NDx Lab Final Practical

C5

Motor: Deltoid (Axillary)

Sensory: Lateral Deltoid

Reflex: Biceps

C6

Motor: Biceps (Musculocutaneous) & Wrist Extensors (Radial/PIN)

Sensory: Lateral antebrachium to thumb/index web

Reflex: Brachioradialis

C7

Motor: Triceps (Radial) & Wrist Flexors (Median)

Sensory: Middle Finger

Reflex: Triceps

C8

Motor: Finger Flexors (Median 2-3/Ulnar 4-5)

Sensory: Ulnar aspect of arm and hand

Reflex: Finger Flexors

T1

Motor: Finger Abd/Add (Ulnar)

Sensory: Medial brachium and elbow

Reflex: Finger Flexors

L4

Motor: Tibialis Anterior (Deep Fibular)

Sensory: Medial Foot

Reflex: Patellar (Femoral)

L5

Motor: Ext Hall Longus (Deep Fibular)

Sensory: Dorsal foot; includes web between 1st and 2nd toes

Reflex: Medial Hamstring (Sciatic N; tib division)

S1

Motor: Peroneous L/Brevis (Superficial Fibular)

Sensory: Lateral foot

Reflex: Achilles (Tibial)

Stereognosis

• How to perform: With eyes closed, the patient must identify a common object (e.g., a coin, key, or comb) placed in their hand by palpating it.

• Area affected: Parietal Lobe.

Joint Position Sense

• How to perform: Hold the distal phalanx of a finger or toe by its sides (to avoid pressure cues) and move it up or down. With eyes closed, the patient must identify the direction of movement.

• Tract affected: Dorsal Columns.

Vibratory Sense

• How to perform: Strike a 128 or 256 Hz tuning fork and place the stem firmly on the distal interphalangeal (DIP) joint of the 5th finger or 5th toe with the patient's eyes closed. The patient should state when the vibration stops.

• Tract affected: Dorsal Columns (specifically the Fasciculus Gracilis or Cuneatus).

Graphesthesia

• How to perform: The examiner traces a number, such as an "8" or a "4," on the patient's palm while their eyes are closed, and the patient identifies the figure.

• Area affected: Parietal Lobe.

Topesthesia

• How to perform: With eyes closed, the patient is touched lightly in various locations and must state exactly where they were touched.

• Area affected: Parietal Lobe.

Double Simultaneous Stimulation

• How to perform: The examiner touches one or both of the patient's arms simultaneously and asks if they feel one or two stimuli.

• Area affected: Parietal Lobe.

Grasp Reflex

• How to perform: Stroke the patient's palm.

• What it tests: A positive response is a reflexive grasping of the hand. This is considered the most reliable sign of cortical disinhibition and early Alzheimer's dementia.

Snout Reflex

• How to perform: Tap the middle of the upper lip.

• What it tests: A positive response is a marked contraction or "pursing" of the lips. (Alzheimer’s)

Rooting Reflex

• How to perform: Stroke the corner of the mouth or the cheek with a tongue blade.

• What it tests: A positive response is the reflexive turning of the head and neck toward the stimulus.

Sucking Reflex

• How to perform: Touch the patient's lips or the corner of their mouth.

• What it tests: A positive response is a reflexive sucking movement.

Palmomental Reflex

• How to perform: Briskly tap or scrape the thenar eminence (the fleshy base of the thumb) of the hand.

• What it tests: A positive response is the contraction of the ipsilateral chin muscle (mentalis). (Alzheimer’s)

Glabellar Reflex

• How to perform: Tap repeatedly on the patient's forehead (glabella).

• What it tests: In a normal response, blinking stops after a few taps; a positive response is persistent, uncontrollable blinking. This is an early sign of Parkinson’s Disease.

Plantar Response (Babinski)

• How to perform: Using the blunt end of a reflex hammer, stroke the lateral portion of the plantar surface of the foot, starting at the heel and turning medially toward the ball of the foot. A positive (abnormal) result is the extension of the great toe, often with fanning of the other toes.

• Tract affected: Corticospinal Tract

Oppenheim

• How to perform: Stroke the blunted end of a reflex hammer handle down the anterolateral tibia (shin), moving from the infrapatellar area down to the ankle.

• Tract affected: Corticospinal Tract. A positive finding is the upward extension of the great toe.

Chaddock

• How to perform: Briskly stroke the blunted end of a reflex hammer handle around the lateral malleolus (outer ankle bone) and continue along the lateral edge of the foot toward the little toe.

• Tract affected: Corticospinal Tract. A positive finding is the upward extension of the great toe.

Gordon

• How to perform: Firmly squeeze the calf muscles.

• Tract affected: Corticospinal Tract. A positive finding is the upward extension of the great toe.

Schaffer

• How to perform: Apply deep pressure by firmly squeezing the Achilles tendon.

• Tract affected: Corticospinal Tract. A positive finding is the upward extension of the great toe.

Hoffman and Tromner’s

• How to perform: For Hoffman’s, support the patient's hand and "flick" the distal phalanx of the middle finger into extension. For Trӧmner’s, sharply flip the pad of the middle finger upward. A positive response is thumb adduction and finger flexion.

• Tract affected: Corticospinal Tract.

Clonus

• How to perform: Abruptly and quickly move the patient's wrist into extension or the foot into dorsiflexion, then maintain pressure at the end of the movement. Count the number of rhythmic contractions (beats) that occur.

• Tract affected: Corticospinal Tract.

Heel Walk

• How to perform: Ask the patient, without shoes or socks, to walk toward you on their heels. You must observe that their toes stay up throughout the walk.

• What it tests:

  • Nerve Roots: L4 and L5.

  • Peripheral Nerve: Deep Peroneal (Fibular) nerve.

  • Muscles: Tibialis Anterior (primarily L4) and Extensor Hallucis Longus (primarily L5).

• Clinical Significance: Inability to perform a heel walk is a clinical sign of "foot drop".

Toe Walk

• How to perform: Ask the patient, without shoes or socks, to walk away from you on their toes. You must observe that their heels remain completely off the floor.

• What it tests:

  • Nerve Roots: L5 and S1 (primarily S1).

  • Peripheral Nerve: Tibial nerve.

  • Muscles: Gastrocnemius and Soleus muscle group.

Arcade of Struthers

This thin aponeurotic band is located approximately 8 cm proximal to the medial epicondyle, extending from the medial head of the triceps to the medial intermuscular septum. It can entrap the ulnar nerve as it courses toward the elbow.

Medial Intermuscular septum (between triceps and brachialis)

This site is located between the triceps and brachialis muscles. It serves as a potential compression point for the ulnar nerve proximal to the elbow.

Cubital Tunnel

This is the most common site of entrapment for the ulnar nerve, located where the nerve passes under the aponeurosis of the two heads of the flexor carpi ulnaris (FCU). The aponeurosis spans from the medial epicondyle to the olecranon. Hand symptoms often predominate here because the sensory and intrinsic hand fibers are located peripherally in the nerve and are more sensitive to external compression.

Deep flexor pronator arch

This site is located distal to the cubital tunnel, more than 4 cm beyond the medial epicondyle. It is a potential compression site for the ulnar nerve.

Tunnel of Guyon

Located at the wrist, this fibro-osseous tunnel is a depression between the pisiform and the hook of the hamate, covered by the pisohamate and volar carpal ligaments. The ulnar nerve bifurcates here into superficial cutaneous and deep motor branches.

• Follow-up: Long-standing damage here results in an "ulnar claw" deformity affecting the ring and little fingers, characterized by MCP hyperextension and IP flexion due to paralyzed medial lumbricals.

Spiral groove on the humerus

• Located on the posterior humerus, this is a common site for radial nerve compression.

  • Clinical Significance: Entrapment here results in Radial Nerve Palsy (also known as "Saturday Night Palsy"), which clinically presents as wrist drop due to paralysis of the extensor muscles.

Arcade of Frohse (PINS entrapment)

This is the proximal edge of the supinator muscle where the posterior interosseous nerve (PIN)—a branch of the radial nerve—enters the radial tunnel.

• Follow-up (PINS): Entrapment here causes Posterior Interosseous Nerve Syndrome (PINS), which is characterized by motor weakness, specifically an inability to extend the fingers (especially the third digit). It is distinguished from Radial Tunnel Syndrome because PINS involves weakness, while Radial Tunnel Syndrome is characterized primarily by pain.

Ligament of Struthers

This is the most proximal site of compression, located 3-5 cm proximal to the medial epicondyle. It is a ligament connecting an anomalous bony spur (supracondylar process) to the medial epicondyle, encasing the median nerve and brachial artery.

Lacertus Fibrosis

This is a medial extension of the biceps tendon that covers the median nerve in the cubital fossa. It is the least common cause of pronator syndrome, usually occurring due to muscle hypertrophy.

Pronator Teres

The median nerve passes between the humeral and ulnar heads of this muscle. Fibrous bands between these heads can cause Pronator Syndrome by compressing the median nerve.

Arch of the Flexor digitorum superficialis (AINS)

This fibrous arch is a known site for the compression of the Anterior Interosseous Nerve (AIN).

• Clinical Significance: Compression here results in Anterior Interosseous Nerve Syndrome (AINS), also known as Kiloh-Nevin syndrome.

Carpal Tunnel

Located at the wrist under the transverse carpal ligament, this is the most common entrapment site for the median nerve. It occurs when an increase in tunnel contents or a decrease in tunnel size compresses the nerve.

Anterior Interossesous Nerve Test (Sign of OK)

This test identifies AINS. A patient is asked to make an "OK" sign by pressing the tips of the thumb and index finger together; if the tips collapse and the patient pads the fingers together instead of forming a circle, the test is positive. This occurs due to the loss of the flexor pollicis longus and the lateral half of the flexor digitorum profundus.

Differentiate spinal and peripheral nerve entrapments in the lower extremities

• Spinal (L5 Root): Commonly caused by an L4-L5 disc protrusion, often presenting with low back pain and positive nerve root tension signs like the Straight Leg Raise. Weakness is most obvious in the extensor hallucis longus, but total paralysis of dorsiflexors is rare due to overlapping root innervation.

• Peripheral (Peroneal Nerve): Often caused by external compression (e.g., a cast or prolonged squatting). It involves lateral leg and dorsal foot pain, motor weakness, and atrophy. Clinicians use the short head of the biceps femoris to localize the lesion; if it is weak, the lesion is in the sciatic nerve or root, as this muscle is innervated by the peroneal branch above the knee.

Claw Hand

This deformity is evident when the hand is at rest. It is caused by ulnar nerve damage that paralyzes the medial lumbricals and the medial flexor digitorum profundus, leading to an imbalance where the long extensors hyperextend the MCP joints and the long flexors flex the IP joints.

Sign of Benediction

This is a motor sign seen only when the patient is asked to make a fist. It indicates median nerve damage at or above the pronator teres, which paralyzes the long flexors of the thumb, index, and middle fingers, leaving them extended while the medial fingers (ulnar-innervated) flex.