larval abdominal segmental nerve [FBbt_00002197]

Larval segmental nerve of a larval abdominal segment. These are only found in segments A1-7, as A8 and A9 do not have separate segmental and intersegmental nerves (Campos-Ortega and Hartenstein, 1997. It has two roots, anterior and posterior, both formed from neurons of the same segment as the nerve (Campos-Ortega and Hartenstein, 1997. Proximally it shares a glial sheath with the intersegmental nerve before branching from it at the ventral edge of the ventral oblique muscles (Campos-Ortega and Hartenstein, 1997. A thick, posteriorly directed branch (SNc) leaves the main trunk of the nerve (SNa) and splits into fine branches - 3 carrying axons from the ventral sensory cluster and a 4th carrying efferents to the ventral acute musculature (Campos-Ortega and Hartenstein, 1997. The SNa branch continues dorsally and carries efferent axons innervating the external lateral transverse and lateral oblique muscles and the axons of v’es2 and v’ch1 (Campos-Ortega and Hartenstein, 1997. (Campos-Ortega and Hartenstein, 1997, Landgraf et al., 1997)