The first check once you are back inside
Dry the coat, let your dog settle on a non-slip surface, and watch him walk a few unhurried steps across the room rather than calling him eagerly toward you. A strain from that sideways slip on ice often shows as a shortened stride on one leg, a slight bob of the head as the sore leg lands, hesitation before sitting, or a yelp when the shoulder, hip, or wrist area is touched lightly. Compare both sides with flat palms: a strained area may feel warmer, look faintly puffy, or tighten under your hand while the matching leg stays relaxed.
A dog who slipped but kept playing, bears weight evenly once warmed up, and moves normally an hour later is less concerning than one whose limp returns every time he rises after lying down. Note which leg he protects on turns, because a rear leg strain often shows most when he pivots or tries to push up from a sit, while a front leg strain shows when he lands coming down a single step.
Strain, bruise, or something more serious
A simple muscle strain usually allows some weight through the leg, even if the gait looks uneven, and the dog often improves noticeably with quiet over a day or two. Trouble signs sit at the other end of that picture: a leg held completely off the ground, a joint bent at an odd angle, rapid swelling, crying out when the limb is barely touched, or a dog who will not stand at all. Those signs after an ice fall deserve a prompt veterinary call the same day, because fractures, dislocated joints, and torn ligaments can look deceptively similar in the first hour.
Cold itself can also confuse the picture. A dog who was simply chilled may move stiffly until he warms through, then loosen up fully.
What proper rest actually looks like
Rest here is stricter than most owners expect. Take him out on a lead only, just long enough for toilet breaks on a gritted or grassy patch rather than the icy path where he fell, then straight back inside. No stairs if you can carry or guide him another way, no jumping onto sofas, no chasing a ball down the hallway, and no off-lead garden time where a squirrel could trigger a sudden sprint that re-pulls the healing fibres.
Simple home observation that helps
Check the same things at the same times each day: how he rises, how he walks to his water bowl, whether he uses the leg on a turn, and whether any puffiness has grown or faded. Short phone videos taken from the side on a flat indoor surface capture change more honestly than memory, especially when the limp is subtle. Avoid stretching the sore leg out to test it, avoid pressing deeply into the muscle, and do not give any human pain relief from your own cabinet, because several common household options are unsafe for dogs.
When this needs the vet, and what to bring
Call your vet promptly if the limp is unchanged or worse after a day or two of strict rest, if swelling increases, if he stops eating, seems unusually quiet, or cannot settle at night, or immediately if he will not bear weight at all. Bring the details you tracked: when the slip happened, which leg you filmed, how rest changed the gait, and whether he has had joint problems before. Storing those dated gait notes and any clinic findings together in KinsLe's Pet Passport means the next vet who sees him starts from the full ice-slip story, not a guess.