Neural Injuries & Entrapments of Wrist & Hand

what type of neural injury has compression but no disruption to sheath or nerve?

Transient; mostly sensory, rarely motor

Can have complete recovery (leg falling asleep)

Neuropraxia

Type of neural damage where axon is disrupted but sheath remains intact.

Affects motor, sensory, & autonomic.

Recovery is possible if decompression is timely & axon regenerates (long term CTS)

Axonotmesis

What nerve injury type involves axon & sheath disruption?

Incomplete recovery possible (laceration)

neurotmesis

Ulnar Nerve provides motor to

FCU, medial ½ FDP, Interossei, medial lumbricals, AP

Ulnar Nerve palmar branch (sensory to hypothenar) branches before the

piso-hamate canal

The main trunk of ulnar nerve palmar branch passes thru piso-hamate canal, then bifurcates into the

Superficial (sensory to medial 1 ½ fingers) & Deep (motor) ulnar nerves

Deep branch of ulnar nerve provides motor to the

hypothenar muscles (AP, 3rd & 4th lumbricals, all dorsal & palmar IO)

Ulnar nerve problem in canal causes

sensory & motor problems distal to canal

Causes of compression of ulnar nerve in canal include fx of hamate, tumor, or loading onto area of canal; leading to no sensory changes to

hypothenar eminence because this branches before canal

No sensory changes to dorsum of hand because innervated by branch in mid-forearm & will not be affected by problem w/ canal

Racket sports, gripping sports can cause ulnar nerve issues from where?

piso-hamate canal

what is located between pisiform & hook of hamate?

Guyon’s Canal

MOI/causes for Guyon’s Canal Entrapment of deep &/or superficial terminal branches of ulnar nerve?

Long distance cycling

Long time crutch users

Trauma (hook of hamate fx)

Clinical Presentation of Ulnar Nerve Compression

↓ grip strength

Weakness in all ulnar innervated intrinsic muscles

Sensory changes (1 ½ medial digits)

Interventions for Guyon’s Canal entrapment includes activity modifications such as

padded handlebars on bicycle &/or riding gloves

intermittently shifting weight off hands

Rest from precipitating activity

Neuromobilization

Surgical decompression

Froment’s sign (test ulnar nerve) is the inability to perform

thumb abduction (if flexes instead median nerve is compensating)

Claw Deformity is an Intrinsic Minus Position, Indicates a

lower Ulnar Nerve injury

Ulnar nerve innervates interossei & lumbrical muscles of ring & little fingers

cannot provide active assistance to extensor mechanism (splinting is necessary)

The Median Nerve passes between the 2 heads of pronator teres. The Anterior interosseous nerve is a branch distal to pronator teres to innervate

FPL, FDP (lateral 2), Pronator Quadratus

A palmar branch of median nerve is given off before the carpal tunnel providing

sensory to palm

A recurrent branch of the median nerve innervates the

thenar muscles

Median Nerve Entrapment may show pronator teres syndrome. As well as signs of

Ape hand (resting pull on thenar muscles)

Rotated & adducted

a pt w/ median nerve Anterior interosseous (AIN) syndrome

can’t make “Okay” sign

Carpal Tunnel Syndrome (CTS) etiology stems from compression of median nerve under flexor retinaculum. Produces

nerve ischemia

↑ carpal pressure

Compression from adjacent structures

Lifetime Prevalence of carpal tunnel syndrome

8%

Women> Men

Older>younger

Carpal Tunnel syndrome MOI

Repetitive use of flexor tendons (keyboard)

Positions of sustained end range wrist ext/flex

Trauma/Cysts/tumors

Lunate palmar dislocation

Pregnancy: Affects 20% of women during pregnancy, 2ndary to fluid retention

Clinical Presentation, signs, & sxs of CTS include pain/discomfort in volar wrist, numbness, tingling, & ↓ tactile sensation in the

median nerve distribution: lateral 3 ½ fingers are affected

Sensation in palm is normal: Palmar branch of median nerve

Fine motor mvmt loss in chronic cases: Due to atrophy of thenar muscles (writing, holding a key)

Common sign is nocturnal pain: prolonged flexion

Carpal Tunnel Syndrome Intrinsic Risk Factors

Obesity

Older Age

Female Sex: Smaller CSA of wrist

CVD, DMII

Smoking/alcohol

Anthropometrics, Physical activity

Carpal Tunnel Syndrome extrinsic risk factors can be occupational such as

Forceful wrist exertions

Prolonged off neutral resting positions

Vibration

Psychological stress

Computer use

CTS Differential Diagnosis. Carpal Tunnel Syndrome vs. proximal entrapment

C6-C7 involvement

Costoclavicular region (TOS)

Pec minor (palpate the muscle you think is involved)

Pronator teres

Carpal Tunnel Syndrome Differential Diagnosis: Polyneuropathy

DMII

Carpal Tunnel Syndrome special testing in addition to EMG/NCV ((-) if central)

Median Nerve ULTT

Pressure provocative tests

Phalen’s test

Tinel’s test

Carpal Tunnel Syndrome Diagnostic techniques include

Hx Taking: Night pain, Shake hands to get rid

Physical Exam: Observation, only see atrophy of thenar eminence in chronic cases. Poor prognostic factor w/ conservative mgmt

Strength, Sensation, Neurodynamic testing

Rule out C-spine/shoulder/elbow (median nerve)

Electrodiagnostic Testing: EMG, NCV studies

Carpal Tunnel Syndrome Tests includes Sensation testing such as

Semmes Weinstein (2.83 or 3.22 monofilament)

Phalen’s Test/Reverse

Tinel Signs

Carpal Compression Test

Neurodynamics: ULNT 1