The fifth lumbar vertebra is characterized by its body being much deeper in front than behind, which accords with the prominence of the sacrovertebral articulation; by the smaller size of its spinous process; by the wide interval between the inferior articular processes, and by the thickness of its transverse processes, which spring from the body as well as from the pedicles. The fifth lumbar vertebra is by far the most common site of spondylolysis and spondylolisthesis.Most individuals have five lumbar vertebrae, while some have four or six. Lumbar disorders that normally affect L5 will affect L4 or L6 in these latter individuals. Segmental movements
The range of segmental movements in a single segment is difficult to measure clinically, not only because of variations between individuals, but also because it is age and sex dependent. Furthermore, flexion and extension in the lumbal spine is the product of a combination of rotation and translation in the sagittal plane between each vertebra.Ranges of segmental movements in the lumbar spine (White and Punjabi, 1990) are (in degrees):

Congenital anomalies
Congenital vertebral anomalies can cause compression of the spinal cord by deforming the vertebral canal or causing instability. Other animals
African apes have three and four lumbar vertebrae, (bonobos have longer spines with an additional vertebra) and humans normally five.
Cognitive theorists believe the disorder to be a result of an underlying belief that other people are unfriendly in combination with a lack of self-awareness. Diagnosis
ICD-10
The World Health Organizations ICD-10 lists paranoid personality disorder under (F60.0). It is a requirement of ICD-10 that a diagnosis of any specific personality disorder also satisfies a set of general personality disorder criteria. It is also pointed out that for different cultures it may be necessary to develop specific sets of criteria with regard to social norms, rules and other obligations.PPD is characterized by at least three of the following symptoms:

excessive sensitivity to setbacks and rebuffs;
tendency to bear grudges persistently (i.e. refusal to forgive insults and injuries or slights);
suspiciousness and a pervasive tendency to distort experience by misconstruing the neutral or friendly actions of others as hostile or contemptuous;
a combative and tenacious sense of self-righteousness out of keeping with the actual situation;
recurrent suspicions, without justification, regarding sexual fidelity of spouse or sexual partner;
tendency to experience excessive self-aggrandizing, manifest in a persistent self-referential attitude;
preoccupation with unsubstantiated "conspiratorial" explanations of events both immediate to the patient and in the world at large.Includes: expansive paranoid, fanatic, querulant and sensitive paranoid personality disorder. Excludes: delusional disorder and schizophrenia. DSM-5
The American Psychiatric Associations DSM-5 has similar criteria for paranoid personality disorder. They require in general the presence of lasting distrust and suspicion of others, interpreting their motives as malevolent, from an early adult age, occurring in a range of situations.