Patterns Reflected by the Skin

Because the human embryo is originally segmental, various structures reflect a segmental pattern that can be appreciated on the surface of the body.

The melanin-producing cells are of neural crest origin and apparently migrate embryologically in a predictable pattern. The pattern was first described by Blaschko. When pigmented streaks reflecting that migration are seen, they are called "Blaschko lines" (Fig. 11.1). Disorders of pigmentation and mosaicism for two or more genetically different cell lines can be associated with the presence of these lines.

The sensory innervation of the skin is structured segmentally, according to the dermatomes (Fig. 11.2a,b). Some skin disorders, such as herpes zoster, may reflect this dermatome distribution. It is extremely useful to know the sensory nerve distribution of specific nerves when trying to pinpoint a neurological disorder. The distribution of motor nerves is also segmented but follows a different distribution than the sensory distribution.

Nervus Peroneus Sensory Innervation

Figure 11.2(a) Sensory innervation of the skin.

Trigeminus I Trigeminus II N. auricularis magnus Trigeminus HI N. transveisus colli

N. supraclaviculares

N. cut. brachii lateralis N. cut. brachii medialis N. cut. antebrachii medialis N. cut. antebrachii lateralis Rr. palmares n. mediani etn. ulnaris N. superficialis N. radialis N. ulnaris

N. medianus

N. ilioinguinalis N. dorsalis penis N. genitalis n. genitofermoralis N. cut. anteriores n. fermoralis N. cut. n. obturatorii N. inirapatcllaris n. saphcni N. cut. surae lateralis N. saphenus N. suialis

N. peronaeus superficialis N. peronaeus profundus

Figure 11.2(a) Sensory innervation of the skin.

Figure 11.2(b)

N. occipitalis major N. occipitalis minor N. auricularis magnus N. transversus colii

Auricularis Magnus

Sensory innervation of the skin.

N. occipitalis major N. occipitalis minor N. auricularis magnus N. transversus colii

N. supraciaviculares N. cut. brachii lateralis N. cut. brachii medialis N. cut. brachii posterions N. cut. antebrachii posterions N. cut. antebrachii medialis N. cut. antebrachii lateralis R. dorsalis manus n. ulnaris R. superficialis n. radialis N. digitalis palmares proprii n. mediani

N. clunium inferious N. cut. femoris posterions N. cut. n. obturatorii N. suralis N. saphenus N. cut. surae lateralis N. suralis

N. plantaris lateralis N. saphenus N. plantaris medialis

Sensory innervation of the skin.

Pregnancy And Childbirth

Pregnancy And Childbirth

If Pregnancy Is Something That Frightens You, It's Time To Convert Your Fear Into Joy. Ready To Give Birth To A Child? Is The New Status Hitting Your State Of Mind? Are You Still Scared To Undergo All The Pain That Your Best Friend Underwent Just A Few Days Back? Not Convinced With The Answers Given By The Experts?

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