Unilateral Levator Scapulae Anatomical Variants




Luu, Dustin
Frangenberg, Alexander
Vasilev, Viktor
Tran, Lianna
Kara, Ramiz
Fisher, Cara


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Background: Neck pain constitutes 13.8% of chief complaints. Causes of neck pain, including Levator Scapulae Syndrome (LPS), have become increasingly important and warrant discussion of contributing factors, such as anatomical variations. We present two discovered anatomical variants of the levator scapulae (LS) muscle. Awareness of the variation in LS accessory muscles may be relevant in differentiating between normal and pathological diagnoses, while remaining a possible target of therapy in pain syndromes, such as LPS.

Case Information: Routine cadaveric dissection of a 41-year-old female and a 50-year-old male donor was performed. Upon dissection of the superficial back of both cadavers, we discovered accessory muscle variants. Dissection of the deep upper back of the female cadaver, we noted a L sided, unilateral, accessory LS muscle slip that casually attached to the serratus posterior superior aponeurosis and tracked with the main body of the LS muscle superiorly. The caudal aspect of the accessory slip inserted perpendicularly onto the broad aponeurotic fibers of the serratus posterior superior muscle around T3. The insertion tracked anterolaterally and superiorly, combining with the muscle belly of the LS around C7-T1 and traveling deep to the right sternocleidomastoid (SCM) to insert on the C1-C4 cervical vertebrae. Following a superior reflection of the R-sided trapezius muscle in the male cadaver, we noted an unilateral accessory muscle band that was attached to the midline spine caudally and tracked with the main body of the LS superiorly. The caudal attachment originated from the T3-T4 spinous process, deep to the rhomboid major muscle and superficial to the posterior serratus superior muscles. The insertion of the accessory runs anteriorly and superiorly, deep to the right SCM, and tracks in a parallel fashion to the main body of the LS.

Conclusions: This case series presents two unilateral LS anatomical variants discovered separately during routine cadaveric dissections.