Final answer:
Calf pain paired with a history of knee fullness may suggest deep vein thrombosis, especially if the fullness is due to a Baker's cyst, but muscle cramp, Achilles tendinitis, and sciatic nerve compression are also possible diagnoses.
Step-by-step explanation:
Calf pain in an individual with a history of fullness behind the knee may suggest several conditions. Considering the symptoms and history provided, deep vein thrombosis (DVT) could be a likely cause. DVT is a serious condition caused by the formation of a blood clot in a deep vein, often in the leg. The fullness behind the knee could be indicative of a Baker's cyst, which can sometimes be associated with DVT. However, a muscular condition like a muscle cramp is also a possibility, typically causing sharp, intense pain in the muscles of the calf. Achilles tendinitis, an inflammation of the tendon that connects the calf muscles to the heel bone, can cause pain in the calf but is usually concentrated in the Achilles tendon area. Lastly, sciatic nerve compression, commonly known as sciatica, can lead to pain that originates in the lower back and travels down to the calf; however, this pain is often associated with back issues rather than fullness behind the knee.