Anatomy & Physiology I and II

Anatomy & Physiology Study Guide Each vertebra consists of three parts: a vertebral body, a vertebral arch, and articular processes. The vertebral body transfers weight along the axis of the vertebral column and allows stability of the trunk. The bodies of adjacent vertebrae are separated by intervertebral discs but interconnected by ligaments. The vertebral canal encloses the spinal cord. The five vertebral regions are the cervical, thoracic, lumbar, sacral, and coccygeal. Seven cervical vertebrae (C1–C7) constitute the neck and extend inferiorly to the trunk. Twelve thoracic vertebrae (T1–T12) make up the superior portion of the back; each bone articulates with one or more pairs of ribs. Five lumbar vertebrae (L1–L5) form the inferior portion of the back; the fifth connects to the sacrum, which articulates with the coccyx. The cervical, thoracic, and lumbar regions consist of individual vertebrae. Note, that when referring to a specific vertebra, the vertebral region is indicated by a capital letter: C, T, L, S, and Co (the cervical, thoracic, lumbar, sacral, and coccygeal regions, respectively). In addition, a subscript number denotes the relative position of the vertebra within that region, in which 1 indicates the vertebra closest to the skull. For example, C3 is the third cervical vertebra; whereas, C1 is in contact with the skull. The Thoracic Cage

©2018 Achieve Test Prep Page 88 of 367 The thoracic cage , or skeleton of the chest, provides support to the walls of the thoracic cavity. The bones of this region are the thoracic vertebrae, the ribs, and the sternum (breastbone). The ribs and the sternum form the rib cage. The thoracic cage serves two functions: it protects the heart, lungs, thymus, and other structures in the thoracic cavity, and it serves as an attachment point for muscles involved in respiration, maintenance of vertebral column positioning, and movements of the upper limbs.