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Inferior angle of scapula

The inferior angle of the scapula is the pointed, triangular projection located at the lowest part of the scapula, where the medial and lateral borders meet. It serves as an important surface landmark of the posterior thoracic wall and plays a key role in shoulder mechanics by providing attachment for muscles that control scapular movement.

It is widely used as a reference point in physical examination, shoulder imaging, orthopedic assessment, and surgical planning.

Synonyms

  • Inferior scapular angle

  • Lower angle of the scapula

Location

  • Situated at the most inferior part of the scapula

  • Formed by the junction of the medial and lateral borders

  • Typically lies opposite the T7 spinous process in the anatomical position

  • Overlies the posterior thoracic wall

  • Moves with scapular rotation and elevation/depression

Anatomical components

  • Triangular bony projection

  • Cortical bone with underlying cancellous marrow

  • Muscle attachment zone:

    • Teres major

    • Serratus anterior

    • Latissimus dorsi (occasionally via fascial slips)

Relations

Anteriorly:

  • Ribs and intercostal muscles

  • Subscapularis muscle

Posteriorly:

  • Skin and subcutaneous tissue

  • Trapezius and latissimus dorsi muscles

Medially:

  • Medial border of scapula

Laterally:

  • Lateral border of scapula

Inferiorly:

  • Thoracic wall

Superiorly:

  • Scapular body

X-ray appearance

Plain radiographs (AP shoulder, scapular Y, and lateral views):

  • Inferior angle: Seen as a pointed projection at the lower end of the scapula

  • Cortical outline: Sharp and well-defined

  • Position: Helps assess scapular alignment and rotation

  • Best visualized on: Scapular Y and lateral scapular views

CT appearance

Non-contrast CT:

  • Inferior angle: Well-defined bony projection

  • Cortical margins: Smooth and sharply outlined

  • Trabecular pattern: Normal cancellous bone texture

  • Spatial evaluation: Excellent for assessing morphology, contour, and subtle fractures

  • Relationship to thoracic wall: Clearly demonstrated

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow: High signal intensity

  • Inferior angle contour: Well delineated against surrounding soft tissues

T2-weighted images:

  • Cortex: Low signal

  • Adjacent muscles and soft tissues: Intermediate to high signal

  • Muscle insertions: Clearly visualized at the inferior angle

STIR:

  • Fat suppression: Uniform suppression of marrow fat

  • Inferior angle margins: Well outlined

  • Surrounding muscle planes: High signal contrast

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Muscle attachments: Seen as low-signal structures inserting at the inferior angle

  • Soft-tissue contrast: Excellent for delineating tendon and muscle interfaces

CT VRT 3D image

Inferior angle of scapula

X-Ray image

Inferior angle of scapula x ray anatomy labelled image-img-00000-00000

CT image

Inferior angle of scapula ct