Massage Therapy and Anatomy – C1, C2 and Arthrology

Question of May 8, 2009 – The C1 and C2 vertebrae are considered “atypical”. Why is this, and explain how the 2 vertebrae relate to each other.

C1 and C2 are considered “atypical” cervical vertebrae because their form and function differ from the other 5 cervical vertebrae.

C1, also known as the ‘atlas’, is a circular ring of bone, which consists of anterior and posterior arches and 2 lateral masses. On the superior surface of the lateral masses are the superior articular facets, on which sit the occipital condyles. This allows for a “nodding Yes” motion of the head. On the posterior surface of the anterior arch is the facet for the odontoid process of C2. (see below).

There are no intervertebral discs between C1 and C2.

C2, also known as the ‘axis’, is somewhat similar to other cervical vertebrae, except for the presence of the “dens” or odontoid process – a bony protrusion which projects upward and articulates with the anterior arch of C1. (it is held in place here by the transverse ligament which attaches on both lateral masses of C1). The axis allows for rotation of the head, as in shaking your head “no”

How is this relevant in Massage Therapy? – This is a very vulnerable part of the body, so understanding the anatomical structures in the area is necessary in the case where a therapist may have clients with a WAD injury (whiplash associated disorder). Clients who may have had a bad slip, fall or accident (car or otherwise) in which acceleration/deceleration occured may have the potential for instability in this area. It is important, ergo, for the client’s physician to give a green light for massage therapy treatment, and then for the therapist to proceed carefully.

Question for today (easier today)

What does the term arthrology mean?