diff --git a/segpy-ext/segpy-numpy/segpy_numpy/extract.py b/segpy-ext/segpy-numpy/segpy_numpy/extract.py
index e0504de..137acdb 100644
--- a/segpy-ext/segpy-numpy/segpy_numpy/extract.py
+++ b/segpy-ext/segpy-numpy/segpy_numpy/extract.py
@@ -9,7 +9,7 @@ class DimensionalityError:
     pass
 
 
-def extract_inline_3d(reader, inline_number, xline_numbers=None, sample_numbers=None, null=None, packed=False):
+def extract_inline_3d(reader, inline_number, xline_numbers=None, sample_numbers=None, null=None):
     """Extract an inline as a two-dimensional array.
 
     Args:
@@ -42,37 +42,39 @@ def extract_inline_3d(reader, inline_number, xline_numbers=None, sample_numbers=
     sample_numbers = ensure_superset(range(0, reader.max_num_trace_samples()), sample_numbers)
     shape = (len(xline_numbers), len(sample_numbers))
     dtype = make_dtype(reader.data_sample_format)
-    sample_start, sample_stop = start_and_stop(sample_numbers)
     array = make_array(shape, dtype, null)
 
-    src_start = sample_numbers.start - sample_start
+    if isinstance(sample_numbers, range):
+        _populate_inline_array_over_sample_range(reader, inline_number, xline_numbers, sample_numbers, array)
+    else:
+        _populate_inline_array_numbered_samples(reader, inline_number, xline_numbers, sample_numbers, array)
 
-    try:
-        src_step = sample_numbers.step
-    except AttributeError:
-        src_step = None
+    return array
 
+
+def _populate_inline_array_numbered_samples(reader, inline_number, xline_numbers, sample_numbers, array):
     for xline_index, xline_number in enumerate(xline_numbers):
         inline_xline_number = (inline_number, xline_number)
         if reader.has_trace_index(inline_xline_number):
             trace_index = reader.trace_index(inline_xline_number)
             num_trace_samples = reader.num_trace_samples(trace_index)
-            trace_sample_stop = max(sample_stop, num_trace_samples)
-            trace_samples = reader.trace_samples(trace_index, sample_start, trace_sample_stop)
-            src_stop = trace_sample_stop - sample_start
+            trace_sample_start = sample_numbers[0]
+            trace_sample_stop = min(sample_numbers[-1] + 1, num_trace_samples)
+            trace_samples = reader.trace_samples(trace_index, trace_sample_start, trace_sample_stop)
+            for sample_index, sample_number in enumerate(sample_numbers):
+                array[xline_index, sample_index] = trace_samples[sample_number - trace_sample_start]
 
-            if src_step is not None:
-                # Assign to a slice of the target array
-                source_slice = slice(
-                    src_start,
-                    src_stop,
-                    src_step)
-                array[xline_index, :] = trace_samples[source_slice]
-            else:
-                # Assign element by element
-                for sample_index, sample_number in enumerate(sample_numbers):
-                    array[xline_index, sample_index] = trace_samples[sample_number - sample_start]
-    return array
+
+def _populate_inline_array_over_sample_range(reader, inline_number, xline_numbers, sample_numbers, array):
+    for xline_index, xline_number in enumerate(xline_numbers):
+        inline_xline_number = (inline_number, xline_number)
+        if reader.has_trace_index(inline_xline_number):
+            trace_index = reader.trace_index(inline_xline_number)
+            num_trace_samples = reader.num_trace_samples(trace_index)
+            trace_sample_stop = min(sample_numbers.stop, num_trace_samples)
+            trace_samples = reader.trace_samples(trace_index, sample_numbers.start, trace_sample_stop)
+            source_slice = slice(sample_numbers.start, trace_sample_stop, sample_numbers.step)
+            array[xline_index, :] = trace_samples[source_slice]
 
 
 def make_array(shape, dtype, null=None):