Connections of the vertebral column to the skull
Last reviewed: 23.04.2024
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With the skull, its occipital bone, connect I and II cervical vertebrae. Compounds are characterized by great strength, mobility and complexity of the structure.
Atlantozatilovy joint (art. Atlantooccipitalis) combined, condylar. It is formed by two crotch of the occipital bone, connected with the corresponding upper articular pits of the atlas. Each of these joints has its own joint capsule. Together they are strengthened by two atlanto-occipital membranes. Anterior atlanto-occipital membrane (membrana atlantooccipitalis anterior) is stretched between the basilar part of the occipital bone and the front arch of the atlas. The posterior atlantocapital membrane (membrana atlantooccipitalis posterior) is thinner and wider than the anterior one. It is attached to the posterior semicircle of the large occipital foramen at the top and the posterior arch of the atlas below.
At the right and left atlanto-occipital joints simultaneous movements (combined joint) are possible. Around the frontal axis, the head is tilted forward and backward (nodal movements). The volume of movements is for the inclination of forward 20 °, for tilting backwards - 30 °. Around the sagittal axis, it is possible to withdraw the head from the median line (slope sideways) and return to its original position with a total volume of up to 20 °.
The medial atlantoaxial joint (art atlantoaxiilis mediana) is formed by the anterior and posterior joint surfaces of the axial vertebra tooth. The tooth from the front is connected to the tooth socket on the back surface of the anterior arch of the atlas. The posterior tooth is articulated with the transverse ligament of the atlas (lig. Transversum atlantis). This bundle is stretched between the inner surfaces of the lateral masses of the atlant. The anterior and posterior joints of the tooth have separate articular cavities and articular capsules, but are usually considered as a single medial Atlanto-axial joint. The medial atlanto-joint is a cylindrical uniaxial joint. It can rotate the head relative to the vertical axis. Rotations of the atlas around the tooth are performed together with the skull by 30-40 ° in each direction.
The lateral atlanto-osseous joint (art., Atlantoaxial lateralis) is paired, formed by the joint fossa on the lateral mass of the atlas and the upper articular surface on the body of the axial vertebra. The right and left Atlanto-osseous joints have separate joint capsules.
Medial and lateral atlantoo joints are strengthened by several ligaments. The ligament of the apex of the tooth (lig. Apicis dentis) is unpaired, thin, stretched between the posterior edge of the anterior circumference of the large occipital foramen and the apex of the tooth. The pterygoid ligament (ligg. Alaria) is paired. Each of them originates on the lateral surface of the tooth, is directed obliquely upwards and laterally, is attached to the inner surface of the condyle of the occipital bone. Pterygoid ligaments limit excessive rotation of the head in the mid-atlanto-axial joint.
A cruciate ligament of the atlas (lig. Cruciforme atlantis) lies posterior to the ligament of the apex of the tooth and the pterygoid ligament . It is formed by the transverse ligament of the atlant and longitudinal fascicles (fasciculi longitudinales) of fibrous tissue, going up and down from the transverse ligament of the atlant. The upper fascicle ends in the anterior semicircumference of the large occipital orifice, the lower one - on the posterior surface of the body of the axial vertebra. At the rear, on the side of the vertebral canal, the atlanto-joints and their ligaments are covered with a broad and strong connective tissue membrane membrane (membrana tectoria). At the level of the axial vertebra, the cover membrane passes into the posterior longitudinal ligament, and at the top ends on the inner surface of the basilar part of the occipital bone. Lateral and medial atlanto-osseous joints are combined. Simultaneously with rotation in the medial atlanto-osseous joint in the lateral atlanto-osseous joints, it is performed only by sliding with a slight displacement of the articular surfaces.
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