Anatomical characteristics of the brachial plexus of the maned sloth (Bradypus torquatus Illiger, 1811)

Abstract

Eight male and female maned sloth (Bradypus torquatus) cadavers, previously fixed in formalin, were used to identify the origin of the brachial plexus, nerves and innervation territory in order to determine an anatomical pattern for this species. The plexus of B. torquatus was derived from the C7 to C10 and T1 to T2 spinal nerves, but the participation of T2 was variable. The spinal nerves gave origin to the cranial and caudal trunks, which joined to form a common trunk, from which two fascicles were formed. All the nerves from the brachial plexus were originated from these two fascicles, except the thoracic, long pectoral and suprascapular nerves, which arose before the formation of the common trunk. The organization of the brachial plexus into trunks and fascicles, and subsequent origin of peripheral nerves, demonstrates that most of the spinal nerves contribute to the composition of the peripheral nerves and the possibility that lesions or traumatic injuries would damage most of the thoracic member.

Keywords

• Forelimb
• Nervous system
• Xenarthra