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Neck of talus

The neck of the talus is the narrowed region between the talar body and head, projecting anteromedially. It serves as a transition zone and is a common site of talar fractures, particularly high-energy injuries such as motor vehicle accidents. The talar neck plays a key role in transmitting force between body and head and is critical for maintaining ankle and subtalar alignment.

Because of its unique retrograde vascular supply, fractures of the talar neck are highly prone to avascular necrosis (AVN). Early detection on MRI and CT is essential for preventing long-term morbidity.

Joints

  • Proximally continuous with body of talus → part of talocrural and subtalar joints

  • Distally continuous with head of talus → forms part of talonavicular joint

Ligament Attachments

  • Medial side: Deltoid ligament (tibiotalar fibers) may insert near the neck

  • Lateral side: Contributions from anterior talofibular ligament (ATFL) and interosseous talocalcaneal ligament support the region

  • Inferiorly: Cervical and interosseous talocalcaneal ligaments connect neck to calcaneus

Tendon and Muscle Relations

  • Anterior to neck: Tibialis anterior, extensor hallucis longus, extensor digitorum longus tendons cross near talar neck

  • Medial to neck: Tibialis posterior tendon courses close along the medial malleolus

  • Lateral: Peroneus tertius tendon passes laterally across the anterior ankle

Nerve Supply

  • Deep peroneal nerve: Anterior ankle and talocrural articulation

  • Tibial nerve: Subtalar and talonavicular contributions

  • Sural and saphenous nerves: Provide minor cutaneous/articular fibers

Arterial Supply

  • Posterior tibial artery: Artery of tarsal canal and deltoid branches supply talar body and neck

  • Dorsalis pedis artery: Artery of tarsal sinus supplies talar neck and head

  • Peroneal artery: Provides small lateral branches

  • Clinical note: Interruption of these vessels in talar neck fractures predisposes to AVN

Venous Drainage

  • Venous plexuses of talar neck drain into posterior tibial, dorsalis pedis, and peroneal veins

Function

  • Transmits forces between body and head of talus

  • Provides articulation for smooth transition from talocrural to talonavicular joint

  • Serves as anchor for ligaments stabilizing ankle and subtalar complexes

Clinical Significance

  • Fractures: Talar neck fractures are common in high-energy trauma

  • Complications: AVN and post-traumatic arthritis

  • Hawkins sign: Subchondral radiolucent band on X-ray after fracture → indicates preserved blood flow

  • Surgical importance: Precise reduction essential to restore ankle mechanics

  • Imaging role: MRI/CT are vital for early detection of AVN and subtle fractures

MRI Appearance

  • T1-weighted images:

    • Normal marrow of talar neck shows intermediate-to-high signal depending on fat content

    • Cortical bone appears as uniform low signal (dark)

    • Fracture lines: linear low-signal defects

    • AVN: diffuse low-signal marrow change

  • T2-weighted images:

    • Marrow signal variable (intermediate to high) depending on fat

    • Cortical bone remains dark low signal

    • Edema or fracture: bright hyperintense marrow signal

    • Osteochondral lesions: focal high-signal defects extending to articular surface

  • STIR:

    • Normal marrow suppressed (dark)

    • Pathology (fractures, edema, AVN): bright hyperintense signal

  • Proton Density Fat-Saturated (PD FS):

    • Normal: homogeneous dark marrow with cortical rim low signal

    • Pathology: bright signal areas highlight fractures, bone bruises, and necrosis

  • T1 Fat-Sat Post-Contrast:

    • Normal: uniform mild enhancement

    • AVN: lack of enhancement in necrotic core with rim enhancement

MRI Arthrogram Appearance

  • Contrast outlines ankle and subtalar joints around talar neck

  • Subtle cartilage or osteochondral defects become more conspicuous with contrast filling

  • Useful in detecting osteochondral lesions of talar dome adjacent to neck

CT Appearance

Non-Contrast CT:

  • Excellent cortical bone detail

  • Talar neck fractures: sharply delineated cortical disruption

  • Cortical bone: high-density rim, sharply defined

  • AVN: sclerotic changes, collapse, or fragmentation

Post-Contrast CT (standard):

  • Rarely used for bone itself

  • May highlight surrounding soft-tissue pathology or vascular compromise

CT Arthrogram Appearance

  • Contrast outlines talocrural and subtalar joints

  • Osteochondral lesions: contrast penetration into subchondral defects

  • Helpful when MRI contraindicated, especially for cartilage surface integrity

MRI image

neck of the Talus agittal MRI cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

CT image

neck of the Talus CT cross sectional anatomy radiology image-img-00000-00000

CT VRT 3D image

Neck of talus