Superior sublabral sulcus

Last revised by Rohit Sharma on 26 Mar 2023

A superior sublabral sulcus or superior sublabral recess is a small synovial lined gap or detachment between the labral free edge and the cartilage, forming a normal glenoid labral variant 1. It can be associated with a sublabral foramen.

The superior labral sulcus or recess is a small groove covered by synovium 2 caused by a loose attachment of the superior labrum to the glenoid rim. It is most often located in the anterior part of the superior labrum but can be also found more centrally 2 at the proximal attachment of the long head biceps tendon to the glenoid labrum.

The sublabral recess can feature different depths ranging from <2 mm to >5 mm 2,3.

A sublabral recess is best detected on coronal oblique oriented fat-saturated T1 weighted images on MR arthrography 2 or in patients with joint effusion 1.

Typical imaging features include the following 1,4:

  • anterior location only extending to the posterior insertion point of the biceps tendon origin

  • smooth regular contour

  • medial orientation paralleling the glenoid cartilage underneath

A superior sublabral sulcus is a frequent finding on MRI and can be found in more than 70% of cases 2,3. It features a similar appearance and needs to be differentiated from sublabral foramen and from type II SLAP lesion 5. The latter is usually characterized by irregular contours that can extend posteriorly to the biceps tendon anchor 2 or laterally into the substance of the glenoid labrum 1.

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