Orthopedic Pathology 300 (U & L extremity nerve pathologies)

Question 1

Thoracic outlet syndrome

Answer 1

Compression of the neurovascular structures as they exit through the thoracic outlet (cervicothoracobrachial) region

Question 2

thoracic outlet

Answer 2

The thoracic outlet is marked by the ANTERIOR scalene muscle anteriorly, the MIDDLE scalene posteriorly, and the first rib inferiorly.

Question 3

tension in anterior and middle scalene

Answer 3

Tension and pain in the anterior and middle scalene muscles can be frequent causes of thoracic outlet syndrome.

Question 4

which neurovascular structures get compressed?

Answer 4

Brachial plexus,
subclavian artery,
subclavian vein

Question 5

thoracic outlet syndrome, controversy

Answer 5

Thoracic outlet syndrome is sometimes considered controversial, as symptoms can be vague and similar to other conditions.

It’s important to be evaluated by someone who can distinguish between the various types of thoracic outlet syndrome and rule out other conditions.

Question 6

thoracic outlet syndrome, progression

Answer 6

Usually begins insidiously and progresses slowly

Question 7

TOS, etiology / risk factors

Answer 7

Cervical rib

Prolonged poor positioning

Poor posture

Systemic immune or metabolic disorders
—> RA, diabetes, hypothyroidism

Trauma
—> With inflammation and subsequent scarring
(E.g. whiplash)

Pregnancy
—> (Increased fluid retention/postural changes)

Question 8

THREE areas problems can occur in TOS

Answer 8

interscalene triangle

costoclavicular space

subcoracoid space

Question 9

interscalene triangle

Answer 9

b/w middle and anterior scalene

—> Brachial plexus, and subclavian artery

Question 10

costoclavicular space

Answer 10

b/w 1st rib and clavicle (& subclavius)

—> subclavian vein
—> ALSO CONTAINS SUBCLAVIAN ARTERY & brachial plexus

—> NOTE THAT THIS IS JUNCTION OF SUBCLAVIAN TO AXILLARY a/v

Question 11

subcoracoid space

Answer 11

below coracoid process (compressed by pectoralis minor)

—> AXILLARY (subclavian???) vein, artery, & brachial plexus

Question 12

Note about interscalene triangle tightness/compression

Answer 12

aka anterior scalene syndrome

Question 13

note about costoclavicular space compression

Answer 13

aka costoclavicular syndrome

—> Contains brachial plexus, subclavian artery and subclavian vein

—> Note that this is actually junction of subclavian a/v & axillary a/v

Question 14

note about subcoracoid space compression

Answer 14

aka pectoralis minor syndrome, hyperabduction syndrome

—> Between coracoid process, pec minor, ribs

—> Contains brachial plexus and subclavian artery

(AXILLARY ARTERY AT THIS POINT???)

& AXILLARY VEIN???????????
–> also contains vein, but vein is not mentioned on class notes

Question 15

note about axillary vein and pectoralis minor syndrome (subcoracoid space compression)

—> this is perhaps why axillary* (subclavian??) vein is not mentioned in notes

Answer 15

“Axillary venous compression by the pectoralis minor is a rare entity that presents with symptoms similar to subclavian vein obstruction.”

HOWEVER, another source says the following:
—>
“Pectoralis minor syndrome (PMS) is defined as compression of the brachial plexus (BP) nerves, axillary artery, and axillary vein under the pectoralis minor muscle.”

Question 16

note how TOS is defined as a group

Answer 16

“Thoracic outlet syndrome (TOS) is a group of disorders that happen due to compression of nerves or blood vessels in your lower neck and upper chest.”

“The thoracic outlet syndromes of the upper extremities consist of many disorders. The most important two are the costoclavicular syndrome (compression of neurovascular structures between the clavicle and the first rib) and the scalenus anticus syndrome (compression of these structures within the scalene triangle).”

Question 17

RADIAL NERVE ENTRAPMENTS

Answer 17

Radial nerve
—> Continuation of the brachial plexus

—> Travels along the spiral groove of the humerus
…
SPIRAL GROOVE, aka radial groove

Question 18

which muscles are innervated via RADIAL NERVE

Answer 18

–> Triceps, anconeus, brachioradialis, ECRL, ECRB, ED, ECU, EDM

–> supinator, ABDPL, EPB, EPL, EI

Question 19

radial nerve entrapment – causes / risk factors

Answer 19

Fracture
–> Spiral groove (radial groove) – I.e. HUMERUS
–> or RADIUS

Dislocation
At the radius/ulna

Post-surgical complications

Compression
Axilla – crutches (??)

Supinator syndrome
—> Compression at the forearm
—> Fibrosis where the nerve penetrates the supinator muscle

Question 20

Supinator syndrome

Answer 20

ARCADE OF FROHSE @ SUPINATOR MUSCLE
—> “sometimes called the supinator arch, is the most superior part of the superficial layer of the supinator muscle, and is a fibrous arch over the posterior interosseous nerve”

Radial nerve itself passes superficial to SUPINATOR muscle
—> branch off the radial nerve @ the elbow = POSTERIOR INTEROSSEOUS NERVE

—> posterior interosseous nerve penetrates supinator muscle via ARCADE OF FROHSE

—> this is the nerve that is compressed during SUPINATOR SYNDROME

Question 21

supinator syndrome, summary

Answer 21

“supinator syndrome” is used for compression at the arcade of Frohse

Question 22

SSx of RADIAL NERVE ENTRAPMENT in general

Answer 22

Wrist drop
—> (In a complete radial nn lesion)
—> Flaccid wrist extensors

Muscle wasting
(muscles innervated via radial nerve)

Sensation dysfunction
—> Posterior arm, forearm and hand
—> Anesthesia – in the web space (DORSAL SURFACE)

Question 23

MEDIAN NERVE ENTRAPMENTS

Answer 23

Median nerve innervates primarily the flexor muscles in the forearm and hand

Question 24

where does median nerve travel?

Answer 24

—> With the BRACHIAL ARTERY

—> In forearm is susceptible to compression by the PRONATOR TERES

—> Through the CARPAL TUNNEL

Question 25

MEDIAN NERVE ENTRAPMENTS – causes / risk factors

Answer 25

Fractures – elbow, wrist, carpal bones

Dislocations – elbow, wrist, carpal bones

Compression

Trauma – (like fractures…)

Question 26

MEDIAN NERVE ENTRAPMENTS – SSx

Answer 26

Ape Hand or oath hand

Muscle atrophy

Altered sensation in the thumb, index, middle and one half of the ring finger
—> (PALMAR SURFACE, and fingertips (distal phalanges) of dorsal surface)

Question 27

ape hand (oath hand)

Answer 27

“Ape hand deformity is a condition in which the thumb is permanently rotated and adducted, resulting in a loss of its opposable function. This deformity is caused by damage to the distal median nerve, which supplies the muscles that control the thumb.”

—> also other fingers whose muscles are innervated by median nerve (?)

Question 28

CARPAL TUNNEL SYNDROME (median nerve entrapment)

Answer 28

Compression of median nerve as it passes through the carpal tunnel

MOST COMMON entrapment syndrome in the arm

Related to highly repetitive flexion/extension at wrist

Aggravated by movement

Unilateral or bilateral

Question 29

causes, carpal tunnel syndrome

Answer 29

Pressure on the nerve where is passes through the canal

—> Increased size of the contents through the tunnel

—> Decreased canal space

—> Acute trauma, infection

—> New activity

Question 30

carpal tunnel syndrome, SSx

Answer 30

Weakness, numbness, tingling, pain, altered sensation

Weak grip

Problem with fine motor movements of hand

Wasting/atrophy of THENAR eminence

Increased symptoms with increase in wrist movements

Question 31

ULNAR NERVE ENTRAPMENTS

Answer 31

Travels…

—> Medial humerus

—> Through the ulnar groove on the medial aspect of the elbow

—>Deep to FCU

—> Over the carpal tunnel and between the pisiform and hook of the hamate bone
= ULNAR (tunnel of Guyon)

Question 32

tunnel of Guyon

Answer 32

“Guyon’s canal also called ulnar tunnel or ulnar canal, is an anatomical fibro-osseous canal located on the medial side of the hand.”

“Guyon canal syndrome is also known as ulnar tunnel syndrome”
—> compression of distal ulnar nerve

Question 33

ulnar nerve innervates which muscles

Answer 33

—> FCU, FDP (4th & 5th digits), hypothenar muscle, 3/4th lumbricals, palmar and dorsal interossei, adductor pollicis, FPB

Question 34

ulnar nerve entrapment causes

Answer 34

Fractures – elbow, Colle’s

Dislocations - elbow

Post-surgical complications

Prolonged compression

Repetitive action

Direct trauma

Question 35

Colle’s fracture

Answer 35

distal radius fracture with dorsal comminution, dorsal angulation, dorsal displacement, radial shortening

—> DINNER FORK DEFORMITY

Question 36

ulnar nerve entrapment – SSx

Answer 36

Claw hand
—> Complete ulnar nerve lesion

Positive Froment’s Sign

Muscle wasting

Altered Sensation
—> Ulnar side of the hand

Question 37

Froment’s sign

Answer 37

The Froment’s sign is used to test the function of the adductor pollicis muscle.

when pinching a piece of paper between the thumb and index finger against resistance, the thumb IP joint will flex if the adductor pollicis muscle is weak.

“Froment’s sign[1][2] is a physical examination of the hand to test for palsy of the ulnar nerve which results in reduced functionality and muscle weakness of the pinch grip.”

Question 38

Ulnar claw hand

Answer 38

Most cases of claw are caused by damage to your ulnar nerve, the nerve that controls some of the muscles that flex and extend your fingers (4th & 5th Digits via FDP)

“The ring- and little finger can usually not fully extend at the proximal interphalangeal joint (PIP).”

Question 39

LOWER EXTREMITY NERVE PATHOLOGIES

Answer 39

..

Question 40

Piriformis Syndrome

Answer 40

Compression or irritation of the sciatic nerve by the piriformis muscle

Causes numbness, tingling, pain down the posterior buttocks and thigh

Sciatic nerve is composed of the Tibial Nerve and Common Fibular Nerve.

Question 41

piriformis syndrome, causes / risk factors

Answer 41

Tight piriformis muscle

Trauma to piriformis

Inflammation/degeneration of piriformis

Posture/position/wallet (?)

Trigger points

Genetic/anatomic abnormalities

SI/pelvic misalignment

Question 42

Lower cross syndrome

Answer 42

:ower Cross Syndrome happens when there is muscular imbalance between weak and tight muscles.

The tight muscles are generally the hip flexors and erector spinae, and weak muscles are the abdominals and gluteal muscles.

Shortening occurs in the hip flexors while weakening occurs in the abdominals and gluteal muscles.

Question 43

APT & Piriformis syndrome

(Note that with APT, there is COUNTER-NUTATION of sacrum)

Answer 43

“The anterior pelvic tilt caused by the characteristics of lower cross syndrome cause the hip saddle to sit more forward and the piriformis to then apply pressure on the nerve root.”

“By addressing the root causes of LCS and prevent we can prevent the anterior pelvic tilt that cause piriformis syndrome.”

Question 44

SI joint counter-nutation vs Piriformis syndrome

Answer 44

“SI joint counternutation can compromise the function of greater sciatic notch and infrapiriform fossa exacerbating piriformis syndrome”

Question 45

piriformis syndrome – clinical manifestation

Answer 45

Unilateral
Pain
Paresthesia
Atrophy
Weakness

Question 46

piriformis syndrome – Tx

Answer 46

Injections of corticosteroids

Stretching/strengthening

SI joint mobilization/manipulation

Hydrotherapy

Self care

Question 47

Tarsal Tunnel Syndrome

Answer 47

Compression of the tibial nerve within the tarsal tunnel

Tarsal tunnel is formed by the flexor retinaculum between the medial malleolus and calcaneus

Question 48

tarsal tunnel contains

Answer 48

–> Tibialis posterior tendon

–> Flexor digitorum longus tendon

–> Flexor hallucis longus tendon

–> Tibial nerve

–> Posterior tibial artery and vein

Question 49

tarsal tunnel syndrome – causes

Answer 49

Repetitive stress activities; running, standing, walking

–> Flat feet; pes planus, hindfoot valgus

–>Trauma

–> Excessive (body?) weight

Question 50

hindfoot valgus and flat feet / collapsed arch

Answer 50

“Flexible Pes Planovalgus, also known as Flexible Flatfoot, is a common idiopathic condition, caused by ligamentous laxity that presents with a decrease in the medial longitudinal arch, A VALGUS HINDFOOT and forefoot abduction with weight-bearing.”

Question 51

tarsal tunnel syndrome –> clinical presentation

Answer 51

Pain; burning or shooting

Numbness, tingling

Question 52

crural, sural

Answer 52

crural = relating to the leg or the thigh.

sural = relating to the calf of the leg.