Muscles that move the head and the neck Lab Practical

The Scalene Muscle

* Located more on lateral than anterior neck; deep to platysma and sternocleidomastoid. *Action= Flex and slightly rotate neck; elevate ribs 1-2 (aid in inspiration)

Sternocleidomastoid

* Two-headed muscle located deep to platysma on anterolateral surface of neck indicate limits of anterior and posterior triangles of neck. *Action= simultaneous contraction of both muscles of pair cause flection of neck, acting independently, rotate head toward shoulder on opposite side.

Semispinalis

*Deep composite muscle of the back-thoracic, crevices, and wapitis portions. *Action= Acting together, extend head and vertebral column; acting independently ( right vs. left), causes rotation toward the opposite side.

The Trapezius

*Most superfical muscle of the posterior throat; very broad origin and insertion. *Action= Extends head; raises, rotates, and retracts (adducts) scapula and stabilizes it; superior fibers elevate scapula (as in shrugging the shoulders); inferior fibers depress scapula.

The Splenius muscle

*Superficial muscle (wapitis and crevices parts) extending from upper thoracic region to skull *Action= As a group, extended for hyperextended head; when only one side is active. head​ is rotated and bent toward the same side.