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이 부분은 두통과 별도로 기억해야겠다.
c1, c2, 3c spinal nerve의 신경 innervation과 연관 근육들에 대한 문제들.
꼭 기억해야 한다.
anatomy and physiology of headache. Bogduk논문.pdf
The Cl and C2 spinal nerves are distinctive in hat they do not emerge through intervertebral foramina. The Cl spinal nerve passes across the posterior arch of the atlas behind its superior artitular process (fig 3C). The C2 spinal nerve crosses the posterior aspect of the lateral atlantoaxial joint (fig 3C), its ganglion lying opposite the radiologic midpoint of that joint [5]. Although the Cl spinal nerve lacks a cutaneous branch it is nonetheless sensory to the suboccipital muscles. Its dorsal root ganglion, however, may be ectopic. When missing from the dorsal root of Cl it is typically found amongst the rootlets of the spinal accessory nerve [40]. The C3 spinal nerve is the first of the typical cervical spinal nerves, and lies in the C2-3 intervertebral foramen.
- C1, 2 척수신경은
The Cl-3 spinal nerves divide into ventral and dorsal rami. Their ventral rami join with that of C4 to form the cervical plexus from which muscular branches are distributed to the prevertebral muscles - longus capitis and cervicis, rectus capitis anterior and lateralis, and to the sternocleidomastoid and trapezius. At their origin, the Cl -3 spinal nerves form recurrent meningeal branches - the sinuvertebral nerves. These nerves supply the ventral surface of the dura mater of the upper cervical spinal cord before entering the skull via the foramen magnum to supply the dura mater over the clivus (fig 3D). En route, they furnish branches to the median atlanto-axial joint, the transverse ligament of the atlas and the alar ligaments [29]. In the posterior cranial fossa Cl-3 sinuvertebral nerves are joined by meningeal branches of the X and XII cranial nerves. Although arising from cranial nerves these branches are cervical in origin having gained the cranial nerves outside the skull where they communicate with the cervical plexus [29]. Other branches of the Cl-3 ventral rami join the vertebral nerve - the plexus accompanying the vertebral artery, and furnish sensory branches to the fourth part of the artery 19, 281.
The dorsal ramus of Cl innervates the muscles of the suboccipital triangle - obliquus superior, obliquus inferior and rectus capitis posterior major and minor (fig 3B). The C2 dorsal ramus has lateral branches directed to the superficial, posterior muscles of the neck - longissimus capitis and splenius, but its large, medial branch becomes the greater occipital nerve [6]. This nerve winds around the inferior border of obliquus inferior, turns upwards and backwards through semispinalis capitis, which it supplies, and enters the scalp through an aperture bounded by the superior nuchal line and the aponeurosis of trapezius [4, 6, 471 (fig 3). Over the occiput it is joined by the lesser occipital nerve which is a cutaneous branch of the cervical plexus and reaches the scalp by passing along the posterior border of sternocleidomastoid.
The C3 dorsal ramus furnishes lateral branches to the longissimus capitis and splenius. It forms two medial branches [6]. The deep medial branch crosses the waist of the C3 articular pillar to enter the multifidus muscle. The superficial medial branch is the third occipital nerve which winds around the lateral and posterior aspect of the C2-3 zygapophysial joint (fig 3). Over the joint this nerve communicates with the C2 dorsal ramus and furnishes articular branches to the joint. Distally the third occipital nerve penetrates the semispinalis capitis and trapezius to become cutaneous over the suboccipital region. En route it furnishes branches to the semispinalis capitis which join those from the greater occipital nerves to supply this muscle.
It is not clear what the sensory innervation of the carotid arteries is in the upper neck; whether nociceptive afferents travel with the special, autonomic afferents of the glossopharyngeal and vagus nerves to the carotid body and carotid sinus
or whether afferents from the adventitia of these arteries return via the sympathetic nervous system and cervical plexus to reach upper cervical spinal nerves, like those of the vertebral artery. Apart from having a similar segmental innervation,
many of the muscles innervated by Cl-3 share the feature that they attach to the skull and, therefore, underlie sites that are commonly tender in various forms of headache. Most superficially, the sternocleidomastoid and trapezius attach along the superior nuchal line from the mastoid process to the external occipital protuberance (fig 3).
Deep to these, the splenius capitis attaches to the mastoid process and outer half or so of the superior nuchal line (fig 3). In the next deeper layer, the bulky semispinalis capitis is anchored to the occiput below the medial half of the superior
nuchal line, and the slender longissimus capitis reaches the mastoid process. Between them the obliquus superior attaches to the occiput, and deep to semispinalis capitis the rectus capitis posterior major and rectus capitis posterior minor attached to the occiput (fig 3).
These details are pertinent to the description and interpretation of tenderness in this region. There is a proclivity amongst some physicians to ascribe tenderness in the suboccipital region to entrapment or irritation of the greater occipital
nerve or the lesser occipital nerve [22, 34, 361. However, the attachment-sites of these various occipital muscles, notably semispinalis capitis and sternocleidomastoid are tender even in normal, asymptomatic individuals [24]. Their tenderness
in patients with headaches needs to be distinguished from normal tenderness or decreased perceptual threshold in the course of headache before being arbitrarily ascribed to nerve entrapment [31, 33, 381.
Fig 3. The anatomy of the suboccipital region, by layers.
A: On the left. the most superficial muscle layer is shown, in which the sternocleidomastoid (SM) and trapezius (T)attach to the superior nuchal line by way of an aponeurosis (a) which connects the two muscles. The greater occipital nerve (gon) emerges through an aperture above the aponeurotic sling between these two muscles to become cutaneous. The lesser occipital nerve (Ion) ascends parallel to sternocleidomastoid to reach the occiput. The third occipital nerve (ton) penetrates the trapezius to become cutaneous. On the right, the trapezius and sternocleidomastoid have been resected, leaving their aponeuroses (a’) attached to the superior nuchal line, to reveal the splenius (SP) and the semispinalis capitis (SS) through which the greater occipital nerve passes.
B: On the left. the splenius has been resected to reveal the longissimus capitis (LG) and the extent of semispinalis capitis. On the right. the semispinalis capitis (SS) has been resected to reveal the course of the greater occipital nerve across the suboccipital muscles: rectus capitis posterior minor (R), rectus capitis posterior major (RM), obliquus inferior (01) and obliquus superior (OS). The attachments of sternocleidomastoid (SM), splenius (SP) and longissimus capitis (LG) to the mastoid process remain in situ,
C: All posterior muscles have been resected, leaving only their occipital attachments, to show the entire course of thegreater occipital nerve, and the course of the third occipital nerve [ton) across the C2-3 zygapophysial joint. The ganglion of the C2 spinal nerve (g) lies behind the lateral atlanto-axial joint. Articular branches (a) arise from the Cl ventral ramus to the atlanto-occipital joint. from the C2 ventral ramus to the lateral atlanto-axial joint, and from the third occipital nerve to the C2-3 zygapophyaial joint. The Cl-3 ventral rami enter the cervical plexus. D: Removal of the posterior elements of the occiput and the Cl-3 vertebra reveals the Cl-3 Gnuvertebral nerves which supply the transverse (t) and alar (a) ligaments before passing through the foramen magnum to innervate the dura mater over the clivus. The meningeal branches of the vagus (XI nerve and hypoglossal nerve (XII) are found emerging from the jugular foramen and hypoglossal canal respectively. (Reproduced with permission from Bogduk
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