Spasmodic torticollis
Torticollis with recurrent, but transient contraction of the muscles of the neck and especially of the sternocleidomastoid, is called spasmodic torticollis. Synonyms are "intermittent torticollis", "cervical dystonia" or "idiopathic cervical dystonia", depending on cause. Trochlear torticollis
Torticollis may be unrelated to the sternocleidomastoid muscle, instead caused by damage to the trochlear nerve (fourth cranial nerve), which supplies the superior oblique muscle of the eye. The superior oblique muscle is involved in depression, abduction, and intorsion of the eye. When the trochlear nerve is damaged, the eye is extorted because the superior oblique is not functioning. The affected person will have vision problems unless they turn their head away from the side that is affected, causing intorsion of the eye and balancing out the extorsion of the eye. This can be diagnosed by the Bielschowsky test, also called the head-tilt test, where the head is turned to the affected side. A positive test occurs when the affected eye elevates, seeming to float up. Anatomy
The underlying anatomical distortion causing torticollis is a shortened sternocleidomastoid muscle. This is the muscle of the neck that originates at the sternum and clavicle and inserts on the mastoid process of the temporal bone on the same side. There are two sternocleidomastoid muscles in the human body and when they both contract, the neck is flexed. The main blood supply for these muscles come from the occipital artery, superior thyroid artery, transverse scapular artery and transverse cervical artery.
It can also result if the ventral pancreatic bud fails to fully rotate, so it remains on the right or if the dorsal bud rotates in the wrong direction, such that the duodenum is surrounded by pancreatic tissue. Blockage of the duodenum develops if inflammation (pancreatitis) develops in the annular pancreas. Diagnosis
Postnatal diagnostic procedures include abdominal x-ray and ultrasound, CT scan, and upper GI and small bowel series. Abdominal radiography can show the classic sign of the "double bubble": the presence of air in the stomach and duodenum. Unfortunately, this double-bubble sign is not pathognomonic for annular pancreas, as it can also be observed in other conditions, such as duodenal atresia and intestinal malrotation. Upper GI series may be suggestive of annular pancreas, especially if they show a duodenal narrowing of the second portion of the duodenum and the concomitant dilatation of the proximal duodenum. In some cases it is possible to have signs of inverse peristalsis of the duodenal tract which is proximal to the narrowing caused by the annular pancreas, and the dilatation of the duodenal portion distal to the anomaly. An abdominal CT scan or an MRI allows to highlight the narrowing of the descending duodenal tract and the ring of pancreatic tissue surrounding the duodenum: this ring can be complete or, in patients with an incomplete annular pancreas, extended in a postero-lateral or anterolateral direction with respect to the second part of the duodenum.