Disorders of the Cervical Spine
Presentation by: Su-Chun Cheng
Introduction
* Two principal functions: support and conduit
* The motion segment: two vertebrae and five articulations- disc, two uncovertebral joints, and two facet joints
* The three sections: OC1-2, C3-5, and C5-T1
The Typical Cervical Vertebrae (C3-6)
* Small oval bodies, large vertebral canal, long laminae, a bifid spine and a broad transverse process with a foramen transversarium
* The vertebral arches arise from the posterolateral aspect of the bodies, giving rise to the pedicles.
* The laminae arise from the pedicles and arch backward to meet in the midline, forming the bifid spinous processes.
* The intervertebral foramen for nerve root
* The foramen transversarium for vertebral artery except C7
* The spinal canal for spinal cord.
* Posterior arch- pedicles, articular process, laminae and spinous process
The Uncinate Process
* The uncovertebral joints of Luschka
* Form at about 10 year of age and better developed in C2/3, C3/4, and C4/5.
* Act as barriers to the extrusion of disc posterolaterally.
* The uncinate processes protect the cervical nerve roots from passing over the inter-vertebral discs.
* Cervical discs cannot protrude into the intervertebral foramina - only posteriorly and into the cord.
Zygapophyseal Joints
* The highest is located at the C2/3 level, and the lowest is at the C7-T1 level.
* The superior facets face upward/backward with the inferior facets facing downward/forward at an angle of 45°.
* Complex movement: rotation and sidebending to the same side.
* The joint capsules are lax and permitting great mobility.
* The relationships between the facet and root complex: the root in front of and below the facets.
* Joint capsules are richly innervated with propri-oceptive and pain receptors
* The joints are lined with synovial membrane and covered with hyaline cartilage. The fibro-cartilaginous meniscus exists in the facet capsules.
The Intervertebral Disc: Nucleus Pulposus
* A disc consists of four parts: a nucleus pulposus, an anulus fibrosus, and two cartilaginous end-plate.
* The end-plate provide a pathway for nutrition
* The nucleus has the remarkable property of absorbing and retaining water against physical and osmotic pressure.
* The nucleus pulposus is fibrocartilaginous and is made up of crisscrossing concentric lamellae between adjacent vertebrae.
* The annulus is reinforced in front and behind by fibers from the anterior and posterior longitudinal ligaments. Laterally, it blends with the periosteum.
* The nucleus is a water-rich mixture of proteoglycan gel and a lattice of collagen fibers.
* The nucleus distributes forces equally in all directions, with converting longitudinal to horizontal forces, and transmits them to the circumferential annuli.
* The resilient annulus and the cartilage plate, capping the upper and lower surfaces of the vertebrae, absorb shock energy.
Nerve Roots
* The posterior root/anterior root emerge from the dorsolateral/ ventrolateral aspect of the cord.
* The roots are invested in pia mater. The posterior and anterior roots separately penetrate the dura and have pial and dural sleeves.
* The dural sleeves are attached to the bony margin of the intervertebral foramen; this adherence becomes much firmer with advanced age and in clinical osteoarthritis.
* In extension of Cs: the root sleeves are slack and folded transversely, and are separated from the lower border of the pedicle.
* In flexion: the root sleeves are straightened and are in contact with the inferior and medial margins of the pedicles.
* In lateral flexion: the root sleeves are slack on the concave side and stretched on the convex side.
* The root ganglia may lie inside or outside the intervertebral foramen.
* Beyond the ganglion, the two roots merge to form the composite spinal nerve with its anterior and posterior primary rami.
* The upper four rami unite to form the cervical plexus; the lower four rami and T1 form the brachial plexus.
The Vertebral Artery
* The verterbal artery is the first branch of the sub-clavian trunk, proceeding to the transverse foramina of C6 to C2
* It lies directly in front of the cervical nerves, medial to the intertransverse muscles.
* It travels to the transverse foramen of the atlas, ne-cessitating a sharp turn around the posterolateral aspect of the superior facet.
* It then runs upward through the foramen magnum into the cranial cavity of pons, where it joins the opposite vertebral artery to form the basilar artery.
* The vertebrobasilar system also supplies the inner ear, the cerebellum, most of the pons and brain stem, and the posterior portion of the cerebral hemispheres, especially the visual cortex.
Vertebrobasilar Artery Insufficiency (VBI)
* After 30º of rotation, kinking of the contra-lateral vertebral artery occurs.
* At 45 º of neck rotation, the ipsilateral artery also begins to kink.
* Typical neurological symptoms include dizziness, visual disturbances and nausea.
* Occlusion of the vertebral artery may occur either at the suboccipital region or at the C6 level.
Mobility of the Cervical Spine- Flexion
* The upper vertebral body slightly forward displaces on the lower one; the laminae and spinous processes are open like a fan.
* The anterior disc is compressed and narrowed; and the dorsal portions is widened and stretched.
* The anterior longitudinal ligament is slack, whereas the posterior longitudinal ligament is stretched.
* The nucleus is dorsally displaced.
* The paired inferior articular facets of the vertebra glide forward on the superior facets of the vertebrae below
* The ligamenta flava and interspinous ligaments are stretched
* The posterior neck muscles are under tension
* The capsules of the zygapophyseal joints are stretched.
Mobility of the Cervical Spine- Extension
* Extension of the neck reverses these events of flexion in the tissues.
* Tension is on the anterior longitundial ligaments with the approximation of the spinous process.
* The lower articular facet glide downward and back- ward on the superior facets.
* The size of the intervertebral foramina increases in flexion and decreases in extension by about one third
* The overall extension is greater than the flexion range.
* The greatest movement occurs at the C5/6 and the least at the C2/3 and C7-T1.
Mobility of the Cervical Spine- Rotation
* In lateral flexion or rotation, the ipsilateral foramen decreases in size, and the contralateral foramen increases in size.
* Approximately 50% of the rotation of the cervical spine occurs at the atlantoaxial articulation, and the remainder occurs in the joints below.
* The dens is tightly bound to the occiput by the apical and the alar ligaments, with the atlantoaxial facet joints limits rotation to 45°
* The wall of the spinal canal narrows the canal at the axis level by about one third.
* The diameter of the canal of C1 is equally occupied by the odontoid process, free space, and the cord.
* With lateral flexion of the head, the spinous processes of the axis and the vertebrae below rotate to the opposite side.
* The vertebral artery is under tension by the rotary action.
Mobility of the Cervical Spine- Lateral flexion
* Lateral flexion occurs with the atlas shifting to the side of the flexion.
* Lateral flexion produces associated rotation of the axis. The spinous processes of the axis and the vertebrae below rotate to the opposite side.
* On X-ray film: narrowing of the space between the dens and the lateral mass of the atlas on the side of flexion and a widening on the other side.
The Upper Cervical Spine
* The upper cervical spine includes OC1 and C1/2 (and sometimes C2/3)
* The atlas has two arches and two lateral masses.
* The axis forms a pivot (dens) for the atlas to rotate on.
* AROM of the OC1: FL-EXT (about 16 ° to 20°), SB (about 5 °), and axial ROT (about 8 °).
* AROM of the C1/2: FL-EXT (about 10 °), SB (about 3 °) and axial ROT (about 40 °)
* Selective motion can occur between the OC1 and between the C1/2 without motion below the axis.
Biomechanics of The Upper Cervical Spine
Atlanto-Occipital joint
* The atlas has no body. It is a solid ring of bone with two pillars. It has no intervertebral foramen.
* The attachment of the posterior atlanto-occipital membrane arches over the artery at the posterior arch of the atlas.
Biomechanics of The Upper Cervical Spine
Atlanto-Occipital joint
* Occipital condyles are in convex surfaces and the superior facets of the atlas are in concave surfaces.
- In flexion, the occipital condyles roll forward and glide backwards. The alar ligament check the flexion of OC1
- In extension, the occipital condyles roll backwards and glide forwards.
Biomechanics of The Upper C/s
Atlanto-Axial joint
* The most obvious characteristic of the axis is the dens.
* The anterior surface of the dens has a facet that articulate with the posterior surface of the anterior arch of the atlas.
* The posterior surface of the dens also has a facet to the transverse ligament with a bursa in between
Biomechanics of The Upper C/s
Atlanto-Axial joint
* On either side of the dens are the inferior facets of the atlantoaxial joints.
* The axis has no intervertebral foramen.
* The spinal canal at this level can be divided into three parts: anterior 1/3 is occupied by the dens and the anterior arch of the atlas; the middle 1/3 is occupied by the cord; the posterior 1/3 is occupied by the sub-arachnoid space.
Atlanto-Axial joint
* Major axial rotation occurs in C1-2 (47degrees). C1-2 rotation is primarily checked by the alar ligaments.
* The convex inferior facets of the atlas and the convex superior facets of the axis.
* Flexion occurs with an anterior roll and a posterior slide of the atlas on the axis; the converse movement occurs in extension. It is restrictedly by the tectorial membranes as it tightens with superior movement.
Ligaments of The Upper Cervical Spine
* Transverse ligament: holds the dens tightly to the anterior arch of the atlas to prevent subluxation.
* Alar ligaments: (occipital portion) run on either side from the tip of the dens to the margins of the foramen magnum; (atlantal portion) run on either side from the tip of the dens to the posterior arches of the atlas.
* Tectorial membrane is a fan-shaped continuation of the posterior longitudinal ligament.
* Anterior longitudinal ligament: is tightly adherent to the front of the vertebral bodies and loosely blends with each annulus.
* Posterior longitudinal ligament: is firmly bound to each disc but only loosely bound to the posterior surface of the vertebral bodies.
* Ligamenta flava: running very elastic spanning the space between the laminae in pairs. They stretch into the fibrous capsule of the facet joints.
Neurological Examination: Upper Quarter
* Abnomalities in the cervical spine are perceived clinically as neurological sign and symptoms in the U/E.
* The neurological examination determine whether pathologic changes in the neck account for the U/E neurologic sign.
* The tests examine motor power, reflex, and sensation by neurologic level from C4 to T2.
* There are eight paired spinal nerves in the cervical spine but only seven vertebrae.
* The first through the seventh nerves exit above the vertebra of corresponding number. The eighth cervical nerve exits below the seventh vertebra and above the first thoracic vertebrae.
* The brachial plexus is composed of nerves emerging from C4 to T1.
* Must do: where the patient’s symptoms extends distal to the tip of the shoulder. Also, in any condition which may indicate a worsening condition.
Degenerative Pathology
* Isolated disc thinning and uncus or zygapophyseal joints become weight bearing
* disc posteriorly bulge into epidural space. The nerve root, the vertebral arteries and the spinal cord are easy to be damaged.
* Mechanisms of cervical disc pain: mechanical v.s. chemical
The Nerve Supply of The Cervical Spine
- The Dorsal Rami and The Ventral Rami
* The dorsal rami of the cervical spine innervate the posterior element of the neck
* The posterior elements of the neck are those structures that lie behind the intervertebral foramina nerve roots
* The lateral branches of the dorsal rami supply the more superficial posterior neck muscles
* The medial branches of the dorsal rami supply the deeper and more medial muscles and zygapophyseal joints
* The ventral rami innervates the anterior elements of the neck
* The anterior elements of the neck include the cervical intervetebral disc, the ALL, the PLL, the preveertebral muscles, the O-C1and C1-2
* Other muscles in the neck also innervated by cervical vertrasl rami are the scalenes, the trapezius, and the SCM
Disorders of the Cervical Spine.ppt
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