Abstract: A device for transverse spinal connection, comprises a transverse bar (4) secured to at least one spinal osteosynthesis rod (2) with a connecting/blocking member (5) between the transverse bar and the osteosynthesis rod. The transverse bar and osteosynthesis rod are adapted to be connected to each other in situ by the connection/blocking device which is constituted of a first part (6) in the shape of a jaw (8), provided with a passage (10) for the transverse bar (4) and a blocking screw (22) adapted to project into the passage. The connecting/blocking device also includes a second part (7) in the form of an oppositely directed jaw (18) pivoted on the first part (6). The bar (4) in place in the passage (10) being adapted, during screwing in of the screw (22), to come to bear both against the first part (6) and against the second part (7) and to cause the two jaws (8, 18) to move toward each other.