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Lateral border of scapula

The lateral border of the scapula, also known as the axillary border, is the thick, oblique margin of the scapula extending from the inferior aspect of the glenoid cavity to the inferior angle. It forms a key structural and muscular attachment zone and plays an important role in shoulder stability and upper limb biomechanics.

It is an important landmark in shoulder anatomy, trauma assessment, and musculoskeletal imaging.

Synonyms

  • Axillary border of the scapula

Location

  • Extends from the inferior margin of the glenoid cavity

  • Runs obliquely downward and medially

  • Terminates at the inferior angle of the scapula

  • Forms the lateral boundary of the scapular body

  • Faces the axilla

Anatomical components

  • Thickened osseous margin of the scapular body

  • Prominent muscular attachment zone

  • Cortical bone with underlying cancellous bone

  • Transition region between glenoid neck and scapular body

Relations

Anteriorly:

  • Subscapularis muscle

Posteriorly:

  • Infraspinatus muscle (upper part)

  • Teres minor and teres major muscles (lower part)

Medially:

  • Body of the scapula

Laterally:

  • Axillary fat and neurovascular structures

Superiorly:

  • Neck of the scapula and glenoid cavity

Inferiorly:

  • Inferior angle of the scapula

Muscle attachments

  • Teres minor: Upper two-thirds of the lateral border

  • Teres major: Lower one-third of the lateral border

  • Long head of triceps brachii: Originates just inferior to the glenoid, adjacent to the upper lateral border

X-ray appearance

Plain radiographs (AP and lateral scapular views):

  • Lateral border: Seen as a dense oblique cortical line extending from the glenoid to the inferior angle

  • Cortical outline: Thick and well-defined

  • Relationship: Forms the lateral margin of the scapular silhouette

CT appearance

Non-contrast CT:

  • Lateral border: Thickened cortical margin with clear definition

  • Trabecular bone: Normal cancellous pattern

  • Anatomical detail: Excellent depiction of contour, thickness, and alignment

  • Glenoid continuity: Clearly visualized superiorly

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow within border: High signal intensity

  • Muscle attachments: Clearly seen adjacent to the border

T2-weighted images:

  • Cortex: Low signal

  • Surrounding muscles: Intermediate signal

  • Joint and soft tissues: Well differentiated

STIR:

  • Bone marrow: Fat suppressed with uniform signal

  • Lateral border margins: Well delineated

  • Adjacent soft tissues: High contrast against suppressed marrow

Proton density fat-saturated (PD FS):

  • Bone marrow: Suppressed fat signal

  • Muscle–bone interface: Clearly visualized

  • Soft-tissue contrast: Excellent for depicting attachments and peri-scapular soft tissues

CT VRT 3D image

Lateral border of scapula

X-Ray image

Lateral border of scapula x ray anatomy labelled image-img-00000-00000