Steppage gait is most often due to weakness of dorsiflexors involving which nerve root?

Steppage gait is most often due to weakness of dorsiflexors involving which nerve root?

• A. L1
• B. L4
• C. S1
• D. L5

Answer: (B)

Steppage gait happens when dorsiflexion is weak, so the foot cannot clear the ground during swing and the person lifts the knee higher to compensate. The main dorsiflexor is the tibialis anterior, which gets its nerve supply from the deep peroneal nerve that carries fibers from the L4-L5 nerve roots. Among the options, L4 is the root most closely linked to the primary dorsiflexor function, so weakness at this level produces the classic high-stepping gait. Other roots either govern different muscle groups (for example, L1 affects proximal muscles, and S1 mainly controls plantarflexion), or contribute to dorsiflexion but are not as closely tied to the typical presentation. Thus, the nerve root involved is L4.

Steppage gait happens when dorsiflexion is weak, so the foot cannot clear the ground during swing and the person lifts the knee higher to compensate. The main dorsiflexor is the tibialis anterior, which gets its nerve supply from the deep peroneal nerve that carries fibers from the L4-L5 nerve roots. Among the options, L4 is the root most closely linked to the primary dorsiflexor function, so weakness at this level produces the classic high-stepping gait. Other roots either govern different muscle groups (for example, L1 affects proximal muscles, and S1 mainly controls plantarflexion), or contribute to dorsiflexion but are not as closely tied to the typical presentation. Thus, the nerve root involved is L4.