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Tubercle of the scaphoid bone

The tubercle of the scaphoid bone is a prominent bony projection located on the palmar (anterior) surface of the scaphoid, one of the proximal row carpal bones of the wrist. It serves as a key palpable landmark on the lateral side of the wrist and provides attachment for important ligamentous and fascial structures that stabilize the carpal tunnel and maintain wrist mechanics.

This tubercle is clinically significant because of its proximity to the flexor retinaculum and radial artery, and because it is often involved in scaphoid fractures or degenerative wrist conditions.

Synonyms

  • Volar tubercle of scaphoid

  • Scaphoid ridge

  • Palmar process of scaphoid

Location and Structure

  • Situated on the palmar (anterior) surface of the scaphoid bone, near its distal end.

  • Lies lateral to the tubercle of the trapezium, forming the lateral boundary of the carpal tunnel.

  • Its surface is rough and slightly elevated, providing strong attachment for ligaments and fascia.

  • The scaphoid articulates proximally with the radius, medially with the lunate, and distally with the trapezium and trapezoid.

Relations

  • Anteriorly (superficial): Palmar fascia, skin, and flexor retinaculum

  • Posteriorly: Body of the scaphoid bone and its trabecular architecture

  • Laterally: Radial artery (in the anatomical snuffbox region)

  • Medially: Tubercle of the trapezium

  • Inferiorly: Carpal tunnel and underlying flexor tendons

Attachments

  • Flexor retinaculum: One of its four major attachments; anchors the retinaculum’s lateral border

  • Palmar radiocarpal ligament: Provides stabilization to anterior wrist joint capsule

  • Palmar aponeurosis fibers: Occasionally attach via fibrous extensions

  • Joint capsule: Strengthens the anterior aspect of the wrist joint

Function

  • Structural support: Forms part of the carpal arch, maintaining the anterior concavity of the wrist

  • Carpal tunnel boundary: Contributes to the lateral wall of the carpal tunnel, opposing the hook of the hamate medially

  • Attachment site: Provides anchorage for key ligamentous and fascial structures that stabilize the wrist

  • Palpation landmark: Used clinically to locate scaphoid fractures and delineate the carpal tunnel

Clinical Significance

  • Fractures: The scaphoid tubercle may fracture in association with scaphoid waist or distal pole fractures; often palpable tenderness in trauma

  • Palpation: Used as a key landmark for evaluating scaphoid tenderness in wrist injury

  • Degenerative changes: May develop osteophytes in chronic stress or osteoarthritis of the wrist

  • Carpal tunnel syndrome: Tubercle serves as a fixed point for flexor retinaculum attachment, sometimes contributing to tunnel narrowing

  • Surgical relevance: Landmark during carpal tunnel release and scaphoid fixation procedures

  • Imaging importance: Helps define orientation of scaphoid and evaluate cortical continuity in trauma

MRI Appearance

  • T1-weighted images:

    • Cortex: Low signal (dark), sharply defined

    • Marrow: Bright (fatty marrow signal) in normal adults

    • Fracture line: Appears as a thin, dark, linear signal crossing cortex or subchondral region

    • Adjacent retinaculum: Intermediate signal attaching to its anterior surface

    • Periosteal reaction or edema: Intermediate-to-bright signal around cortical margins

  • T2-weighted images:

    • Cortex: Low signal

    • Marrow: Bright signal, slightly less intense than T1

    • Fracture or bone bruise: Hyperintense marrow signal with cortical disruption

    • Soft-tissue inflammation: Bright periosseous signal around tubercle

    • Joint fluid: High signal outlining adjacent articulations

  • STIR:

    • Normal tubercle: Intermediate-to-dark signal

    • Pathology: Bright hyperintense signal indicating edema, contusion, or inflammation

    • Useful for early detection of occult fractures or stress reactions

  • Proton Density Fat-Saturated (PD FS):

    • Normal marrow: Intermediate-to-dark signal

    • Fractures or contusions: Focal bright hyperintensity within subcortical bone

    • Excellent for evaluating marrow edema, cortical breach, or ligament attachment pathology

  • T1 Fat-Sat Post-Contrast:

    • Normal bone: Mild uniform enhancement of marrow

    • Fracture or osteitis: Focal or diffuse enhancement near cortical break

    • Infection or inflammation: Patchy marrow enhancement with surrounding soft-tissue enhancement

CT Appearance

Non-Contrast CT:

  • Cortex: High-density, well-defined margins

  • Marrow cavity: Homogeneous low attenuation (fatty content)

  • Fracture: Linear lucency through tubercle or extending into scaphoid body

  • Cortical irregularity: May indicate osteophytes, avulsion, or degenerative change

  • Soft tissues: Flexor retinaculum and tendons identifiable anterior to tubercle

CT VRT 3D image

Tubercle of scaphoid bone 3d coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT VRT 3D image

Tubercle of scaphoid bone 3d coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001

MRI image

Tubercle of scaphoid bone axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Tubercle of scaphoid bone coronal cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Tubercle of scaphoid bone sag cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

Tubercle of scaphoid ct axial image