Which of the following muscles is innervated by the common fibular (peroneal) nerve?

Explanation

## Common Fibular Nerve Innervation **Key Point:** The common fibular nerve innervates the **anterior compartment** (dorsiflexors) and **lateral compartment** (evertors) of the leg. It does NOT innervate any muscles in the posterior compartment. ### Motor Supply of Common Fibular Nerve #### Deep Fibular (Peroneal) Nerve Branch - **Tibialis anterior** — primary dorsiflexor of the foot - **Extensor digitorum longus** — extends toes - **Extensor hallucis longus** — extends great toe - **Fibularis tertius** — assists dorsiflexion and eversion #### Superficial Fibular (Peroneal) Nerve Branch - **Fibularis longus** — eversion and weak plantarflexion - **Fibularis brevis** — eversion **High-Yield:** A helpful mnemonic is **"Fibular = Foot Evertors + Toe Extensors."** The common fibular nerve supplies muscles that move the foot AWAY from the midline (eversion) and lift the toes (dorsiflexion). ### Clinical Pearl: Common Fibular Nerve Palsy **Mnemonic:** **"Foot Drop"** — Loss of dorsiflexion is the hallmark sign. - Patient cannot dorsiflex the foot → steppage gait - Loss of toe extension - Sensory loss over dorsum of foot and lateral leg - Eversion weakness (fibularis muscles affected) ### Comparison: Tibial vs. Common Fibular Nerve | Feature | Tibial Nerve | Common Fibular Nerve | |---------|--------------|----------------------| | **Compartment** | Posterior leg | Anterior + lateral leg | | **Main Action** | Plantarflexion, toe flexion | Dorsiflexion, eversion | | **Key Muscle** | Gastrocnemius, soleus | Tibialis anterior, fibularis | | **Injury Sign** | Foot inversion, weak plantarflexion | Foot drop, foot eversion | [cite:Clinically Oriented Anatomy 8e Ch 5]