Dorsal Scapular Neuropathy
Introduction
Periscapular pain is a common clinical presentation. Amongst other causes an entrapment neuropathy of the dorsal scapular nerve can cause these symptoms. These conditions can be treat with conservative treatment.
The article is split into:
Anatomy of the dorsal scapular nerve.
Symptoms of dorsal scapular neuropathy.
Pathology of dorsal scapular neuropathy.
Anatomy of the dorsal scapular nerve
Muir (2017) identified the course of the dorsal scapular nerve as:
Originates from the anterior ramus of the C5 nerve root directly, or, as the first branch of the superior trunk of the brachial plexus. Variations include sharing a common branching trunk with the long thoracic nerve, C4 nerve root or C4 and C5 nerve root. Trescot (2016) said the nerve can receive nerve roots from as low as T1.
Arises within the posterior cervical triangle deep to the prevertebral fascia. It then passes obliquely and inferiorly through the middle scalene without innervating it. Variations include the nerve piercing the middle and posterior scalene muscles.
Runs inferior and slightly laterally between the superior fibres of the upper trapezius medially and the levator scapulae laterally. Variations include the dorsal scapular nerve piercing the levator scapulae.
Passes deep to the upper trapezius fibres between the rhomboid major/minor and the serratus posterior superior muscle.
Runs inferiorly along the medial boarder of the scapula to the inferior medial boarder of the scapula.
Variations in the course of the dorsal scapular nerve includes a looping of the nerve around the deep branch of the cervical artery and dorsal scapular artery.
Signs and symptoms of dorsal scapular neuropathy
The signs and symptoms of dorsal scapular neuropathy as:
Pain, stiffness, dysesthesia in the scapular, thoracic and costovertebral area (& Sultan et al 2013) and cervical spine (Trescot 2016).
Posterolateral arm symptoms (Muir 2017). Lateral arm and forearm symptoms (Trescot 2016).
Notalgia paresthetica (NP): pruritis, numbness and tingling, and pain in the upper to mid-thoracic spine (Muir 2017).
Winged scapula or ‘SICK’ scapula: acronym for Scapular malposition, Inferior medial boarder prominence, Coracoid pain and malposition, and dysKinesis of scapular movement (Muir 2017).
Anterior chest pain and pain on palpating the anterior chest wall over the T4 sternocostal boarder (Trescot 2016).
Rhythmic involuntary jerking movements of the shoulder (Trescot 2016).
In chronic cases atrophy of the Rhomboid and Levator Scapula (Trescot 2016).
Pathology of dorsal scapular neuropathy
Vascular (Muir 2017):
Variations from the standard anatomical description of the dorsal scapular nerve can cause the nerve to become compressed by:
Deep branch of the cervical artery.
Dorsal scapular artery.
Musculoskeletal
If following the standard anatomical description the dorsal scapular nerve can become entrapped in the:
Scalene Medius (Muir 2017, Sultan et al 2013, Hanson & Auyong, 2013).
Rhomboids (Sultan et al 2013).
Variations from the standard anatomical description of the dorsal scapular nerve can cause the nerve to become compressed by (Muir 2017):
Tendonous fibrous tissue at the inferior edge of the Scalene Medius (Trescot 2016).
Posterior Scalene.
Levator Scapulae.
Elongation of the C7 TP (Sultan et al 2013).
As well as the dorsal scapula nerve the long thoracic nerve can also course through the Scalene Medius (Hanson & Auyong 2013).
Hester et al (2000) found the long thoracic nerve in close relation to a tight fascial band of tissue. This fascial tissue arose from the inferior aspect of the brachial plexus, extended just superior to the middle scalene muscle insertion on the first rib, and to the proximal aspect of the serratus anterior muscle.
Abduction and external rotation (e.g. a throwing action) caused the long thoracic nerve to "bow-string" across this fascial band. This was postulated as dynamically compressing the long thoracic nerve (Hester al 2000).
Winging of the scapula caused by a long thoracic or dorsal scapula neuropathy may:
Further compress the long thoracic nerve: (Hester et al 2000) found medial and upward migration of the superior most aspect of the scapula was found to further compress the long thoracic nerve.
Induce a stretch of the cutaneous medial branches of the dorsal primary rami of thoracic spinal nerves: this will refer further pain to the interscapular region (Sultan et al 2013).
References
Muir, B. Dorsal scapular nerve neuropathy: a narrative review of the literature (2017)
Sultan HE, Younis El-Tantawi GA. Role of dorsal scapular nerve entrapment in unilateral interscapular pain. (2013).
Hanson NA, Auyong DB.Systematic ultrasound identification of the dorsal scapular and long thoracic nerves during interscalene block. (2013).
Trescot A. Dorsal Scapular Nerve Entrapment (2016)
Hester P, Caborn DN, Nyland J. Cause of long thoracic nerve palsy: a possible dynamic fascial sling cause. (2000).
