Orthopedic Pathology 300 (U & L extremity nerve pathologies) Flashcards
Thoracic outlet syndrome
Compression of the neurovascular structures as they exit through the thoracic outlet (cervicothoracobrachial) region
thoracic outlet
The thoracic outlet is marked by the ANTERIOR scalene muscle anteriorly, the MIDDLE scalene posteriorly, and the first rib inferiorly.
tension in anterior and middle scalene
Tension and pain in the anterior and middle scalene muscles can be frequent causes of thoracic outlet syndrome.
which neurovascular structures get compressed?
Brachial plexus,
subclavian artery,
subclavian vein
thoracic outlet syndrome, controversy
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.
thoracic outlet syndrome, progression
Usually begins insidiously and progresses slowly
TOS, etiology / risk factors
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)
THREE areas problems can occur in TOS
interscalene triangle
costoclavicular space
subcoracoid space
interscalene triangle
b/w middle and anterior scalene
—> Brachial plexus, and subclavian artery
costoclavicular space
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
subcoracoid space
below coracoid process (compressed by pectoralis minor)
—> AXILLARY (subclavian???) vein, artery, & brachial plexus
Note about interscalene triangle tightness/compression
aka anterior scalene syndrome
note about costoclavicular space compression
aka costoclavicular syndrome
—> Contains brachial plexus, subclavian artery and subclavian vein
—> Note that this is actually junction of subclavian a/v & axillary a/v
note about subcoracoid space compression
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
note about axillary vein and pectoralis minor syndrome (subcoracoid space compression)
—> this is perhaps why axillary* (subclavian??) vein is not mentioned in notes
“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.”
note how TOS is defined as a group
“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).”
RADIAL NERVE ENTRAPMENTS
Radial nerve
—> Continuation of the brachial plexus
—> Travels along the spiral groove of the humerus
…
SPIRAL GROOVE, aka radial groove
which muscles are innervated via RADIAL NERVE
–> Triceps, anconeus, brachioradialis, ECRL, ECRB, ED, ECU, EDM
–> supinator, ABDPL, EPB, EPL, EI
radial nerve entrapment – causes / risk factors
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
Supinator syndrome
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
supinator syndrome, summary
“supinator syndrome” is used for compression at the arcade of Frohse
SSx of RADIAL NERVE ENTRAPMENT in general
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)
MEDIAN NERVE ENTRAPMENTS
Median nerve innervates primarily the flexor muscles in the forearm and hand
where does median nerve travel?
—> With the BRACHIAL ARTERY
—> In forearm is susceptible to compression by the PRONATOR TERES
—> Through the CARPAL TUNNEL
MEDIAN NERVE ENTRAPMENTS – causes / risk factors
Fractures – elbow, wrist, carpal bones
Dislocations – elbow, wrist, carpal bones
Compression
Trauma – (like fractures…)
MEDIAN NERVE ENTRAPMENTS – SSx
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)
ape hand (oath hand)
“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 (?)
CARPAL TUNNEL SYNDROME (median nerve entrapment)
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
causes, carpal tunnel syndrome
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
carpal tunnel syndrome, SSx
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
ULNAR NERVE ENTRAPMENTS
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)
tunnel of Guyon
“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
ulnar nerve innervates which muscles
—> FCU, FDP (4th & 5th digits), hypothenar muscle, 3/4th lumbricals, palmar and dorsal interossei, adductor pollicis, FPB
ulnar nerve entrapment causes
Fractures – elbow, Colle’s
Dislocations - elbow
Post-surgical complications
Prolonged compression
Repetitive action
Direct trauma
Colle’s fracture
distal radius fracture with dorsal comminution, dorsal angulation, dorsal displacement, radial shortening
—> DINNER FORK DEFORMITY
ulnar nerve entrapment – SSx
Claw hand
—> Complete ulnar nerve lesion
Positive Froment’s Sign
Muscle wasting
Altered Sensation
—> Ulnar side of the hand
Froment’s sign
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.”
Ulnar claw hand
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).”
LOWER EXTREMITY NERVE PATHOLOGIES
..
Piriformis Syndrome
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.
piriformis syndrome, causes / risk factors
Tight piriformis muscle
Trauma to piriformis
Inflammation/degeneration of piriformis
Posture/position/wallet (?)
Trigger points
Genetic/anatomic abnormalities
SI/pelvic misalignment
Lower cross syndrome
: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.
APT & Piriformis syndrome
(Note that with APT, there is COUNTER-NUTATION of sacrum)
“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.”
SI joint counter-nutation vs Piriformis syndrome
“SI joint counternutation can compromise the function of greater sciatic notch and infrapiriform fossa exacerbating piriformis syndrome”
piriformis syndrome – clinical manifestation
Unilateral
Pain
Paresthesia
Atrophy
Weakness
piriformis syndrome – Tx
Injections of corticosteroids
Stretching/strengthening
SI joint mobilization/manipulation
Hydrotherapy
Self care
Tarsal Tunnel Syndrome
Compression of the tibial nerve within the tarsal tunnel
Tarsal tunnel is formed by the flexor retinaculum between the medial malleolus and calcaneus
tarsal tunnel contains
–> Tibialis posterior tendon
–> Flexor digitorum longus tendon
–> Flexor hallucis longus tendon
–> Tibial nerve
–> Posterior tibial artery and vein
tarsal tunnel syndrome – causes
Repetitive stress activities; running, standing, walking
–> Flat feet; pes planus, hindfoot valgus
–>Trauma
–> Excessive (body?) weight
hindfoot valgus and flat feet / collapsed arch
“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.”
tarsal tunnel syndrome –> clinical presentation
Pain; burning or shooting
Numbness, tingling
crural, sural
crural = relating to the leg or the thigh.
sural = relating to the calf of the leg.
