Lab 4: Peripheral Nerves Disorder and Treatment

Functionally, the nervous system should be considered as…

One continuous tissue tract

How are neurons interconnected?

Via interneurons

What flows inside the nerve tissue?

Cytoplasm

T/F: The same neurotransmitters are present in the CNS as in the PNS

True

T/F: When considering nerve, connective tissue is not continuous

False (it is continuous)

What are the three connective tissue layers of nerve?

• Endoneurium

• Perineurium

• Epineurium

What is convergence of a nerve?

Nerve guiding toward the moving joint

What is divergence of a nerve?

Nerve gliding is away from the moving joint

The tension (gliding) of the nerve that is closest to the joint moving with _________ and furthest away from the joint during _________

The tension (gliding) of the nerve that is closest to the joint moving with convergence and furthest away from the joint during divergence

What are some common sites of injury above the peripheral nerve?

• Nerve Roots (Spinal Nerves) at the Spinal Leve

• Brachial Plexus

  • Thoracic Outlet

  • Upper Plexus Injury (Erbs)

  • Middle Plexus Injury (C7)

  • Lower Plexus Injury (Klumpe)

What is the C1-2 myotome?

Cervical Flexion

What is the C3 myotome?

Cervical Side Bending

What is the C4 myotome?

Scapular Elevation

What is the C5 myotome?

Shoulder Abduction

What is the C6 myotome?

Elbow Flexion / Wrist Extension

What is the C7 myotome?

Elbow Extension / Wrist Flexion

What is the C8 myotome?

Thumb Extension

What is the T1 myotome?

Finger Abduction

What is the L1-2 myotome?

Hip Flexion

What is the L3 myotome?

Knee Extension

What is the L4 myotome?

Ankle Dorsiflexion

What is the L5 myotome?

Great Toe Extension

What is the S1 myotome?

Ankle Eversion & Plantarflexion

Hip Extension

What is the S2 myotome?

Knee Flexion

What is the S3 myotome?

Intrinsic Foot Muscles

What is the C4 dermatome?

Upper Trapezius

What is the C5 dermatome?

Lateral Humerus

What is the C6 dermatome?

Thumb & Index Finger

What is the C7 dermatome?

Middle Finger

What is the C8 dermatome?

4th and 5th Fingers

What is the T1 dermatome?

Medial Forearm

What is the L1 dermatome?

Anterior Upper Thigh

What is the L2 dermatome?

Anterior and Medial Upper Thigh

What is the L3 dermatome?

Medial to the Knee

What is the L4 dermatome?

Over the Knee and Into the Foot

What is the L5 dermatome?

Anterior Lateral Calf / Dorsum of Foot / Great Toe

What is the S1 dermatome?

Plantar Aspect of the Foot

What is the S2 dermatome?

Posterior Thigh

What is the S3 dermatome?

Medial Inner Thigh Near Peroneal Region

What are the roots of the brachial plexus?

C5 - T1

What are the trunks of the brachial plexus (and their root contributions)?

• Superior Trunk (C5, C6)

• Middle Trunk (C7)

• Inferior Trunk (C8, T1)

What are the cords of the brachial plexus? What trunk(s) do they come from?

• Lateral (Superior & Middle)

• Posterior (Superior, Middle, & Inferior)

• Medial (Inferior)

From what cord does the musculocutaneous nerve arise?

Lateral Cord

What are the nerve roots for the musculocutaneous nerve?

C5, C6, C7

From what cord does the axillary nerve arise?

Posterior Cord

What are the nerve roots for the axillary nerve?

C5, C6

From what cord does the radial nerve arise?

Posterior Cord

What are the nerve roots of the radial nerve?

C5 - T1

From what cord does the median nerve arise?

Lateral and Medial Cord

What are the nerve roots for the median nerve?

C5 - T1

From what cord does the ulnar nerve arise?

Medial Cord

What are the nerve roots for the ulnar nerve?

C7, C8, T1

If the axillary nerve was injured, what muscle(s) would be affected?

• Deltoid

• Teres Minor

If the musculocutaneous nerve was injured, what muscle(s) would be affected?

• Coracobrachialis

• Biceps Brachii

• Brachialis

If the median nerve was injured, what muscle(s) in the forearm would be affected?

• Pronator teres

• Palmaris longus

• Flexor digitorum profundus and superficialis

• Flexor pollicis longus

• Flexor carpi radialis

• Pronator quadratus

If the median nerve was injured, what muscle(s) in the wrist/hand would be affected?

• Opponens pollicis

• Abductor pollicis brevis

• Flexor pollicis brevis

• Lumbricals I and II

If the ulnar nerve was injured, what muscle(s) in the forearm would be affected?

• Flexor carpi ulnaris

• Flexor digitorum profundus

If the ulnar nerve was injured, what muscle(s) in the wrist/hand would be affected?

• Abductor, opponens, and flexor digiti minimi

• Lumbricals III and IV

• Interossei

• Adductor pollicis

• Flexor pollicis brevis

If the radial nerve was injured, what muscle(s) would be affected?

• Triceps brachii

• Anconeus

• Brachialis

• Brachioradialis

• Extensor carpi radialis longus/brevis and ulnaris

• Supinator

• Abductor/Extensor Pollicis Longus (and Brevis)

Injury of the axillary nerve would limit/restrict what motion(s)?

• Abduction

• External Rotation

Disucss the course of the axillary nerve.

• Terminal branch of posterior cord

• Courses posteriorly behind the surgical neck of the humerus

How is the axillary nerve typically injured?

Injured with proximal humeral fracture or anterior dislocation of GH

Discuss the course of the musculocutaneous nerve.

• Terminal branch of the lateral cord

• Crosses the axilla with the median nerve and then travels in the flexor musculature of the arm

• Terminates as the lateral cutaneous nerve of the forearm

Why does injury typically not occur to the musculocutaneous nerve?

The nerve is protected from injury due to the deep route and soft tissue support

Discuss the course of the median nerve.

• Terminal branch of the medial and lateral cords

• Travels through the medial aspect of the arm and anterior to the elbow joint (where it becomes prone to impingement)

What are some typical sites of impingement for the median nerve?

• Pronator Teres

• Bicipital Aponeurosis (Ligament of Struther’s)

• Carpal Tunnel in Wrist

What are some possible limitations that can result due to median nerve injury?

• Forearm pronation weakness

• Weak grip

• Weak or absent thumb abduction and opposition (atrophy in thenar emminence may be prominent)

Discuss the course of the ulnar nerve.

• Terminal branch of the medial cord

• Travels through the medial aspect of the arm and posterior to the elbow joint in the cubital tunnel (formed from fibrous sheath)

• Ulnar nerves enters the forearm by passing between the two heads of the FCU

What are some common sites of impingement for the ulnar nerve?

• Cubital Tunnel

• Between heads of FCU

• Tunnel of Guyon (between pisiform and hook of hamate)

What impairments may result from an ulnar nerve injury?

Loss of intrinsic hand muscles (hypothenar emminence, medial two lumbricals, adductor pollicus, interrossei)

Discuss the course of the radial nerve.

• Terminal branch of the posterior cord

• Spirals posteriorly around the humerus

How does damage typically occur to the radial nerve?

• Mid-Humeral Fracture

• Shoulder Dislocation

• Saturday Night Palsy

• Crutch Palsy

• Radial Head Fracture

What impairments may result due to radial nerve injury?

• Inability to extend wrist

• Inability to extend fingers at MCPs

• Weakens supination

What are the three stages of nerve injury?

• Neuropraxia

• Axomotmesis

• Neurotmesis

What are the characteristics of neuropraxia?

• Segmental demyelination

• NO motor symptoms

• Sensory only

• Usually complete recovery

What are the characteristics of axomotmesis?

• Loss of axonal continuity

• Connective tissue remains intact

• Wallerian Degeneration

• Muscle atrophy

• Sensory loss

• Recovery incomplete

What are the characteristics of neurotmesis?

• Complete severance of nerve fiber with disruption of CT coverings

• Wallerian degeneration

• No recovery (without surgery and correct re-growth of individual fibers)

Discuss the components of the maximum protection phase.

• Immobilization (time depends on the symptoms present)

• Protect Movement (amount and intensity depends on symptoms

• Spinting/Braching (to prevent deformity)

• Patient education on skin care

Discuss the components of the moderate protection phase.

• Motor Retraining (muscle “hold” in the shortened position… isometric)

• De-sensitization (different textures, etc.)

• Progressive discriminative sensory re-education

Discuss the components of the minimal protection phase.

• Compensatory Functions

• Preventative Care

• (Chronic condition; no signs of further recovery)

What are the signs/symptoms of nerve mobility?

• Pain (chief complaint)

• Pain provoked with stretching

• Patient may complain of “cold”, paresthesia, or numbness

• May or may not have MOI

What are the contraindications for nerve treatment testing?

• Irritability related to nervous system

• Worsening disorder

• Acute/unstable presence of neurological symptoms

• General health problems

• Dizziness

• Circulatory disturbances

• If changes are recent AND worsening rapidly, cauda equina lesions, or injury to SC are present SHOULD NOT perform tension test