Download Neuro Anatomy

Neuro Anatomy
Cervical Spine
Spinal Nerves
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Spinal nerves emerge from dura mater as ventral (anterior) and dorsal (posterior) nerve roots
The ventral nerve root carries motor information away from the spine
The dorsal nerve root carries sensory information from the body to the spine
The dorsal root ganglion contains the cell bodies of the sensory neurons
The dorsal root ganglion is particularly sensitive and is often the cause of radicular pain
The two nerve roots then come together as they go through intervertebral foramen
They will then split into ventral and dorsal rami to become peripheral nerves
Dorsal rami supplies posterior back muscles
Ventral rami progress, forming a plexus supplying the rest of the body
Cervical Nerve Roots
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Although there are 7 cervical vertebrae there are 8 cervical nerve roots
The nerve exiting at C0-C1 is named the C1 Nerve root
Each nerve root is named in relation to the vertebrae below, i.e C4 nerve root is between C3-C4
The nerve root between C7- T1 is the C8 nerve root
From T1 down the nerve root is named by the vertebrae above
Brachial Plexus
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Formed by the ventral rami of the lower four cervical nerves and first thoracic nerve
Forms just outside the intervertebral foramen in between scalenus anterior and medius
Collectively named the roots of the plexus
Upper two roots (C5,6) - > Upper trunk
C7 root -> Middle Trunk
Lower two roots (C8, T1) -> Lower trunk (forms very close to the subclavian artery and first rib)
All trunks are between the scalenes and clavicle
Each trunk then divides into anterior and posterior divisions
Upper, Middle and Lower trunk posterior divisions -> posterior cord
Upper, Middle trunk anterior divisions -> lateral cord
Lower trunk anterior division -> medial cord
All cords pass into the axilla posterolateral to the axillary artery
They then move into their named positions (posterior, lateral, medial) relative to the axillary artery when
posterior to pectoralis minor
The brachial plexus is susceptible to injury from traction or even compression
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Nerves From The Brachial Plexus
Branches from the ‘Roots’
 Dorsal scapular nerve (C5)
 Long thoracic nerve (C5,6,7)
Branches from the ‘Trunks’
 Subclavius nerve (C4,5,6)
 Suprascapular nerve (C4,5,6)
Branches from the ‘Cords’
Medial Cord
 Medial pectoral nerve (C8, T1)
 Medial cutaneous nerve of the forearm (C8, T1)
 Medial cutaneous nerve of the arm (T1)
 Ulnar nerve (C7,8,T1)
 Medial part of the median nerve (C8,T1)
Posterior Cord
 Upper subscapular nerve (C4,5,6,7)
 Thoracodorsal nerve (C6,7,8)
 Lower subscapular nerve (C5,6)
 Axillary nerve (C5,6)
 Radial nerve (C5,6,7,8,T1)
Lateral Cord
 Lateral pectoral nerve (C5,6,7)
 Musculocutaneous nerve (C5,6,7)
 Lateral part of the median nerve (C5,6,7)
Axillary Nerve
From
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Posterior cord of brachial plexus
Root Value
 C5,6
Anatomy
 Descends posterior to axillary artery but anterior to subscapularis
 Passes into quadrilateral space supplying shoulder joint
 Divides into anterior and posterior branches
 Anterior branch winds around surgical neck of humerus to anterior deltoid
 Posterior branch continues posteriorly to teres minor and posterior deltoid
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Muscles Supplied
 Deltoid
 Teres Minor
Cutaneous branch
 Upper lateral cutaneous nerve of the arm
 Supplies the skin over lower part of deltoid and lateral head of triceps
Musculocutaneous Nerve
From
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Lateral cord of brachial plexus
Root Value
 C5,6,7
Anatomy
 Descends laterally between axillary artery and coracobrachialis
 Pierces coracobrachialis and runs distally inbetween biceps and brachialis to lateral arm
 Surfaces at elbow between biceps and brachioradialis
 Extends as lateral cutaneous nerve of forearm to lateral forearm and base of thumb
Muscles Supplied
 Coracobrachialis
 Biceps Brachii
 Brachialis (2/3)
Cutaneous Branch
 Lateral cutaneous nerve of forearm
 Supplies skin over lateral half of forearm to base of thumb
Ulnar Nerve
From
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Medial cord of brachial plexus
Root Value
 C7,C8,T1
Anatomy
 Descends medial to axillary artery and then anterior to triceps
 Pierces the medial intermuscular septum to pass into posterior compartment of the arm
 Passes between the medial epicondyle of humerus and olecranon of ulna
 Than passes into anterior compartment of forearm medially
 Travels laterally past the pisiform
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Muscles Supplied
 Flexor carpi ulnaris
 Flexor digitorum profundus
 Palmaris brevis
 Abductor, flexor and opponens digiti minimi
 Medial 2 lumbricals
 Palmar and dorsal interossei
 Adductor pollicis
Cutaneous branches
 Palmar cutaneous branch
 Dorsal branch
 Superficial branch
 Digital branch
 Supplies skin over medial palmar and dorsal wrist to 5th digit and the medial aspect of the 4th digit
Radial Nerve
From
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Posterior cord of brachial plexus
Root Value
 C5,6,7,8,T1
Anatomy
 Passes posterior to axillary artery, but anterior to subscapularis, latissums dorsi and teres major tendons
 Nerve passes posteriorly to humerus and wrap around the radial groove of humerus between medial and
lateral triceps heads
 Nerve then pierces the intermuscular septum to anterior compartment of between brachialis and
brachioradialis
 Passes anterior to lateral epicondyle, divides into superficial and deep branches into lateral forearm , thumb
and digits 2-4
Muscles Supplied
 Triceps
 Anconeus
 Brachialis (lateral third)
 Brachioradialis
 Wrist extensors
 Extensor indicis
 Abductor pollicis longus
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Cutaneous branches
 Posterior cutaneous nerve of the arm
 Lower lateral cutaneous nerve of the arm
 Posterior cutaneous nerve of the forearm
 Superficial radial branch
 Supplies skin over lateral and posterior aspect of upper arm, posterior middle aspect of forearm, dorsal wrist
and hand, not into finger tips
Median Nerve
From
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Medial and lateral cords of the brachial plexus
Root Value
 C5,6,7 (lateral cord)
 C8,T1 (medial cord)
Anatomy
 Descends under biceps brachii and into elbow under cubital fossa
 Passes through the anterior forearm and enters the hand deep to the flexor retinaculum
 Continues to thumb and 2nd-4th digits
Muscles Supplied
 Pronator teres
 Wrist Flexors
 Opponens pollicis
 Lateral 2 lumbricals
Cutaneous branches
 Palmar cutaneous branch
 Lateral and medial branches
 Digital branches
 Supplies skin over palmar aspect of lateral wrist, thumb, digits 2, 3 and half of 4. Dorsal finger tips of digits 13 and half of 4
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Neurodynamics
The Neurodynamic System
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Refers to the interaction of the nervous system with its surrounding structures
Made up of 3 components
o Mechanical Interface
 All the structures that surround the nervous system, i.e tendons, ligaments, fascia, blood
vessels, disc etc
o Neural Structures
 Brain, spinal cord, dura mater, nerve rootlets, nerve roots, peripheral nerves
o Innervated Tissues
 Any structure that is innervated by a nerve
 If there is a restriction or alteration in any neural structure MTrP’s can develop in the
muscles it may supply
 Sensory AND motor functions can be inhibited.
Abnormal Neurodynamic System
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Can be the result of one or a combination of the following three components
o Tension
 As the nervous system is connected at both ends it will act like a piece of string with certain
movements taking up the slack increasing the amount of tension
o Sliding
 The nervous system will slide in relation to the mechanical interface.
 There can be areas where the nervous system will struggle to slide through or between
structures
o Compression
 The mechanical interface can physically compress the nervous system
Movement of the Nervous System
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Generally as a joint moves the neural structures move towards the joint distally and proximally. This
temporarily increases the slack of the nerve surrounding the joint, allowing tension to be increased as the
joint moves
The sequence of movements can affect the localization of stress
The first region to be moved or moved strongest will increase the chance of a response in this area
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Assessing Neurodynamics
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Start with standard Upper Limb Tension Test
Change the mechanical interface
o E.g ipsilateral cervical rotation and side flexion will close the intervertebral foramen
Check neural structures sliding and tensioners
Check the innervated tissues
o Dermatome, Myotome and Deep Tendon Reflexes
o Also check anatomical muscular contraction vs muscular contraction under neural load
Median Nerve Tension Test
Position
1. Client supine
2. Therapist standing to side facing cephalad
3. Therapists closest hand above clients shoulder ready to depress
4. Therapists furthest hand pistol grip with clients thumb extended
Procedure
1. Glenohumeral abduction to 90-110° - resist scapular elevation
2. Glenohumeral external rotation
3. Forearm supination and wrist and finger extension
4. Elbow extension
Ulnar Nerve Tension Test
Position
1. Client supine
2. Therapist standing to side facing cephalad
3. Therapists closest hand above clients shoulder ready to depress
Procedure
1. Shoulder depression
2. Wrist and finger extension
3. Forearm pronation
4. Elbow flexion
5. Glenohumeral external rotation
6. Glenohumeral abduction
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Radial Nerve Tension Test
Position
1. Client supine
2. Therapist standing caudad
3. Web space of therapists closest hand over shoulder ready to depress
Procedure
1. Scapular Depression
2. Elbow extension
3. Glenohumeral internal rotation
4. Forearm pronation
5. Glenohumeral abduction
6. Wrist thumb and finger flexion
Determining The Outcome Of A Test
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Neurodynamic tests are never positive or negative
They are best described as normal or abnormal
Abnormal results include
o Reproduction of clients familiar symptoms (pain or radiculopathy) that is altered through structural
differentiation
o Reduced OR Increased range of movement compared to normal side
o Reproduction of pain or radiculopathy in an area that they would not be expected confirmed by
structural differentiation
Therefore when writing patient notes the following can be used
o ULTT – Ulnar Nerve – Right- Abnormal- Restricted ROM (unable to reach head with hand)- Familiar
pain reported little finger- Decreased with contralateral cervical flexion
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Structural Differentiation
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To determine whether symptoms reported during testing is due to the neurodynamic system structural
differentiation must be used
This is done in the following way
o Elicit a response using a test and hold this position
o Move a joint that is at least 2 steps away from the area of symptoms
o If this increases/decreases symptoms the neurodynamic system is the structure at fault
o Should symptoms remain exactly the same there is a mechanical cause to the clients symptoms
during testing
E.G
o Radial Nerve testing reproduces familiar lateral forearm and thumb pain
o Cervical contralateral flexion is introduced (2 steps away)
o This INCREASES symptoms
o Ipsilateral cervical flexion is performed
o This DECREASES symptoms
o This would indicate the neurodynamic system is dysfunctional
E.G 2
o Ulna Nerve testing produces shoulder pain
o Finger flexion is introduced (2 steps away)
o Symptoms remain the same
o Wrist flexion is introduced
o Symptoms remain the same
o This would indicate a mechanical dysfunction of the shoulder
Dermatome Testing
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Test the dermatome patterns of the cervical spine bilaterally simultaneously
Abnormalities require further investigation which can be completed with sharp or blunt testing
N.B there is considerable overlapping of dermatome patterns which often differ between texts
Dermatome abnormalities that fail to respond to physiotherapy require investigation by a spinal or
neurological specialist
o C1: top of head
o C2: side and back of the head, upper half of the ear, cheek and upper lip, nape of the neck
o C3: entire neck, lower mandible, chin, lower half of the ear
o C4: epaulette area of the shoulder
o C5: anterolateral aspect of the arm and forearm as far as the base of the thumb
o C6: anterolateral aspect of the arm and forearm, thenar eminence, thumb and index finger
o C7: posterior aspect of the arm and forearm, index, middle and ring fingers
o C8: medial aspect of the forearm, medial half of the hand, middle, ring and little fingers
o T 1: medial aspect of the forearm, upper boundary uncertain
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Myotome Testing
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Test the myotomes of the cervical spine bilaterally and simultaneously where possible
Maintain resistance for 5 seconds at least
Nerve root weakness will be evident after 5 seconds, peripheral nerve weakness is evident immediately
Myotomal weakness requires further investigation by a spinal or neurological specialist
As with dermatomes there is some overlap and differences between texts
o C1/2: Cervical Flexion/ Extension
o C3: Cervical Lateral Flexion
o C4: Scapular Elevation
o C5: Shoulder Abduction, Shoulder Lateral Rotation
o C6: Elbow Flexion, Wrist Extension
o C7: Elbow Extension, Wrist Flexion
o C8: Thumb Adduction/ Extension
o T1: Finger Adduction
Management
Soft Tissue Release
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While holding the limb in a position that represents the abnormal tension test perform soft tissue release
along the pathway of the peripheral nerve from the cervical spine to the fingers
Mobilisations
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Sliders
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The neurodynamic system can be mobilised by either ‘sliders’ or ‘tensioners’
Tension is never increased through the nerve
Point A and B of a nerve will always stay the same distance from one another
E.g Median Nerve testing- oscillate between wrist flexion/elbow extension and wrist extension/elbow flexion
Sliders are the treatment of choice for very irritable symptoms
Tensioners
 Point A and B of a nerve will increase in distance from one another
 E.G Medial Nerve testing- Grade II Physiological Elbow Extension Mobilisation
 This can be done into resistance or symptoms, or can be completed before the onset of symptoms
Home Exercise Programme
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Clients can be instructed of self- mobilisations to complete at home
Caution-ensure correct technique of sliders and tensioners etc to avoid aggravation of symptoms
Monitor symptom response from neurodynamic home exercise programmes as regular self-mobilisations
may aggravate symptoms if done too aggressively and regularly
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