Some New Observations on the Functional Anatomy of the Lower Cervical Spine

Dynamic mechanical properties of intact human cervical spine ligaments

“…Although only six cervical spines were used, bone-ligament-bone preparations from all spinal levels were combined to maximize the sample size for each ligament ( Table 1). The maximum number of samples per spinal level was six for CL and was three for all other ligaments, however difficulties in specimen preparation and mounting and lack of ISL+SSL in some spines [5] resulted in decreased sample sizes. In addition, every attempt was made to elongate each ligament along the direction of its fibers.…”

“…Main cervical spine ligaments inferior to the C2 vertebra, besides the intervertebral disc, include the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), capsular ligament (CL), ligamentum flavum (LF), and interspinous and supraspinous ligaments (ISL+SSL). The ALL and PLL, spanning the anterior and posterior aspects of vertebral bodies, respectively, have similar composition, with PLL consisting of approximately 67% collagen and 6% elastin fibers [5][6][7][8]. Located between vertebral bodies, the intervertebral disc consists of a central nucleus pulposus, which is viscous and jelly-like in the young, encased by annulus fibrosis fibers, having a high collagen composition with an increasing percentage of elastin near the cartilaginous endplates [4,9].…”

“…The LF, the most elastic tissue in the human body, attaches at adjacent laminae bilaterally and consists of approximately 80% elastin and 20% collagen [11,12]. The ISL, not present in all adult cervical spines, is composed of approximately 5% to 20% elastin [5,13]. The SSL, the most posterior cervical ligament, has been described as histologically similar to and continuous with ISL, making it difficult to identify as a separate structure [14,15].…”

A Dynamic Model of the Cervical Spine and Head

“…Zn addition to the basic ligaments already described, which are found in the lower cervical spinu, there are specialized ligamentous structures connecting the vertebrae with the head to allow for coarse and fine movements of the head. The largest and most rigid ligaments in the cervical spine are the longitudinal ligament, the annulus fibrosus, if it can be considered a ligament, and the capsular ligaments (Johnson et al, 1975). These ligaments stabilize the cervical spine, whereas the others play a more specialized but secondary role (Johnson, 1975).…”

“…In the neck, they consistently limit fleJion and anterior horizontal displacement (Johnson et al*# 1975).…”