The remarkable anatomy of the giraffe's neck

Mammalian cervical vertebrae 6 and 7 and thoracic vertebra 1 possess many d istinguishing characteristics. In the giraffe, bone morphology, muscle orig ins and insertions, as well as the location of the brachial plexus (describ ed as many osteological and some soft tissue characters) are identical to t hose in other mammals but are all displaced posteriorly by one vertebra. Th ere are two exceptions to these observations: the pre-sacral vertebral coun t is unchanged when compared with that in the okapi and C7 supports the fir st rib. Thus, one vertebra has been added in the neck of the giraffe betwee n cervical 2 and 6, and some type of structural blending has occurred in th e region of the first rib. The junction of the giraffe neck with the thorax is unusual and results in a protruding forelimb. It is possible that the u nusual position of the neck relates to balancing of a cantilevered neck and head upon a relatively slight body. Characteristic drinking postures may h ave also influenced the observed anatomical modifications.