The spine & spinal cord

The Spine & Spinal Cord Faisal Majid 4 th year (Endo BSc) MM Education rep [email_address]

Recognise and name the following parts of a typical vertebra in osteological specimens or in suitable imaging: body, pedicle, lamina, transverse process, spinous process, articular surfaces Recognise the distinctive features of cervical, thoracic and lumbar vertebrae Explain the roles of intervertebral discs, ligaments and muscles in load bearing in the vertebral column Describe the relative extents of antero-posterior flexion, lateral flexion and axial rotation in the major regions of the vertebral column and explain this in terms of skeletal anatomy Identify the atlas and axis and explain their functions in head movement Identify the main muscle groups involved in head movements Demonstrate on each other the location of C7, T3, T7, L2 and L4 vertebrae State the number of vertebrae in each region of the spine, and how the pairs of spinal nerves are related to them Explain the arrangement of the meninges around the spinal cord and roots, and indicate any differences from the cranial meninges Identify two major reasons for carrying out lumbar puncture, and explain the basis for the puncture site Explain the danger of carrying out lumbar puncture without excluding the presence of raised intracranial pressure Outline the steps taken to avoid neurological complication in casualties with a possibility of cervical spine injury Explain in anatomical terms the most common causes of back pain Describe the most common abnormalities of spinal curvature

C1-C7 T1-T12 L1-L5 S1-S5 Coccyx LANDMARKS

C7 – Prom. Spinous Process T3- Level with Medial Scapular Spine T7 – Inferior angle of scapula L2 – Lowest Rib L4 – Iliac Crest

Cervical vs Thoracic vs Lumbar Cervical vertebrae Smallest Foramen in each transverse process

What is this? C1 –Atlas Forms the joint connecting the skull and spine Has no body

AXIS (Second cervical vertebra) (C2) of the spine is named the axis . It forms the pivot upon which the Atlas- rotates strong odontoid process which rises perpendicularly from the upper surface of the body.

Thoracic Vertebra Intermediate in size Increase in size as one proceeds down the spine They are distinguished by the presence of facets on the sides of the bodies Facets on the transverse processes of all, except the eleventh and twelfth,

Lumbar Vertebra The lumbar vertebrae are the largest segments of the movable part of the vertebral column Absence of a foramen in the transverse process, Absence of facets on the sides of the body.

The cervical curve, convex forward, C1/2 – T7 The thoracic curve, is concave T2 – T12 The lumbar T12 – L4, It is convex anteriorly. The pelvic curve L4/5 - Coccyx

Intervertebral Disk Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together. The annulus fibrosus consists of several layers of fibrocartilage. The strong annular fibers distribute pressure evenly across the disc. The nucleus pulposus contains loose fibers- like JELLY. The nucleus of the disc acts as a shock absorber, absorbing the impact of the body's daily activities and keeping the two vertebrae separated.

Intervertebral Disk - INJURY Degenerative Disk Disease: As people age, the nucleus pulposus begins to dehydrate, which limits its ability to absorb shock. The annulus fibrosus gets weaker with age and begins to tear. While this may not cause pain in some people, in others one or both of these may cause chronic pain. Disk Herniation: When the annulus fibrosus tears due to an injury or the aging process, the nucleus pulposus can begin to extrude through the tear. Leads to Pinched nerve: Radiating pain, numbness, tingling, and diminished strength and/or range of motion. Radicular Pain

From Course Guide Why is backache more common in the lumbar region? The lower spine is subject to increased stresses of weight-bearing. We tend to abuse our backs, particularly when lifting heavy objects. Extending the spine from the fully flexed position under a heavy load can inflame intervertebral joints or place unequal pressure on the intervertebral disks, leading to local joint pain and referred neurological pain, if there is also pressure on the spinal nerve. Additional attempts to rotate the spine at the same time creates extra stress on the lumbar joints. Good practice includes holding the load close to the body, and using extension of the knee joints instead of extension of the spine to raise the load.

Flexibility and Mobility Flexion (forward bending) Extension (backward bending) Side bending (left and right) Rotation (left and right) Combination of above MUSCLES ASSOCIATED WITH

From Course Guide… 0 + ++ L1-sacrum ++ ++ + T7-T12 + + 0 T1-T6 ++ ++ ++ C1-C7 Rotation Lateral flexion Flexion/extension

Abnormalities in curvature The following abnormal curvatures may occur in some people: Kyphosis is an exaggerated posterior curvature in the thoracic region. This produces the so-called "humpback". Lordosis is an exaggerated anterior curvature of the lumbar region, "swayback". Temporary lordosis is common among pregnant women . Scoliosis , lateral curvature, is the most common abnormal curvature, occurring in 0.5% of the population. It is more common among females and may result from unequal growth of the two sides of one or more vertebrae.

Lumbar Puncture Indications Collect cerebrospinal fluid- in a case of suspected meningitis. (Subarachnoid hemorrhage, hydrocephalus, benign intracranial hypertension and other diagnoses may be supported or excluded with this test.) Lumbar punctures may also be done to inject medications into the cerebrospinal fluid or lumbar epidural space. Risks Damage to the spinal cord or spinal nerve roots resulting in weakness or loss of sensation, or even paraplegia. The latter is very rare. The procedure is not recommended when epidural infection is present or suspected, when topical infections or dermatological conditions pose a risk of infection at the puncture site or in patients with severe psychosis or neurosis with back pain. Elevated or reduced pressure in the brain may also pose risks during lumbar punctures.

Vertebrae & Nerve Roots C1-C7 = Above C8 = Above T1 T1 – Coccygeal = Below Cervical Cord = 1 above SP Thoracic = 2 above SP Lumbar = 4 above

COVER THIS ELSEWHERE!!! Grey Matter White Matter Pia Mater Arachnoid Mater (nt attatched to Dura) Dura Mater DENTICULATE LIGAMENT

Lesion Through Cord Motor innervation: Partial lesion- Normally via 2 or more segments of motor neurones, so may WEAKEN but unlikely to paralyse Problem is – WHITE MATTER

Factors affecting the severity of a spinal lesion Loss of neural tissue - obvious Vertical level – Higher up, the greater the damage Transverse plane – What Diameter has a lesion

Transverse Plane Descending tracts Ascending tracts

Remember Where is it coming from (Up or Down) Where does it synapse Where does it cross over How many Synapses

Lateral corticospinal tract MOTOR UP –DOWN Motor cortex Internal Capsule Pyramidal Decussation Lateral Corticospinal Synapse in ANTERIOR HORN?

Dorsal columns Touch and Proprioception Bottom Up Sensory Periphery – Dorsal Root Ganglion Ascending Dorsal Columns Synapse in Medulla Decussation in Medulla Synapse in Thalamus Projection to Sensory Cortex

Central pathway [touch & proprioception] Fasciculus Gracilis (M) Fasciculus Cuneatus (L) Tirgeminal CROSS IN MEDULLA UMN – CONTRALATERAL LMN - IPSILATERAL

Gracile fasciculus Cuneate fasciculus Gracile nucleus Cuneate nucleus Medial lemniscus

Spinothalamic tract Sensory DOWN –UP LIMB – DRG – SYNAPSE IN DORSAL HORN CROSSES@ or near ENTRY ASCENDING SPINOTHALAMIC SYNAPSE in THALAMUS Project onto Cortex

Central pathway [pain & temperature] SLTC TRIGEMINAL UMN – Contralateral LMN - CONTRALATERAL

SPINAL TRAUMA NERVE ROOT: Herniated Disk/ Spondylosis Cervical & Lumbar Pain Paraesthesia Weakness & muscle wasting Reduced Sensation Loss of Reflexes

Upper Cervical Cord Lesion Is effectively an UMN lesion Spastic Quadriplegia Hyperreflexia Extensor Plantars (upgoing) Sesnory Loss below lesion Sensory ataxia (un coordinated)

Lower Cervical Cord Lesion Is effectively a LMN lesion Weakness, wasting, fasciculation of muscles in upper limbs And UMN lesion: in LOWER LIMBS Spastic Paraparesis Hyperreflexia & Ext.Plantar Extensor Plantars (upgoing) Sesnory Loss below lesion Sensory ataxia (un coordinated)

Thoracic Cord Lesion LOWER LIMBS Spastic paraparesis Hyperreflexia Extensor Plantar responses Incontinence Sensory loss below lesion Sensory Ataxia

Lumbar Cord Lesion Weakness, wasting and fasciculations of muscles Areflexia of lower limbs Sensory loss Ataxia

FRACTURE Basics GO look at your lecture - it is good Learn what is on there…… it’s better than mine Quick run through

Priority 1 – Save a life Priority 2 – Save the Spine

Spinal Trauma - Initially If spinal trauma indicated then…. ASSUME IT- until excluded Gunshot – Head= dnt immobilise Stab – dnt immobilise

Pre- hospital ACHIEVE ALIGNMENT Conscious – Active Unconscious – Passive—but be careful Long Spinal board

Multiple Injuries Immobilise the WHOLE spine PAD and STRAP Head Shoulders Pelvis

In Hospital Off board – Onto firm trolley Log roll ABC DEFG now more relevant REMEMBER: Spinal immobilisation is a priority in multiple trauma, spinal clearance is not. TREAT THE TRAUMA, then worry about the spine

Spinal Clearance Asymptomatic injury – possible but VERY unlikely to be serious Can’t clear in the field – normally radiology Clinical clearance: Fully alert and orientated No head injury No drugs or alcohol No neck pain No abnormal neurology No significant other 'distracting' injury (another injury which may 'distract' the patient from complaining about a possible spinal injury).

Radiology Lateral: C7-T1 junction Alignment: Posterior more significant than ant. A translation of > 3.5mm is significant anywhere. Spinal canal diameter- >18mm Anterior subluxation of one vertebra on another indicates facet dislocation. Examination of the vertebral bodies and the intervertebral disc space Compression and burst type injuries Bodies should be regular cuboids similar in size and shape to the vertebrae immediately above and below (not C1/C2). Compression fractures may present as anterior wedging of the vertebral body or teardrop fractures of the antero-inferior portion of the body (compression in flexion).

AP - spinous processes of C2 to T1. The open-mouth view should visualise the lateral masses of C1 and the entire odontoid peg.

Additionally CT scan if required Soft Tissue injury – image appropriately ? MRI

Unconscious, Intubated Patients The odontoid view is unreliable in intubated patients. Clinical examination is impossible in the unconscious patient. Plain film radiology cannot exclude ligamentous instability. Watch/MRI/CT/Fluroscopy

Thoracolumbar spine Indicated if there is pain, bruising, swelling, deformity or abnormal neurology attributable to the thoracic or lumbar spinal regions. The presence of a fracture anywhere in the spine mandates full spinal imaging. Unconscious patients who cannot be assessed clinically also require radiological clearance of the whole spine.

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The spine & spinal cord

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