5 posteriorly. Bifurcation of trachea Aortic arch
- 9. 9 Costovertebral joint Typical costoverterbral joint - synovial type of joint 2nd to 9th ribs - typical costoverterbral joint 1st, 10th, 11th and 12th atypical ribs articulate only with their corresponding vertebra
- 10. 10 The costovertebral joints are the articulations that connect the heads of the ribs with the bodies of the thoracic vertebrae. Joining of ribs to the vertebrae occurs at two places, the head and the tubercle of the rib. Two convex facets from the head attach to two adjacent vertebrae. This forms a trochoid joint, which is strengthened by the ligament of the head and the intercapital ligament.
- 11. 11 Costotransverse joint Synovial joint surrounded by thin fibrous capsule Is present from T1 to T10 vertebra and 1st to 10th ribs This articulation is reinforced by the dorsal costotransverse ligament
- 12. 12 Upper CT joints the primary movement - rotation costal facet concave shape and costal tubercle convex shape T7 to T10 both articular surfaces are flat and gliding motion predominates
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- 14. Costochondral joints are synchondroses with no ligamentous support 1st through 7th ribs articulate anterolaterally with costal cartilages forming costochondral joint 14
- 15. Costosternal (CS) joints are formed by attachment of the costal cartilages of ribs to sternum anteriorly CS joints of 1st, 6th and 7th ribs are synchondroses CS joints of 2nd to 5th ribs are synovial joints 15 Interchondral joints costosternal
- 16. Interchondral joints are formed when 6th through 10th costal cartilages articulate with cartilage above them and this is only way by which 8th to 10th ribs are connected to sternum Interchondral joints are synovial type of joints 16
- 17. Costovertebral and costotransverse form a joint couple mechanically linked Common movement - rotation about an axis passing through centre of each joint for 1st to 10th ribs 11th and 12th ribs it passes through the CV joints as CT is absent for these two ribs 17
- 18. Axis of motion - more towards frontal plane for upper ribs and towards saggital plane for lower ribs. During inspiration - ribs elevate, in upper ribs motion simulates that of pump handle due to frontal plane orientation of axis of motion, this increases the anteroposterior diameter of ribcage 18
- 19. Axis of motion lying nearly in the saggital plane, movement takes place more in lateral part in the lower ribs Movement of 11th and 12th ribs varies from the rest of the ribs Quadratus Lumborum muscle depresses and fixes these ribs to provide adequate diaphragmatic muscle tension 19
- 20. 20 Axis towards frontal plane Axis towards saggital plane
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- 23. 23 MUSCLES
- 24. Muscles of the ribcage - ventilatory muscles Increased fatigue capacity and contract rhythmically throughout life rather than episodically Act primarily against the elastic properties of lungs and airway resistance rather than gravitational forces 24
- 25. Neurological control of ventilatory muscles is both voluntary and involuntary Recruitment of these muscles for ventilation depends on the type of ventilation required Primary muscles of ventilation - Diaphragm, Intercostals and scalenes 25
- 26. 26
- 27. Diaphragm 27
- 28. Diaphragm - accounts for 70% to 80% of quiet breathing Functionally, muscle portion of diaphragm can be divided as Costal and Crural parts Costal part - sternum, ribs (lower 6) and costal cartilages Crural part - vertebral bodies (L1-L3) 28
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- 30. Diaphragm contracts and pulls central tendon down increasing vertical diameter of thorax Decrease in the pleural pressure Decrease in intrapulmonary pressure responsible for inspiration 30
- 31. Costal fibers of diaphragm run vertically from their origin close to the ribcage before getting inserted into central tendon Portion of diaphragm which is close to inner wall of lower ribcage - “ZONE OF APPOSIOTION” During tidal breathing, descent of dome of diaphragm causes only slight change in its shape, maintaining most of zone of apposition 31
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- 33. Crural portion has an indirect effect on inspiration, it helps central tendon to descend thus increasing pressure which is transmitted through apposed diaphragm thus helping lower ribcage to expand 33
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- 35. Diaphragm increases all three diameters of the ribcage Vertical diameter by contraction of central tendon Transverse diameter by elevating the lower ribs Anteroposterior diameter by elevating the upper ribs with the help of sternum 35
- 36. 36 Intercostals Intercostal muscles - internal and external intercostals Act as splints during inspiration and expiration, by maintaining a constant tone Internal intercostal muscles run caudally and posteriorly continuing dorsally where they become posterior intercostal membrane at angle of the ribs
- 37. 37 External intercostals run caudally and at an oblique angle to internal intercostals till costochondral junction where they become anterior intercostal membrane
- 38. 38
- 39. Anteriorly portion where only internal intercostals are present - parasternal muscles Posteriorly only external intercostals are present from the tubercle of ribs to the angle of ribs Laterally both external and internal intercostals are present and are referred to as interosseous or lateral intercostals 39
- 40. Both set of intercostal muscles may be activated during phases of respiration as minute ventilation increases Activation of intercostals is from cephalic to caudal end 40
- 41. 41
- 42. Parasternal muscles - primary inspiratory muscles during quiet breathing and stabilizers of ribcage Scalene are one of the primary muscles of quiet respiration, their activity begins with onset of inspiration and increases as inspiration gets closer to total lung capacity 42
- 43. 43 Accessory musclesof respiration Inspiration Levatores costarum Pectoralis major/minor Rhomboids Anterior/medial/posterior scalenes Serratus anterior and posterior superior Subclavius, SCM Thoracic erector spinae Trapezius Expiration Iliocostalis lumborum Transversus thoracis Inspiration/Expiration Latissimus dorsi Quadratus lumborum Serratus posterior inferior Maintenance of rib cage shape Intercostals
- 44. Accessory muscles of ventilation When thorax is fixed, accessory muscles of inspiration move vertebral column, arm or head on the trunk Reverse muscle action 44
- 45. 45
- 46. Sternocleidomastoid flexes the cervical spine when acting bilaterally When cervical spine is fixed the muscle moves the ribcage superiorly, which expands upper ribcage in pump handle mechanism 46
- 47. Pectoralis major elevates upper ribcage when shoulders and humerus are fixed. It can act both as an inspiratory and an expiratory muscle Pectoralis minor can help raise third, fourth and fifth ribs during a forced respiration 47
- 48. Upper Trapezius can be helpful in active inspiration in fixing the head so that sternocledomastoid can act as a muscle of active inspiration Subclavius is between the clavicle and first rib, when acting in reverse action it can assist in raising upper chest for inspiration 48
- 49. 49 Serratus anterior Serratus posterior Lat dorsi Sterno costalis
- 50. Abdominal muscles – Tranversus abdominis Internal abdominal oblique External abdominal oblique Rectus abdominis 50
- 52. 52 Antagonismand synergismof diaphragm and abdominal muscles : During inspiration – with diaphragmatic contraction the central tendon descends down increasing vertical thoracic diameter but this is opposed by elongation of mediastinal elements and also resistance of abdominal viscera. At this time the abdominals relax allowing the abdomen to bulge. This shows the synergistic activity of abdominals
- 53. During expiration – diaphragm relaxes and contraction of abdominal muscles lowers the thoracic floor thereby decreasing simultaneously the transverse and anteroposterior diameters of thorax Also by pushing the viscera up abdominals raise the central tendon This shows the antagonistic activity of abdominals 53
- 54. 54 In normal breathing the respiratory muscles should use less than 5% of the O2 taken in the breath. If the diaphragm not working it is much more.
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- 56. 56 Differencesassociated with neonates Healthy new born has an extremely compliant chest wall because it is primarily cartilaginous Primary responsibility of ribcage stability on ribcage muscles to counteract negative pleural pressure of diaphragm during inspiration Ribs are also more horizontally placed this alters angle of insertion of costal fibers of diaphragm
- 57. Increased tendency of diaphragm fibers to pull lower ribs inwards, thereby decreasing efficiency of ventilation Only 20% of fibers of diaphragm are fatigue resistance as compared to 50% in adults Accessory muscles are also at a disadvantage 57
- 58. 58 Differencesassociated with elderly Pulmonary changes that occur may affect pulmonary function Costal cartilages ossify, which interferes with their axial rotation Many articulations undergo fibrosis with advancing age Synovial joints undergo morphological changes reducing mobility
- 59. 59 Chest wall compliance also reduces with age Lung tissue decreases in elasticity, thus affecting elastic recoil property of lung and outward pull of ribcage Results of these skeletal and tissue changes are increase in functional residual capacity and decrease in inspiratory capacity of thorax
- 60. Loss of strength of skeletal muscles of respiration Ventilatory muscles become more energy expensive Resting position of diaphragm becomes less domed with decrease in tone of abdominal muscles 60
- 61. 61 Scoliosis In scoliosis, if the curve is structural it affects chest wall biomechanics and hence ventilation Lumbar and cervical curves cause minimal change in chest wall biomechanics but a thoracic curve causes restriction in ventilatory capacity, restriction proportional to severity of curve
- 62. 62 3 Types: 1. Nonstructural scoliosis 2. Transient structural scoliosis 3. Structural scoliosis (idiopathic accounts for 70– 80% of cases of scoliosis)
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- 64. 64 Kyphosis An exaggeration of the normal posterior curve of the spine. Results from change in structure and shape in spine or posture. Fracture of anterior aspect of vertebral body – Osteoporosis (OP). Scheuermann’s disease – Hereditary disorder that results in kyphosis.
- 65. 65 COPD In COPD, major manifestation is hyperinflation of lungs due to destruction of alveolar walls Resting position of thorax in more of inspiratory cycle against the normal resting position in expiration This leads diaphragm to adapt a more flattened configuration in its resting state rather than acquiring its usual dome shape
- 66. Flattened diaphragm will pull lower rib cage inward, actually working against lung inflation This also decreases the zone of apposition Majority of inspiration performed by accessory muscles, particularly the parasternal and scalene 66
- 67. Pectuscarinatum 67 Some patients develop a rigid chest wall, in which the AP diameter is almost fixed in full inspiration. In these patients, respiratory efforts are less efficient.
- 68. 68 Vital capacity is reduced Residual air is increased Alveolar hypoventilation may ensue, with arterial hypoxemia and the development of cor pulmonale. As the lungs lose compliance, incidence of emphysema and frequency of infection are increased.
- 69. Pectusexcavatum 69 Unless severe does not cause restriction in breathing , but due to altered biomechanics –shallow breathing and dyspnea on exertion may be present
- 70. 70 Flail chest
- 71. 71 The characteristic paradoxical motion of the flail segment occurs due to pressure changes associated with respiration that the rib cage normally resists: During normal inspiration, the diaphragm contracts and intercostal muscles push the rib cage out. Pressure in the thorax decreases below atmospheric pressure, and air rushes in through the trachea. However, a flail segment will not resist the decreased pressure and will appear to push in while the rest of the rib cage expands.
- 72. 72 During normal expiration, the diaphragm and intercostal muscles relax, allowing the abdominal organs to push air upwards and out of the thorax. However, a flail segment will also be pushed out while the rest of the rib cage contracts. The constant motion of the ribs in the flail segment is painful, and, untreated, the sharp broken edges of the ribs are likely to eventually puncture the pleural sac and lung, possibly causing a pneumothorax.
- 74. 74 Positioning
- 76. 76 Impaired Muscle Performance Sources: Neurologic impairment or pathology Muscle strain or injury Disuse resulting in atrophy and general deconditioning Length-associated changes resulting in altered length-tension properties
- 77. 77 Treatment • Neural input must be restored for muscle performance to improve. • Protect weakened muscles from overstretch with proper support. • Stretch short muscles to maintain extensibility and prevent contracture. • For example: Impaired respiration – Stretch short muscles and apply manual or elastic band resistance to facilitate strength.
- 78. 78 Stretch Lateral Trunk and Intercostal Muscles
- 79. 79 Muscle Strain or Injury Address posture and movement patterns. Improve performance of underused synergists. For example, in the case of overuse of anterior scalene during breathing, reduce anterior scalene use by improving performance of deep anterior cervical flexors and instruct in proper pump and bucket handle diaphragmatic breathing.
- 80. 80 Disuse Resulting in Atrophyand General Deconditioning Caused by illness, immobilization, sedentary lifestyle, subtle shifts in muscle balance. Progressive resistive exercises for the upper body. Initially, weight of limb is ample stimulus. Progress in small increments. Address balance between abdominal and spinal extensors as well as thoracic multifidii.
- 81. 81 Length-Associated Changes Subtle imbalances in muscle length lead to length- associated strength changes and positional weakness of one synergist compared with agonist or antagonist. • Strengthen weak overstretched muscle groups in shortened range. • Stretch adaptively shortened muscles. • Supportive taping adjunctive. • Correction of posture and movement patterns.
- 82. 82 Supportive Taping forThoracic Spine
- 83. 83 Impaired ROM, Muscle Length, and Joint Mobility/Integrity Optimal function of the thoracic region requires full symmetrical cardinal plane motion and full rib motion. Consider symmetrical breathing patterns. Diagnose restrictions that are joint versus soft tissue origin.
- 84. 84 Establish the neutral spine
- 85. 85 Exercise to PromoteThoracic Extension
- 86. 86 Exercise Managementof Scoliosis • Avoid symmetrical and spine flexibility exercises. • Strengthen overstretched antagonist/synergist in shortened range. • Promote strength of the relatively weak muscle or groups of muscles in the anterior thoracolumbar region and the pelvic-hip complex. • Trunk curl exercises or sit-ups are not indicated methods of strengthening anterior thoracolumbar muscles.
- 87. 87 Thoracic Outlet Syndrome • Characteristically young, slender women with drooping shoulders and poor posture • Treatment aimed at improving muscle performance and reducing stretch to upper and middle trapezius • Supportive taping to elevate scapula
- 88. 88 • Correct posture and movement relative to neurovascular compression or stretching (i.e., depressed or anterior tilt scapula) • Tape scapula into elevation to relieve compression • Alter sleeping habits • Improve diaphragmatic breathing • Address associated physiologic/psychological impairments
- 89. 89 Summary Functions Joints Movements Muscles Differences associated with neonates and elderly Chest wall deformities Treatment and correction of thoracic mechanics
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Editor's Notes
- #10: The costovertebral joints are the articulations that connect the heads of the ribs with the bodies of the thoracic vertebrae. Joining of ribs to the vertebrae occurs at two places, the head and the tubercle of the rib. Two convex facets from the head attach to two adjacent vertebrae. This forms a trochoid joint, which is strengthened by the ligament of the head and the intercapital ligament. Articulation of the tubercle is to the transverse process of the adjacent vertebrae. This articulation is reinforced by the dorsal costotransverse ligament.
- #70: Add flail chest and symmetric and asymmetric chest wall abnormalities