A protective boot for use by a person lying in a supine position and supporting a lower leg, heel, and foot thereof, the boot comprising: a body formed of a flexible and compressible foam material, the body having a proximal leg portion, a distal forefoot portion contiguous with and projecting from the leg portion in a transverse direction thereto, a continuous cavity defined by and within the leg and forefoot portions (24,26) and being complementary in size and shape to support the lower leg of the person while supporting the foot of the person in an upright position, an anterior opening defined in the leg and forefoot portions (24,26) to permit the foot and lower leg to pass therethrough into the cavity within the leg and forefoot portions (24,26), oppositely-disposed lateral regions defined by the leg portion and separated by the anterior opening, oppositely-disposed lateral regions defined by the forefoot portion and separated by the anterior opening, an interior surface defined by the leg and forefoot portions (24,26) within the cavity, an exterior surface defined by the leg and forefoot portions (24,26), and a continuous rim separating the interior and exterior surfaces (14,16); a cushion within the cavity within the lower leg portion for supporting the lower leg of the person and suspending the heel of the person within the cavity; a first low-friction material defining the exterior surface at the leg and forefoot portions (24,26); a trim being a second low-friction fabric at the continuous rim separating the interior and exterior surfaces (14, 16), the second low-friction fabric trim being a separate material from the first low-friction material defining the exterior surface of the body and being sewn onto the body so as to form and cover the continuous rim in its entirety by compressing and narrowing the foam material of the body along the entire perimeter of the anterior opening; first means (38,50) for adjustably closing the anterior opening in the leg portion with the lateral regions of the leg portion; and second means (42, 52) for adjustably closing a portion of the anterior opening in the forefoot portion with the lateral regions of the forefoot portion by drawing the lateral regions of the forefoot portion inward and toward the medial and lateral sides of the foot of the person within the forefoot portion without applying pressure to the dorsum of the foot. a body formed of a flexible and compressible foam material, the body having a proximal leg portion, a distal forefoot portion contiguous with and projecting from the leg portion in a transverse direction thereto, a continuous cavity defined by and within the leg and forefoot portions (24,26) and being complementary in size and shape to support the lower leg of the person while supporting the foot of the person in an upright position, an anterior opening defined in the leg and forefoot portions (24,26) to permit the foot and lower leg to pass therethrough into the cavity within the leg and forefoot portions (24,26), oppositely-disposed lateral regions defined by the leg portion and separated by the anterior opening, oppositely-disposed lateral regions defined by the forefoot portion and separated by the anterior opening, an interior surface defined by the leg and forefoot portions (24,26) within the cavity, an exterior surface defined by the leg and forefoot portions (24,26), and a continuous rim separating the interior and exterior surfaces (14,16); a cushion within the cavity within the lower leg portion for supporting the lower leg of the person and suspending the heel of the person within the cavity; a first low-friction material defining the exterior surface at the leg and forefoot portions (24,26); a trim being a second low-friction fabric at the continuous rim separating the interior and exterior surfaces (14, 16), the second low-friction fabric trim being a separate material from the first low-friction material defining the exterior surface of the body and being sewn onto the body so as to form and cover the continuous rim in its entirety by compressing and narrowing the foam material of the body along the entire perimeter of the anterior opening; first means (38,50) for adjustably closing the anterior opening in the leg portion with the lateral regions of the leg portion; and second means (42, 52) for adjustably closing a portion of the anterior opening in the forefoot portion with the lateral regions of the forefoot portion by drawing the lateral regions of the forefoot portion inward and toward the medial and lateral sides of the foot of the person within the forefoot portion without applying pressure to the dorsum of the foot.