The structure of the foot makes it uniquely suited for ambulation and shock absorption. It also provides flexibility on uneven terrain.
A foot is composed of three units: hindfoot, midfoot and forefoot. The hindfoot is formed by the calcaneus and talus. These bones form the subtalar joint, which allows for the foot inversion and eversion. The midfoot is composed of the navicular, cuboid and three cuneiform bones. Finally, the forefoot consists of the five metatarsal bones and the phalanges of the toes, which are connected by the metatarsophalangeal, or the MTP, joints. The bones and joints of the foot are supported by numerous ligaments, tendons, and muscles. One of the most notable structures is the plantar fascia, which is a band of a fibrous tissue that runs from the heel to the forefoot, to support the foot's arch.
Due to their role in weight bearing and ambulation, the feet are especially prone to injury, inflammation, and pain. Foot pain may also result from the disorders of vascular system, peripheral nerves or nerve roots. Therefore, a foot exam should also include assessment of the peripheral pulses and the neurological evaluation.
Foot and ankle examination are usually performed together. However, this presentation will just display the maneuvers that a physician should perform to evaluate the integrity and functioning of key foot structures. The ankle examination is covered in a separate video of this collection.
The foot exam is performed in a systematic way, starting with careful inspection and palpation of both feet.
Before starting the exam wash your hands thoroughly. Ask the patient to remove their shoes and socks, and sit on the examination table. Begin with inspection of both feet. Look at them from all aspects. Note any asymmetry, swelling, ecchymoses and deformities, while comparing between sides.
Carefully examine the skin and nails for calluses, corns, ulcers, and signs of fungal nail infection, such as deformity and discoloration of nails. Also look for Tinea Pedis, which refers to the redness and peeling of the skin between the toes and on the bottom of the feet. Lastly, inspect the patient's shoes for abnormal wear pattern.
Following inspection, palpate the tarsal bones, the metatarsals, the extensor tendons, and each of the toes checking for any tenderness, swelling, or deformities. Next, move on to the spaces between the metatarsal heads. Tenderness and numbness between the third and fourth metatarsal heads is seen in people with Morton's Neuroma - referring to the thickening of the nerve tissue. If present, squeezing the metatarsal heads together would accentuate the pain. Also, feel for the dorsalis pedis pulse in the midline of the midfoot, which can be weak or even absent in patients with peripheral arterial disease.
Subsequently, move onto the medial foot and palpate along the navicular bone, first metatarsal bone, and plantar fascia. Note any bunion, which is the prominence at the first MTP joint caused by rubbing of the shoes. Then examine the lateral foot along the fifth metatarsal bone up to the fifth toe. A prominence at the fifth MTP joint, called the bunionette, can be seen due to excessive rubbing in this area. Finally, palpate the plantar surface of both feet starting at the heel pad and calcaneus, moving distally along the plantar fascia, the metatarsal heads, and the phalanges. Tenderness at the proximal plantar fascia is seen with plantar fasciitis.
Next part of the systematic foot examination is range of motion testing. During these maneuvers, compare between sides and note any limited motion or pain.
Start by grasping the patient's calcaneus with one hand, to hold it steady. Then with your other hand, push the forefoot laterally. This tests foot abduction, for which the normal range of motion is approximately 5°. Similarly, test foot adduction by pushing the forefoot medially. Again, the maximum range is about 5°.
For the following maneuvers, ask the patient to perform instructed actions actively. To assess great toe extension and flexion instruct the patient to only point the great toe up towards the ceiling and then down towards the floor. Normally, the range of motion for great toe extension is 70° and for flexion is 45°. Similarly, test the lesser toes extension and flexion by asking the patient to extend and then flex all their toes at the same time. As patient does that, compare the range of motion between feet. Normally, the ranges are about the same.
The following section describes strength testing, which is performed as a series of resisted isometric movements, while checking for pain or muscle weakness.
Start by asking the patient to maximally extend their great toe and keep it in this position, while you attempt to push it down. This maneuver tests the strength of the extensor halluces longus muscle, which is innervated by the peroneal nerve.
Next, test great toe flexion by asking the patient to bend their great toe down, while you try to push it up. This examines the flexor halluces longus muscle, which is innervated by the tibial nerve.
Subsequently, perform the resisted lesser toe flexion and extension by testing all toes at once in a similar fashion as described before. This maneuver tests the flexor digitorum brevis muscle innervated by L4, L5, S1, and the extensor digitorum brevis muscle innervated by L5, S1.
Complete the foot examination by testing the sensation in the feet. Now with the patient sitting and eyes closed lightly touch the skin at the lateral border of the foot, which is innervated by the sural nerve. Ask the patient if they can feel the sensation. Then touch the same area on the contralateral foot and ask the patient to compare the feeling between sides.
Similarly, test the web space between the first and second toe, which is innervated by the deep peroneal nerve , followed by the dorsum of the foot, innervated by the superficial peroneal nerve. Lastly, assess sensation in each of the dermatome of the plantar aspect of the foot.
You've just watched JoVE's video on foot exam. Here, we first reviewed inspection and palpation of the foot followed by the range of motion maneuvers and muscle strength testing. We also demonstrated how to evaluate feet for neurological deficits by doing a few simple sensory tests. As always, thanks for watching!