Structural and mechanical problems
The largest single category. These are problems caused by the way the foot is shaped, or by the way it moves under load, or both. They include plantar heel pain, bunions and hammertoes, flatfoot and high-arched foot types, arch strain, tendon problems around the ankle, and the family of overuse injuries that appear when a person suddenly asks their feet to do considerably more than they are used to.
Mechanical problems are the ones most likely to respond to non-surgical measures: changes in footwear, a period of relative rest, targeted stretching and strengthening, taping, and — where the assessment supports it — foot orthoses. Surgery exists for most of them but sits at the end of the sequence, not the start.
Skin and nail conditions
Corns and calluses, plantar warts, fissured heels, athlete's foot, thickened nails, discoloured nails and ingrown toenails. This category is easy to dismiss as cosmetic and frequently is not. A callus in the wrong place on an insensate foot is a pre-ulcer; a nail that has been thickened and lifting for months may be fungal, may be psoriatic, may be traumatic, and occasionally is something that needs a biopsy.
The general-interest versions of these problems are described well by national health services — the NHS page on athlete's foot is a good example of the level of detail most people need — but the ones that recur, spread or refuse to clear are the ones worth having looked at.
Nerve and circulation problems
Burning, tingling, numbness, night pain, cramping in the calf on walking, cold feet, colour change. Some of these originate in the foot, like Morton's neuroma or a compressed nerve at the ankle. Many do not: peripheral neuropathy from diabetes, nerve root irritation from the lumbar spine, and peripheral arterial disease all present in the feet while living elsewhere.
This is the category where a foot symptom most often turns out to be a systemic sign, and it is why a competent foot assessment includes checking pulses and testing sensation rather than only looking at the sore spot.
Diabetes-related foot care
Large enough and consequential enough to be treated as its own discipline. It combines regular assessment of sensation and blood supply, skin and nail care performed safely on a foot that may not feel injury, pressure redistribution, footwear provision, and the management of ulceration when it occurs. The stakes are high and well documented: the U.S. National Institute of Diabetes and Digestive and Kidney Diseases sets out the essentials on its diabetes and foot problems page, and this site covers it at length under the diabetic foot and wound care.
Sports and activity injuries
Sprains, stress fractures, tendinopathies, sesamoid problems, turf toe, and the broad category of load-related injury that follows a training change. The distinguishing feature of this group is that management has to account for what the person wants to get back to, and on what timescale, which changes the calculus considerably compared with the same injury in a sedentary person.
Trauma
Fractures, dislocations, crush injuries, puncture wounds and lacerations. Acute trauma is emergency territory rather than reference-reading territory. If a foot cannot bear weight after an injury, is visibly deformed, is numb, or has a wound that penetrated deeply, that is a same-day assessment.
Surgical treatment
Foot and ankle surgery ranges from small procedures done under local anaesthetic in a clinic room — a partial nail avulsion, for instance — up to reconstructive bone and joint procedures done in an operating theatre with a long recovery. The important thing a reference can usefully say is that the existence of an operation for a condition is not an argument for having it. For most of the mechanical conditions on this site, non-surgical management is tried first, for months rather than weeks, and a good proportion of people never need to go further.
Assessment itself
Underlying all of the above is examination: history, inspection of the foot loaded and unloaded, palpation, joint range, muscle strength, sensory testing, pulse checks, gait observation, and imaging when it will change the plan. It is worth knowing that this is what a thorough foot assessment consists of, because it tells you what to expect and gives you a way to judge whether the assessment you received was a thorough one.
For the individual conditions, start at the condition index. For what a foot and ankle specialist is and how they are trained, see what is a podiatrist.