NOTE: This post focuses on the location, palpation, and mechanical environment of nerves and their fasciae. The physiology of nerve entrapment and specific diagnostic/assessment criteria are not covered here.
“I always get pain right here“, says your patient, pointing vaguely to their shoulder blade. They say it with diagnostic emphasis, but you don’t share their enthusiasm. It’s the fourth patient today to confess such discomfort, and, judging from the abundance of persons curled around laptops and steering wheels, you’re likely to keep seeing folks with shoulder blade problems. You could be forgiven for blurring each case together, or wondering if your ministrations can create lasting change.
But the commonality of shoulder blade problems shouldn’t lead us to treat all sufferers the same, nor should we shrink from the challenge of creating long-term improvement. We use our shoulder blades constantly, in all kinds of ways, and so it’s not surprising that multiple schools of emphasis have arisen to explain scapular pain and dysfunction. The dominant models are something like these:
— Muscle-centric (“Tight pecs, overstretched rhomboids”),
— Bone-joint centric (“Rib Head dysfunction”), or
— Function-centric (“Improper stabilization/activation”).
None of these models are exclusive of each other… in fact I recommend gaining familiarity with each. But they each have blind spots, and when these modes of reasoning fail you, I urge you to consider the neurofascial tissues surrounding the shoulder blades as your primary object of inquiry.
THINKING OUTWARD FROM DURA
You can’t connect a local neural tension pattern to the whole system unless you can visualize what the spinal dura mater is experiencing. This may be fine if your patient has plenty of slack in their system. But what if one or both sciatic nerves are under tension? What about that old L4 disc herniation? That kidney surgery? That contralateral C1-C2 fixation? Make at least a cursory assessment of midline tension — whether it’s excessive, and where it’s coming from — before zooming into the local area. (NOTE: I plan to cover specific methods of midline assessment in later posts.)
From the scapula to the dura, the primary vector of mechanical tension is through the upper and posterior brachial plexus. Because mid-cervical nerve roots (unlike their thoracic and lumbar cousins) have small ligamentous tethers to their exiting transverse foramina, neural tension at the brachial plexus can exert unusually strong influence on vertebral position. So if you’re noticing a tendency of C5 and C6 to laterally deviate or rotate, check out the scapular neurofascia on the same side.
SUPERFICIAL NERVES
Before dropping into familiar muscles and bones of the shoulder blade, assess the mobility and sensitivity of skin. Branching in the subcutaneous fascia, and anchored down to the first layer of deep fascia, are a host of cutaneous nerves. When inflamed, these superficial nerves can generate pain, fascial restriction, and reflexive holding. (As a fun experiment, try working onlythis surface layer, and do a before-after assessment of scapular mobility.)
Supraclavicular nerves (C3-C4)
Spilling over the collarbone in front, and anchored to the acromion and lateral spine of the scapula, are these spindly branching fibers from the cervical plexus.They can be palpated as hard filaments on the surface of the clavicular and acromial periosteum.
C5-T7 Dorsal Rami (medial branch)
These emerge posteriorly from the nerve roots, perforate through the paraspinal compartments and the spine-attached scapular muscles, and then join the surface layer about 1 cm lateral to the spinous processes. From there they travel laterally and inferiorly, roughly along with classic dermatomes. (Warning when looking at dermatome maps: skin innervation is highly irregular and redundant.) These dorsal rami can become irritated at the nerve root (e.g. rib head subluxation), at their perforations, or where they cross over the scapula. Sometimes a winging scapula’s medial border can “rake” these nerves from below, and cause them to inflame locally.
Spinal Accessory Nerve (Cranial XI)
A strange hybrid, this nerve sidles up to the spinal cord within the cervical spinal canal, gathering itself from the C1-C5 rootlets, climbing into the cranial base, and then exiting through the jugular foramen. (For this reason, don’t ignore the cervical dura when treating this nerve). From its exit, the Accessory nerve splits into an SCM division (anteriorly) and a Trapezius division (posteriorly).
It can be palpated along the length of Trapezius on its underside, feeling like a squiggly branching vine, whose main trunk is about 1 cm medial to the medial border of the scapula. As with the dorsal rami, this nerve can become irritated by excessive winging of the scapula, and likewise by scapular protraction/anterior tilt.