The transverse cervical nerve (superficial cervical or cutaneous cervical) arises from the second and third cervical nerves

Cervical nerves

The cervical nerves are the spinal nerves from the cervical vertebrae.Although there are seven cervical vertebrae , there are eight cervical nerves . All nerves except C8 emerge above their corresponding vertebrae, while the C8 nerve emerges below the C7 vertebra...

, turns around the posterior border of the sternocleidomastoideus about its middle, and, passing obliquely forward beneath the external jugular vein

External jugular vein

The external jugular vein receives the greater part of the blood from the exterior of the cranium and the deep parts of the face, being formed by the junction of the posterior division of the retromandibular vein with the posterior auricular vein.-Path:...

 to the anterior border of the muscle, it perforates the deep cervical fascia

Deep cervical fascia

The deep cervical fascia lies under cover of the Platysma, and invests the neck; it also forms sheaths for the carotid vessels, and for the structures situated in front of the vertebral column...

, and divides beneath the Platysma into ascending and descending branches, which are distributed to the antero-lateral parts of the neck

Neck

The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

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During dissection, the SCM is the landmark. The transverse cervical nerves will pass horizontally directly over the SCM from Erb's point.