Tortikolis

01Pathophysiology

Congenital muscular torticollis (CMT) is the most common cause of torticollis in the pediatric population and the third most common congenital musculoskeletal anomaly. The underlying mechanism involves fibrosis and contracture of the sternocleidomastoid muscle on the affected side. The prevailing theory is that during a difficult or prolonged delivery (particularly breech), the SCM undergoes ischemic injury or a form of compartment syndrome. This leads to edema, followed by fibroblast proliferation and eventual replacement of normal muscle fibers with dense fibrous tissue.

The SCM has two heads of origin: one from the sternum and one from the clavicle. It inserts on the mastoid process of the temporal bone. When the muscle contracts unilaterally, it produces ipsilateral lateral flexion (tilting the ear toward the shoulder on the same side) and contralateral rotation (turning the chin toward the opposite shoulder). When the affected SCM becomes shortened and fibrotic, it pulls the head into a fixed position of tilt toward the affected side and chin rotation away from the affected side. This is the hallmark presentation that test-writers rely on.

The palpable mass within the SCM, sometimes called a "sternocleidomastoid pseudotumor of infancy," typically appears at 2 to 4 weeks of life. It represents the area of maximal fibrosis and is firm, non-tender, and mobile within the muscle belly. This mass usually regresses spontaneously over several months, but if the underlying contracture is not addressed, the positional deformity persists.

A secondary consequence of the persistent head position is positional plagiocephaly, where the ipsilateral occiput becomes flattened because the infant consistently rests on the same side of the head. Test-writers may describe this skull asymmetry as an additional clue. There is also a well-established association between CMT and developmental dysplasia of the hip (DDH), both of which share intrauterine crowding as a common risk factor. A hip examination (and often a hip ultrasound) should be performed in any infant diagnosed with CMT.

02Classification and Clinical Manifestation

Acquired Torticollis

The distinction between congenital and acquired torticollis is a favorite testing point. Acquired torticollis in a child older than the neonatal period, particularly with neurologic signs, warrants urgent imaging to exclude a posterior fossa lesion.

03Diagnostic Workup

Congenital muscular torticollis is fundamentally a clinical diagnosis. The test-writer expects you to recognize the classic triad: head tilt, contralateral chin rotation, and a palpable SCM mass in a young infant with a history of difficult delivery. No lab work is needed.

When imaging is indicated, ultrasound of the SCM is the best initial imaging modality. It is non-invasive, avoids radiation, and directly visualizes the fibrotic changes within the muscle. This is the confirmatory test for CMT.

Cervical spine radiographs should be obtained when there is clinical suspicion of a bony etiology, particularly if the torticollis is not associated with a palpable SCM abnormality, if passive range of motion is restricted in all planes (suggesting a structural block rather than a unilateral muscular contracture), or if there are features suggestive of Klippel-Feil syndrome (low posterior hairline, short neck, limited neck motion).

MRI of the brain and cervical spine is the critical "next step" when the presentation is atypical. A child presenting with new-onset torticollis beyond infancy, without SCM pathology, with neurologic signs such as ataxia, nystagmus, vomiting, or cranial nerve deficits, must be evaluated with MRI to rule out a posterior fossa tumor. This is a high-yield testing point: the exam tests whether you recognize that acquired torticollis in a child can be a presenting sign of a brain tumor.

04Management and Treatment

The cornerstone of management for CMT is early initiation of physical therapy. When stretching is started before 3 months of age, resolution rates exceed 90%. The stretching program involves gentle passive movements: laterally flexing the neck away from the affected SCM (stretching the tight muscle) and rotating the chin toward the affected side. Parents are taught these maneuvers and perform them multiple times daily at home.

Repositioning strategies are equally important and serve two purposes: they encourage active range of motion toward the restricted side and prevent worsening of positional plagiocephaly. Placing toys, lights, and the parent's face on the side the infant does not prefer to look toward promotes active turning. Supervised tummy time strengthens cervical extensors and reduces prolonged pressure on the flattened occiput.

If the torticollis persists despite 6 to 12 months of dedicated physical therapy, or if the child is older than 1 year at presentation with a fixed contracture, surgical release of the SCM is indicated. The procedure involves sectioning the fibrous bands at the distal insertion (unipolar release) or at both the origin and insertion (bipolar release). Postoperatively, physical therapy is resumed, and some surgeons prescribe a tubular orthosis for torticollis (TOT) collar to maintain the corrected position during healing.

For plagiocephaly that does not improve with repositioning, a cranial molding helmet may be considered. Helmet therapy works by applying gentle external pressure to the prominent areas of the skull while allowing growth in the flattened regions. It is most effective when started between 4 and 12 months, as cranial growth velocity is highest during this period.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most tested trap with torticollis is the failure to distinguish congenital muscular torticollis from acquired causes that signal dangerous pathology. When the vignette describes a neonate or young infant with a birth history of breech presentation or difficult delivery, a palpable SCM mass, and the classic tilt-rotation pattern, the answer is CMT and the management is physical therapy. Students go wrong when they overcomplicate this straightforward presentation by ordering advanced imaging.

The reverse trap is equally important: when the vignette describes torticollis in an older child (beyond infancy), particularly with progressive symptoms, neurologic findings, or without a palpable SCM abnormality, the test-writer is asking you to recognize that this is not benign CMT. The "next best step" in that scenario is MRI of the brain and cervical spine, and the diagnosis they are testing is often a posterior fossa tumor.

Other commonly tested associations: always screen for developmental dysplasia of the hip in any infant with CMT (the examiner may test this as "what else should you evaluate"). Remember that the head tilts toward the affected (shortened) SCM and the chin rotates away from it. Students who confuse the direction of tilt versus rotation will misidentify the affected side. Finally, understand that the SCM pseudotumor is a benign fibrotic mass, not a neoplasm, and it does not require biopsy. A vignette describing a "neck mass in a newborn" is designed to test whether you can confidently identify this as CMT rather than pursuing an oncologic workup.