Anatomy: The muscles on the back of the upper arm (brachium) comprise the 3-headed arm stretcher (M triceps brachii). The muscle primarily stretches the elbow joint (and the shoulder joint). 1  Clavicula.  Bursa subcutanea acromialis.
Overview. The cervical spine is made up of 7 vertebrae. The first 2, C1 and C2, are highly specialized and are given unique names: atlas and axis, respectively. C3-C7 are more classic vertebrae, having a body, pedicles, laminae, spinous processes, and facet joints.
Spine. The spine (backbone) is composed of 33 interlocking bones called vertebrae that are separated by soft, compressible discs and supported by many different ligaments and muscles.he spine (backbone) is composed of 33 interlocking bones called vertebrae that are separated by soft, compressible discs and supported by many different ligaments and muscles.