Paracondylar process: Manifestation of an occipital vertebra

Abstract

In the examination of over 1300 burials from medieval Canterbury, one individual displayed a well‐defined paracondylar process. Four other adults and two children presented with small tubercles at the same site. The aetiology of the trait is discussed with reference to cranial base variants and the so‐called manifestation of an occipital vertebra.

Embryology of the craniocervical junction and posterior cranial fossa, part I: Development of the upper vertebrae and skull

“…Hypertrophy of the occipital condyles; can cause cervicomedullary compression Ohaegbulam et al (2005); Halanski et al (2006) Paracondylar (paramastoid or jugular) process A pneumatized osseous process in the lateral condylar area (jugular process of the occipital bone) located between the occipital condyle and mastoid process at the point of insertion of the rectus capitis lateralis muscle; can be unilateral or bilateral; may or may not fuse with the transverse process of the atlas; has an incidence of 2-4% Lang (2001); Tubbs et al (2005); Anderson (1996); Taitz (2000); Prescher (1997) Lateral (transverse) process of the occipital condyle Is homologous to the transverse process of the atlas arising from the its lateral mass; is a proatlas remnant Stratemeier and Jensen (1980); Gladstone and Erichsen-Powell (1915) Prebasioccipital arch or anterior lip of the foramen magnum A U-shaped ridge connecting the end of the occipital condyles; manifests as the ventral arch of the proatlas Prescher (1997); Taitz (2000); Oetteking (1923) Basilar process Lateral tubercle and the remains of the prebasioccipital arch; a proatlas remnant; is sometimes considered a variant of or the same as the precondylar process Prescher (1997); Oetteking (1923) Condylus tertius A downward bony projection located just at the anterior margin of the foramen magnum; associated with an increased prevalence of os odontoideum; has an incidence of 1% (1994);Prescher 1996Prescher , 1997 sclerotomes with a segmentation pattern, which follows that in the final vertebrae (Sensenig, 1957). Somitogenesis and the formation and rearrangement of primary sclerotomes all occur in a craniocaudal direction.…”

Unusual case of occipital vertebra in a medieval skeleton

“…Among the many manifestations of occipital vertebra, either a complete or partial bony bipartition of the hypoglossal canal may occur. In a recent archeological report on an English medieval population, this abnormality has been found to be associated with a specific type of occipital vertebra called the paracondylar process in 57.2% of cases (Anderson, 1996). In the present case this supplementary conduit does not seem to represent a duplication of the hypoglossal canal because, when this anomaly occurs, both conduits present an inner and an outer orifice.…”

Surgical treatment for an uncommon headache: A gap of 4800 years

“…The presence of PCP and ETP in archaeological remains is anecdotal. The most extensive study on archaeological remains was carried out in the United Kingdom in 1996 (10), in which 1300 skulls from the medieval period were studied during the excavation of St Gregory's Priory. In this study there were 1 PCP (9 mm in SK 188 individual) and six paracondylar tubercles (less than 8 mm), which is a frequency of about 0.5%.…”