Petroleum is closely related to the carbon group and as such has the sluggish venous conditions causing venous stasis, associated with skin manifestations of chilblains and eczema of hands and scalp. The stiffness is > from warm air. It is an anti-syphilitic causing rheumatic stiffness of the shoulders and chest muscles. Compare : the carbons, Colchicum, Sulphur, Tabacum. NECK AND BACK . — (Petroleum) Drawing pains in nape of neck extending to occiput. STIFF NECK GIVING A CRACKING NOISE ON MOTION. SHARP PAINS SHOOTING UP DORSAL BACK INTO OCCIPUT. PAINS IN SPINE EXTENDING OVER THE BODY. Catching pains in rectus abdominis, external oblique and lumbar muscles from exposure or from too much walking. Pain in back does not allow patient to move or stand. Rheumatic pains in back < before rising. Weakness and stiffness of back, especially the small of the back. SUPERIOR EXTREMITIES . — (Petroleum) Drawing in fingers. Rigidity of first one finger then others, the stiffness extending up arm. Arthritic stiffness of finger joints. INFERIOR EXTREMITIES . — (Petroleum) Thighs stiff and heavy when walking. Tearing pain in thighs and spots on legs painful to touch. SWELLING OF LEFT LEG FROM KNEE TO ANKLE JOINT. STIFFNESS IN LEGS, KNEES AND ANKLES. Stiffness of knees. Cramps in calves, thighs and feet all day. Cramps in soles at night. JOINTS . — (Petroleum) LIMBS SEEM STIFF AND WITHOUT JOINTS IN MORNING AFTER RISING. Rheumatic stiffness of joints, which crack when joints are moved. RHEUMATIC STIFFNESS OF SHOULDERS AND ANKLES. INFLEXIBILITY OF JOINTS, THEY CRACK ON MOTION. KNEES STIFF ; SHARP STICKING PAINS, CRACKING ON MOTION.