Thoracic Outlet & Nerve Compression

• Thoracic Outlet Syndrome (TOS) involves compression/entrapment of the neurovascular tissues of the brachial plexus.

Anatomy & Compression Sites

• Three main compression sites for TOS include the interscalene triangle (anterior-middle scalenes), clavicle & first rib, and coracoid process & pec minor.
• An additional compression site involves an anatomical anomaly: a cervical rib, where an overgrown C7 TvP resembles a rib growing from C7 TvP to Rib 1.

Brachial Plexus

• Roots: C5-C8 & T1
• Trunks: superior, middle, and inferior.
• Divisions: anterior and posterior.
• Cords: lateral (C5-C7 nerve roots), posterior (C5-T1 nerve roots), medial (C8-T1 nerve roots).
• Branches: musculocutaneous (lat cord), axillary (post cord), radial (post cord), median (lat & med cords), ulnar (med cord), plus 11 other nerves.

Palpation

• Palpate the lateral edge of clavicular head of SCM, then the anterior scalene, then the brachial plexus.
• Palpation of plexus may cause discomfort radiating under the clavicle towards the coracoid process and possible paresthesia in the hand.
• Palpate affected tissue, assessing for low muscle tone in muscles down the upper extremity.
• Edema in the hand (especially dorsum) can result from venous occlusion.

Pathophysiology & Symptoms

• TOS involves compression of the medial cord of the brachial plexus, which stems from roots C8 & T1 and terminates in the ulnar nerve.
• Neural symptoms of TOS usually occur in an ulnar nerve distribution (90% of cases).
• Nerve symptoms include pain (local and referred), sensory loss/changes, and subtle motor weakness (not flaccidity).
• Vein symptoms include edema (especially dorsum of hand) and cyanosis.
• Artery symptoms include coldness in extremities, pallor, and trophic changes (if severe).

Subtle Weakness & Atrophy

• Wrist flexion and ulnar deviation.
• Adductor pollicis weakness (Froment's sign).
• Intrinsic hand muscle weakness (lumbricals, PIM, DIM).

Sensory Symptoms

• Sensory symptoms include issues in digits 5 & medial half of 4 (both palm and dorsum).
• Sometimes through the forearm distal to cubital tunnel (under FCU).

Onset & Causes

• Onset is usually insidious.
• Causes: internal compression (cervical rib), external compression (crutches), poor posture (hyperkyphosis, scoliosis), systemic disorders (RA, diabetes, hypothyroid), trauma/joint subluxation (whiplash), and pregnancy (fluid retention plus postural changes).

Cervical Rib Compression

• Prevalence is about 3%.
• Cervical rib can put pressure on the plexus.
• Presents variable symptoms and severity.

Anterior Scalene Syndrome

• Related to hypertoned/inflamed scalenes, or TrP in scalenes
• Symptoms can be neural or arterial.
• Subclavian vein does not go through the interscalene triangle.
• Venous symptoms suggest compression is not occurring at the interscalene triangle

Costoclavicular Syndrome

• Related to tone/inflammation of subclavius, or TrP in subclavius.
• Related to depressed shoulders (associated with wearing heavy bags) or chronic respiratory problems.
• Symptoms can be neural, arterial, or venous.
• This syndrome most likely causes distal edema

Pec Minor Syndrome

• Related to sustained/habitual overhead postures or activities.
• Overhead position stretches the neurovascular bundle between coracoid process and pec minor tendon.
• Symptoms can be neural, arterial, or venous.

Compression, Sensory, Venous, Arterial Symptoms & Tests

• Scalenii
  • Sensory: Digit 5 & Medial 4
  • Venous: None
  • Arterial: Pallor, Coldness, Heaviness
  • MOI: Neck postures supine/side lying
  • Positive Test: Adson's, Halstead's/Travell's
• Costoclavicular
  • Sensory: Digit 5 & Medial 4
  • Venous: Most likely site cyanosis, edema
  • Arterial: Pallor, Coldness, Heaviness
  • MOI: Carrying heavy stuff on shoulders
  • Positive test: Costoclavicular Syndrome test, Eden's
• Pec Minor/Coracoid
  • Sensory: Digit 5 & Medial 4
  • Venous: Possible cyanosis, edema
  • Arterial: Pallor, Coldness, Heaviness
  • MOI: Overhead postures or activities
  • Positive Test: Wright's

Precautions

• Standard precautions for systemic conditions/comorbidities apply to TOS.
• Inform patient that alleviating compression can recreate symptoms, and discomfort may last 1-2 days.

History Questions

• Exact location and nature of symptoms (pain, prickling, tingling, numbness).
• Weakness in wrist or hand?
• Clumsiness or decreased dexterity?
• Changes to skin/nails?
• Changes to color/temperature of hands?

Sleeping Position

• Elbows flexed (tension on ulnar nerve).
• Arm overhead (pec minor syndrome).
• Too many pillows supine (scalenes).
• Not enough pillows side-lying (scalenes).

ADLs

• Overhead postures or activities- "carrying heavy baggage" or "weight on shoulders" "depressing them."

Assessment Tests

• Adson's Test: assesses anterior scalenes compression.
• Halstead's/Travell's Variation Test: assesses middle scalenes compression.
• Costoclavicular Syndrome Test: assesses costoclavicular compression.
• Eden's Test: assesses costoclavicular compression.
• Wright's Hyperabduction Test: assesses pec minor compression.
• Scalene Cramp Test: assesses scalenes TrP.

Additional Tests:

• Pec Minor Length Test: assesses pec minor shortness.
• ULTT 4: assesses C8-T1 nerve roots or ulnar nerve tension.
• Froment's Sign: assesses adductor pollicis weakness.

Differential Diagnosis

• Scalenes TrP.
• Subclavius TrP.
• Pec Minor TrP.
• Raynaud's.
• Peripheral ulnar nerve compression (ulnar groove/cubital tunnel, Guyon's canal).
• Ulnar nerve tension.
• Nerve root compression (C8).
• Person sleeps with flexed elbow.

Treatment

• Decompress the glitchy bits with massage, PIR, NMT, MFR, lateral translations, PA glides.
• Treat costoclavicular space with subclavius, superior/anterior glides to the SC joint for pec major and minor.
• Pec minor can be treated with massage, supine/sidelying stretches or sidelying stretches/inhibition.
• Continue through the distal end of the medial cord by addressing the medial intermuscular septum, FCU, hypothenar
• Work on any TrP which may contribute.
• If apical breathing: work on diaphragm and intercostals with diaphragmatic breathing.
• Venous symptoms: elevate, unidirectional stroking, manual lymphatic drainage.

Home Care Suggestions

• Hydrotherapy and stretches.
• Diaphragmatic breathing/breathing reeducation (away from apical).
• Education and ADL modifications.

Scalenes MET

• Patient lies supine with a cushion or folded towel under the upper thoracic area.
• Head is rotated contralaterally (away from the side to be treated) to three positions of rotation:
  • Full contralateral: for posterior fibers.
  • 45°: for middle fibers.
  • Slight contralateral: for anterior fibers.
• Practitioner restrains the isometric contraction.
• Patient tries to lift the forehead and turn the head toward the affected side while practitioner resists.
• Effort and counterpressure should be modest and painless.
• After 7-10 second contraction, the head eases into extension.
• Patient's contralateral hand is placed inferior to the clavicle.
• Practitioner's applies stretch by pushing obliquely away towards the foot.
• Stretch is held for 20 seconds after each isometric contraction.
• The process is repeated at least more than once.

Questions about nerve compression syndromes, particularly thoracic outlet syndrome and ulnar nerve compression. Covers symptoms, diagnosis, and anatomical considerations related to these conditions. Focuses on clinical presentation and exacerbating factors.