Review Question - QID 220120

The patient in this vignette has medial scapular winging, where the medial border of the scapula displaces medially from the thoracic wall, most prominently during forward flexion or a wall push-up. Medial scapular winging is a disorder characterized by a dysfunctional serratus anterior muscle, leading to compensatory overactivity of the rhomboids (major and minor) and the levator scapulae (answer choice 5).

Scapular winging is a rare condition caused by neuromuscular imbalances in the scapulothoracic stabilizer muscles. Scapular winging can be classified as medial or lateral, based on the displacement of the scapula on the thoracic wall. Medial scapular winging is caused by dysfunction or injury to the long thoracic nerve (LTN) (C5-C7), resulting in weakness or paralysis of the serratus anterior muscle. As a result of the neuromuscular dysfunction, the scapula is often found elevated superiorly with a prominent medial border and medial rotation of the inferior pole of the scapula. The deformity is especially pronounced with forward elevation or when attempting wall push-ups. Medial winging is most commonly a result of damage (blunt or stretching) of the long thoracic nerve but can also occur with nontraumatic etiologies such as Pasonaage-Turner, viral illness, or iatrogenic injury. Treatment is typically nonsurgical initially, with therapy focused on the strengthening of periscapular muscles. Most patients will find a spontaneous recovery within one year. Approximately 25% of patients will require surgery with treatments involving a nerve transfer or a split pectoralis muscle transfer.

Vastamäki et al. published a retrospective review of 92 patients with scapular winging diagnosed as isolated neurogenic serratus anterior palsy. All patients were treated conservatively with a mean follow-up of 18.1 years to measure the long-term outcome of the various etiologies of serratus anterior palsy. The authors reported 37 (40%) cases were from exertion, 22 (24%) cases were from trauma, and surgery/anesthesia caused 10 (11%) cases. The authors found that palsies as a result of infection had better recovery outcomes, while palsies from surgery or anesthesia had poorer outcomes. Overall, the authors concluded that etiology influenced long-term outcomes less than hypothesized.

Patteta et al. published a review of various nerve compression syndromes in the shoulder, including long thoracic nerve palsy. The long thoracic nerve (LTN) originates from C5, C6, and C7 nerve roots before passing beneath the clavicle and first rib and coursing on the lateral chest wall. Due to the superficial course of the LTN, the nerve is highly susceptible to injury. The authors note that blunt trauma is the most common compressive cause of LTN palsy, with other traumatic causes including sudden depression of the shoulder girdle and neck twisting. The authors conclude by discussing treatment for recalcitrant LTN palsy, which includes a split pectoralis transfer, and in chronic cases, LTN neurolysis and decompression alone have shown to be sufficient.

Meninger et al. published a review on scapular winging, covering etiologies, examination findings, and various treatments and outcomes. The authors again highlight that neuropraxia from blunt or stretch injury to the LTN is the most common cause of medial winging. In the setting of suspected blunt trauma or stretching of the LTN, the authors recommend an electromyogram at the six-week mark to confirm the diagnosis. Physical therapy with or without scapular bracing can be attempted for at least a year without improvement before surgical interventions are considered. The authors' preferred treatment in these cases is a transfer of the entire ipsilateral pectoralis major tendon with autogenous hamstring graft augmentation to the inferior pole of the scapula.

Incorrect Answers:
Answer 1: Although medial scapular winging results from injury to the long thoracic nerve (LTN), the nerve roots in this answer choice are incorrect. The LTN originates from C5, C6, and C7.
Answer 2: This answer choice describes the Eden-Lange transfer, which is used to treat chronic or delayed lateral scapular winging. Medial scapular winging, as presented in the stem, is treated with a pectoralis major muscle transfer to provide a dynamic stabilizer to the inferomedial scapula.
Answer 3: The most common etiology for medial scapular winging is damage to the LTN from blunt trauma or stretching. Iatrogenic injury to the spinal accessory nerve, causing trapezius dysfunction, is the most common cause (up to 70%) of lateral scapular winging. This can occur during certain procedures such as a cervical node biopsy or post-carotid endarterectomy.
Answer 4: This statement is incorrect. The serratus anterior muscle is deficient or dysfunctional in medial scapular winging. The serratus anterior functions include scapular protraction (pulling the scapula forward and around the ribcage), upward rotation, and stabilization.