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Book

Anatomy, Shoulder and Upper Limb, Arm Quadrangular Space

Irfan A. Khan  1 , Marjorie V. Launico  2 , Matthew A. Varacallo  3
In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan.
.
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Book

Anatomy, Shoulder and Upper Limb, Arm Quadrangular Space

Irfan A. Khan et al.
Free Books & Documents

Excerpt

The quadrangular (or quadrilateral) space is so named because of the shape of its anatomic boundaries (see Image. Quadrangular Space, Posterior View). The posterior humeral circumflex artery (PHCA) and axillary nerve exit the axilla and transit this space to their destinations within the posterolateral shoulder. The axillary nerve arises from the posterior brachial plexus cord and divides into musculocutaneous branches, typically before entering or within the quadrangular space. The PHCA bifurcates into anterior and posterior branches inside the region.

The quadrangular space is a significant anatomic landmark for various diagnostic and surgical procedures. Quadrangular space syndrome (QSS) is a condition manifesting with axillary nerve or PHCA compression symptoms arising from various etiologies. Understanding this space's anatomy and functional significance is imperative for treating various upper limb conditions.

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Conflict of interest statement

Disclosure: Irfan Khan declares no relevant financial relationships with ineligible companies.

Disclosure: Marjorie Launico declares no relevant financial relationships with ineligible companies.

Disclosure: Matthew Varacallo declares no relevant financial relationships with ineligible companies.

References

    1. Beytell L, Mennen E, van Schoor AN, Keough N. The surgical anatomy of the axillary approach for nerve transfer procedures targeting the axillary nerve. Surg Radiol Anat. 2023 Jul;45(7):865-873. - PMC - PubMed
    1. Tang A, Varacallo MA. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2023. Aug 14, Anatomy, Head and Neck, Posterior Humeral Circumflex Artery.
    1. Rothe C, Lund J, Jenstrup MT, Steen-Hansen C, Lundstrøm LH, Andreasen AM, Lange KHW. A randomized controlled trial evaluating the impact of selective axillary nerve block after arthroscopic subacromial decompression. BMC Anesthesiol. 2020 Jan 31;20(1):33. - PMC - PubMed
    1. Flynn LS, Wright TW, King JJ. Quadrilateral space syndrome: a review. J Shoulder Elbow Surg. 2018 May;27(5):950-956. - PubMed
    1. Mostafa E, Imonugo O, Varacallo MA. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2023. Aug 7, Anatomy, Shoulder and Upper Limb, Humerus.

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