The goal of surgery in congenital muscular torticollis is to cut and then reattach the SCM muscle in a way that will remove the constricting bands of fibrous tissue, improve range of motion, and allow the head to be held vertically.
It is believed that either pressure on the SCM muscle due to position of the head in the uterus causes the muscle to become fibrous and shorten or that the blood supply to the muscle is disturbed and the muscle becomes scarred.
A uniploar SCM release, sometimes called an inferior open tenotomy of the SCM, cuts and then reattaches the SCM muscle where it meets both the breastbone and collarbone.
Surgery is highly successful on children who do not respond to conservative treatment, so long as their torticollis is caused by restriction of the SCM muscle.
A bipolar SCM release, also called a bipolar z-plasty, releases muscle where it is attached to the skull and at the collarbone.
Although this lump disappears by itself after about three months, the SCM muscle becomes tight, contracted, and fibrous.
Wryneck affects the SCM muscle, usually on only one side of the neck, causing the neck to spasm painfully and twist.
One theory suggests that damage occurs during the birth causing a blood clot to form in the SCM muscle.
In either case, the result is scarring and shortening of the SCM muscle.
Ses formed upon the persons of the plural, while continental Catalan says ets (anciently est), as also, in the plural, scm, seu, instead of som, sou, are to.be noted; tenere has passed over to the conjugation in re (trenda=tendre), but it is at the same time true that in ordinary Catalan also we have hindrer alongside of tenir the habitual form; dicere gives not dir but diure, which is more regular.