Hump attachment structure of the two-humped camel (Camelus bactrianus)

The hump attachment structure was morphologically examined in the two-humpe d camel (Camelus bactrianus). The cranial hump is fixed by the trapezius an d rhomboid muscles in the thoracic region. The strong collagen sheet in the basement of the hump is attached to the segmented bellies of the trapezius muscle, and the thoracic rhomboid muscle and the nuchal-supraspinous ligam ent support the attachment function of the trapezius muscle. The basement s heet possesses the line structure of collagen fibers, which are fitted to t he segmented bundles of the trapezius muscle, and we observed that the musc le cells of the trapezius muscle are intermingled with the collagen fibers around the attachment line structure. In contrast, the caudal hump is direc tly attached to the subcutaneous tissue in the superficial region of the lu mbar longissimus and lumbar iliocostal muscles. These findings demonstrated that the caudal hump of the two-humped camel is consistent with the hump o f the one-humped camel in the attachment structure.