Cervical lordosis: the effect of age and gender

Abstract

Background Context

Cervical lordosis is of great importance to posture and function. Neck pain and disability is often associated with cervical lordosis malalignment. Surgical procedures involving cervical lordosis stabilization or restoration must take into account age and gender differences in cervical lordosis architecture to avoid further complications.

Purpose

Therefore, the purpose of the present study was to evaluate differences in cervical lordosis between males and females from childhood to adulthood.

Study Design

This is a retrospective descriptive study.

Patient Sample

A total of 197 lateral cervical radiographs of patients aged 6–50 years were examined. These were divided into two age groups: the younger group (76 children aged 6–19; 48 boys and 28 girls) and the adult group (121 adults aged 20–50; 61 males and 60 females). The retrospective review of the radiographs was approved by the institutional review board.

Methods

On each radiograph, six lordosis angles were measured including total cervical lordosis (FM–C7), upper (FM–C3; C1–C3) and lower (C3–C7) cervical lordosis, C1–C7 lordosis, and the angle between foramen magnum and the atlas (FM–C1). Wedging angles of each vertebral body (C3–C7) and intervertebral discs (C2–C3 to C6–C7) were also measured. Vertebral body wedging and intervertebral disc wedging were defined as the sum of the individual body or disc wedging of C3 to C7, respectively. Each cervical radiograph was classified according to four postural categories: A-lordotic, B-straight, C-double curve, and D-kyphotic.

Results

The total cervical lordosis of males and females was similar. Males had smaller upper cervical lordosis (FM–C3) and higher lower cervical lordosis (C3–C7) than females. The sum of vertebral body wedging of males and females is kyphotic (anterior height smaller than posterior height). Males had more lordotic intervertebral discs than females. Half of the adults (51%) had lordotic cervical spine, 41% had straight spine, and less than 10% had double curve or kyphotic spine. Children had similar total cervical lordosis (FM–C7) to adults. The sum of vertebral body wedging for children was more kyphotic—by 7°—than that of adults, whereas the sum of intervertebral disc wedging in children was more lordotic—by11°—than that of adults. Seventy-one percent of the children had lordotic cervical spine, 23% had straight spine, and less than 6% had double curve spine. Gender differences are already apparent in children as girls had higher upper cervical lordosis (FM–C3; C1–C3) than boys do.

Conclusions

Although the total cervical lordosis (FM–C7) did not change between age groups, and between males and females, the internal architecture of the cervical lordosis changed significantly. Practitioners before neck stabilization procedures or correction and restoration should therefore take into account the gender and age differences in cervical lordosis.

Introduction

Cervical lordosis is the anterior convexity of the cervical spine from the first thoracic vertebra to the foramen magnum. It is situated at an important intersection between the neural and respiratory systems, the masticatory apparatus, major blood vessels, and endocrine glands. Cervical lordosis is essential for maintaining the head above the thorax in upright posture, enabling a forward gaze.

The degree of lordosis is determined by the orientation of the foramen magnum and by the wedging of the cervical vertebral bodies and intervertebral discs. Dorsal wedging of the vertebral bodies and discs (anterior height greater than posterior height) will increase the amount of cervical lordosis, whereas ventral wedging will decrease it [1], [2], [3].

An appropriate cervical lordosis is essential for efficient mastication function, breathing control, vocal production, and eye movement, and serves as part of the shock-absorbing mechanism during walking and running. Loss of the normal cervical curvature may be associated with pain, temporomandibular joint dysfunction, and other disorders [4], [5], [6].

Cervical lordosis begins development during intrauterine life [7]. It becomes clinically apparent at ages 3–4 months with head-lifting and becomes most pronounced at age 9 months with sitting [8], [9]. Thereafter, lordosis is the more common sagittal profile of the cervical spine [10], [11]. Cervical lordosis normally decreases from age 1 years to 9 years, and increases afterwards in response to increased thoracic kyphosis [12], [13].

Most studies did not find differences in the degree of cervical lordosis between males and females in young and adults [5], [12], [13]. However, Boyle et al. [14] found that in elderly subjects (above 75 years), the cervical lordosis measured between C2 and C7 was higher in females (26 degrees) than in males (12 degrees). Recently, it has been suggested that although the total cervical lordosis between the foramen magnum and C7 of males and females was similar, there are significant gender differences in the upper and lower cervical lordosis [2].

The cervical spine is a complex structure; its flexibility allows a wide range of motion while at the same time it provides stability to bear the weight of the head and maintain horizontal gaze. This complex nature of the cervical region lends it susceptible to a variety of disorders and complications, many of which associate with alignment pathology that may lead to surgical consideration. Cervical malalignment contributes to the pathogenesis of greater cord tension, an increase in intramedullary pressure, myelopathy, and headaches [15], [16]. Maintenance of cervical sagittal balance is reported to help improve symptoms and general health-related quality of life in patients undergoing posterior cervical fusion. Therefore, cervical lordosis values, of the nonpathological population, should be taken into account before any procedures involving cervical stabilization, lordosis correction, and lordosis restoration.

Therefore, the purpose of the present study was to evaluate postural differences in the cervical lordosis between males and females from childhood to adulthood.