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Medial supracondylar ridge

The medial supracondylar ridge is a prominent bony elevation located on the distal medial border of the humeral shaft, extending from the lower third of the humerus down to the medial epicondyle. It forms the superior boundary of the medial supracondylar region and serves as an important site for muscular and fascial attachment.

This ridge provides origin for forearm flexor muscles and contributes to the structural contour of the distal humerus. It also serves as a palpable landmark in the distal arm, clinically relevant in fractures and surgical exposures of the humerus.

Synonyms

  • Medial supracondylar line

  • Medial supracondylar crest

  • Inferior medial border of the humerus

Location and Structure

  • Situated along the distal one-third of the humeral shaft on its medial aspect.

  • Extends inferiorly and medially toward the medial epicondyle.

  • The ridge is sharp and prominent in its lower portion, blending superiorly with the medial border of the shaft.

  • Forms part of the anterior and posterior compartments of the distal arm by giving attachment to the medial intermuscular septum.

  • Lies superior to the medial epicondyle, which projects more distally and medially.

Attachments

  • Anterior surface: Origin of the pronator teres (humeral head) and part of the brachialis muscle.

  • Posterior surface: Attachment for the medial intermuscular septum, separating anterior (flexor) and posterior (extensor) compartments of the arm.

  • Medial border: Fascial attachment contributing to the continuity of the deep brachial fascia.

Relations

  • Anteriorly: Brachialis and pronator teres muscles.

  • Posteriorly: Triceps brachii (medial head) near the distal shaft.

  • Superiorly: Continuous with the medial border of the humerus.

  • Inferiorly: Terminates at the medial epicondyle.

  • Laterally: Medial surface of the humerus forming part of the distal shaft contour.

Function

  • Muscle attachment: Provides stable origin points for the pronator teres and brachialis muscles.

  • Structural reinforcement: Contributes to the strength and rigidity of the distal humerus.

  • Compartmental separation: Anchors the medial intermuscular septum, separating flexor and extensor muscle groups.

  • Anatomic landmark: Serves as a guide during orthopedic surgery and palpation in distal arm fractures.

Clinical Significance

  • Fractures: Commonly involved in supracondylar or distal humeral fractures, which may extend through the ridge into the epicondylar region.

  • Muscle avulsion: Pronator teres origin may avulse in high-energy trauma.

  • Surgical landmark: Important for approaches to the distal humerus and medial elbow; guides fixation plate positioning.

  • Radiological importance: The ridge helps identify the humeral orientation and detect subtle fractures or cortical irregularities on imaging.

  • Myositis ossificans: May occur along the ridge following trauma or chronic muscle strain.

MRI Appearance

  • T1-weighted images:

    • Cortical bone: low signal (dark).

    • Marrow within humeral shaft: bright fatty signal.

    • Muscle attachments: intermediate signal with clear cortical interface.

    • Periosteum and intermuscular septum: low-signal linear structures.

  • T2-weighted images:

    • Cortical bone: dark.

    • Marrow: bright, slightly less than on T1.

    • Muscle and fascia: intermediate signal.

    • Edema or fracture line: bright hyperintense focus adjacent to cortical margin.

  • STIR:

    • Normal bone: intermediate-to-dark signal.

    • Pathology (fracture, periostitis, edema): bright hyperintense signal.

    • Sensitive for early bone injury or inflammatory change.

  • Proton Density Fat-Saturated (PD FS):

    • Normal cortex: dark linear outline.

    • Marrow: intermediate-to-dark.

    • Pathologic changes: bright high-signal areas in bone or muscle indicating edema, contusion, or periosteal reaction.

  • T1 Fat-Sat Post-Contrast:

    • Normal ridge: minimal enhancement of periosteum and adjacent soft tissues.

    • Fracture or inflammation: focal enhancement along cortical surface or muscular attachments.

    • Myositis ossificans or osteomyelitis: heterogeneous peripheral enhancement with low-signal core.

CT Appearance

Non-Contrast CT:

  • Cortical ridge: high-attenuation dense bony line along distal medial humeral shaft.

  • Surface: sharply defined with smooth contour in normal anatomy.

  • Fractures: linear cortical breaks, step-offs, or periosteal thickening visible with high spatial resolution.

  • Helpful for evaluating subtle nondisplaced fractures, cortical irregularities, or enthesopathic changes at muscular origins.

Post-Contrast CT (standard):

  • Enhancement of surrounding soft tissues may indicate inflammation, hematoma, or vascular injury.

  • Useful in assessing post-traumatic swelling, periosteal reaction, or tumor infiltration around the distal humerus.

CT VRT 3D image

Medial supracondylar ridge 3D VRT IMAGE

MRI image

Medial supracondylar ridge coronal cross sectional anatomy 3T MRI AI enhanced radiology image -img-00000-00000

MRI image

Medial supracondylar ridge coronal cross sectional anatomy 3T MRI AI enhanced radiology image -img-00000-00000_00001

CT image

Medial supracondylar ridge ct coronal image