Spinal Anatomy Flashcards
Number of SC segments
31
Number of cervical nerves
8
Origin of C1
Between occipital bone and atlas
Number of thoracic nerves
12, the first emerges below the first thoracic vertebra
Number of lumbar nerves
5
Number of sacral nerves
5
Number of coccygeal nerves
1
Borders of the anterior spinal column
Anterior median fissure
Anterolateral sulcus
Borders of the lateral spinal column
Anterolateral sulcus
Posterolateral suclus
What do the anterolateral and posterolateral sulci represent?
Point of entry for the ventrally located (motor) and dorsal (sensory) nerve roots
Borders of the posterior spinal column
Posterolateral sulcus
Posterior median fissure
What happens to the posterior spinal column above the level of T6?
Further divided into two tracts by the posterior intermediate sulcus
The medial fasciculus gracile and the more lateral fasciculus cuneatus
What structures fix the SC in place
Rostrally it is continuous with the brainstem
Laterally the spinal nerves exiting the vertebral foramina
Two attachments of dura mater
Dentate ligaments which are located between ventral and dorsal spinal roots and are extensions of the pia and arachnoid mater
What are the two attachments of the spinal dura mater?
Caudally as the filum terminalis with the coccyx and sacrum
Rostrally with the periosteum of the skull.
Rexed lamina I
Posteriomarginal nucleus
Rexed lamina II
Substantia gelatinosa
Rexed III + IV
Nucleus proprius
Function of Rexed lamina I-IV
Exteroreceptive sensations
Rexed lamina V
Neck of posterior horn
Rexed lamina VI
Base of posterior horn
Function of Rexed lamina V+VI
Proprioceptive sensations
Divisions of Rexed lamina VII
Medial
Two lateral
Medial division of Rexed lamina VII
Thoracic nucleus
Lateral divisions of Rexed lamina VII
Intermediomedial zone
Intermediolateral zone
Function of medial nucleus of Rexed VII
From C8-L3 receive information from muscle spindles and golgi tendon organ
Function of intermediomedial zone?
Gamma motor neurones involved in motor reflexes
Function of intermediolateral zone
Motor visceral function
Thoracolumbar sympathetic outflow
Caudal parasympathetic outflow
Rexed VIII
Commissural nucleus
Function of Rexed VIII
Regulates skeletal muscle contraction
Rexed IX
Ventral horn
Main motor area composed of alpha neurones
Rexed X
Grisea centralis
Function of Rexed X
Contains nuclei from autonomic system
Def: myotome
A group of muscles that is innervated by a single spinal nerve
Def: dermatome
Area of skin that receives sensory innervation from a single spinal nerve
Formation of spinal nerve
Dorsal nerve root (afferent), cell body in the DRG, fibres enter through dorsal suclus
Ventral nerve root (efferent) originate in cell bodies of ventral gray horn.
Unite to forma. spinal nerve and exit through corresponding intervertebral foramen.
After exiting from foramen, it divides into dorsal and ventral rami.
Dorsal rami-> skin on dorsal aspect of trunk and longitudinal muscles
VEntral rami_> motor and sesnory innervation to limbs and nonaxial skeleton.
Ventral ramus also communicates with sympathetic chain via white and gray rami communicantes
C1-4 nerve roots
Supply innervation to muscles and skin of neck and head
Contribute to diaphragm
Difficult to evaluate muscles so sensory distribution is the most effective
C2 landmarks
1cm lateral to the occipital protruberance or a point at least 3cm behind the ear
C3 landmark
Supraclavicular fossa MCL
C4 landmark
ACJ
C5 nerve root
Motor:
Deltoid (C5- axillary)- abduction
Biceps (C5,6- musculocutaneous nerve)- elbow flexion
Sensory:
Lateral aspect of arm (axillary nerve)
Reflex:
Biceps (C5.6)
How to assess integrity of C5
Motor:
Shoulder abduction
Elbow flexion
Sensory:
Regimental patch
Reflex:
Biceps
Motor:
Shoulder abduction
Elbow flexion
Sensory:
Regimental patch
Reflex:
Biceps
C5
How to assess integrity of C6
Motor:
Biceps (C5,6- musculocutaenous)
Wrist extension (C6,7- ulnar). Weakness in wrist extension due to isolated C6 compromise results in ulnar deviation
Sesnory:
Lateral forearm, thumb, index finger and one half of middle finger
Reflex:
Biceps (C5,6)
Brachioradials C6
Motor:
Biceps
Wrist extension
Sensory:
Lateral forearm, thumb, index finger and one half of middle finger
Reflex:
Biceps
Brachioradialis
C6
What is the best reflex to test C6 nerve root?
Brachioradialis
How to assess the integrity of C76 lesions
Motor:
Elbow extensors (radial)
Wrist flexors (median, ulnar), with C7 lesion wrist flexion results in ulnar deviation
Finger extensors
Sensory:
Middle finger, though it can also receive supply from C6 or 8
Reflex:
Triceps
Motor:
Elbow extensors (radial)
Wrist flexors (median, ulnar)
Finger extensors
Sensory:
Middle finger
Reflex:
Triceps
C7
How to assess the integrity of C8
Motor:
Finger flexion
Sensory:
Little finger
Reflex:
None
Motor:
Finger flexion
Sensory:
Little finger
Reflex:
None
C8
How to assess integrity of T1
Motor:
Finger abduction (T1, ulnar)
Finger adduction (C8,T1, ulnar)
Sensory:
Upper half of medial forearm and medial portion of arm
Motor:
Finger abduction
Finger adduction
Sensory:
Upper half of medial forearm and medial portion of arm
T1
Beevor’s sign
Present when the umbilicus of a patient is drawn up or down or to one side or the other when the patient is quarter way through a sit up
Indicates asymmetric weakness of the abdominal muscles
T4
Nipples
T6
Xiphoid process
T10
Umbilicus
T12
Inguinal ligament
How to assess the integrity of L1-3
Motor:
No specific muscle groups
Ilipsoas (L1-3)
Quadriceps (L-4)
Adductor L2-4
Sensory:
L1- oblique band just below the IL
L3- oblique band just above knee
L2- oblique band between L1 and L3
Motor:
No specific muscle groups
Ilipsoas
Quadriceps
Adductor
Sensory:
Oblique band just below the IL
Oblique band just above knee
Oblique band between L1 and L3
L1-3
How to assess integrity of L4
Motor:
Dorsiflexion and foot inversion (tibialis anterior, deep peroneal nerve)
Sensory:
Medial side of leg below the knee
Reflex:
Patellar (L2,3,4)
Motor:
Dorsiflexion and foot inversion (tibialis anterior, deep peroneal nerve)
Sensory:
Medial side of leg below the knee
Reflex:
Patellar
L4
Explain how to differentiate between L4 radiculopathy and peroneal nerve lesion
In peroneal nerve lesion, foot inversion is preserved as the peroneal nerve does not supply the foot inverter (tibialis posterior, tibial nerve) which is supplied by L4
https://www.youtube.com/watch?v=fJo0rERyBJM&feature=emb_title
How to assess for the integrity of L5
Motor:
EHL and extensor digitorum (deep peroneal nerve)- toe extension
Gluteus medius (SGN)- abduction of the hip
Reflex:
None
Sensory;
First dorsal webspace
How to differentiate between an L5 and deep peroneal nerve lesion
In an L5 lesion there will may also be loss of hip abduction (gluteus medius, SGN)
Motor:
Toe extension
Hip abduction
Reflex:
None
Sensory;
First dorsal webspace
L5 nerve root
How to assess integrity of S1
Motor:
Peroneus longus and brevis (superficial peroneal nerve)- ankle eversion
Gastrocnemius (S1/2, tibial nerve)- Ankle plantarflexors
Gluteus maximus (S1, IGN)- hip extensor
Reflex:
Achilles
Sensory:
Lateral aspect and part of plantar aspect of foot
Motor:
Peroneus longus and brevis (superficial peroneal nerve)- ankle eversion
Gastrocnemius (S1/2, tibial nerve)- Ankle plantarflexors
Gluteus maximus (S1, IGN)- hip extensor
Reflex:
Achilles
Sensory:
Lateral aspect and part of plantar aspect of foot
How to assess integrity of S1
How to assess integrity of S2-4
Motor;
Intrinsic muscles of foot- not testable
Anal sphincter
Sensory:
Skin surrounding anus
Reflex:
Anal wink
Unilateral
Neck and arm pain in distribution of single nerve root
Paraesthesia
Weakness may develop with association atrophy and fasciculations.
Hyporeflexia
?Cervical disk causing radiculopathy
Relationship between cervical disc and nerve roots
Typically impingement occurs in the spinal canal at the level of the disk space proximal to the the nerve’s exit point from the spinal canal
First exits between occiput and C1, second between C1 and 2
Eighth between C7 and T1
Herniated C3-4 disc impinges on
C4 nerve
Posterior neck and suboccipital pain sometimes affecting the ear
No motor deficit
?C3 radiculopathy
Paraspinous pain extending from root of the neck to mid-shoulder and posteriorly to level of scapula
May be aggravated by neck extension
Rarely, numbness
No motor deficit
?C4 radiculopathy
Shoulder pain to midpoint of lateral upper arm
No pain on manual rotation of shoulder
Deltoid weakness
+/- biceps hypreflexia
C5 radiculopathy
Most common cervical disc herniation
C6/7
Then C5/6
Pain and paraesthesia radiating from neck to lateral aspect of forearm and hand
Weakness of wrist extension and elbow flexion
Numbness involving lateral forearm and first and second digits
Brachioradialis reflex and biceps reduced
C6 radiculopathy
Pain and paraesthesia radiating across back of shoulder through triceps and posterolateral forearm into middle finger
Weakness in elbow extension, wrist flexion and finger extension
Reduced or absent triceps reflex
C7 radiculopathy
Pain involving little and ring finger, medial aspect of forearm
Weakness in finger flexion causing loss of grip strength or other fine motor activities
C8 radiculopathy
Uncinate process
Ridge of bone extending from superior lateral aspect of each cervical vertebra
Stabilises the spine and forms inferior medial wall of neural formanina
Enlargement can cause radiculopathy
Symptoms may be aggravated by neck extension
What clinical features differentiate cervical disc disease from spondylosis?
More than one cervical segment may be affected
Chronic and episodic in spondylosis rather than acute in cervical disc disease, thus more commonly associated with muscle atrophy and fasciculations
Features of thoracic disc disease
No typical clinical syndrome
Radicular pain may predominate in cases where there is lateral disc protrusion
Can cause cardiac like pain across the chest wall which does not cross the midline.
Can be confused for cardiac or GI disease
Acute persistent unilateral monoradiculopathy
Aggravated by sitting, sneezing or coughing, relieved by standing or bed rest
SLR positive
Motor/sensory deficit
L5/S1 distribution typically
?Lumbar disc disease
Paracentral disk herniation involves which nerve root
To the vertebra below the herniated disc
L4-5 paracentral disc contacts the L5 nerve root
Far lateral lumbar disc herniation affects which nerve root
Affects the exiting nerve root
i.e. L4/5 disc affects the L4 nerve
Chronic intermittent bilatearl posterior leg pain
Typically beginning in the buttocks and radiating downward in a non-radicular distribution, often burning, cramping or heavy feeling
Frequently associated with numbness or paraesrthesias
Pain precipitated by prolonged standing or walking (spinal extension) and relieved by forward bending, stiting or bed rest (flexion)
Reduced walking distances
Minimal or no back pain and motor or sphincteric dysfunction are late and inconsistent findings.
Negative SLR
Lumbar canal stenosis
Borders of lumbar lateral recess
Ventrally by posterior vertebral body
Laterally by pedicle
Dorsally by superior articular facet
Bilateral radicular pain associated with numbness and paraesthesias with mild or no low back pain
Tends to be worse on standing or walking
SLR negative
Neurologic findings are usually minimal though patients tend to have weakness or atrophy more often than those with central stenosis
Lateral recess stenosis
Mechanical low back pain aggravated by activity and improved with rest
May also produce radicular symptoms by traction or compression
Uncommon neurologic findings
Spondylolisthesis
Causes of spondylolisthesis
Degenerative
Isthmic
Traumatic
Dysplastic
Degenerative sponylolisthesis most commonly occrus
At L4/5
Traumatic and dysplastic spondylolisthesis most commonly involves which level
L5/S1
Def: Arachnoiditis
Chronic inflammatory condition affecting the meninges which occurs commonly at the lumbar spine
Can be secondary to surgery, myelography or introduction of other agents
Usually present with back pain and radicular leg pain
Aggravated by activity and not relieved by rest. Can be unilateral or bilateral symptoms.
Trauma
Radicular type pain with severe upper limb motor and sensory loss in a radicular distribution
Can be masked by associated brachial plexus injury
Cervical nerve root avulsion
Characteristic electrophysiological findings of nerve root avulsion
EMG and NCV used to differentiate from brachial plexus injury
Severe reduction or absence in compound motor action potentions, increase in pathological fibrillation potentials, completely normal sensory nerve action potentials
Why are there preserved SNAPs in cervical nerve root avulsion
Sensory root avulsion occurs proximal to DRG
Acute viral infection involving anterior horn cells
Presenting with myotomal weakness
Variable patterns of weakness- young children commonly have lower limb weakness, adults quadrapaaresis
?Polio
Why is isolated foot drop a relatively common finding in polio patients
Presence and extent of redundant innervation of a partiacular muscle e.g. quadriceps L2-4 is relatively spared whereas tibialis anterior L4 which is a single nerve root may present with more severe form of weakness
Why is complete resection of neurofibroma more difficult than Schwannoma
Nerve fibres are typically transversing the tumour whereas an schwannoma they are splayed over the fcapsule
Ascending weakness with lower extremities involved earlier.
Proximal and distal limb muscles equaly involved
Pain and myalgia
Progress to respiratory failiure
Autonomic dysregulation
GBS
T2DM
Painful paraesthesia of feet
Weakness atrophy typically of femoral or sciatic nervesS
Skin ulcers and loss of achilles reflex
Autonomic symptoms e.g. bladder dysfunction and hypotension
?Diabetic radiculopathy
Filum terminale
Caudal prolongation of the spinal pia mater that terminates on the dorsal surface of the coccyx
What are the main cell group of the dorsal horn
4:
Posteromarginal nucleus
Substantia gelatinosa
Nucleus proprious
Nucleus dosralis
Posteromarginal nucleus
Forms the cap of the dorsal horn
Many of the axons of the cells in this nucleus contribute to the spinothalamic tract
Substantia gelatinosa
Occupies most of the apex of the dorsal horn
Contains neurones and their processes as well as afferent fibres from te dirsal nerve eoot and descending fibres from supraspinal levels
Nucleus proprios
Anterior to substantia gelatinosa
Axons carried in the spinothalamic, spinocerebellar and propriospinal system
Nucleus dorsalis
Clark’es colum
Present in the base of the dorsal horn in segments C8-L3
Contains cell bodes whose axons form the dorsal spinocerebellar tract
Two cell groups of the intermediate gray
Intermediolateral cell group
Intermediomedial cell group
Intermediolateral cell group
Forms the lateral horn in segments T1-L2, gives rise to preganglionic sympathetic fibres
In segments S2-4 an equivalent column of cells projects preganglionic parasympathetic fibres
Intermediomedial cell group
Lies lateral to central canal throughout the length of the spinal cord
Receives visceral afferent fibres from the dorsal roots
Arrangement of fibres in the ventral horn
Somatotopically orientated in two ways
Neurones that innervate flexors are dorsal to extensors
Those that innervate te hand are lateral to the trunk
What are the two groups of neurones in the ventral horn
Medial group- axial musculature
Lateral- present only in cervical and lumbosacral enlargements- limb muscles
Lamina I II and V
Important in transmisison of information about pain
Lamina VII
Contains nucleus odrsalis, intermediolateral cell columna nd sacral autonomic nucleus
Lamina IX
Contains motor neurones that innervate extremities
In addition the phrenic nucleus, spinal accessory nucleus and Onuf’s nucleus (spincteric control)
Divisions of white matter in spinal cord
Ventral, lateral and dorsal funiculi
Which contain ascending and descending fibre bundles that transmit signals within the SC and brain
What are the asending tracts of the dorsal funiculi?
Fasciculus gracilisi
Fasciculus cuneatus
Mediate proprioception, vibration and discriminative touch
At what level does the fasciculus cuneatus begin?
T6, below this there is only gracilis
Somatotopic arrangement of the dorsal column
Legs are medial (gracilis), arms laterally (cuneatus)
GC
What are the ascending tracts of the lateral funiculi
Posterior spinocerebellar tract
Anterior spinocerebellar tract
Lateral spinothalamic tract
Spinotectal tract
Posterolateral tract
Spinoreticular tract
Spino-olivary tract
Anterior spinothalamic tract
Located anteromedial to the lateral spinothalamic tract, involved in light touch and pressure sensation
Posterior spinocerebellar tract
Lateral funiculi
Occupies posterior part of the periphery
Conveys position, sense, touch and pressure to the cerebellum.
It ascends uncrossed in the spinal cord
Anterior spinocerebellar tract
Lateral funiculi
Anterior part of the periphery
Majority of fibres are crossed
Lateral spinothalmic stract
Lateral funiculi
Main ascending nerve mediating pain and temperature organisation
Somatotopically organised- arms central, legs laterally
Crossed in the spinal cord
Spinotectal tract
Closely associated with the lateral and anterior spinothalamic tract
Conveys information to the superior colliculus
Unknown functional significance
Posterolateral tract
Lateral funiculus
AKA Lissaue’rs tract
Caps the dorsal gray horn
Carries fibres from the dorsal nerve root and getaltinosa cells that interconnect different levels of the substantia gelatinosa.
Spinoreticular tract
Lateral funiculus
Travels in association with lateral spinothalamic tract
Conveys information related to behavioural awareness
Spino-olivary tract
Lateral funiculus
Lies anterior to the anterior spinocerebellar tract, conveys sesnosry information to the cerebellum
What are the descending tracts of the ventral funciuli
Anterior corticospinal tract
Vestibulospinal tract
Tectospinal tract
Scattered reticulospinal fibres
What are the descending tracts in the lateral funiculi
Lateral corticospinal tract
Rubrospinal tract
Descending autonomic fibres
Reticulospinal fibres
Anterior corticospinal tract
Ventral funiculi
Present only in cervical and upper thoracic segments
Lies adjacent to the median fissure
Voluntary movement
Vestibulospinal tract
Descending tract, ventral funiculi
Occupies periphery of anterior funiculi
Descends uncrossed in the spinal cord
Facilitates extensor tone of muscles and maintains tone in antigravity muscles
Tectospinal tract
Between anterior corticospinal tract and vestibulospinal tract
Cross in the dorsal segmentation and are only present in the cervical levlels.
Thought to be involved in reflex postural movements in response to visual/auditory stimuli
Lateral corticospinal tract
Lateral funiculi
Lateral to dorsal gray horn and medial to spinocerebellar tract
Mediates impulses concerned with voluntary movement, particularly fine motore movement
Somatotopic orientation, medial arms, lateral legs.
Rubrospinal tract
Lateral funiculi
Anterior to lateral corticospinal tract
Facilitates flexor muscle tone
Descending autonomic fibres
Lateral funiculi
Carry impulses associated with control of smooth muscle, cardiac muscle, glands and body visecera
Which regions of the spinal cord are distinguished by relative richness of arterial supply
Cervicothoracic C1-T2
Thoracolumbar T9-conus which receives radicular artery of Adamkiewicz
Most common location of entry for great radicular atery of Adamkiewicz
75% enters the SC at T9-L2 segment from the left
Quadriplegia
IMpaired bowel and bladder control
Loss of pain and temperature sensation
Sparing of proprioception
Anterior spinal artery syndrome
Anterior spinl artery syndrome
Quadriplegia (corticospinal tract)
IMpaired bowel and bladder control (corticospinal)
Loss of pain and temperature sensation (lateral spinothalamic)
Sparing of proprioception (preservation of dorsal column
What is the most common vascular syndrome of the SC/
Anterior spinal artery occlusion
Posterior spinal artery syndrome
Loss of poisition, vibratory and light touch sensation below level of lesion
Preservation of motor, pain and temperature modalities
Loss of poisition, vibratory and light touch sensation below level of lesion
Preservation of motor, pain and temperature modalities
Posterior spinal artery syndrome
Categorisation of spinal tumours
Extradural extramedullary tumours
Intradural extramedullary tumours
Intramedullary tumours
Clinical features of extramedullary tumours
Radicular pain
Tender to palpation
Loss of pain and temperature sensation
Spastic paraparesis
Little or no muscle atrophy
Muscle fasciculations common
Trophic skin disturbance absent
Bowel and bladder distrubance late
Spinal tumour- intra or extramedullary
Radicular pain
Tender to palpation
Loss of pain and temperature sensation
Spastic paraparesis
Little or no muscle atrophy
Muscle fasciculations common
Trophic skin disturbance absent
Bowel and bladder distrubance late
Extramedullary
Clinical features of intramedullary tumours
Dysesthesia and paraesthesia common
Dissociated sensory loss with sacral sparing
Paraparesis is only spastic in 50%
Muscle atrophy common
Muscle fasciculations rare
Trophic skin disturbance common
Bowel and bladder distrubance early
Respiratory disturbance and spinal cord
C3-5 lesions may involve phrenic nucleus resulting in diaphragmatic paralysis-> respiratory compromise
Cardiovascular disturbance and spinal cord
Upper cervial SC lesions may be associated with bradycardia due to nterruprtion of ascendin fibres to the medulla with hypotension 2o to descending sympathetic disruption
Describe passage of sympathetic fibres
Originate in hypothalamus-> intermediolateral gray matter of the C8-T2 spinal segments (1o)
Subsequent fibres are projected to the superior cervical ganglion (2o)
Finally from superior cervical ganglion to the superior tarsal, dilator pupillae and swet glands of face
Horner’s
Partial ptosis (denervation of superior tarsal muscle)
Enophthalmos
Miosis (denervation of dilator pupillae)
Anhydrosis (denervation of sweat glands of face)
What are the muscle groups mediating bladder function
Detrusor muscle
External sphincter
Detrusor muscle
Spiral, longitudinal and circular smooth musle bundles that surround the body of the bladder wall.
Contraction results in micturition
EUS
Skeletal muscle bundle that occurs on the distal segment of the urethra
Reflexive relaxation is coordinated with contraction of detrusor muscle during icturition.
VOluntary contaction stops micturition
IUS
Extnesion of detrusor that consists of longitudinal muscles which incompletely surround the proximal urethra
Limited role in micturition, primary function is to prevent retrograde ejaculation
Main innervation of bladder
PNS
Cerebrospinopudendal pathway (voluntary control of EUS)
Sensory afferents carried in pelvic splanchnic and pudendal nerves which ascend in the lateral spinothalamic and dosral column tracts, relay in the reticular formation and terminate in the paracetntral lobule of the frontal lobe
Paracentral lobule in turn exerts voluntary control on the EUS via corticospinal efferents
SNS
What are the 5 syndromes of bladder disturbance
Uninhibited bladder
Reflex bladder
Autonomous bladder
Motor paralytic bladder
Sensory paralytic bladder
Uninhibited bladder
Interruption of supraspinal control
Disorder charactersised by susdden uncontrollable evaucation of urine due to a lack of supraspinal inhibition
Normal bladder tone
Normal bladder capacity
Micturition occurs precipitously at low bladder volumes (detrusor hyperreflexia)
Usually complete micturition with no residual
Intact bladder sensation
Frontal lobe tumours, parasagittal meningiomas, ACA aneurysms, NPH
Normal bladder tone
Normal bladder capacity
Micturition occurs precipitously at low bladder volumes (detrusor hyperreflexia)
Usually complete micturition with no residual
Intact bladder sensation
Uninhibited bladder
Distruption of suprapsinal control e.g. NPH
Reflex bladder
In spinal cord lesions above the S1 segment, bladder function is mediated solely by a reflex arc
Increased bladder tone
Reduced bladder capacity
If incomplete lesion, there is urgency with little filling though urgency absence if lesion complete, in which case a rise in intravesical pressure may be manifest by pallor, flexor spasms, hypertension (autonomic dysreflexia)
Retention-> overflow incontinence-> Automaticity
Small post-void residual
Interrupted bladder sensation
e.g. MS, SCI, tumour
Increased bladder tone
Reduced bladder capacity
Retention-> overflow incontinence-> Automaticity
Small post-void residual
Interrupted bladder sensation
Reflex bladder
Lesion above S1
e.g. SCI
Autonomous bladder
In lesions involving sacral level there is denervation of both afferent and efferent supply to bladder
Overflow incontinence
Flaccid tone
Absen t urgency
Increased capacity
Increaesd PVR
Absent sensation
High risk of infection
e.g. CES
Overflow incontinence
Flaccid tone
Absen t urgency
Increased capacity
Increased PVR
Absent sensation
High risk of infection
e.g. CES
Autonomous bladder
In lesions involving sacral level there is denervation of both afferent and efferent supply to bladder
Motor paralytic bladder
Lesions involving efferent motor fibres to detrusor in the sacral spinal cord
Produce a paralysed bladder with intact sensation
Flaccid bladder tone
Urgency present
Painful urinary retention or impaired emptying
Increased bladder capacity and PVR
Infection risk high
Produce a paralysed bladder with intact sensation
Flaccid bladder tone
Urgency present
Painful urinary retention or impaired emptying
Increased bladder capacity and PVR
Infection risk high
Motor paralytic bladder
Sensory paralytic bladder
With lesions involving afferent pathways, voluntary micturition is possible but bladder sensation is impaired.
Urinary retention or overflow incontinence results.
Infection risk is high
E.g. tabes dosralis, DM
Innervation of rectum
PNS- S3-5 responsible for reciprocal contaction of rectal muscles and relaxation of IAS.
Afferent fibres also carried in PNS
SNS inhibits rectal emptying
Voluntary control is via somatic efferents from the paracetnral lobule which descend in the corticospinal tract. Synapse on ventral horn cells in segments T6-12 which in turn innervate abdominal muscles used in emptying rectum
Anatomical disturbances of rectal function
Lesions above sacral level
Conus and cauda lesions
Rectal dysfunction
Lesions above sacral level
Loss of voluntary control and loss of sensation of rectal fullness
Faecal retention
Reflexive contraction of the sphincter usually persists causing sphincter spasticity.
High spinal lesions tend to produce less severe sphincter dysfunction compared with lower level lesions
Rectal dysfunction
Conus and cauda lesions
Lesions involving S3-4 produce sphincter muscle paralysis-> incontinence
Describe the innervation of erection
PNS
Supplies corpus cavernosum via pelvic splanchnic nerves
Consequence of complete lesion of S2-4 on erection
Complete lesion resultsin loss of reflex erection though psychogenic erection may still be possible.
This is due to hypothalamic impulses that are partially sympathetically mediated.
Psychogenic erections are abolished by lesions above T12
Consequence of spinal lesion above T12 on erection
Loss of psychogenic erection (sympathetically mediated)
Refelex erection preserved
Describe the biomechanics of erection
PNS facilitates erections by causing relaxation of the muscular cushions within the lumina of the cavernosus arteries, which nor ally obstruct the inflow of blood
How do spinal cord lesions cause pripaism
Abnormal persistent erection thought to be due to PNS induced vasodilation and is seen in lesions that occur above the lower thoracic levels.
Tonic contraction of the transverse perineal, bulbocavernousus and ischiocavernosus muscles probably also contribute by preventing escape of venous blood
Describe the reflex arc of ejaculation
Two part process- propulsion of semen into urethra (emission) and ejaculation proper
Afferent limb- dorsal nerve of penis to the S3-4 segments via pudendal nerve
Efferent from S3-4 -> 2 spinal centres, the sympathetic centre (T6-L3) which projects efferenet fibres in the pelvic plexus and the superior hypogastric plexus. Sympathetic ganglion at L2 is particularly important in this.
The second is the somatomotor centre that projects its efferent fibres in the pudendal nerve.
Impact of spinal lesions on ejaculation
Lesions abve T6 may abolish normal ejaculation though ejaculatory reflex activity may be preserved
In lesions involving S3-5, ejaculation does not occur
Pattern of weaknss with foramen magnum lesions
Suboccipital neck pain
Dysaesthesia of the extremities (UE>LE)
Gait disturbance
Weakness (UE>LE)
Weakness may involve arm, then the ipsilateral leg, then contralateral leg “around the clock” pattern
Other early symptoms- clumsiness of the hands, bladder disturbance, dysphagia, nausea and vomiting, drop attacks, dizziness.
Wasting of intrinsic hand muscles
Downbeat nystagmus
Suboccipital neck pain
Dysaesthesia of the extremities (UE>LE)
Gait disturbance
Weakness (UE>LE)
Weakness may involve arm, then the ipsilateral leg, then contralateral leg “around the clock” pattern
Other early symptoms- clumsiness of the hands, bladder disturbance, dysphagia, nausea and vomiting, drop attacks, dizziness.
Wasting of intrinsic hand muscles
Downbeat nystagmus
Foramen magnum lesion
Round the clock weakness
Foramen magnum
What may cause wasting of intrinsic hand mucles in foramen magnum lesions
?Venous obstruction in upper SC that leads to venous infarction in lower cervical gray matter
C3 lesion
Motor-
Quadriplegia
Sensory:
Abolished below base of neck
Reflexes:
In acute phase all absent then they may return and become hyperreflexic
Respiratory failure
Motor-
Quadriplegia
Sensory:
Abolished below the base of neck
Reflexes:
In acute phase all absent then they may return and become hyperreflexic
Respiratory failure
C3 lesion
C4 lesion
Motor-
Quadriplegia
Sensory:
Present in upper anterior chest wall
Reflexes:
In acute phase all absent then they may return and become hyperreflexic
Respiratory function may be partially preserved, though paralysis of the intercostal muscles and abdominal muscles hampers spontaneous respiration
Motor-
Quadriplegia
Sensory:
Present in upper anterior chest wall
Reflexes:
In acute phase all absent then they may return and become hyperreflexic
Respiratory function may be partially preserved, though paralysis of the intercostal muscles and abdominal muscles hampers spontaneous respiration
C4 lesion
C5 lesion
Motor:
Preserved shoulder abduction, may be some flexion of elbow
Sensory:
Preserved in upper anterior chest and lateral aspect of arm above the elbow
Reflexes:
Biceps is normal or slightly decreased
Repsiratory reserve is compromised
Motor:
Preserved shoulder abduction, may be some flexion of elbow
Sensory:
Preserved in upper anterior chest and lateral aspect of arm above the elbow
Reflexes:
Biceps is normal or slightly decreased
Repsiratory reserve is compromised
C5 lesion
C6 lesion
Motor:
Shoulder abduction, elbow flexion, wrist extension present
Sensory:
Normal in the lateral UE including thumb, index finger and half of middle finger
Reflexes:
Biceps and brachioradialis normal
Respiratory reserve is low
Motor:
Shoulder abduciton, elbow flexion, wrist extension present
Sensory:
Normal in the lateral UE including thumb, index finger and half of middle finger
Reflexes:
Biceps and brachioradialis normal
Respiratory reserve is low
C6 lesion
C7 lesion
Motor:
Triceps, wrist flexors, long finger extensors functional
Sensation:
Preserved in lateral aspect of UE
Reflexes:
Biceps, BR, triceps are normal
Respiratory reserve is low
Motor:
Triceps, wrist flexors, long finger extensors functional
Sensation:
Preserved in lateral aspect of UE
Reflexes:
Biceps, BR, triceps are normal
Respiratory reserve is low
C7 lesion
C8 lesion
Motor:
UE motor function normal except finger abduction
Sensory:
Preserved up to medial forearm
Reflexes:
Normal in UE
Motor:
UE motor function normal except finger abduction
Sensory:
Preserved up to medial forearm
Reflexes:
Normal in UE
C8 (C8 spared)
T1 lesion
Motor:
UE normal, patient paraplegic
Reflexes:
Normal in UE
Sensory:
Normal in the upper anterior chest and entire upper extremity except for the medial aspect of the most proximal part of the arm
Motor:
UE normal, patient paraplegic
Reflexes:
Normal in UE
Sensory:
Normal in the upper anterior chest and entire upper extremity except for the medial aspect of the most proximal part of the arm
T1 lesion (T1 spared)
T2-T12 spinal levels
Motor:
Paraplegic, Beevor’s sign which is present when the umbilicus is pulled away from its normal location as te patient sits up
Sensory:
Level of the lesion determines the level of intact sensation
Reflex:
UE refelexes normal, LE may be absent or hyper-reflexic
Motor:
Paraplegic, Beevor’s sign which is present when the umbilicus is pulled away from its normal location as te patient sits up
Sensory:
Level of the lesion determines the level of intact sensation
Reflex:
UE refelexes normal, LE may be absent or hyper-reflexic
T12 lesion
L1 lesion
Motor:
Paraplegic excpet for some hip flexion due to partial innervation of ilipsoas
Sensation:
Present on the most proximal portion of anterior thigh
Reflex:
Patella and ankle reflexes absent initially, later they may become increased
Bowel and bladder:
Bladder function absent
Anal sphincter tone decreased with absence of superifical anal reflex
With time anal tone returns
Motor:
Paraplegic excpet for some hip flexion due to partial innervation of ilipsoas
Sensation:
Present on the most proximal portion of anterior thigh
Reflex:
Patella and ankle reflexes absent initially, later they may become increased
Bowel and bladder:
Bladder function absent
Anal sphincter tone decreased with absence of superifical anal reflex
With time anal tone returns
L1 lesion
L2 lesions
Motor:
Hip flexion present though diminished
Adductors partially funcional
Flexion and adduction deformity may be present
Sensory:
Absent from point halfway between hip and knee
Reflexes:
None
Bowel and bladder:
Voluntary control is absent
Motor:
Hip flexion present though diminished
Adductors partially funcional
Flexion and adduction deformity may be present
Sensory:
Absent from point halfway between hip and knee
Reflexes:
None
Bowel and bladder:
Voluntary control is absent
L2
L3 lesion
Motor:
Iliopsoas, adductors and quadriceps all show signficiant power
Reflexes:
Patellar present, Achilles absent
Sensory:
Absent below the knee
Bladder/bowel:
No voluntary control
Motor:
Iliopsoas, adductors and quadriceps all show signficiant power
Reflexes:
Patellar present, ahilles absent
Sensory:
Absent below the knee
Bladder/bowel:
No voliuntary contorl
L3 lesions
L4 lesion
Motor:
Quadriceps normal, ankle dorsiflexion is the only functional muscle below the knee
Sensory:
Normal along the medial aspect of lower limb
Reflex:
Patellar present, achilles absent
Bowel and bladder:
Voluntary control still absent
L5 lesion
Motor:
Hip assumes flexed posture as gluteus maximus not functional, adduction resisted by partial innervation of the gluteus medius
Foot inversion and dorsiflexion present
EHL present
Sensation:
Normal except plantar aspects of foot
Reflexes:
Patellar normal, Achilles absent
Voluntary control of bowel and bladder is absent
Motor:
Hip assumes flexed posture as gluteus maximus not functional, adduction resisted by partial innervation of the gluteus medius
Foot inversion and dorsiflexion present
EHL present
Sensation:
Normal except plantar aspects of foot
Reflexes:
Patellar normal, Achilles absent
Voluntary control of bowel and bladder is absent
L5
Motor:
Quadriceps normal, ankle dorsiflexion is the only functional muscle below the knee
Sensory:
Normal along the medial aspect of lower limb
Reflex:
Patellar present, achilles absent
Bowel and bladder:
Voluntary control still absent
L4 lesion
S1 lesion
Motor:
Normal except intrinsic muscles of foot- toe defomrity
Reflexes
Normal in lower limb
Sensation in LE normal but saddle anaesthesia persists
Loss of normal bowel and bladder function
Motor:
Normal except intrinsic muscles of foot- toe defomrity
Reflexes
Normal in lower limb
Sensation in LE normal but saddle anaesthesia persists
Loss of normal bowel and bladder function
S1 lesion
Difference between conus and cauda lesions
Conus pain tends to occur late
Sphincter disturbance early
Saddle anaesthesia is symmetrical and motor disturbacnes in LE are absent
Conus medullaris syndrome
Autonomous bladder
Faecal incontinence
Impotence
Saddle anaesthesia
Absence of corticospinal tract or LE weakness
Autonomous bladder
Faecal incontinence
Impotence
Saddle anaesthesia
Absence of corticospinal tract or LE weakness
Conus medullaris
Radicular pain
Autonomous bladder
Impotence
Asymmetric saddle anaesthesia
Flaccid paraplegia
Absent deep tendon reflexes
CES
CES
Radicular pain
Autonomous bladder
Impotence
Asymmetric saddle anaesthesia
Flaccid paraplegia
Absent deep tendon reflexes
Four cardinal manifestations of SC lesiosn
Spastic para/quadriparesis
Bowel and bladder dysfunction
Sensory level
Features of UMN lesion
Def: sensory level
Dermatome below which no sensation is felt
What are the signs of sacral sparing
Flexion of S1 intact
Anal sphincter intact
Intact perianal sensation
Transverse myelopathy
Motor- LMN at level of lesion, UMN below
Sensory: sensory level
Why might the sensory level appear lower than the actual level of the lesion
In the lateral spinothalamic tract, lower spinal segments are represented more superficially
Clinical evidence of segmental pain or paraesthesias may identify lesion more precisely.
Autonomic signs seen in transverse myelopathy
Dependent on level;
Respiratory compromise
Hypotension, bradycardia
Horner syndrome
Bowerl or bladder impairment
Sexual dysfunction
Brown-Sequard Syndreome
Due to hemisection of the SC usually due to penetrating spinal injury
Ipsilateral loss of position and vibration sense below level of inury
Contralateral loss of temperature/pain sensation
Ipsilateral spastic parapareiss
+/- UMN signs at level of lesion
Ipsilateral loss of position and vibration sense below the level of injury
Contralateral loss of temperature/pain sensation
Ipsilateral spastic paraparesis
Brown-Sequard
Anterior SCI syndrome
Spastic quadraparesis
Loss of pain and temperature sensation below level of lesion
Preservation of position and vibration sense
Spastic quadraparesis
Loss of pain and temperature sensation below level of lesion
Preservation of position and vibration sense
Anterior SCI syndrome
Central cord syndrome
Weakness in UE>LE which is more severe distally than proximally
Explained by somatotopy of the CTS
Semsory loss is variable but tends to disproprotionally involve the UE.
Weakness in UE>LE which is more severe distally than proximally
Explained by somatotopy of the CTS
Semsory loss is variable but tends to disproprotionally involve the UE.
Central cord syndrome
Anterior horn cell syndrome
Selective destruction of anterior horn cells e.g. poliomyositis or progressive spinal muscular atrophy
Flaccid paralysis of muscles at the level with LMN signs
Intact sensation
Flaccid paralysis of muscles at the level with LMN signs
Intact sensation
Anterior horn cell syndrome
Central cord lesions
Suspended sensory level- decussating fibres of the spinothalamic tract which in cervical levels results in shawl distribution
Asymmetric involvement of centrally located fibres in the corticospinal tract may result in ipsilateral spastic monoparesis.
Flaccid paralysis at the level of the lesion may occur due to involvement of anterior horn cells.
Dorsal columns frequently spared
Suspended sensory level- decussating fibres of the spinothalamic tract which in cervical levels results in shawl distribution
Asymmetric involvement of centrally located fibres in the corticospinal tract may result in ipsilateral spastic monoparesis.
Flaccid paralysis at level of lesion may occur due to involvement of anterior horn cels.
Dorsal columns frequently spared
Central cord lesions
Amyotrophic lateral sclerosis
Degenration of lateral corticospinal tracts and anterior horn cells
Flaccid paralysis at level of lesion
Spastic paralysis below level of lesion
Tongue atrophy and weakness
Initially may be focal or unilateral but spreads to involve both sides +/- bulbar musculature
Flaccid paralysis at level of lesion
Spastic paralysis below level of lesion
Tongue atrophy and weakness
Initially may be focal or unilateral but spreads to involve both sides +/- bulbar musculature
ALS
What differentiates between ALS and cervical spondylotic myelopathy?
Cervical spondylotic myelopath may also have mixture of UMN and LMN signs but in ALS there is no sensory component
Tabes dorsalis
Neurological sequelae of neurosyphilis, typically developing 10-20y post infection
Selective destruction of dorsal columns
Loss of proprioception and vibration sensation below level- gait ataxia, Rombeg’s and reduced patellar and achilles tendon reflexes
Urinary incontinence
Lancinating pain in the LE
Clinical features of Friedreich’s ataxia
Degeneration in 3 tracts
Corticospinal, dorsal column and spinocerebellar
Loss of position and vibration sensation, Romberg’s sign
Ataxia
Spastic paraparesis
Pes cavus and spinal kyphosis may also be found
B12 deficiency
Loss of position and vibration sense
Spastic paraparesis
SACD
Lesion of the anterior horn of SC
Purely LMN
Purely LMN affecting ventral horn of SC, found in infants
Progressive infantile muscular atrophy (Werdnig-Hoffman disorder)
Juvenile hereditary LMN disease
Disease affecting ventral horns of SC
(Kugelburg Wilender disease)
Hereditary spastic paraplegia/diplegia
Hereditary lesion of UMN causing bilateral spastic paresis with UMN signs.
Where do pain and temperature first order afferents synapse in the spinal cord?
Ascend through dorsolateral tract of Lissauer to ascend or decsend one to three spinal levels from their level of entry and synapse in either:
substantia gelatinosa
posteromarginal nucleus
nucleus proprius
Spinal lemniscus
Lateral spinothalamic tract in the brainstem
Gives off collateral branches to the reticular formation at several levels of the brainstem
Somatotopy of lateral spinothalamic tract
Hand medial to legs and sacrum
Through which portion of the internal capsule do ascending thalamocortical fibres from VPL pass?
Posterior limb
What is unique about trigeminal proprioceptive fibres?
Cell bodies of axons carrying proprioceptive information are located within the brainstem (mesencephalic nucleus) rather than in a peripheral ganglion
Ventral trigeminothalamic tract
Carries crossed second-order spinothalamic input from spinal trigeminal nucleus to VPM of thalamus
Dorsal trigeminothalamic tract
Second-order crossed and uncrossed fibres from the main sensory nucleus ascend to the VPM of the thalamus
Astereognosis
Inability to identify common object when held in hand while eyes are closed
Agraphaesthesia
Inability to recognise letters or numbers drawn on the hand
What are the three tubercles on the TP of the lumbar spine
Lateral cosiform process
Superior mamillary process
Accessory process
Which muscle attaches to the mammillary process?
Multifidus
Intrinisc ligaments of the CCJ
Odontoid ligmaents:
Apical- dens to basion
Alar- dens to occipital condyls and bone bilaterally
Cruciform ligament:
Transverse ligament
Superior crus
INferior crus
Tectorial membrane
Tectorial ligament is a continuation of what/
PLL
Runs from C2 to anterior margin of FM
Extrinsic ligaments of the CCJ
Anterior atlanto-occipital ligament (continuation of ALL)
Posterior atlanto-occipital ligament (continuation of flavum)
Ligamentum nuchae (continuation of supraspinous)
Interspinous ligaments
Function of tectorial membrane
Stabilises Atlanto-axial joint
Restricts extension, flexion and vertical translation
Function of alar ligaments
Stabilises atlanto-axial joint
Limits excessive rotation, lateral flexion
Function of the transverse ligament
Stabilises atlantoaxial joint, limits anterior atlas motion
Allows axial rotation
Attachment point of transverse ligament
Colliculus atlantis
Rectus capitis anterior
Longus capitis
Borders of lateral recess
Anterior: Posterolateral suraface of vertebral body and PLL
Posteriorly: Superior articular facet and overlying ligamentum flavum
Laterally: Pedicle
