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Topic

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Femoral shaft

The femoral shaft, or diaphysis, is the long cylindrical portion of the femur between the proximal and distal ends. It is the longest and strongest part of the femur, designed to withstand significant axial loading and muscular forces. Its structure is essential for bipedal locomotion and weight bearing. The shaft is clinically important due to its susceptibility to fractures, tumors, and infections, making it a frequent focus in orthopedic and radiological practice.

Synonyms

  • Femoral diaphysis

  • Shaft of femur

  • Middle femoral bone

Structure and Relations

  • Shape: Cylindrical and slightly bowed anteriorly, with a triangular cross-section

  • Surfaces:

    • Anterior surface: Smooth, provides origin for vastus intermedius

    • Medial surface: Narrow, origin of vastus medialis

    • Lateral surface: Broad, origin of vastus lateralis

  • Borders:

    • Linea aspera: Prominent posterior ridge, attachment for adductors and intermuscular septa

  • Relations:

    • Anteriorly related to quadriceps muscles

    • Medially related to adductors

    • Laterally related to vastus lateralis and iliotibial tract

    • Posteriorly related to hamstrings

Nerve Supply

  • No direct innervation to bone tissue itself

  • Periosteum supplied by sensory branches of femoral, obturator, and sciatic nerves (pain sensitive)

Arterial Supply

  • Nutrient artery (branch of profunda femoris artery) entering nutrient foramen in midshaft

  • Periosteal vessels from femoral and profunda femoris arteries

  • Metaphyseal and epiphyseal branches near ends

Venous Drainage

  • Nutrient vein accompanies the nutrient artery into the femoral vein system

  • Periosteal veins drain into profunda femoris and femoral veins

Function

  • Provides structural strength and support for body weight transmission from hip to knee

  • Serves as the site of major muscular attachments (quadriceps, adductors, hamstrings)

  • Essential for locomotion, standing balance, and lower limb stability

Clinical Significance

  • Fractures: Common site for high-energy trauma fractures (transverse, spiral, comminuted)

  • Tumors: Osteosarcoma, Ewing sarcoma, and metastases often involve shaft

  • Infections: Osteomyelitis frequently affects the shaft due to vascular distribution

  • Surgical relevance: Target for intramedullary nailing and orthopedic fixation

MRI Appearance

T1-weighted images:

  • Cortical bone: very dark (signal void)

  • Marrow: bright to intermediate signal depending on fatty content

  • Fractures: dark fracture line through marrow

T2-weighted images:

  • Cortex: very dark

  • Marrow: bright signal due to fatty marrow

  • Pathology (edema, tumor infiltration, osteomyelitis): areas of focal hyperintensity replacing normal marrow

STIR (Short Tau Inversion Recovery):

  • Cortex: dark

  • Marrow: normally suppressed to low signal

  • Pathology (marrow edema, infection, tumor): bright hyperintensity

T1 Fat-Sat Post-Contrast:

  • Cortex: no enhancement

  • Normal marrow: mild homogeneous enhancement

  • Tumor, infection, or inflammation: heterogeneous or nodular enhancement

  • Abscess: peripheral rim enhancement with central non-enhancement

CT Appearance

Non-Contrast CT:

  • Cortex: very dense (bright white)

  • Medullary cavity: lower attenuation than cortex

  • Fractures: visible as cortical disruption or lucent lines

  • Lytic lesions: focal lucent areas

  • Sclerotic lesions: focal dense areas

Post-Contrast CT:

  • Cortex: does not enhance

  • Marrow: mild uniform enhancement

  • Tumors, infection, metastases: heterogeneous enhancement

  • Abscess/necrosis: rim enhancement with central low attenuation

MRI image

Femoral shaft MRI CORONAL anatomy image-img-00000-00000

MRI image

Femoral shaft MRI SAG anatomy image-img-00000-00000

CT image

Femoral shaft CT CORONAL IMAGE

CT VRT 3D image

Femoral shaft 3D CT VRT image