Pathogenesis
The
pathogenesis of thoracic outlet syndrome can be linked with the anatomy of
the anterior scalene muscle. The anterior scalene muscle starts from the
transverse processes of C3-C6, slanting downward and forward, and inserts
into the first rib. When it contracts, the head bends to the same side and
forward.
The causes of anterior scalene muscle syndrome are:
1.
Cervical spondylosis – Spinal nerves C3-C8 provide motor innervation to
the anterior scalene muscle. Their irritation or compression evokes
increased tension in the anterior scalene muscle.
2.
Chronic overload and muscular strain – Chronic physical overload of the
anterior scalene muscle or its strain also produce the clinical picture of
anterior scalene muscle syndrome. Because the anterior scalene muscle
participates in inspiration, patients with bronchial asthma frequently
have anterior scalene muscle syndrome.
3.
Visceral pathology – The heart and lungs are innervated by the same
segments of the spinal cord as the anterior scalene muscle. Thus, chronic
cardiac and pulmonary disorders evoke reflex zones in the anterior scalene
muscle and are responsible for anterior scalene muscle syndrome. Radiating
pain to the left arm caused by this syndrome can also mimic heart
pathology.
The
brachial plexus is located between the anterior scalene and middle scalene
muscles. If the tonus of the anterior scalene muscle is increased, the
brachial plexus is found in the sphincter between these two muscles. As a
result, the brachial plexus becomes chronically irritated and produces a
rich neurological picture. The spinal nerves of C7-C8 are involved to the
greatest degree (C6-C7 and C7-T1 segments of spine.)
Anterior scalene muscle syndrome causes an abundance
of circulatory problems. The subclavian artery and vein pass between the
anterior scalene muscle and the first rib. An over-tensed muscle can
compress the artery and vein, or evoke their vasospasm by irritation of
the brachial plexus. Compression of the subclavian artery produces
symptoms of insufficient blood supply to the upper limb; compression of
the subclavian vein produces symptoms of insufficient blood drainage
(edema). Additionally, the anterior scalene muscle can compress the
vertebral artery or evoke vasospasm by irritating its sympathetic plexus.
Clinical
symptoms
The
main clinical symptom is pain that increases: at night, during deep
breathing, when the head is bent and turned to the unaffected side, and
when the arm is abducted. The pain spreads to the shoulder, armpit and
lateral part of the thoracic cage. Also, patients complain about numbness
and paraesthesia on the ulnar edge of the hand (hypothenar and 4th-5th
fingers) and arm. One of the most important diagnostic signs is diversity
of vasomotor changes. These can be the result of insufficient arterial
blood supply to the arm (pain in the hand especially after exposure to
lower temperatures; pale, cold skin; cyanosis; weak pulse) or insufficient
venous blood drainage from the arm (edemas and increased skin
temperature). If anterior scalene muscle syndrome exists for a long period
of time, without adequate treatment, the hand will lose its strength
because of muscle atrophy mostly at the ulnar edge of the arm and the
hypothenar.
An important clinical sign involves Wartenberg’s
test. If the examiner palpates in the spot where the anterior scalene
muscle inserts into the first rib, local pain will appear. This test
allows the practitioner to differentiate anterior scalene muscle syndrome
can secondarily evoke rotator cuff syndrome. This is a very important
diagnostic test because irritation of the brachial plexus by an
over-tensed anterior scalene muscle can secondarily evoke rotator cuff
syndrome. if the practitioner mistakenly starts treatment of this
pathology as a rotator cuff syndrome, it will not yield significant
results because the real cause of the problem is anterior scalene muscle
syndrome.
Massage
Steps
Begin with patient in prone position.
1. Perform combination of effleurage and Freccion on
all areas of the upper back.
2.
Working in the inhibitory regime, perform petrissage #1 and #2 on all
areas of the upper back including the trapezius.
3. Perform
petrissage #3 on the neck for 3-4 minutes.
Turn patient over face
up.
1. Turn the patient’s head 45
degrees to the unaffected side.
2.
With thumbs, shift upwards (medially) the sternocleidomastoid muscles and
compress the anterior scalene muscle. Apply initial pressure from
approximately C3 level, and in a circular motion, massage the anterior
scalene muscle down towards its insertion (try to reach this place of
insertion) into the first rib. Repeat this technique 5-6 times
3.
Palpate to detect any trigger points in the area, especially where they
are commonly found approximately in the middle of the belly of the
anterior scalene muscle. Of course, it is important to detect all trigger
points.
4.
Once a trigger point is discovered, hold a finger over its place but do
not compress (yet). Turn the head to the same side, and slowly apply
ischemic compression.
5.
With one hand fix the scalene on the level of C3, and with the other hand,
fix the scalene at the C7 level. Slowly pull hands apart to apply traction
on the anterior scalene muscle.
6.
Perform massage; effleurage, Freccion action; on all areas of the forearm
and arm.
7.
Palpate to discover all possible trigger points in the arm. Eliminate all
detected trigger points with ischemic compression.
|