The Anatomy of the Chest Wall and Breathing Physiology PDF

The anatomy of the chest wall and the physiology of breathing Learning objectives To be able to: Identify the bony structures of the chest wall Identify the muscular and soft tissue structures of the chest wall Identify the nervous system involved in breathing...

The anatomy of the chest wall and the physiology of breathing Learning objectives To be able to: Identify the bony structures of the chest wall Identify the muscular and soft tissue structures of the chest wall Identify the nervous system involved in breathing Understand and explain the mechanics of breathing : Inspiration Expiration Control of breathing Explain the relevance to physiotherapy The chest wall : Overview The chest wall: 10 layers Epidermis, dermis, superficial and deep fascia Extrinsic and intrinsic muscles Ribs, Sternum and spine Endothoracic fascia Parietal pleura Bony Structures of the Chest wall The structure of the rib cage : Thoracic spine T1to T12 Clavicle ( collarbone) Ribs 1 to 12 True ribs 1-7 False ribs 8-10 Floating ribs 11-12 Costal Cartilage Sternum Manubrium Xiphoid process Thoracic Cage Thoracic cage Clavicle : 1st costal cartilage attach to the manubrium 2nd costal cartilage : Attach to the Sternal angle Thoracic cage True ribs: 1-7th lies deep to the clavicle ( difficult to palpate) Attached to sternum ( via costochondral joints False ribs: 8-10th Attached anteriorly only (via costochondral joints) Form interchondral + chondrocostal joints Free floating ribs : 11th-12th ribs Only attach posteriorly Thoracic cage Sternal angle : acts as a hinge enabling movement Ossifies with age Synovial Joints: Freely mobile Ribs, costal cartilage, vertebrae and sternum : synovial Primary Cartilaginous Joints: Bones connected by hyaline cartilage 1st costal cartilage and manubrium Sternocostal joints Key facts about the sternocostal joints Type Sternocondral Joint 1: Primary cartilaginous joint (synchondrosis) Sternochondral Joints 2-7: Synovial Planar Joints: Nonaxial, uniplanar Articular surfaces Sternal ends of costal cartilages of the true ribs, costal notches on sternum Ligaments Radiate sternochondral, xiphichondral and intra-articular sternochondral ligaments. Innervation Intercostal nerve Blood Supply Internal Thoracic Artery Movements Sternochondral Joint 1: almost no movement Sternochondral Joint 2-7: translation, mainly superinferioraly Manubriosternal joint Key facts about the manubriosternal joint Type Secondary Cartilaginous joint (Symphysis) Articular surfaces Inferior margin of the manubrium of sternum, articular disc, superior margin of sternal body. Ligaments Manubriosternal Ligament Movements Angulation, anteroposterior displacement Xiphisternal joint Key facts about the xiphisternal joint Type Secondary Cartilaginous joint (Symphysis) Articular surfaces Superior margin of the xiphoid process, articular disc, inferior margin of sternal body. Ligaments Anterior and posterior Xiphichondral Ligaments Movements No movement Thoracic Spine T2-T9 T1, T10-T12 Ribs: Rib 3 - 10 Typical Ribs Two articular facets: Superior demi facet: articulates with numerically corresponding body of thoracic vertebrae eg T3 Inferior demi facet Tubercle: Articulates with numerically corresponding transverse process of the vertebrae Non-articulating part: attachment for lateral costotransverse ligament Angle tear shaped shaft Ribs: 1st, 2nd , 11th and 12th (sometimes 10 ) th The first rib The second rib The eleventh and twelfth rib Short, strong, flat and very Tubercle for scalenus Do not have tubercles and do not attach to curved posterior anything anteriorly. Has a tubercle for scalenus Tubercle for serratus anterior Only have a single facet on their head. anterior Single facet on the rib head The Tenth Rib Only sometime atypical as may Grooves for subclavian only articulate with the 10th vessels. vertebrae. Costovetebral Joints and facet joints Joints of the vertebral bodies Key facts about the Facet joints/ zygopophaseal joint Type Synovial plane joint Articular surfaces Inferior and superior articular facets Ligaments Ligamenta flava, interspinous ligaments, supraspinous ligament and intertransverse ligaments Innervation Lateral branches of the posterior rami of C8 –T11 spinal nerves. Blood supply Supreme intercostal, posterior intercostal arteries 1-10 Movements In the thoracic region of the spine, the superior articular facets largely project posteriorly whereas inferior facets are mainly anteriorly positioned. The joint planes are therefore vertically placed, restricting flexion and extension, but allow for rotation movement Pitch Deck 20XX 18 Joints of the vertebral bodies Key facts about the intervertebral discs Type Secondary Cartilaginous joint Articular surfaces Adjacent vertebral bodies Ligaments Ligamenta flava, interspinous ligaments, supraspinous ligament and intertransverse ligaments- also act as a ligament in itself. Innervation Sinovertebral nerves Blood supply Osmotic supply Movements Flexion, extension, lateral flexion and rotation. Pitch Deck 20XX 19 Boundaries of the Thoracic cavity 20 Thoracic outlet Transmits structures passing from chest into neck and upper limb Suprapleural membrane - Tough fascia - Attaches around bony- cartilaginous margins - Preventing lung expansion in upward direction - Continuous with endothoracic fascia (lines entire chest cavity) - Trachea, oesophagus, blood vessels pierce fascia Thoracic Outlet Syndrome (TOS): - Compression of neurovasculature in the inlet - Apical lung cancer, of clavicle, fractures, extra cervical rib ( C7 (specifically posterior tubercles of transverse processes of vertebrae in C3-C7) plexus (C2-C3) Insertion: superior border of rib 1 (posterior to subclavian groove) Blood supply Superior thyroid artery Innervation: anterior rami of spinal nerves C3-C8 Blood supply: ascending cervical branch of the inferior thyroid artery Functions Unilateral contraction: cervical spine: neck Function: neck lateral flexion, elevates rib 1 ipsilateral flexion, neck contralateral rotation Bilateral contraction: atlantooccipital joint/ superior cervical spine: head/neck extension; Posterior scalene muscle Origin: posterior tubercles of transverse processes of vertebrae C4-C6/C5-C7 Inferior cervical vertebrae: neck flexion; Insertion: external surface of rib 2 sternoclavicular joint: elevation of clavicle and manubrium of sternum Innervation: anterior rami of spinal nerves C6-C8 Blood supply: ascending cervical branch of the inferior thyroid artery; superficial cervical artery Function: neck lateral flexion, Elevates rib 2 28 Accessory muscles of the shoulder girdle Key facts: Pec Major Key facts about the trapezius muscle Key fact Pec Minor Origins Sternal head: superior part of anterior surface of Origin Descending part (superior fibers): medial third of the superior nuchal line, external occipital protuberance, manubrium sterni Origin Anterior surface, costal nuchal ligament Clavicular head: superior surface of medial third cartilages of ribs 3-5 Transverse part (middle fibers): spinous processes and supraspinous ligaments of vertebrae T1-T4 (or C7-T3) of the clavicle Ascending part (inferior fibers): spinous processes and supraspinous ligaments of vertebrae T4-T12 Insertions Inserti Medial border and coracoid Lateral surface of mastoid process of the temporal bone, Lateral half of superior nuchal line of the on process of scapula occipital bone Insertion Descending part (superior fibers): lateral third of clavicle Innerv Medial and lateral pectoral Transverse part (middle fibers): medial acromial margin, superior crest of spine of scapula Ascending part (inferior fibers): lateral apex of the medial end of scapular spine Innervation Accessory nerve (CN XI), branches of cervical ation nerves (C5-T1) plexus (C2-C3) Blood supply Superior thyroid artery Innervation Motor: accessory nerve (CN XI) Blood Thoracoacromial a. (pectoral Motor/Sensory: anterior rami of spinal nerves C3-C4 (via cervical plexus) Functions Unilateral contraction: cervical spine: neck supply and deltoid branches), superior Descending part (superior fibers) ipsilateral flexion, neck contralateral rotation thoracic a., lateral thoracic a. - Scapulothoracic joint: draws scapula superomedially Bilateral contraction: atlantooccipital joint/ - Atlantooccipital joint: extension of head and neck, lateral flexion of head and neck (ipsilateral) superior cervical spine: head/neck extension; - Altantoaxial joint: rotation of head (contralateral) Inferior cervical vertebrae: neck flexion; sternoclavicular joint: elevation of clavicle and Functio Scapulothoracic joint: draws Transverse part (middle fibers) - Scapulothoracic joint: draws scapula medially manubrium of sternum n scapula anteroinferiorly, Ascending part (inferior fibers) stabilizes scapula on thoracic - Scapulothoracic joint: Draws scapula inferomedially wall Blood supply 29 Occipital artery (descending part), superficial or transverse cervical artery (transverse part), dorsal scapular artery (ascending part) Accessory inspiratory muscles of the shoulder girdle and back. Key facts about the serratus anterior muscleTable quiz Key facts about the quadratus lumborum Origin Superior part: Ribs 1-2, Intercostal fascia Origin Iliac crest, iliolumbar ligament Middle part: Ribs-3-6 Inferior part: Ribs 7-8/9 (variably extends to rib 10 (+ external oblique muscle)) Insertion Inferior border of rib 12, transverse processes of vertebrae L1-L4 Insertion Scapula (Superior part: Anterior surface of superior angle Middle part: Anterior surface of medial border Innervation Subcostal nerve (T12), anterior rami of spinal nerves L1-L4 Inferior part: Anterior surface of inferior angle and medial border) Innervation Long thoracic nerve (C5- C7) Mnemonics: 'SALT' (stands for serratus anterior - long thoracic) & 'C5, 6, 7 raise Blood supply Lumbar, median sacral, iliolumbar and subcostal arteries your arms to heaven!' Blood supply Superior and lateral thoracic arteries, thoracodorsal artery branches Function Bilateral contraction - fixes Ribs 12 during inspiration, trunk extension Unilateral contraction - lateral flexion of trunk (ipsilateral) Function Scapulothoracic joint: Draws scapula anterolaterally, Suspends scapula on thoracic wall, Rotates scapula (draws inferiorly angle laterally) 30 Accessory muscles of the back. Key facts about the iliocostalis Key facts Erector Spinae muscleTable quiz Origin Iliocostalis cervicis: Angle of ribs 3-6 Definition Three groups of deep muscles Iliocostalis thoracis: Angle of located on either side of the ribs 7-12 vertebral column Iliocostalis lumborum: Lateral crest of sacrum, medial end of iliac crest, thoracolumbar fascia Insertio Iliocostalis cervicis: Function Bilateral contraction - extension n Transverse processes of of spine vertebrae C4-C6 Unilateral contraction - lateral Iliocostalis thoracis: Angles of flexion of spine (ipsilateral) ribs 1-6, transverse process of vertebra C7 Iliocostalis lumborum: Angle of ribs 5-12, transverse processes of vertebrae L1-L4 (+ Adjacent thoracolumbar fascia) Key facts Latissimus Dorsi Action Bilateral contraction: Origin Vertebral part: Spinous processes of vertebrae T7-T12, Thoracolumbar fascia Extension of spine Unilateral contraction: Iliac part: Posterior third of crest of ilium Lateral flexion of spine Costal part: Ribs 9-12 (ipsilateral) Scapular part: Inferior angle of scapula Innerva Lateral branches of posterior tion rami of spinal nerves Insertion Intertubercular sulcus of the humerus, between pectoralis major and Blood Iliocostalis cervicis: occipital, teres major muscles supply deep cervical and vertebral Mnemonic: Lady between two majors (lady refers to latissimus dorsi) arteries Iliocostalis thoracis: dorsal branches of posterior Innervation Thoracodorsal nerve (C6-C8) intercostal and subcostal Blood supply Thoracodorsal artery, perforating arteries of the 9th-11th posterior intercostal arteries Iliocostalis lumborum: dorsal arteries, and 1st-3rd lumbar arteries branches of lumbar and Functions Shoulder joint: Arm internal rotation, Arm adduction, Arm extension; Assists in lateral sacral arteries respiration 31 Expiratory muscles Rectus Abdominus Transverse abdominus External Oblique Internal Oblique Latissimus Dorsi 32  Key facts about the transversus abdominis muscle Origin Internal surfaces of costal cartilages Expiratory muscles of ribs 7-12, thoracolumbar fascia, anterior two thirds of iliac crest, iliopectineal arch Insertion Linea alba, aponeurosis of internal abdominal oblique muscle; pubic crest, pectinal line of pubis Action Bilateral contraction - Compresses abdominal viscera, expiration Unilateral contraction - Trunk rotation (ipsilateral) Innervati Intercostal nerves (T7-T11), on subcostal nerve (T12), iliohypogastric nerve (L1), ilioinguinal nerve (L1) Blood Lower posterior intercostal and Key facts about the internal abdominal oblique Key facts about the external abdominal oblique muscle supply subcostal arteries, superior and inferior epigastric arteries, Origin Anterior two-thirds of iliac crest, iliopectineal arch, superficial and deep circumflex Origin External surfaces of ribs 5-12 thoracolumbar arteries,posterior lumbar arteries fascia Insertion Linea alba, pubic tubercle, anterior half of iliac crest Insertion Inferior borders of ribs 10-12, linea alba, pubic crest & pectin pubis (via conjoint tendon) Action Bilateral contraction - Trunk flexion, compresses abdominal viscera, Key facts about the rectus abdominis muscle expiration Action Bilateral contraction - Trunk flexion, compresses Unilateral contraction - Trunk lateral Origin Pubic symphysis, pubic crest abdominal viscera, expiration flexion (ipsilateral), trunk rotation Insertion Xiphoid process, costal cartilages of ribs 5-7 Unilateral contraction - Trunk lateral flexion (ipsilateral), (contralateral) trunk rotation (ipsilateral) Innervation Intercostal nerves (T7-T11), subcostal nerve (T12) Innervati Motor: Intercostal nerves (T7- T11), Innervation Intercostal nerves (T7-T11), subcostal nerve (T12), on Subcostal nerve (T12) Blood supply Inferior epigastric and superior epigastric arteries; iliohypogastric nerve (L1), ilioinguinal nerve (L1) contributions from posterior intercostal, subcostal Sensory: Iliohypogastric nerve (L1) and deep circumflex arteries Blood supply Lower posterior intercostal and subcostal arteries, Blood Lower posterior intercostal arteries, superior and inferior epigastric arteries, superficial and supply subcostal artery, deep circumflex iliac deep circumflex arteries,posterior lumbar arteries artery Function Trunk flexion, compresses abdominal viscera, expiration 33 Neurology of the chest wall Dermatome Dermatome An area of skin supplied by a single nerve root Intercostal nerves supply a dermatome Dermatomes over chest wall overlap Half by nerve above and below Anterior rami - Supplies skin & parietal pleura 35 Innervation of the chest wall Anterior rami, of thoracic spinal nerves supply - intercostal spaces ( intercostal muscles) - Associated skin - Serrous membrane ( inside of parietal pleura) Posterior rami supply - post vertebral muscles - overlying skin Thoracocentesis (pleural Tap) or nerve block - Middle of space safest - Nerve block: Rib above and below target nerve 36 Innervation of the chest wall Mechano-receptors in the chest wall and within the respiratory muscles have an effect in our sensation of dyspnoea and so part of our sensation of breathlessness is carried via the afferent fibres of the spinal cord. 20XX 37 Innervation of chest wall Schematic representation of afferent pathways of dyspnea from vagal receptors and peripheral chemoreceptors to the CNS. The precise pathways from the nucleus tractus Motor stimulation: solitarius to the limbic system and cortex are not clearly delineated and, hence, are shown as broken lines. RAR = The motor control of our rapidly adapting receptor; SAR = slowly adapting receptor. breathing is via the phrenic nerve that innervates the diaphragm. This comes from C3, C4 and C5. The intercostal muscles are Innervated by the intercostal Nerves. 20XX 38 The lymphatic system The Lymphatic System Series of vessels and nodes Superficial and deep drainage Infections and cancer can spread via system Vital part of the body’s immune defence / response to infection collect and filter excess tissue fluid (lymph) Filters blood from foreign particles Returns blood it to the venous circulation. 39 The lymphatic system Superficial: Posterior chest wall: Drain to axillary lymph nodes Anterior chest wall: axillary nodes (laterally) and Parasternal ( medially) Pitch Deck 20XX 40 Deep lymphatic system Drain mostly via the Bronchmediastinal lymph trunk and Thoracic duct Viscera drained by posterior mediastinal, brachiocephalic or tracheobronchial ( all converge into bronchomediastinal lymph trunk) Pitch Deck 20XX 41 Vasculature to the chest wall 42 The physiology of breathing Physiology of breathing Sensation from sensory nerve endings triggers the respiratory centre Relaxation of the diaphragm and Respiratory centres then intercostal muscles leads trigger the breath to the natural recoil of the lungs. Motor response leads to Triggering of sensory the contraction of the nerves to stop the diaphragm and contraction of the intercostal muscles via diaphragm and the phrenic and intercostal muscles. intercostal nerves The physiology of breathing It’s all about pressure!!! Facilitated by: Contraction of respiratory muscles Movement of the ribs Movement of the diaphragm A concentration gradient There are two types of breathing: Normal Quiet or Tidal breathing Forced breathing (e.g. breathing during exercise) Physiology of breathing : Movement of the ribs Two types of movement at rest or during quiet/tidal breathing: Bucket handle : Primarily involves the lower ribs (7-10) The ribs move upward and outward This motion increases the anterior-posterior diameter of the thorax Pump Handle : Mainly involves the upper ribs (1-6) The ribs rotate and move laterally outward This motion increases the transverse diameter of the thorax  Quiet / Tidal breathing : Inhalation Contraction of the external intercostals and the diaphragm Ribs move up and out Diaphragm flattens and moves down Increased volume in the chest Decreases the pressure in the thorax ( intrathoracic pressure) Air sucked in Air moves down a pressure gradient from high ( atmospheric pressure) to low  Quiet / Tidal breathing : Expiration Relaxation of the diaphragm and external intercostals Diaphragm domes and Ribs move down and in Lung fibres recoil moves up Decreased volume in the chest Increases the pressure in the thorax (intrathoracic pressure) Air pushed out Air moves down a pressure gradient from high to low Breathing under stress or forced expiration Uses the abdominal muscles Contraction of the internal intercoastal muscles Main takeaways Breathing in is an active but unconscious process Air moves in and out of the lungs down a pressure gradient Breathing out is passive at rest Main muscles of respiration are: Diaphragm Intercostal muscles Questions?