What does c2 innervate

In an effort to explore alternative means of treating atlanto-axial joint pain, one of the present authors undertook a pilot study [15]. This study involved 18 patients, whose headache was relieved by intra-articular blocks of the lateral atlanto-axial joint.

As a preparation for radiofrequency treatment, percutaneous sensory stimulation, with a 22G electrode, was used to identify possible pain pathways from the joint, in these patients.

Low-voltage stimulation over the ventral aspect of the vertebral body of C2, near its junction with the transverse process Figure 1 reproduced the patient's headache. Injection of contrast medium at this site opacified a diagonally orientated space, congruent with the concave gutter that marks the anterolateral aspect of the C2 vertebral body Figure 2.

The C2 ventral gutter is bounded medially by the C2 vertebral body, dorsally by the base of the C2 transverse process, ventrally by the belly of the longus cervicis, laterally by the anterior intertransversarius, and caudally by the anterior tubercle of the C3 transverse process. It is separated from the C2—3 intervertebral foramen by a tough connective tissue membrane Figure 3.

C2 ventral gutter: image of upper cervical spine, ventral aspect. Shaded area denotes C2 ventral gutter. Gray arrow simulates an electrode and points to where electrical stimulation typically reproduced headache. Fluoroscopic images of an injection of contrast medium arrow into the ventral gutter. A Antero-posterior view. B Lateral view. A dissection of the connective tissue membrane that separates the C2 ventral gutter from the C2—3 intervertebral foramen.

The arrows point to the membrane. All 18 patients underwent controlled blocks of the C2 ventral gutter, using sufficient local anaesthetic 0. Blocks were considered positive if short-lasting relief occurred after a short-acting agent lidocaine was used, and if long-lasting relief occurred after a long-acting agent bupivacaine was used.

Six patients had headache only, which was relieved by blocks of the C2 ventral gutter. They subsequently underwent radiofrequency thermocoagulation of the C2 ventral gutter. Twelve patients had neck pain as well as headache. Blocks of the C2 ventral gutter relieved their headache, yet not their neck pain; but their neck pain was relieved by blocks of cervical medial branches. These patients underwent combined radiofrequency thermocoagulation both of their C2 ventral gutter, and the medial branches responsible for their neck pain.

An anatomical basis for these clinical observations is lacking. Textbooks of anatomy provide no description of nerves in the C2 gutter. Nor does any description appear in the journal literature. Classical descriptions portray the upper cervical ventral rami as forming the cervical plexus over the anterior surface of the scalenus medius [16]. In the plane of the prevertebral fascia, anterior to longus cervicis and the anterior tubercles of the transverse processes, grey rami communicantes leave the sympathetic trunk and reach the upper cervical rami [16,17].

Outside the intervertebral foramina, branches of the ventral rami and grey rami join to form the vertebral nerve [18—20] , which accompanies the vertebral artery, and gives rise to the upper cervical sinuvertebral nerves [19—21].

Otherwise, the cervical ventral rami are understood to innervate the longus cervicis and longus capitis [16] but details of the course and location of these nerves are lacking. In addition, although studies have demonstrated an innervation to the atlanto-occipital and lateral atlantoaxial joints from their dorsal aspects [10] , there is no evidence that these joints received any innervation from their ventral aspects.

The present study was undertaken to explore an anatomical basis for the apparent sensitivity of the C2 vertebral gutter to noxious stimulation, and its role in apparently producing relief of headache ostensibly stemming from the lateral atlanto-axial joint following the creation of radiofrequency thermal lesions. The results extend our knowledge of the innervation of the upper cervical spine and lateral atlanto-axial joints. Cadavers were selected from those used by students, provided that the anterior cervical structures including the longus capitis, the lateral atlantoaxial joint capsules, and the structures medial to the middle scalene were intact.

Six additional cadavers were used for subsequent microscopic dissection of the neck. Gross dissection was performed using an illuminated magnifying lens 1. In specimens with the occiput intact, the head was carefully disarticulated at the atlanto-occipital joint, with the ventral joint capsule preserved as much as possible. In every specimen, the ventral rami of the C2, C3, and C4 spinal nerves were identified and carefully freed from surrounding connective tissue and vessels.

The cervical viscera were removed, preserving the prevertebral musculature. The longus capitis was identified and removed fascicle by fascicle with fine-tip forceps. Branches arising from segmental spinal nerves were carefully identified, and their course exposed relative to the intertransversarii, longus cervicis, longus capitis, vertebral artery, C2 ventral gutter, and the ventral capsule of the lateral atlanto-axial joint.

The medial and lateral bands of the longus cervicis were removed, fascicle-by-fascicle, permitting small branches to these muscles and deeper structures to be carefully identified and preserved.

At each stage of dissection, digital photographs were taken Nikon D, 28— mm Nikkor Macro lens, 60 mm or mm Nikkor Micro lens with PK extension tube and immediately downloaded to an on-site laptop computer. Digital images were labelled as recorded utilizing digital imaging software Adobe Photoshop, Seattle, WA. In 10 sides following gross dissection, fine wire segments were shaped to conform to the nerves in the C2 ventral gutter, and carefully laid directly on these nerves.

The specimens were then placed on a radiolucent table and fluoroscopic radiographs Zhiem Vista, Riverside, CA were obtained in the anterior-posterior and lateral projections. Radiographic images were printed as acquired on transparency film and stored as digital bitmap images on removable magnetic media Iomega MB Zip drive for subsequent transfer to on-site laptop computers.

Once a consistent pattern emerged from gross dissection, microscopic dissection was performed to identify the relationships of the superficial and deep cervical prevertebral plexuses with the vertebral artery, deep prevertebral musculature, spinal nerves, and the capsules of the ventral atlanto-occipital and atlanto-axial joints. Following exposure of the C1, C2, and C3 ventral gutters, the anterior tubercles of segmental transverse processes were carefully removed with fine-tip bone ronguers under microscopic visualization.

To further delineate the relationships of the deep cervical prevertebral plexus with the vertebral artery, the transverse process and part of the vertebral body of C2 and the lateral aspect of the lateral atlanto-axial joint was also removed. In one intact specimen not used by students, dissection from the skin to the superficial and deep cervical prevertebral plexuses was performed under the microscope without disarticulating the occiput. The cervical sympathetic trunk and other cervical plexuses were carefully preserved, and communicating branches and gray rami carefully exposed.

Tissue whole mounts were prepared and cover slipped with glycerol. For histological controls, Osmium-stained sections of epimysium, small vessels, adipose tissue, and strands of diaphanous connective tissue were compared with samples of brachial plexus. During the early phases of the dissections, the familiar cervical plexus and the plexus accompanying the carotid arteries were identified.

However, once these were mobilized or resected, deeper dissection revealed two further plexuses. Deep to the longus capitis and ventral to the anterior tubercules of the cervical transverse processes and intervertebral foramina, branches from the C1—3 ventral rami formed a superficial cervical prevertebral plexus, consisting of numerous interconnecting arcades Figure 4. Some of the laterally located branches from this plexus terminated in the longus capitis and longus cervicis.

Others ascended along the ventral aspect of the anterior intertransversarius, over the ventral capsule of the lateral atlanto-axial joint and toward the ventral capsule of the atlanto-occipital joint. Medially located branches of the plexus passed ventral or through the bellies of the anterior intertransverse muscles at C2—C3 and C3—C4, and ascended toward the dens, superficial to the ventral surface of the longus cervicis at the level of C2.

Some of these ascending branches formed loops along the ventral surface of the longus cervicis and communicated with the lateral branches of the plexus. Other medial branches supplied twigs to the intertransversarii and longus cervicis, before sending penetrating branches either between the bellies of these muscles or through the belly of the longus cervicis to reach a deeper plexus lying in the ventral gutter of C2. Superficial cervical prevertebral plexus: the superficial cervical prevertebral plexus black arrows can be seen arising from the C3 ventral ramus large white triangle and lies superficial to the ventral aspect of the longus cervicis l.

More laterally located branches of the plexus can be seen bridging the ventral rami of C2, C3, and C4 white arrows. The deep cervical prevertebral plexus was located deep to the longus cervicis and within the periosteum of the C2 vertebral body in its ventral gutter Figure 5. Nerves composing the deep plexus primarily arose from the ventral ramus of C3, and passed medially, superficial to the vertebral artery, in close association with nerves of the vertebral plexus. After passing over the vertebral artery, these nerves entered the fascia covering the C2 ventral gutter, after penetrating a tough connective tissue membrane that separated the ventral neural foramen from the gutter, and ascended medially to enter the ventral capsule of the lateral atlanto-axial joint and the anterior atlanto-axial membrane.

Deep cervical prevertebral plexus: branches of the deep cervical prevertebral plexus white arrows can be seen within the C2 ventral gutter. The longus cervicis l. Branches from the plexus terminate along the ventral joint capsule of the lateral C1—C2 joint C1—C2. A vein can be seen as well black arrow. Variations of the plexus were seen, including medially oriented branches from the ventral C3 ramus that passed over the anterior tubercle of the C3 transverse process, as well as branches that passed caudal to the anterior tubercle, ventral to the C3—C4 anterior intertransversarius, before ascending over the longus cervicis toward the dens.

In 12 sides, more than one nerve was identified. Small arteries arising from the vertebral artery were also seen in the C2 ventral gutter, but typically travelled medial to the nerves of the deep cervical prevertebral plexus.

From there, the spinal nerve branches into a network of nerves that innervate its dermatome for sensations and myotome for motor controls. When discussing symptoms with a patient, it is common for doctors and other medical experts to simplify the terminology by referring to a single nerve root rather than two, or by using the terms for nerve root and spinal nerve interchangeably. A dermatome is the area of sensory nerves near the skin that are supplied by a specific spinal nerve root.

For example, the C5 dermatome is supplied by the C5 nerve root. Cervical spinal nerves, also called cervical nerves, provide functional control and sensation to different parts of the body based on the spinal level where they branch out from the spinal cord. While innervation can vary from person to person, some common patterns include:. What Causes Hand Pain and Numbness? Cervical Spinal Cord Anatomy Animation.

Understanding Hand Pain and Numbness. You are here Conditions Spine Anatomy. Cervical Spinal Nerves share pin it Newsletters. See Treatment for Neck Pain. What Causes Neck Pain and Dizziness? Neck Strain: Causes and Remedies. You are here Conditions Spine Anatomy.

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