The mobility of the sphenoid and occiput has long been regarded as a main focus in cranial treatments. Sutherland described the following motions between the sphenoid and the occiput around or at the sphenobasilar junction, which were later detailed in works by Magoun and Upledger: Extension and flexion of the neck, rotation of the head on the axis of the sphenoid, upward and downward movement of the head relative to the trunk. He further noted that injury to the sphenoid bone may result in deformity of the skull because it can no longer hold its normal relationship with the other bones of the cranium. This could be due to injury to or degeneration of the ligaments connecting it to the surrounding bones, or instability within the bone itself. Injury to the sphenoid bone is common because it is highly susceptible to trauma. Patients typically report symptoms such as pain, swelling, and deformity of the nose or face. If not treated, these injuries may lead to neurological problems such as hearing loss, tinnitus (ringing in the ears), blindness, or memory issues. Sphenoids are bone fragments that can migrate through the body after severe head injuries. These fragments are usually found near the spine, in the chest or abdomen. They are rare but do occur. A study published in 2004 looked at how often the sphenoid bone moves over time.