Supraspinous Fossa: Anatomy and Pathology

Abstract

Supraspinous fossa is an important location in the periscapular region, which houses important structures such as the supraspinatus muscle and the suprascapular nerve. The supraspinous fossa can be affected by pathologies involving its contents (supraspinatus muscle and suprascapular nerve), osseous boundary (scapular body, distal clavicle, and spinous process), or superficial soft tissue covering it. In this pictorial review, we describe the detailed anatomy of the supraspinous fossa. We have also covered imaging of wide range of pathologies that can affect supraspinous fossa such as paralabral cyst, muscle edema/atrophy, malignancies (primary and secondary), and miscellaneous lesions (myositis ossificans, fibromatosis, nerve sheath tumor, etc.). An awareness of the imaging findings of these entities is essential for a radiologist to avoid misinterpretation and can aid a timely diagnosis.

Keywords: MRI; suprascapular nerve; supraspinatus muscle; ultrasonography.

Fig. 1

Graphic showing ( A ) supraspinous fossa anatomy and ( B ) the course of suprascapular nerve.

Fig. 2

Graphic showing Rengachary classification.

Fig. 3

Muscle magnetic resonance imaging showing ( A ) normal (orange star) muscle with intermediate signal intensity on proton density-weighted sagittal sequence. Note that supraspinatus and infraspinatus muscles show increase signal intensity suggesting edema along with volume loss (red arrows in A ), and ( B ) T1-weighted sagittal sequence showing fatty atrophy of supraspinatus muscle (blue arrow).

Fig. 4

Magnetic resonance (MR) imaging showing normal suprascapular nerve in suprascapular notch (circle in A) and spinoglenoid notch (arrow in B), and MR neurography showing high-signal nerves (arrow in C) standing out from the darker fat-suppressed background soft tissues.

Fig. 5

Goutallier classification of fatty atrophy of muscle.

Fig. 6

Sagittal magnetic resonance imaging (Y view) showing “tangent sign” for supraspinatus fatty atrophy; note that normal muscle ( A ) crosses the tangent, whereas atrophic muscle ( B ) does not cross it.

Fig. 7

Parsonage–Turner's syndrome in two different patients showing edema in supraspinatus and infraspinatus muscles.

Fig. 8

Magnetic resonance imaging of the shoulder showing superior labral tear (arrow in A ) with paralabral cyst (star in A ) and ( B ) formation extending into spinoglenoid notch causing compression of suprascapular nerve.

Fig. 9

Conventional radiograph ( A ) and magnetic resonance imaging ( B – D ) of a 66-year-old man with chondrosarcoma affecting scapular spine with extension into supraspinous fossa.

Fig. 10

Magnetic resonance imaging in different patient showing osteochondroma (arrow in A ), nerve sheath tumor (arrow in B and C ), metastasis (arrow in D and E ), and lymphoma (arrow in F and G ) affecting supraspinous fossa.

Fig. 11

Magnetic resonance imaging showing lipoma (star) in supraspinous fossa following fat signal intensity.

Fig. 12

Magnetic resonance imaging showing fibromatosis (star) in supraspinous fossa showing heterogeneous signal intensity with areas of low signal intensity in it.

Fig. 13

Conventional radiograph ( A ) and magnetic resonance imaging ( B – D ) showing myositis ossificans (arrow) in supraspinous fossa.