The Thoracic Spine PDF

PP6012 The Thoracic Spine Maria Hill Acknowledgements: Niamh Brady Learning Outcomes Review the structure and function of the vertebral column Discuss how various anatomical architectural features of the vertebral column and its joint structures play a role in movement and stability Describe typical...

PP6012 The Thoracic Spine Maria Hill Acknowledgements: Niamh Brady Learning Outcomes Review the structure and function of the vertebral column Discuss how various anatomical architectural features of the vertebral column and its joint structures play a role in movement and stability Describe typical features of a vertebrae in the thoracic spine Describe how the vertebrae articulate with each other at various joints and how the shape of these joints influence movement Discuss the ligaments that provide support of the thoracic spine Discuss the muscles that support and move the thoracic spine Describe the arrangement of spinal nerves of the thoracic spine Functions of the Thorax To house and protect vital organs To support the neck To enable diverse head movement Protects Sympathetic Nervous System Trunk Muscles of Thorax responsible for Postural Control Respiration – movement with lung expansion Designed for Movement – Primary Rotation The “Back” Posterior neck and trunk Skin Fascia Muscle Ligament Vertebral Column Disc Thorax Blood Vessels Nerves The Vertebral Column (The Spine) Axial Skeleton – a flexible curved central axis of the skeleton (approx 70cm long in male) 33 vertebrae arranged in 5 regionally distinct groups 7 cervical 12 thoracic 5 lumbar 5 sacral (fused) 4 coccygeal (fused) Curvatures of the VC in the Adult Primary curvature (foetal) is flexed, 2 secondary curvatures develop after birth Cervical – development of head control/extensor muscles – cervical spine develops a lordosis Thoracic – Maintains primary curvature - kyphosis Lumbar – Development of upright posture produces a lumbar lordosis Saccrococcygeal – maintains primary curve - kyphosis Deviations from normal curvatures Maldevelopment or pathological Kyphosis Increased or Hyperkyphosis Associated with Osteoporosis Lordosis Hyperlordosis - neuromuscular Swayback Pregnancy Scoliosis Lateral S-Shaped curvature Accompanied by rotation of the vertebrae The Thorax – the most poorly researched region of the spine The Thorax - Osteology Clavicle Jugular notch Manubrium 3rd Rib Body of sternum Costal Cartilage Xiphoid Process The Sternum and articulations Parts A: Manubrium B: Body C: Xiphoid Process D A B E Joints D: Manubriosternal E: Xiphisternal C The Thorax Superior & inferior thoracic aperture Thoracic Inlet AKA thoracic inlet & outlet 12 ribs (2 floating) Costal cartilages – 7-10 common (costal arch) – facilitate movement Sternum – 3 parts Thoracic Outlet The Ribs 12 pairs Types Typical/True 2nd – 7th Articulate directly with sternum via respective costal catilage Atypical/False 1st & 8-10th Rib 1 – described shortly Rib 8-10 – articulate with sternum via 7th costal cartilage Floating 11/12th The Rib Spiral shaped curve Outside smooth Inside - groove for intercostal vessels Angle of Rib – Iliocostalis attachment Head Neck Tubercle Articular facets The st 1 Rib Articulates with manubrium Sternocostal joint very stable Elevates on breathing Pump handle: Involves vertebrosternal ribs 2-6 Bucket Handle: Involves ribs 7-10 Features of a Typical Vertebra 2 main parts – body and neural arch Body Supports weight. Increased size with descent. Arch Pedicles (anterior) Laminae (posterior) Vertebral Foramen Form Spinal Canal Contain Spinal Cord, Meninges, Nerves, Blood Vessels Spinal cord is 40-45cm long, extending from foramen magnum to L1/2 spinal level Features of a typical vertebra Spinous Process x 1 Posterior projections, junction of laminae Transverse Process x 2 Posterolateral projections, junctions laminae and pedicles Articular Process x 4 X 2 superior, x 2 inferior Articulate with vertebrae superiorly and inferiorly – facet joints Intervertebral foramina Posterolateral to vertebral bodies, transmit spinal nerves and vessels Thoracic Vertebra 12 Thoracic Vertebrae Thoracic Vertebrae - Typical Features Heart Shaped vertebral bodies Costal facets – on body and transverse process Long Spinous process – slope downwards Long transverse process Rounded articular processes - vertical Superior facets face posterolaterally Inferior facets face anteromedially What does this mean for movement?? Thoracic Vertebra Transverse Process Superior articular process Vertebral foramen Spinous process Body Inferior articular process Costal facet Costal facet Costal facet Joints of the VC Intervertebral Facet or Zygapophyseal Uncovertebral (Cx) Atlanto-occipital/Craniovertebral (Cx) Atlanto-axial (Cx) Costovertebral (Tx) Costotransverse (Tx) Lumbosacral Sacroiliac – covered next lecture Intervertebral Joints (IVJs) Between vertebral bodies Secondary cartilaginous Bone – Endplate – Disc – Endplate - Bone Function – designed for WB & movement Intervertebral Disc (IVD) Endplate Hyaline & fibrocartilage Diffusion of nutrients through endplate arteries Outer annulus fibrosis Rings of fibrocartilage – lamellae (20) Attaches rims of VB’s 60-70% water Inner nucleus pulposus Gelatinous (toothpaste) centre Cartilage cells, collagen fibres (Type II), semifluid ground substance – proteoglycan gel 70-90% water Clinical - Disc Herniation Disc Protrusion, Prolapse, Extrusion, Sequestration What is it? Tear of annular fibrosis, herniation of nucleus pulposus, make cause compression of neural structures Uncommon/Asymptomatic in Tx Spine Cause Dehydration, degeneration, loss of resilience Mechanism – flexion, rotation, load Ligaments of Spine Anterior Longitudinal Ligament Strong fibrous band Connects anterior aspects of vertebral bodies Function Stability Prevents Hyperextension Ligaments of Spine Posterior Longitudinal Ligament (PLL) Weaker than ALL Within vertebral canal Attaches to IVD’s Function Prevent Hyperflexion Prevent disc protrusion Facet joints (Zygapophyseal) Between articular facets of vertebrae Plane Synovial Joints Loose articular capsule Movements Gliding Orientation of articular facets Regional differences Thoracic?? Vertical orientation – resist anterior translation and flexion Coupled rotation and LF in upper Tx Facet Joint strain/arthritis Potential cause of back/chest pain Associated with disc degeneration MRI – narrowing of facet joint space and osteophyte formation Clinical – Pain map from viscera 4: Pancreas 5: Small Intestine 6: Colon 7: Oesophagus 8: Stomach/Duodenum 9: Liver/Gall Bladder 10: Stomach/Duodenum Accessory Ligaments Ligamentum flavum Between adjacent laminae Limit flexion of VC Intertransverse ligament Between transverse processes Interspinous ligament Weak Between SP’s Accessory Ligaments Supraspinous Strong Between SP’s Merges with ligamentum Nuchae Ligamentum Nuchae Not found in Tx spine Costovertebral Joints Head of rib articulates with body of vertebra – upper and lower full/demifacets and IVD One rib articulates with body above and below Synovial joints Ligaments Radiate ligaments Costotransverse Joints Tubercle of rib articulates with transverse process Synovial Joints Ligaments Superior costotransverse ligament Lateral costotransverse ligament Costal Articulations Sternocostal Joints CC Ribs 1-7 → Sternum Ribs 8-10 via costal arch Costochondral Joints Ribs → Costal cartilage Spinal Coupling is the phenomenon where movement within any plane throughout the vertebral column is associated with an automatic movement in another plane. Thoracic Spine Coupling is highly variable Thoracic Lateral Flexion Contralateral Rotation Thoracic Rotation Ipsilateral LF LJ Lee 2003 Coupling of costal and thoracic movement Flexion of Tx spine = superior glide and anterior rotation LJ Lee 2003 Coupling of costal and thoracic movement Extension = inferior glide and posterior rotation LJ Lee 2003 Coupling of costal and thoracic movement Rotation = ipsilateral posterior rotation, contralateral anterior rotation Also coupled with ipsilateral Tx LF Diane Lee 2015 LJ Lee 2003 Thoracic Biomechanics in Respiration Deep inspiration associated with spinal extension and posterior rotation of the ribs Expiration = vice versa Thoracic Spine Musculature Diaphragm Intercostals Serratus Posterior Scalenes, SCM, Pec Minor Erector Spinae Semispinalis Multifidus Diaphragm Skeletal muscle Separates thoracic and abdominal cavities Attachments L1-3 Costal cartilages 7-10, Ribs 11, 12 Xiphoid Process Nerve Supply Phrenic Nerve, C3-5 “C 3, 4, 5 keeps the diaphragm alive” Intercostals Run inferoanteriorly from VB above to below Intercostal Vein, Artery, Nerve Run inferoposteriorly from VB above to below Run inferoposteriorly from VB above to below Serratus Posterior Superior Prox – Nuchal Lig, SP C7-T3 Distal – Superior borders Ribs 2-5 N.S. – 2nd-5th intercostal nerves Action – Rib elevation Inferior Prox – Inferior borders Ribs 9-12 Distal – SP T11-L2 N.S. – 9-11th intercostal, subcostal nerve Action – Rib depression Erector Spinae Columns: Iliocostalis, Longissimus, Spinalis Divisions: Iliocostalis Lumborum, Thoracis, Cervicis Longissimus Thoracis, Cervicis, Capitis Spinalis Thoracis, Cervicis, Capitis Iliocostalis Thoracis Proximal TP C7, Rib angle 1-6 Distal Rib angles 6-12 Nerve Supply Adjacent posterior rami Action Extension of VC, Rotation (ipsi), Lateral Flexion Longissimus thoracis Largest component of ES - 11-12 fascicles Proximal: Ribs and TPs of T1-T12 (2 tendons) Distal L2 – S3 Spinous Processes Nerve Supply: Dorsal rami of spinal nerves Action: Extension, Lateral flexion, Ipsilateral Rotation (mainly acting on Tx spine) Lumbar lordosis Spinalis Thoracis Proximal Spinous process of upper Tx vertebrae Distal SP lower Tx vertebrae Nerve Supply Adjacent posterior rami Action Extension of VC, Rotation (ipsi) Semispinalis Proximal SP C5 – T4 Distal TP 6-10 Nerve Supply Posterior rami of adjacent spinal nerves Action Extension and contralateral rotation Multifidus Proximal SP T1-12 Distal TP T1-12 Superficial span 3-4 levels, intermediate 2-3 levels, deep 1 level Nerve Supply Posterior rami of adjacent spinal nerves Action Segmental stability, rotation and extension Thoracic Spinal Nerves Nerve roots T1-12 Spinal Nerves exit at each level below their corresponding vertebra eg T1 exist between T1 and T2 Autonomic NS Clinical Thoracic Disc protrusion – rare (rarely symptomatic) Scheurmans Disease Scoliosis Osteoporosis Spinal Tumours – Haemangioma Rib fractures Respiratory conditions Pectus Carinatum (Pigeon chest) Pectus Excavatum (Sunken Chest) Masqueraders