[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Spine](https://durgical.com/en/anatomy/region/spine/) › Alar ligaments [Joints and ligaments](https://durgical.com/en/anatomy/system/joints-and-ligaments/) · [Spine](https://durgical.com/en/anatomy/region/spine/) # Alar ligaments The alar ligaments are two short, strong cords from the tip of the dens to the skull; they limit turning and tilting of the head. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=spine&select=alar_ligs&side=r) Opens in the Durgical app, no sign-up needed. ## What it is Two short, strong cords from the tip of the dens to the sides of the skull opening. ## What it does Limit head rotation and side bending at the top of the neck; can be injured in whiplash. ## Key points - With the transverse ligament of the atlas and the tectorial membrane they are the key stabilisers of C0–C1–C2, where there is no disc and stability rests on ligaments - The ligament of one side checks rotation of the head to the opposite side; after a one-sided tear, rotation to the other side may increase - Type I odontoid fracture (Anderson–D'Alonzo) and type III occipital condyle fracture (Anderson–Montesano) are both avulsions at the alar attachments - Secondary restraint to forward slip of the [atlas](https://durgical.com/en/anatomy/atlas/): they cannot hold C1 on their own once the [transverse ligament](https://durgical.com/en/anatomy/transverse-ligament-of-knee/) has failed ## Key facts **Attaches** Sides of the dens tip to the inner sides of the occipital condyles **Function** Check ligaments of the craniovertebral junction; limit head rotation and side bending; can tear in whiplash **Tight in** Head rotation (contralateral ligament) and lateral flexion ## Relations **Medial** The apical ligament of the dens, a thin midline cord between the two alar ligaments, running from the dens tip to the front rim of the [foramen magnum](https://durgical.com/en/anatomy/foramen-magnum/) **Behind** Superior band of the cruciform ligament, then the tectorial membrane, the dura and the junction of the medulla and the [spinal cord](https://durgical.com/en/anatomy/spinal-cord/) **Below** The dens of the [axis (C2)](https://durgical.com/en/anatomy/axis/) and the median atlantoaxial joint, with the [transverse ligament of the atlas](https://durgical.com/en/anatomy/transverse-ligament-of-atlas/) wrapped behind the dens ## Examination - Alar ligament stress test (manual therapy): the examiner holds the C2 spinous process and side-bends the head; with an intact ligament C2 moves almost at once, while free side-bending before C2 moves suggests laxity. Not done in acute trauma until fracture and instability are ruled out on imaging ## On imaging They cannot be felt. Thin-slice MRI (coronal and axial, proton density or T2) shows two dark bands running up and out from the dens tip to the occipital condyles; a gap or high signal suggests a tear. CT shows avulsion fragments from the dens tip or the condyle. ## Common problems - Weakened in rheumatoid arthritis or Down syndrome, or torn by trauma: C1-C2 instability that can press on the cord. ## How it is diagnosed Flexion-extension X-rays (the gap between the atlas and the dens), CT and MRI. ## Treatment - Surgical C1-C2 fusion if the joint is unstable. ## Clinical notes - A dens-tip (type I) avulsion is usually stable by itself, but it can be a sign of a wider craniocervical (occipitocervical) injury - In whiplash, alar ligament damage has been proposed as a cause of chronic upper neck pain; the MRI findings are debated - In atlantoaxial instability from rheumatoid arthritis, they loosen together with the transverse ligament of the atlas ## Memory aid Alar means wing: two short wings spread out from the tip of the dens to the skull. ## Test yourself Think of the answer, then tap the question to see it. ## What are the attachments of the alar ligaments? From the sides of the tip of the dens (C2) to the inner sides of the occipital condyles: two short, strong cords. ## Which head movements do the alar ligaments limit? Rotation and side bending at the top of the neck: the ligament of one side checks rotation of the head to the opposite side. ## Which fracture of the dens is an avulsion at the alar ligament attachment? Type I odontoid fracture (Anderson–D'Alonzo), at the dens tip; usually stable by itself, but it can signal a wider craniocervical injury. ## Can the alar ligaments hold the atlas in place if the transverse ligament of the atlas has failed? No. They are only a secondary restraint to forward slip of C1 and cannot hold it on their own once the transverse ligament has failed. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/alar-ligaments/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ligamenta alaria TA2 1695 **Official Spanish (DeCS)** Ligamentos alares **English (TA2)** Alar ligaments **Also called** Mauchart's ligaments ## Related - [Transverse ligament of the atlas](https://durgical.com/en/anatomy/transverse-ligament-of-atlas/) - [Axis (C2)](https://durgical.com/en/anatomy/axis/) - [Base of the skull](https://durgical.com/en/anatomy/occipital-bone/) Sources: Terminologia Anatomica (TA2); [Anatomy, Head and Neck: Atlantoaxial Joint](https://www.ncbi.nlm.nih.gov/books/NBK563271/); [Anatomy, Head and Neck: Foramen Magnum](https://www.ncbi.nlm.nih.gov/books/NBK526041/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/alar-ligaments/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/alar-ligaments/