Development of Human Palmar and Digital Flexion Creases

8, 13

Observations show that palmar and digital creases develop between __ and __ fetal weeks.

10

Digital creases are well defined by __ weeks.

13

Palmar creases are consistently seen by __ weeks of gestation.

8, 14

The volar pads are present from __ to __ fetal weeks.

7 weeks

The fingers are separated, but the hand has a smooth, glove-like appearance without pads or creases. It is difficult to distinguish between the dorsal and volar surfaces of the hand, and the thumb is in the same plane as the fingers.

8 weeks

The first creases, primarily the distal interphalangeal and metacarpophalangeal creases, are faintly visible. The digital (fingertip) and interdigital pads are also seen. The thumb is starting to rotate into a different plane.

9 weeks

The distal interphalangeal and metacarpophalangeal creases are more distinct. Additionally, the proximal interphalangeal creases are faintly visible. The thenar crease originates at the radial side of the hand and extends proximally, encircling the thenar eminence. The thumb is now fully rotated, and the nail beds are beginning to form.

10 weeks

All digital creases are well defined by this time. The interdigital pads are beginning to regress, and a central depression is seen in each digital pad. Many small papillary integumentary thickenings are present in the center of the palm. The nail beds are better defined.

11 weeks

By this time, the distal palmar crease is well defined. It extends from the area between the second and third metacarpophalangeal joints to the ulnar border of the palm. The proximal palmar crease is faintly seen, first visible at the radial edge of the palm and either fused with or just distal to the thenar crease.

12 weeks

The proximal palmar crease is consistently seen extending from the radial edge of the palm to the medial border of the hypothenar eminence. The digital pads are well seen, but the interdigital pads are now gone.

13 weeks

By ___ weeks of gestation, all palmar and digital creases are well defined. The digital pads are beginning to regress.

14 to 16 weeks

There is little change in appearance of the fetal hand during this time. The digital pads are absent by 15 weeks.

17 to 19 weeks

The proximal interphalangeal creases appear double. This extra crease, which appears distal to the proximal interphalangeal crease, is limited to the volar side of the digit, whereas the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal creases all extend onto the lateral aspect of the digit.