Orthopaedic Neurology Diagnostic Guide to Neurological Levels

Motor Power Interruption of the nerve root causes denervation and paralysis of its myotome. Pressure on a nerve root can cause a decrease in muscle strength. Muscle testing is utilized to evaluate whether or not a lesion is present and to what degree it is effecting the muscle strength.

Muscle Grading Chart Muscle gradations Description. 5 – normal 4 – good 3 – fair 2 – poor 1 – trace 0 - zero Description. Complete range of motion against gravity with full resistance. Complete range of motion against gravity with some resistance. Complete range of motion against gravity. Complete range of motion with gravity eliminated. Evidence of slight contractility. No joint motion. No evidence of contractility.

Sensation Pathology to the cord or nerve root results in loss of light touch, followed by loss of sensation of pain. During recovery from nerve root injury, sensation of pain returns before light touch.

Sensation The 2 sensations are tested separately, light touch with a cotton swab, pain with pinpricks. Pinwheels can be utilized to evaluate sensation. Results can be recorded on a dermatome chart as normal, hyperesthetic (increased), hyposthetic (decreased), dyesthetic (altered), or anesthetic (absent).

Reflex Interruption in the basic reflex arc results in the loss of reflex, while pressures on the nerve root itself may decrease its intensity (hyporeflexia). Interruption of the upper motor neuron’s regulatory control results in a hyperactive nerve (hyperreflexia). Reflexes should be reported as normal, increased, or decreased utilizing bilateral comparison.

Stretch Reflex Arc

Nerve Root Lesions by Neurologic Level

Evaluation of Nerve Root Lesions Upper Extremity

Cervical Spine C5 is the 1st significant contribution to the brachial plexus. C1-4 are difficult to test; However, C4 is the major innervation to the diaphragm (via the phrenic nerve).

The Cervical Spine

Deltoid & Supraspinatous

Elbow Flexion and Extension

Biceps Brachii & Brachialis

Functions of the Biceps

Muscle Test for the Biceps

Biceps Reflex Test

Memory Trick

Muscle Test Shoulder Abduction

Sensory Distribution C5

Wrist Extension and Flexion

Extensor Carpi Ulnaris (Left), Extensor Carpi Radialis (Right)

Muscle Test Wrist Extension

Brachioradialis Reflex Test

Memory Trick

Triceps Brachii

Walking With a Crutch Utilizes the Triceps Muscle

Muscle Test Wrist Flexors

Flexor Carpi Radialis (Left), Flexor Carpi Ulnaris (Right)

Finger Extension and Flexion

Extensor Digitorum

Muscle Test Finger Extension

Triceps Reflex Test

Flexor Digitorum Superficialis (Left), and Profundus (Right)

Lumbricales

Muscle Test Finger Flexors

Memory Trick

Finger Abduction and Adduction

Muscle Test Finger Abduction

Muscle Test Finger Adduction

Summary of Muscle Testing for the Upper Extremity

Summary of Reflex Testing for the Upper Extremity

Summary of Sensation for the Upper Extremity

Cervical Vertebrae and Nerve Roots

Herniated Cervical Disc

Occiput & C1 Articulation

C1 and C2 Articulation

Anatomic Basis for Posterior Cervical Disc Herniation

Neurologic Levels in Upper Extremity Motor C5 – shoulder abduction C6 – wrist extension C7 – wrist flexion and finger extension C8 – finger flexion T1 – finger abduction, adduction

Neurologic Levels in Upper Extremity Sensation C5 – lateral arm C6 – lateral forearm, thumb, and index finger C7 – middle finger (variable) C8 – medial forearm, ring, and small finger T1 – medial arm T2 - Axilla

Neurologic Levels in Upper Extremity Reflex C5 – biceps C6 – Brachioradialis C7 - triceps

Whiplash Injury to the Cervical Spine

Anatomy of a Cervical Vertebrae

Orthopedic Tests Cervical Spine Valsalva test Distraction test Compression test

Valsalva Test

Distraction Test

Compression Test

Thoracic Spine

Beevor’s Spine

Hip Flexion

Iliopsoas

Muscle Test Iliopsoas

Knee Extension

Rectus Femoris (Left), Vastus Intermedius and Lateralis (Right)

Extension Lag

Muscle Test Quadriceps

Hip Adduction

Adductors

Muscle Test Hip Adductors

Dermatomes of the Lower Extremity

Foot Inversion

Muscle Test Tibialis Anterior

Patellar Tendon Reflex

Memory Trick

Foot Dorsiflexion (Ankle Extension)

Extensor Hallucis Longus

Muscle Test Extensor Hallucis Longus

Muscle Test Toe Extensors

Memory Trick

Hip Abduction

Gluteus Medius

Muscle Test Gluteus Medius

L5 Sensory Dermatome

Foot Eversion

Peroneus Longus & Brevis

Muscle Test Peronei Muscles

Foot Plantarflexion

Gastrocnemius & Soleus

Muscle Test Gastrocnemius

Hip Extension

Gluteus Maximus

Muscle Test Gluteus Maximus

Achilles Reflex Test

Memory Trick

Sensory Dermatomes S2, S3, S4, S5

Sensory Dermatomes L4-S1

Testing Sensation

Anatomic Basis for Posterior Lumbar Disc Herniation

Neurologic Levels in Lower Extremity Motor L3 – quadriceps (L2, L3, L4) L4 – Tibialis anterior L5 – toe extensors S1 - Peronei

Neurologic Levels in Lower Extremity Sensation T12 – lower abdomen just proximal to inguinal ligament L1 – upper thigh just distal to inguinal ligament L2 – mid thigh L3 – lower thigh L4 – medial leg – medial side of foot L5 – lateral leg – dorsum of foot S1 – lateral side of foot S2 – longitudinal strip, posterior thigh

Neurologic Levels in Lower Extremity Reflex L4 – patellar L5 – Tibialis posterior (difficult to obtain) S1 – Achilles tendon