Sacrum a lateral surface. The base of the sacrum, which is broad and expanded, is directed upward and forward. On either side of the base is a large projection known as an ala of sacrum and these alae (wings) articulate with the sacroiliac joints. The alae support the psoas major muscles and the lumbosacral trunk which connects the lumbar plexus with the sacral plexus. In the articulated pelvis the alae are continuous with the iliac fossa. Each ala is slightly concave from side to side, and convex from the back and gives attachment to a few of the fibers of the
Canticum Sacrum him” . Canticum Sacrum Canticum Sacrum ad Honorem Sancti Marci Nominis is a 17-minute choral-orchestral piece composed in 1955 by Igor Stravinsky (1882–1971) in tribute "To the City of Venice, in praise of its Patron Saint, the Blessed Mark, Apostle." The piece is compact and stylistically varied, ranging from established neoclassical modes to experimental new techniques. The second movement, "Surge, Aquilo", represents Stravinsky's first movement based entirely on a tone row. Though most often abbreviated ""Canticum Sacrum"", the piece's full name is "Canticum Sacrum ad honorem Sancti Marci Nominis", or "Canticle to Honor the Name of Saint Mark". Stravinsky selected