BIOMECHANICS

REFERENCES1. Echarri, J.J. and Forriol, F. ‘Influence of the type of load on the cervical spine: a study on Congolese bearers.’

The Spine Journal 5; 2005; 291-296.2. Geere, J. L., Hunter, P.R. and Jagals, P. ‘Domestic water carrying and its implications for health: a review and

mixed methods pilot study in Limpopo Province, South Africa.’ Environmental Health 9(52); 2010; 1-13.3. Geere, J.L., Mokoena, M.M., Jagals, P., Poland, F. and Hartley, S. ‘How do children perceive health to be affected

by domestic water carrying? Qualitative findings from a mixed methods study in rural South Africa.’ Child: care, health and development 36(6); 2010; 818-826.

4. Jäger, H.J., Gordon-Harris, L., Mehring, U-M., Goetz, G.F. and Mathias, K.D. ‘Degenerative change in the cervical spine and load-carrying on the head.’ Skeletal Radiol 26; 1997; 475-481.

5. Joosab, M., Torode, M. and Rao, P.V.V.P. ‘Preliminary findings on the effect of load-carrying to the structural integrity of the cervical spine.’ Surg Radiol Anat 16; 1994; 383-398.

6. Levy, L.F. ‘Porter’s Neck.’ British Medical Journal 2; 1968; 16-19.7. Lloyd, R., Parr, B., Davies, S. and Cooke, C. ‘A comparison of the physiological consequences of head-loading

and back-loading for African and European women.’ Eur J Appl Physiol 109; 2010; 607-616.8. Mahbub, M.H., Laskar, M.S., Seikh, F.A., Altaf, M.H., Inoue, M., Yokoyama, K., Wakui, T. and Harada, N.

‘Prevalence of cervical spondylosis and musculoskeletal symptoms among coolies in a city of Bangladesh.’ Journal of Occupational Health 48; 2006; 69-73.

9. Scher, A.T. ‘Injuries to the cervical spine sustained while carrying loads on the head.’ Paraplegia 16; 1978; 94-101.

DISCUSSION

EFFECTS ON ADULTS AND CHILDREN

DEFINITION

ADVERSE EFFECTS OF HEAD-LOADING ON SPINE

HEAD-LOADING

Adopted from Echarri and Forriol (2005).

http://www.chinadaily.com.cn/photo/2007-01/31/content_797874.htm

Thumbs.dreamtime.comAdopted from Mahbub et.al (2007)

In poor African nations and developing countries in Asia, it is a very common practice to carry goods, water, firewood, harvested crops etc. on the head and this method of transporting loads using head can be termed as head-loading [1-9].

• Load on the head is carried downward the spine due to the gravitational pull [5].

• Cervical spine transmits its load downwards through the anterior column and the zygapophyseal joints between the vertebrae [5].

• X-ray imaging have proved that head-loading straightens the cervical curvature to relieve the associate muscles and ligaments which in-turn produces enormous pressure on the vertebrae and the I.V discs. [5, 6, 9].

Line of Action of Weight on Spine.

[Adopted from Lecture Notes, Unit II, R.M. Hall.]

Normal Cervical Spine [6].

Cervical Spine after Being Loaded with 200lb Sack [6].

BIOMECHANICS OF HEAD-LOADINGRoopam Dey,

University of Leeds, Department of Mechanical Engineering, mn11rd@leeds.ac.uk.

Disk Degeneration

C3/C4

C4/C5

C5/C6

C6/C7

• Disk degeneration increases in head loaders, leading to disc height reduction [4, 5].

• Spinal canal gets narrowed over time [5].

• Herniation of discs are also reported in the lower cervical region [1, 6].

• Young head loaders develop cervical spondylosis [8].

• Strength of the ligaments and tendons attached to the cervical region decreases due to fatigue [5, 6].

• Large number of anterior osteophytes have been reported in subjects [1].

• Injuries due to over flexion affects the upper [6] and lower vertebrae [9].

Higher Disk Degeneration observed in head-loaders [4].

Regions of Disk Degeneration. Obtained from the data provided in [4].

O2 usage shoots up during head-loading [7].

• Neck pain, over exertion is a common complain of both the adults and the children [2, 3].

• Travelling longer distances aggravates the risk of spinal injury as the way is full of obstacles [2].

• Young girls and women have to do most of the load carrying as men are prohibited from indulging in these kind of jobs [2].

• Children doesn’t have time to study and play. Still a few of them feel happy by carrying loads as they think they are helping their families [3].

• Fractured necks have been reported in male porters due to incorrect loading of sacks [6].

• The villagers wished that the sources of water were close to them [2, 3].

A young girl carrying a heavy bucket of water [3].

Amount of load carried by a child increases with age [3].

• There were contradiction in results regarding the actual region of the cervical spine that is affected by head loading

- According to Levy (1968), the upper part of the spine i.e. C1- C4 are the regions where most of the degeneration occurs [6]. - After a decade Scher contradicted the above findings and stated that the vertebrae from C4-C6 are the regions most likely to have adverse affects due to head-loading [9]. - The contradicting findings can be because of the differences in sample size, Levy(1968) had examined more head-loaders than Scher(1978). The distance travelled by the volunteers examined by Levy was 37-50 yards, no such information was provided by Scher and moreover the methods of loading incorporated by the researchers were different, these things might account for the dissimilar findings [6, 9].• The language used by some of the researchers was kind of

racial, regarding the native Africans as ‘blacks’ and ‘Negros’ and the immigrants as ‘whites’ [4, 6, 9].

• The studies regarding children did not take into account any X-rays of the cervical column and all the judgements were made depending on the subjective questionnaire asked to the children. The real effect of head-loading on children’s spine remains unknown [2, 3].

• None of the studies took into account the affect of the small cloth cushion kept between the head and the load. Apart from cushioning it also helps one to balance the load on the head and might have some effect on the cervical spine [1-9].