anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

, the transverse ligament of the atlas is a

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal li ...

which arches across the ring of the

atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geographic ...

(the topmost

cervical vertebra In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sau ...

, which directly supports the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

), and keeps the

odontoid process In anatomy, the axis (from Latin ''axis'', "axle") or epistropheus is the second cervical vertebra (C2) of the spine, immediately inferior to the atlas, upon which the head rests. The axis' defining feature is its strong odontoid process (bon ...

in contact with the atlas.

Anatomy

It is concave in front, convex behind, broader and thicker in the middle than at the ends, and firmly attached on either side to a small tubercle on the medial surface of the

lateral mass of the atlas In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. It is named for Atlas of Greek mythology because, just as Atlas supported the globe, it supports the entire head. The atlas is ...

Gray's anatomy ''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter, and first published in London in 1858. It has gone through multiple revised editions and the current edition, the 42nd (Octob ...

, 1918 As it crosses the odontoid process, a small fasciculus (''crus superius'') is prolonged upward, and another (''crus inferius'') downward, from the superficial or posterior fibers of the ligament. The former is attached to the basilar part of the occipital bone, in close relation with the membrana tectoria; the latter is fixed to the posterior surface of the body of the axis; hence, the whole ligament is named the

cruciate ligament of the atlas The cruciate ligament of the atlas (cruciate may substitute for cruciform) is a ligament in the neck. It forms part of the atlanto-axial joint. The ligament is named after its cross shape. It consists of transverse and longitudinal components. The ...

. The transverse ligament divides the ring of the atlas into two unequal parts: of these, the posterior and larger serves for the transmission of the

medulla spinalis The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spin ...

and its membranes and the accessory nerves; the anterior and smaller contains the odontoid process. The neck of the odontoid process is constricted where it is embraced posteriorly by the transverse ligament, so that this ligament suffices to retain the odontoid process in position after all the other ligaments have been divided.

Role in disease

Excessive laxity of the posterior transverse ligament can lead to

atlantoaxial instability In anatomy, the transverse ligament of the atlas is a ligament which arches across the ring of the atlas (the topmost cervical vertebra, which directly supports the skull), and keeps the odontoid process in contact with the atlas. Anatomy It is co ...

, a common complication in patients with Down's Syndrome. Laxity has also been hypothesized as the cause of degenerative hypertrophy and mechanical atlantoaxial stress. Degenerative processes can give rise to transverse ligament cysts, resulting in progressive cervical myelopathy. The treatment of choice for transverse ligament cysts with progressive neurological decline is surgical resection and cervical fusion. Conservative treatment with external neck immobilization is less commonly reported , but may be very useful in select cases where immediate surgical intervention is not indicated.

References

{{Authority control Ligaments of the head and neck Bones of the vertebral column

Anatomy

Role in disease

See also

References