What Causes the Neck Muscle to Loosen?

In most cases, the neck muscle tends to loosen simply as a result of genetics. Many patients find that their face and neck anatomy and aging process tends to resemble that of their parents. Other factors such as skin quality, sun exposure, physical activity, repetitive movements, etc may also play a less prominent role in overall neck laxity and appearance.Regardless of the cause, neck lifting procedures are highly effective at producing significant, long-lasting neck improvements.All the best,

The platysmal muscle in the neck is not bound to other muscles or ligaments and so is extra vulnerable to the effects of gravity and aging. In addition, most people don't exercise their necks, and so the muscle atrophies over time. Another factor that causes sagging neck skin and “turkey necks” is that the skin on the neck tends to be quite thin and is not well-connected to the platysma. The only way to make a dramatic change in the way loose neck muscles and skin look is to perform either a full facelift or a necklift, where the platysmal muscle is tightened and the excess skin removed and tightened. A well-performed neck lift can last up to 10 years. I hope this helps.

There are many reasons for neck laxity and these have been touched upon and include skin laxity due to decreased elastin formation, actinic damage, subcutaneous atrophy, gravitational changes, bony volume loss, etc.

 The main reason is gravity, gravity, gravity! Combine that with loss of fat in the neck and loss of elasticity of the skin and muscle, bone absorption, --------well you get the picture.

Its actually your skin that losens more than your neck muscles. With age the tighter collagen is replaced by more lose collagen and the elasticity decreases. Muscles do not play a big part in the aging appearance of the neck. Its the THINNER and LOSER skin that actually makes the neck look old with prominent muscle bands.
Regards

 Unfortunately, over time as you age, gravity continues to pull as the connective tissues in your body loosen.  This causes the skin to loosen and fall.

Hi @Jay123
Combined effects of weight fluctuations, sun exposure, aging, genetics, and gravity all play a role in loosening of neck muscles and skin. This results in the appearance of neck bands, thin crepey skin and laxity. This is addressed with a surgical necklift that removes excess fat, tightens the muscles and recreates an attractive neckline. 
This requires a small incision under the chin and another in your hairline. The incision under your chin is used to tighten the midline neck muscles and the posterior hairline incision is designed to help remove and redrape the neck skin in a natural shape. These scars tend to heal very well and remain inconspicuous. Best of luck,
Dr. Karan Chopra
★★★★★
Minneapolis Plastic Surgeon
Face ⨀ Breast ⨀ Body Expert
Johns Hopkins Trained
Cosmetic Fellowship Trained

The neck muscles (platysma) do not have a fixed attachment like other muscles that attach to ligaments and bone. The platysma muscles are free-floating in the neck and actually are pulled forward by their own contraction.

In facelift surgery, I pull the back portion of the muscle close to the ear again. You can see this in yourself in the mirror. Just pull on the neck at the angle of the jaw towards the ear and see the neck tighten. Once you do this, you will see why most non-surgical treatments for neck sagging don't work if the muscle position is not addressed.

As you age the neck muscles become a little lax and the skin looses its tone and that is why people need neck lifts.

The muscles in the neck that sag and create an aged appearance are the platysma muscles. The platysma muscles shorten, fibrose, and contract; this creates two bands in the front portion of the neck as we grow older. These bands are tightened in front above the hyoid bone and Adam’s apple and are cut and released down low below the Adam’s apple. This gives a normal neck contour and the bands disappear. The muscle itself is actually shortening, contracting, fibrosing, and bowstringing out from the neck skin. The fascia attachments around the muscle are actually what are loose.