The isthmus, or pars interarticularis, is a small, thin segment of bone that connects the facet joints at the back of the spine.

峡部或称椎弓峡部，是脊柱背侧连接上下关节突之间的一段小而细的骨段。

youdao

Conclusion. This case report discusses the rare occurrence of multiple lumbar pedicle fractures and pars interarticularis (spondylolysis) fractures in a patient with osteopetrosis.

结论：本文就一例少见的复发性多处腰椎椎弓根骨折伴椎弓峡部骨折的石骨症病例的相关问题进行了讨论。

youdao