Mechanics function of the spine
The human body is meticulously designed with a complex and specialized skeletal system that helps not only provide support and structure for the body but enhances motion and stability. The spinal cord is the extension of the brain and it forms an essential part of the central nervous system. As people age the mechanics of the body are altered (NiosiOxland 2004). Degenerative processes are inevitable and as such, the facet joints, discs and vertebrae are affected. These degenerative issues of the spine include the degenerative disc disease, which is well known; others include Slipped discs, Spinal stenosis Osteoarthritis and low back pains (Pope 2001). All these are characterized by an intense amount of pain, sensory loss in some areas and limited motion as well.
The mechanics of the spine deal with the motion and movement of various parts along the spinal cord. These specific parts are each unique and specific to their jobs. The motion and structure of the spine has a great impact on the way a person’s peripheral nervous system functions, as such scientists in this field have extensively studied the various parts and related them to the development of the human body as they grow (AdamsDolan 2005). The spine has three specific areas namely Lumber, thoracic and the cervical vertebrae.
Image 1: courtesy of http://www.spineuniverse.com/anatomy/thoracic-spine
The spinal Length
The spinal cord’s length depends on the age and height of each individual. However, there are certain percentages of specific parts that make up this area of the body. Approximately three quarters of the spinal length is contributed by the vertebral bodies. A quarter of this length is made up of disc material. The disc contribution isn’t evenly spread out throughout the spine and approximately 20 percent of the thoracic and cervical length is from the disc height. About 30 percent of the lumber span is from the disc height. Age plays a big role on the contribution by the discs in each of these regions.
Spine Ligaments
Image 2
courtesy of http://www.spineuniverse.com/anatomy/thoracic-spine
The discs in the spine help in weight absorption from regular activities such as running waking and jumping. These discs also help absorb the pressure from more intense activities such as lifting of weighty objects. The structural support and stability of the spine are enhanced by the spine’s four natural curves. The spine is able to bend and move in different ways thanks to the facet joints on the discs. Various muscles allow coordination of movement in different directions (Tsukamoto, Maeda, Miura, Jingushi, Hosokawa, Harimaya, Higaki, KurataIwamoto 2006).
Nerves Nerves are fibers responsible for transmitting of information and sensation between the brain, the spine and other body parts. Without the motor neurons and sensory neurons it would be absolutely impossible for the brain to command motion of any part. The spinal cord is made up of several nerves and it is the main link between the body parts and the central nervous system. this is why when an individual damages their spine in certain areas, they lose either partial or total movement in parts of the spine and in other related areas. There are 31 pairs of nerves which branch out from the spine allowing for communication between the spine and other muscles of the body causing motion and sensation. The spinal nerves are each equipped with two roots, the ventral root, which carries motor impulses from the brain and the dorsal which carries impulses towards the brain. These roots fuse together forming a spinal nerve, the nerve moves down the spine and towards its exit hole the intervertebral foramen once this happens, the nerves branch into two, the part supplying the back muscles and skin is known as the posterior primary ramus. The other part supplying the front of the body with sensory information form movement is referred to as the anterior primary ramus.
Image 3 courtesy of: http://www.mayfieldclinic.com/PE-AnatSpine.htm
The spinal curves and discs
Image 4
courtesy of http://www.nytimes.com/health/guides/disease/herniated-nucleus-pulposus-slipped-disk
The different parts of the spine combine to form different shapes of curves that perform some very important activities in a human being. The thoracic and the sacral regions of the spine have a convex curve while the cervical and the lumbar spine have a concave curve (Faciszewski 2001). The curves in the spine aid the body in maintaining stability and the absorption of any kind of shock as well as in maintaining motion throughout the spinal column. It is important to note that good posture helps the spine maintain it’s normal curve, any form of pressure applied on the spinal area such as additional body weight can automatically cause spinal cord realignment.Spinal Disks
Spinal disks are made up of three parts, which help in maintaining flexibility in the entire body. These parts are the annulus fibrosus, end plates, and nucleus polposus. The end-plates main function is to ensure that herniation of the nucleus that may cause realignment does not occur; the vertebral bodies that are close together are held together against any form of pressure by the annulus fibrosus. The nucleus polposus on the other hand, is responsible for ensuring that motion is maintained throughout the body by preventing the forces of any internal or external pressure and keeping everything in balance .
Image 5
courtesy of : http://chiropractic-care.com.au/how-can-a-chiropractor-help-with-my-disc-problem
It is important to note that without the spinal cord, body movements cannot take place. Through it’s five main areas, the cervical area, thoracic area, sacral area, coccygeal area and lumbar area, it facilitates the production of nerves in each of these areas which send information to and from the brain to other parts of the body facilitating motion (Kettler, WernerWilke 2007). The lumbar area produces five lumbar nerves, the cervical area has eight, thoracic has twelve, coccygeal has one and the sacral has five nerves (Tsukamoto, Maeda, Miura, Jingushi, Hosokawa, Harimaya, Higaki, KurataIwamoto 2006). For the spinal cord to continue being healthy one should always ensure that they have maintained a good posture at all times. There are several issues that come about as a result of age and others are injuries that affect the spine and thus affecting mobility and other body functions, some of these complications relating to an injured spine include bladder control, bowel control, skin sensation, circulatory control and detrimental effects on sexual health. The spine controls a lot of sensation and motion on various parts of the body as aforementioned, clearly explaining why an affected area could cause malfunction in other parts of the body. Anything from herniated discs to spinal tumors all have their effect on the sensation and mechanics of other body parts.
I believe that one should be especially careful when it comes to considering issues of spinal health. Especially because certain injuries can be detrimental. Any back pains need to be checked out as early as possible because in some instances people have been known to suffer issues relating to the spine at a relatively young age. Regular exercises and check-ups ought to be put as priority because they help keep the spinal cord area healthy.
Works Cited
Adams, Michael A. and Dolan, Patricia, 2005, Spine biomechanics. Journal of Biomechanics. 2005. Vol. 38, no. 10, p. 1972-1983. DOI 10.1016/j.jbiomech.2005.03.028. Elsevier BV
Faciszewski, Tom, 2001, Biomechanics of Spine Stabilization. The Spine Journal. 2001. Vol. 1, no. 4, p. 304-305. DOI 10.1016/s1529-9430(01)00122-x. Elsevier BV
Kettler, A., Werner, K. and Wilke, H.-J., 2007, Morphological changes of cervical facet joints in elderly individuals. European Spine Journal. 2007. Vol. 16, no. 7, p. 987-992. DOI 10.1007/s00586-006-0275-9. Springer Science + Business Media
Niosi, Christina A. and Oxland, Thomas R., 2004, Degenerative mechanics of the lumbar spine. The Spine Journal. 2004. Vol. 4, no. 6, p. S202-S208. DOI 10.1016/j.spinee.2004.07.013. Elsevier BV
Pope, M., 2001, Spine Keynote Address. Journal of Biomechanics. 2001. Vol. 34, p. 1. DOI 10.1016/s0021-9290(01)00135-x. Elsevier BV
Tsukamoto, Nobuaki, Maeda, Takeshi, Miura, Hiromasa, Jingushi, Seiya, Hosokawa, Akira, Harimaya, Katsumi, Higaki, Hidehiko, Kurata, Kousaku and Iwamoto, Yukihide, 2006, Repetitive tensile stress to rat caudal vertebrae inducing cartilage formation in the spinal ligaments: a possible role of mechanical stress in the development of ossification of the spinal ligaments. Journal of Neurosurgery: Spine. 2006. Vol. 5, no. 3, p. 234-242. DOI 10.3171/spi.2006.5.3.234. Journal of Neurosurgery Publishing Group (JNSPG)
