Obex

The obex (from the Latin for barrier) is the point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord.

The obex occurs in the caudal medulla.

The decussation of sensory fibers happens at this point.

Clinical significance

Lesions at the location can result in obstructive hydrocephalus. The most common lesion at this location is a subependymoma, a benign tumor.Hemangioblastoma has been observed in this location. Neurological surgical intervention in the treatment of syringomyelia or hydromyelia may involve plugging the obex to prevent the transmission of cerebrospinal fluid to the central canal of the spinal cord.Gardner suggested plugging of obex with muscle prevents transmission of CSF wave into central canal.

Additional images

Fourth ventricle. Posterior view.Deep dissection.

Fourth ventricle. Posterior view.Deep dissection.

References

OBject EXchange

OBEX (abbreviation of OBject EXchange, also termed IrOBEX) is a communications protocol that facilitates the exchange of binary objects between devices. It is maintained by the Infrared Data Association but has also been adopted by the Bluetooth Special Interest Group and the SyncML wing of the Open Mobile Alliance (OMA). One of OBEX's earliest popular applications was in the Palm III personal digital assistant. This PDA and its many successors use OBEX to exchange business cards, data, even applications.

Although OBEX was initially designed for infrared, it has now been adopted by Bluetooth, and is also used over RS-232, USB, WAP, and in devices such as Livescribe smartpens.

Comparison to HTTP

OBEX is similar in design and function to HTTP in providing the client with a reliable transport for connecting to a server and may then request or provide objects. But OBEX differs in many important respects: