The alar ligaments are strong, rounded cords, which arise one on either side of the upper part of the odontoid process, and, passing obliquely upward and lateralward, are inserted into the rough depressions on the medial sides of the condyles of the occipital bone.
What is the purpose of the alar ligament?
Function. The function of the alar ligaments is to limit the amount of rotation of the head, and by their action on the dens of the axis, they attach the skull to the axis, the second cervical vertebra.
What is Alar test?
Purpose: To assess the integrity of the alar ligaments and thus upper cervical stability. Test Position: Supine, hooklying. Performing the Test: Place one hand on the occiput and use the other hand to palpate the spinous process of C2.
What movement does alar ligament restrict?
The alar ligaments are fibrous cords that attach to the dens bilaterally and insert on the base of the skull. They function to limit axial rotation and lateral bending on the contralateral side, and flexion secondarily [1-2].
Where are alar ligaments?
The alar ligaments join the lateral margins of the sloping upper posterior margin of the dens of C2 to the lateral margins of the foramen magnum (adjacent to the occipital condyles) and lie on either side of the apical ligament. They may be oblique or vertical and are thickest at the occipital attachment.
Where are the Denticulate ligaments?
spinal cord Denticulate ligaments arise from the pia mater on the lateral edge of the spinal cord and fuse to the overlying dura mater and the filum terminale extends from the conus medullaris to the end of the dural sac in order to anchor the inferior tip of the spinal cord.
How do you test for alar ligaments?
What movement does the atlanto occipital joint allow?
neck flexion The atlas and the occipital bone form the atlanto-occipital joint, which allows neck flexion. When you nod your head as if to say “yes,” that is neck flexion. The atlas and axis form the atlanto-axial joint, which allows head rotation.
Why is it called a hangman’s fracture?
The hangman’s fracture refers to a break in a bone known as C2, because it is the second bone down from the skull in your cervical (neck) vertebrae.
How do you heal alar ligaments?
When the diagnosis of isolated unilateral alar ligament rupture is established, external immobilization should be adequate treatment. Among the reported cases, 2 patients were immobilized in a halo orthosis for 12 weeks; and 3 patients wore a hard collar for 4 weeks (2 patients) to 4 months (1 patient).
How do you palpate c2?
How do you test for atlantoaxial instability?
The patient is asked to slowly flex the head performing a slight cervical nod, at the same time the examiner presses posteriorly on the patient’s forehead. A sliding motion of the head in relation to the axis indicates atlantoaxial instability.
How many alar ligaments are there?
Each of the five ligaments with transverse bands displayed a large proportion of fibres traversing directly from occipital condyle to occipital condyle.
How do you test cervical instability?
The following tests can be used to measure cervical instability but little is known about the diagnostic accuracy of upper cervical spine instability tests:
- Sharp-Purser test.
- Transverse Ligament Stress Test.
- Cervical flexion-rotation test.
- Neck Flexor Muscle Endurance Test and Craniocervical flexion test.
What is the sharp Purser test?
Purpose: To assess the integrity of the transverse ligament/upper cervical spine instability. Test Position: Sitting. Performing the Test: The patient should perform a slight cervical nod.
What is the role of the Intertransverse ligaments?
The intertransverse ligaments are ligaments that are placed between the transverse processes of the spine. In the cervical region they consist of a few irregular, scattered fibers that are often replaced by muscles. The function of the intertransverse ligaments is to limit lateral flexion of the spine.
What are the attachments of the Sacrotuberous ligament?
It is a remnant of part of Biceps femoris muscle. The sacrotuberous ligament is attached by its broad base to the posterior superior iliac spine, the posterior sacroiliac ligaments (with which it is partly blended), to the lower transverse sacral tubercles and the lateral margins of the lower sacrum and upper coccyx.
What is the atlanto occipital membrane?
The anterior atlanto-occipital membrane is a thin membrane that joins the upper border of the anterior arch of the atlas (C1) to the anterior inferior surface of the foramen magnum. It is a continuation of the anterior longitudinal ligament above the C1 level. It is immediately posterior to the prevertebral muscles.
What transmits information from the spinal cord to the extremities of the body?
Equivalent information from the upper extremities are conveyed by the cuneocerebellar and the rostral spinocerebellar tracts of the spinal cord.
Which region of the spinal cord is formed by sensory neurons?
Spinal Cord Regions In cross-section, the peripheral region of the cord displays neuronal white matter tracts containing sensory and motor neurons. Internal to this peripheral region is the gray, butterfly-shaped central region made up of nerve cell bodies.
What is the spinal theca?
The thecal sac or dural sac is the membranous sheath (theca) or tube of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the cerebrospinal fluid which provides nutrients and buoyancy to the spinal cord.