Phenotype: secondary motor neuron axon extension decreased occurrence, abnormal
Note: This statement combines anatomy and/or ontology terms with phenotype quality terms to create a complete phenotype (EQ) statement. For detailed information on individual terms, click the hyperlinked term name.
Name: secondary motor neuron
Synonyms: secondary motoneuron
Definition: Motor neurons that develop several hours later than primary motoneurons and sprout axons several hours after the primary motor growth cones have extended to the periphery. They have smaller cell bodies and are located more ventrally and laterally in the spinal cord than primary motoneurons. Axons usually project directly out of the spinal cord with no apparent contact with the Mauthner axon and are positioned lateral to the Mauthner axon in their path to the ventral root. Secondary motoneurons have smaller fields, which can overlap one another, and innervate many fewer muscle fibers than primary motoneurons.
Ontology: Anatomy Ontology [ZFA:0009247]
Name: axon extension
Synonyms: axon extension involved in development
Definition: Long distance growth of a single axon process involved in cellular development.
Ontology: GO: Biological Process [GO:0048675]    QuickGO    AmiGO
Name: decreased occurrence
Synonyms: decreased incidence
Definition: An occurrence which is relatively low.
Ontology: Phenotypic Quality Ontology [PATO:0002052]