Why is the Colonel Called "Kernal"?
The Origin of the Ranks and Rank Insignia Now Used by the United States Armed Forces

Officers

Lieutenant Commander

The Lieutenant Commander rank is one instance where our Navy did not adopt something from the British navy. Shortly after 1775 a senior Lieutenant who was "Captain" of a smaller, 10- to 20-gun warship was called a Lieutenant Commanding, sometimes Lieutenant Commandant. In 1862 that rank became Lieutenant Commander. The British used the rank Senior Lieutenant until 1914 when they changed it to Lieutenant Commander.

These officers in our Navy began wearing embroidered gold oak leaves on their shoulder straps in 1862 and the two and one-half stripes of gold lace on their sleeve cuffs in 1874.