Foot drop is a feeling of weakness while attempting to lift the foot and/or toes upward (dorsiflexion).1 Foot drop typically causes the individual to involuntarily drag the toes of the affected foot while attempting to walk.2 To compensate for this dragging, a high steppage or slapping gait1 is attempted, where the leg is lifted higher than normal on the affected side for the toes to clear the surface.3
Foot drop is usually present when one or both of the following signs are present:
- Difficulty or inability to walk on the heels of the feet
- Loss of balance while standing without support and with the eyes closed (also called Romberg’s sign)3
Foot drop may affect one or both feet at a time.4
Foot Drop Is the Symptom of an Underlying Medical Condition
Foot drop usually occurs when there is a problem with the nerves in the lower spine, leg, or foot or the muscles of the leg and foot.4
Typically, if the heel strikes the floor first as the foot lands, a dysfunction of the lower spinal nerve root(s) or peripheral nerve(s) may be suspected.3 Neurological causes may include one or more of the following:
- Radiculopathy: Symptoms following nerve root irritation or compression in the lumbar spine, for example, radiculopathy of the L5 nerve root5,6
- Neuropathy: Damage to a peripheral nerve in the leg at any point along its path, for example, neuropathy of the common peroneal nerve, deep peroneal nerve, or the sciatic nerve6
- Lumbosacral plexopathy: Damage to a group of nerves (plexus) in the lumbar and sacral spine6
Foot drop may also occur when the nerves in the leg and/or feet are damaged due to systemic conditions or genetic disorders. A few examples include diabetes, vasculitis (inflammation of blood vessels), and hereditary neuropathy with liability to pressure palsies (HNPP).7 Rarely, a tumor, blocked blood vessel, or bleeding in the brain may cause foot drop.8
If the toes strike first as the foot lands on the floor, the cause may be weakness or paralysis of the pretibial, peroneal, or hip flexor muscles.3
Foot drop vs. flail foot
While foot drop typically causes severe foot weakness, bending the foot downward or turning it to the left and/or right side is usually possible with some degree of weakness.1
It is important to distinguish foot drop from flail foot, where no ankle and/or foot movements are possible in any direction.4 A flail foot may indicate a more serious condition or a medical emergency, such as cauda equina syndrome or stroke.
Characteristics of Foot Drop
Foot drop can occur in several ways. A few characteristics of foot drop are described below.
Foot drop may go unnoticed
It is possible to have foot drop without being aware of the symptom. Individuals may walk as usual, but intermittently or repeatedly trip over themselves or feel like their footwear is loose. These symptoms may indicate an initial stage of foot drop due to nerve dysfunction and/or muscle weakness.
Foot drop may be the only presenting symptom
A mild foot drop causing intermittent tripping or a severe form, where lifting the foot and/or walking is difficult may sometimes be the only symptom a person experiences. Foot drop without associated pain or other discomfort may occur when a nerve root, most frequently, L5 is compressed or irritated, causing muscle weakness in the leg.5
Foot drop usually resolves or decreases when the cause is treated
Foot drop may resolve in a few days to weeks when the underlying condition is treated. For example, if a lumbar herniated disc causes the foot drop symptoms, as the herniation in the disc resolves, the foot drop may improve at the same time. Conversely, if the lower back condition persists, the foot drop may also remain.
If the underlying cause is left untreated, over time the foot drop may be accompanied by pain, numbness, and/or tingling.
When Foot Drop Is Serious
Sometimes, foot drop may be accompanied by certain symptoms, which may indicate serious medical conditions. A few examples of serious symptoms include:
- Severe weakness causing an inability to move the foot in any direction (flail foot)
- Severe pain and numbness
- Loss of appetite and/or weight
- Loss of bowel and/or bladder control
These symptoms may indicate medical emergencies such as cauda equina syndrome, tumors, stroke, or infections and must be treated immediately.
Both nonsurgical and/or surgical methods may be used for treating foot drop. Typically, nonsurgical treatments such as medication and/or physical therapy are tried first.