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Proper plantar digital nerves

The proper plantar digital nerves are the terminal sensory branches of the medial and lateral plantar nerves, which arise from the tibial nerve. They provide cutaneous sensation to the toes and adjacent interdigital spaces and carry motor fibers to small intrinsic muscles of the foot. These nerves are vital for fine touch, proprioception, and pain perception across the plantar surface of the digits.

There are typically four plantar digital nerves from the medial plantar nerve and three from the lateral plantar nerve. Each common plantar digital nerve divides into two proper plantar digital branches, which run along the sides of the toes, innervating the skin, nail bed, and soft tissue of the distal digits.

Synonyms

  • Plantar digital branches of medial and lateral plantar nerves

  • Digital nerves of the toes

  • Proper plantar nerves

Origin, Course, and Distribution

  • Origin: Arise from the terminal divisions of the medial and lateral plantar nerves in the sole of the foot (branches of the tibial nerve).

  • Course:

    • Each proper plantar digital nerve runs distally along the side of each toe, accompanying the plantar digital artery within a fibrous neurovascular sheath.

    • The medial plantar nerve typically gives rise to three common plantar digital nerves, which bifurcate into proper plantar digital nerves supplying the medial 3½ toes.

    • The lateral plantar nerve gives one common digital branch, dividing into proper digital nerves for the lateral 1½ toes.

  • Termination: Each nerve ends at the tip of the toe, providing terminal cutaneous and nail bed branches.

Relations

  • Superficial: Plantar skin and subcutaneous fat of the digits

  • Deep: Digital tendons of flexor digitorum longus and flexor hallucis longus

  • Medial and Lateral: Plantar digital arteries within common fibrous sheaths

  • Inferior (Plantar): Fibrous septa of the subcutaneous tissue separating the digital pads

  • Proximal: Branches of medial and lateral plantar nerves in the distal sole

Nerve Supply

  • Parent nerves: Medial and lateral plantar nerves (branches of the tibial nerve, S1–S3)

  • Type: Mixed (primarily sensory with small motor fibers to lumbricals and flexor muscles)

  • Distribution:

    • Medial plantar digital nerves: Medial 3½ toes (including the great toe)

    • Lateral plantar digital nerves: Lateral 1½ toes (including the lateral side of the little toe)

Function

  • Sensory innervation: Provides sensation to the plantar surface, nail bed, and skin of the toes

  • Motor contribution: Small branches supply the lumbricals and flexor hallucis brevis

  • Proprioception: Provides feedback for balance and toe positioning during gait

  • Pain and temperature perception: Important for protective sensation in weight-bearing

Clinical Significance

  • Entrapment neuropathy: Compression beneath the deep transverse metatarsal ligament may lead to interdigital neuritis (Morton’s neuroma)

  • Traumatic injury: Lacerations or crush injuries to the toe may damage digital nerves, causing numbness or neuropathic pain

  • Iatrogenic injury: Possible during plantar incisions or bunion and neuroma surgeries

  • Peripheral neuropathy: In diabetes or tarsal tunnel syndrome, distal digital sensation is often affected first

  • Clinical presentation: Tingling, burning, numbness, or shooting pain in the toes; positive Mulder’s click in neuroma

  • Imaging importance: MRI and high-resolution ultrasound assess nerve integrity, neuroma formation, or entrapment

MRI Appearance

  • T1-weighted images:

    • Normal nerve: low-to-intermediate signal linear structure within the neurovascular bundle

    • Surrounded by bright subcutaneous fat of the plantar tissue

    • Neuroma: oval or fusiform mass, intermediate-to-low signal intensity

    • Fatty tissue planes around nerve sharply delineated

  • T2-weighted images:

    • Normal nerve: intermediate-to-low signal, slightly darker than adjacent vessels

    • Neuroma or neuritis: bright hyperintense lesion continuous with the nerve

    • Edematous changes or fibrosis cause signal heterogeneity

    • Interdigital bursitis: adjacent fluid-bright collection between metatarsal heads

  • STIR:

    • Normal nerve: intermediate-to-dark signal

    • Pathology: bright hyperintensity in neuritis, trauma, or Morton’s neuroma

    • STIR accentuates edema and perineural fluid around the affected nerve

  • Proton Density Fat-Saturated (PD FS):

    • Normal: intermediate-to-dark signal

    • Neuroma: hyperintense fusiform lesion with tapering nerve continuity

    • Excellent for differentiating nerve thickening from adjacent vascular or soft-tissue lesions

  • T1 Fat-Sat Post-Contrast:

    • Normal nerve: minimal enhancement

    • Neuroma or neuritis: shows variable, often heterogeneous enhancement

    • Fibrotic lesion: mild peripheral enhancement

    • Helpful in distinguishing Morton’s neuroma from small ganglion cysts or bursitis

CT Appearance

Non-Contrast CT:

  • Nerve not directly visualized due to small caliber and soft-tissue density

  • May show widened intermetatarsal space or soft-tissue thickening in neuroma

  • Adjacent bone changes (pressure erosion or cortical remodeling) occasionally visible in chronic entrapment

Post-Contrast CT (standard):

  • Nerve enhancement subtle or absent in normal cases

  • Neuroma or inflamed nerve: mild-to-moderate contrast enhancement in intermetatarsal region

  • CT useful for detecting associated osseous deformities, masses, or postoperative changes

MRI image

Proper plantar digital nerve of foot axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000

MRI image

Proper plantar digital nerve of foot axial cross sectional anatomy 3T MRI AI enhanced radiology image-img-00000-00000_00001