diff --git a/src/numpydantic/ndarray.py b/src/numpydantic/ndarray.py
index 5ad42ba..81efb7f 100644
--- a/src/numpydantic/ndarray.py
+++ b/src/numpydantic/ndarray.py
@@ -16,12 +16,12 @@ Extension of nptyping NDArray for pydantic that allows for JSON-Schema serializa
 from typing import TYPE_CHECKING, Any, Tuple
 
 import numpy as np
-from nptyping.error import InvalidArgumentsError
-from nptyping.ndarray import NDArrayMeta as _NDArrayMeta
-from nptyping.nptyping_type import NPTypingType
-from nptyping.structure import Structure
-from nptyping.structure_expression import check_type_names
-from nptyping.typing_ import (
+from numpydantic.vendor.nptyping.error import InvalidArgumentsError
+from numpydantic.vendor.nptyping.ndarray import NDArrayMeta as _NDArrayMeta
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.structure import Structure
+from numpydantic.vendor.nptyping.structure_expression import check_type_names
+from numpydantic.vendor.nptyping.typing_ import (
     dtype_per_name,
 )
 from pydantic import GetJsonSchemaHandler
diff --git a/src/numpydantic/schema.py b/src/numpydantic/schema.py
index 084ac7c..0a6c568 100644
--- a/src/numpydantic/schema.py
+++ b/src/numpydantic/schema.py
@@ -7,7 +7,7 @@ import hashlib
 import json
 from typing import TYPE_CHECKING, Any, Callable, Optional, Union
 
-import nptyping.structure
+from numpydantic.vendor.nptyping.structure import StructureMeta
 import numpy as np
 from pydantic import SerializationInfo
 from pydantic_core import CoreSchema, core_schema
@@ -45,7 +45,7 @@ def _numeric_dtype(dtype: DtypeType, _handler: _handler_type) -> CoreSchema:
 
 def _lol_dtype(dtype: DtypeType, _handler: _handler_type) -> CoreSchema:
     """Get the innermost dtype schema to use in the generated pydantic schema"""
-    if isinstance(dtype, nptyping.structure.StructureMeta):  # pragma: no cover
+    if isinstance(dtype, StructureMeta):  # pragma: no cover
         raise NotImplementedError("Structured dtypes are currently unsupported")
 
     if isinstance(dtype, tuple):
diff --git a/src/numpydantic/shape.py b/src/numpydantic/shape.py
index 366e572..62a567f 100644
--- a/src/numpydantic/shape.py
+++ b/src/numpydantic/shape.py
@@ -29,15 +29,15 @@ from abc import ABC
 from functools import lru_cache
 from typing import Any, Dict, List, Union
 
-from nptyping.base_meta_classes import ContainerMeta
-from nptyping.error import InvalidShapeError, NPTypingError
-from nptyping.nptyping_type import NPTypingType
-from nptyping.shape_expression import (
+from numpydantic.vendor.nptyping.base_meta_classes import ContainerMeta
+from numpydantic.vendor.nptyping.error import InvalidShapeError, NPTypingError
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.shape_expression import (
     get_dimensions,
     normalize_shape_expression,
     remove_labels,
 )
-from nptyping.typing_ import ShapeExpression, ShapeTuple
+from numpydantic.vendor.nptyping.typing_ import ShapeExpression, ShapeTuple
 
 
 class ShapeMeta(ContainerMeta, implementation="Shape"):
diff --git a/src/numpydantic/vendor/nptyping/__init__.py b/src/numpydantic/vendor/nptyping/__init__.py
index 35e11cc..8641108 100644
--- a/src/numpydantic/vendor/nptyping/__init__.py
+++ b/src/numpydantic/vendor/nptyping/__init__.py
@@ -22,25 +22,25 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 """
 
-from nptyping.assert_isinstance import assert_isinstance
-from nptyping.error import (
+from numpydantic.vendor.nptyping.assert_isinstance import assert_isinstance
+from numpydantic.vendor.nptyping.error import (
     InvalidArgumentsError,
     InvalidDTypeError,
     InvalidShapeError,
     InvalidStructureError,
     NPTypingError,
 )
-from nptyping.ndarray import NDArray
-from nptyping.package_info import __version__
-from nptyping.pandas_.dataframe import DataFrame
-from nptyping.recarray import RecArray
-from nptyping.shape import Shape
-from nptyping.shape_expression import (
+from numpydantic.vendor.nptyping.ndarray import NDArray
+from numpydantic.vendor.nptyping.package_info import __version__
+from numpydantic.vendor.nptyping.pandas_.dataframe import DataFrame
+from numpydantic.vendor.nptyping.recarray import RecArray
+from numpydantic.vendor.nptyping.shape import Shape
+from numpydantic.vendor.nptyping.shape_expression import (
     normalize_shape_expression,
     validate_shape_expression,
 )
-from nptyping.structure import Structure
-from nptyping.typing_ import (
+from numpydantic.vendor.nptyping.structure import Structure
+from numpydantic.vendor.nptyping.typing_ import (
     Bool,
     Bool8,
     Byte,
diff --git a/src/numpydantic/vendor/nptyping/base_meta_classes.py b/src/numpydantic/vendor/nptyping/base_meta_classes.py
index c2ca1e3..01b5c12 100644
--- a/src/numpydantic/vendor/nptyping/base_meta_classes.py
+++ b/src/numpydantic/vendor/nptyping/base_meta_classes.py
@@ -23,7 +23,8 @@ SOFTWARE.
 """
 
 from abc import ABCMeta, abstractmethod
-from inspect import FrameInfo
+from inspect import FrameInfo, getframeinfo
+from types import FrameType
 from typing import (
     Any,
     Dict,
@@ -34,7 +35,7 @@ from typing import (
     TypeVar,
 )
 
-from nptyping.error import InvalidArgumentsError, NPTypingError
+from numpydantic.vendor.nptyping.error import InvalidArgumentsError, NPTypingError
 
 _T = TypeVar("_T")
 
@@ -126,10 +127,14 @@ class SubscriptableMeta(ABCMeta):
     @abstractmethod
     def _get_item(cls, item: Any) -> Tuple[Any, ...]: ...  # pragma: no cover
 
-    def _get_module(cls, stack: List[FrameInfo], module: str) -> str:
+    def _get_module(cls, stack: FrameType, module: str) -> str:
         # The magic below makes Python's help function display a meaningful
         # text with nptyping types.
-        return "typing" if stack[1][3] == "formatannotation" else module
+        return (
+            "typing"
+            if getframeinfo(stack.f_back).function == "formatannotation"
+            else module
+        )
 
     def _get_additional_values(
         cls, item: Any  # pylint: disable=unused-argument
diff --git a/src/numpydantic/vendor/nptyping/ndarray.py b/src/numpydantic/vendor/nptyping/ndarray.py
index a3a8daf..c891af5 100644
--- a/src/numpydantic/vendor/nptyping/ndarray.py
+++ b/src/numpydantic/vendor/nptyping/ndarray.py
@@ -27,7 +27,7 @@ from abc import ABC
 from typing import Any, Tuple
 
 import numpy as np
-from nptyping.base_meta_classes import (
+from numpydantic.vendor.nptyping.base_meta_classes import (
     FinalMeta,
     ImmutableMeta,
     InconstructableMeta,
@@ -35,13 +35,16 @@ from nptyping.base_meta_classes import (
     PrintableMeta,
     SubscriptableMeta,
 )
-from nptyping.error import InvalidArgumentsError
-from nptyping.nptyping_type import NPTypingType
-from nptyping.shape import Shape
-from nptyping.shape_expression import check_shape
-from nptyping.structure import Structure
-from nptyping.structure_expression import check_structure, check_type_names
-from nptyping.typing_ import (
+from numpydantic.vendor.nptyping.error import InvalidArgumentsError
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.shape import Shape
+from numpydantic.vendor.nptyping.shape_expression import check_shape
+from numpydantic.vendor.nptyping.structure import Structure
+from numpydantic.vendor.nptyping.structure_expression import (
+    check_structure,
+    check_type_names,
+)
+from numpydantic.vendor.nptyping.typing_ import (
     DType,
     dtype_per_name,
     name_per_dtype,
@@ -67,7 +70,7 @@ class NDArrayMeta(
 
     @property
     def __module__(cls) -> str:
-        return cls._get_module(inspect.stack(), "nptyping.ndarray")
+        return cls._get_module(inspect.currentframe(), "nptyping.ndarray")
 
     def _get_item(cls, item: Any) -> Tuple[Any, ...]:
         cls._check_item(item)
diff --git a/src/numpydantic/vendor/nptyping/pandas_/dataframe.py b/src/numpydantic/vendor/nptyping/pandas_/dataframe.py
index 9dd5ee7..dd270cf 100644
--- a/src/numpydantic/vendor/nptyping/pandas_/dataframe.py
+++ b/src/numpydantic/vendor/nptyping/pandas_/dataframe.py
@@ -27,8 +27,8 @@ from abc import ABC
 from typing import Any, Tuple
 
 import numpy as np
-from nptyping import InvalidArgumentsError
-from nptyping.base_meta_classes import (
+from numpydantic.vendor.nptyping import InvalidArgumentsError
+from numpydantic.vendor.nptyping.base_meta_classes import (
     FinalMeta,
     ImmutableMeta,
     InconstructableMeta,
@@ -36,11 +36,11 @@ from nptyping.base_meta_classes import (
     PrintableMeta,
     SubscriptableMeta,
 )
-from nptyping.error import DependencyError
-from nptyping.nptyping_type import NPTypingType
-from nptyping.pandas_.typing_ import dtype_per_name
-from nptyping.structure import Structure
-from nptyping.structure_expression import check_structure
+from numpydantic.vendor.nptyping.error import DependencyError
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.pandas_.typing_ import dtype_per_name
+from numpydantic.vendor.nptyping.structure import Structure
+from numpydantic.vendor.nptyping.structure_expression import check_structure
 
 try:
     import pandas as pd
@@ -105,7 +105,7 @@ class DataFrameMeta(
 
     @property
     def __module__(cls) -> str:
-        return cls._get_module(inspect.stack(), "nptyping.pandas_.dataframe")
+        return cls._get_module(inspect.currentframe(), "nptyping.ndarray")
 
     def _check_item(cls, item: Any) -> None:
         # Check if the item is what we expect and raise if it is not.
diff --git a/src/numpydantic/vendor/nptyping/pandas_/typing_.py b/src/numpydantic/vendor/nptyping/pandas_/typing_.py
index 37dfdbe..461fa1f 100644
--- a/src/numpydantic/vendor/nptyping/pandas_/typing_.py
+++ b/src/numpydantic/vendor/nptyping/pandas_/typing_.py
@@ -22,8 +22,8 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 """
 
-from nptyping.typing_ import Object
-from nptyping.typing_ import dtype_per_name as dtype_per_name_default
+from numpydantic.vendor.nptyping.typing_ import Object
+from numpydantic.vendor.nptyping.typing_ import dtype_per_name as dtype_per_name_default
 
 dtype_per_name = {
     **dtype_per_name_default,  # type: ignore[arg-type]
diff --git a/src/numpydantic/vendor/nptyping/recarray.py b/src/numpydantic/vendor/nptyping/recarray.py
index a90b13b..931a135 100644
--- a/src/numpydantic/vendor/nptyping/recarray.py
+++ b/src/numpydantic/vendor/nptyping/recarray.py
@@ -26,10 +26,11 @@ import inspect
 from typing import Any, Tuple
 
 import numpy as np
-from nptyping.error import InvalidArgumentsError
-from nptyping.ndarray import NDArray, NDArrayMeta
-from nptyping.structure import Structure
-from nptyping.typing_ import DType
+
+from numpydantic.vendor.nptyping.error import InvalidArgumentsError
+from numpydantic.vendor.nptyping.ndarray import NDArray, NDArrayMeta
+from numpydantic.vendor.nptyping.structure import Structure
+from numpydantic.vendor.nptyping.typing_ import DType
 
 
 class RecArrayMeta(NDArrayMeta, implementation="RecArray"):
@@ -52,7 +53,7 @@ class RecArrayMeta(NDArrayMeta, implementation="RecArray"):
 
     @property
     def __module__(cls) -> str:
-        return cls._get_module(inspect.stack(), "nptyping.recarray")
+        return cls._get_module(inspect.currentframe(), "nptyping.ndarray")
 
     def __instancecheck__(  # pylint: disable=bad-mcs-method-argument
         self, instance: Any
diff --git a/src/numpydantic/vendor/nptyping/shape.py b/src/numpydantic/vendor/nptyping/shape.py
index c30aefc..b4d4698 100644
--- a/src/numpydantic/vendor/nptyping/shape.py
+++ b/src/numpydantic/vendor/nptyping/shape.py
@@ -25,9 +25,9 @@ SOFTWARE.
 from abc import ABC
 from typing import Any, Dict
 
-from nptyping.base_meta_classes import ContainerMeta
-from nptyping.nptyping_type import NPTypingType
-from nptyping.shape_expression import (
+from numpydantic.vendor.nptyping.base_meta_classes import ContainerMeta
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.shape_expression import (
     get_dimensions,
     normalize_shape_expression,
     remove_labels,
diff --git a/src/numpydantic/vendor/nptyping/shape_expression.py b/src/numpydantic/vendor/nptyping/shape_expression.py
index 8d55a56..6234031 100644
--- a/src/numpydantic/vendor/nptyping/shape_expression.py
+++ b/src/numpydantic/vendor/nptyping/shape_expression.py
@@ -33,8 +33,8 @@ from typing import (
     Union,
 )
 
-from nptyping.error import InvalidShapeError
-from nptyping.typing_ import ShapeExpression, ShapeTuple
+from numpydantic.vendor.nptyping.error import InvalidShapeError
+from numpydantic.vendor.nptyping.typing_ import ShapeExpression, ShapeTuple
 
 if TYPE_CHECKING:
     from nptyping.shape import Shape  # pragma: no cover
diff --git a/src/numpydantic/vendor/nptyping/structure.py b/src/numpydantic/vendor/nptyping/structure.py
index 71da5ef..8ad5d5b 100644
--- a/src/numpydantic/vendor/nptyping/structure.py
+++ b/src/numpydantic/vendor/nptyping/structure.py
@@ -29,9 +29,9 @@ from typing import (
     List,
 )
 
-from nptyping.base_meta_classes import ContainerMeta
-from nptyping.nptyping_type import NPTypingType
-from nptyping.structure_expression import (
+from numpydantic.vendor.nptyping.base_meta_classes import ContainerMeta
+from numpydantic.vendor.nptyping.nptyping_type import NPTypingType
+from numpydantic.vendor.nptyping.structure_expression import (
     create_name_to_type_dict,
     normalize_structure_expression,
     validate_structure_expression,
diff --git a/src/numpydantic/vendor/nptyping/structure.pyi b/src/numpydantic/vendor/nptyping/structure.pyi
index 608c094..a0ba8eb 100644
--- a/src/numpydantic/vendor/nptyping/structure.pyi
+++ b/src/numpydantic/vendor/nptyping/structure.pyi
@@ -27,9 +27,18 @@ try:
 except ImportError:
     from typing_extensions import Literal  # type: ignore[attr-defined,misc,assignment]
 
-from typing import Any, cast
+from typing import Any, Dict, cast
 
 import numpy as np
+from numpydantic.vendor.nptyping.base_meta_classes import ContainerMeta
+
+class StructureMeta(ContainerMeta, implementation="Structure"):
+
+    __args__ = tuple()
+
+    def _validate_expression(cls, item: str) -> None: ...
+    def _normalize_expression(cls, item: str) -> str: ...
+    def _get_additional_values(cls, item: Any) -> Dict[str, Any]: ...
 
 # For MyPy:
 Structure = cast(Literal, Structure)  # type: ignore[has-type,misc,valid-type]
diff --git a/src/numpydantic/vendor/nptyping/structure_expression.py b/src/numpydantic/vendor/nptyping/structure_expression.py
index f175381..dd9d8f1 100644
--- a/src/numpydantic/vendor/nptyping/structure_expression.py
+++ b/src/numpydantic/vendor/nptyping/structure_expression.py
@@ -38,14 +38,14 @@ from typing import (
 )
 
 import numpy as np
-from nptyping.error import InvalidShapeError, InvalidStructureError
-from nptyping.shape import Shape
-from nptyping.shape_expression import (
+from numpydantic.vendor.nptyping.error import InvalidShapeError, InvalidStructureError
+from numpydantic.vendor.nptyping.shape import Shape
+from numpydantic.vendor.nptyping.shape_expression import (
     check_shape,
     normalize_shape_expression,
     validate_shape_expression,
 )
-from nptyping.typing_ import StructureExpression
+from numpydantic.vendor.nptyping.typing_ import StructureExpression
 
 if TYPE_CHECKING:
     from nptyping.structure import Structure  # pragma: no cover