MCQ – 101727

Injury to which part causes difficulty in dorsiflexion of the foot?

Correct Answer » B Explanation

Difficulty in dorsiflexion of the foot occurs due to injury to the common peroneal nerve (also called the common fibular nerve).

About the Common Peroneal Nerve

• It winds around the neck of the fibula.

• It lies superficially at this point, so it is easily injured.

• It divides into:

  • Deep peroneal nerve → controls dorsiflexion.

  • Superficial peroneal nerve → controls eversion.

Identification in the X-ray

In the AP view of the knee:

• Label B represents the neck of the fibula.

• The common peroneal nerve passes around this area.

• Injury at B damages the nerve and causes foot drop.

Reason Why Dorsiflexion is Affected

The deep peroneal nerve supplies:

• Tibialis anterior

• Extensor hallucis longus

• Extensor digitorum longus

These muscles are responsible for lifting the foot upward (dorsiflexion).

Effects of Injury

Damage to this nerve causes:

• Foot drop

• High-stepping gait

• Dragging of toes while walking