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  Indian J Med Microbiol
 

Figure 4: Stepwise dissection of posterior approach to craniovertebral junction, foramen magnum, and jugular foramen. (a) Skin subcutaneous tissue and trapezius have been removed to show splenius capitis laterally and semispinalis capitis medially. Superior nuchal line can be seen extending laterally from the external occipital protuberance. (b) Splenius capitis is reflected laterally exposing the second layer of neck muscle, i.e., semispinalis capitis. (c) Semispinalis capitis is reflected from its occipital attachment exposing the third layer of deep muscles of neck. Rectus capitis posterior major and minor are seen with some parts of superior oblique and inferior oblique. (d) Suboccipital triangle is seen here formed by rectus capitis posterior major, superior oblique, and inferior oblique. Connective tissue and venous plexus are cleared exposing vertebral artery on both sides. (e) Semispinalis cervicis, superior oblique, and inferior oblique are removed showing C2 ganglion in relation to vertebral artery before it enters transverse foramina of atlas. Rectus capitis lateralis is now visible extending from the upper surface of transverse process of atlas to the jugular process of occipital bone. (f) Overview of dissection after retrosigmoid craniectomy to visualize intracranial course of vertebral artery and cranial nerves. Carotid sheath has been opened on the left side to expose internal jugular vein, internal carotid artery, and lower cranial nerves. (g) Close-up view of vertebral artery and rectus capitis lateralis muscle. C2 ganglion can be seen lying over atlantoaxial joint. Dorsal rami of C1 nerve can be seen traveling below vertebral artery and above the arch of atlas. EOP, external occipital protuberance; ICA, internal carotid artery; IJV, internal jugular vein; Inf ob, inferior oblique; RCLa, rectus capitis lateralis; RCPMi, rectus capitis posterior minor; RCPMo, rectus capitis posterior major; SNL, superior nuchal line; Sm cap, semispinalis capitis; Sp cap, splenius capitis; Sup ob, superior oblique; VA, vertebral artery

Figure 4: Stepwise dissection of posterior approach to craniovertebral junction, foramen magnum, and jugular foramen. (a) Skin subcutaneous tissue and trapezius have been removed to show splenius capitis laterally and semispinalis capitis medially. Superior nuchal line can be seen extending laterally from the external occipital protuberance. (b) Splenius capitis is reflected laterally exposing the second layer of neck muscle, i.e., semispinalis capitis. (c) Semispinalis capitis is reflected from its occipital attachment exposing the third layer of deep muscles of neck. Rectus capitis posterior major and minor are seen with some parts of superior oblique and inferior oblique. (d) Suboccipital triangle is seen here formed by rectus capitis posterior major, superior oblique, and inferior oblique. Connective tissue and venous plexus are cleared exposing vertebral artery on both sides. (e) Semispinalis cervicis, superior oblique, and inferior oblique are removed showing C2 ganglion in relation to vertebral artery before it enters transverse foramina of atlas. Rectus capitis lateralis is now visible extending from the upper surface of transverse process of atlas to the jugular process of occipital bone. (f) Overview of dissection after retrosigmoid craniectomy to visualize intracranial course of vertebral artery and cranial nerves. Carotid sheath has been opened on the left side to expose internal jugular vein, internal carotid artery, and lower cranial nerves. (g) Close-up view of vertebral artery and rectus capitis lateralis muscle. C2 ganglion can be seen lying over atlantoaxial joint. Dorsal rami of C1 nerve can be seen traveling below vertebral artery and above the arch of atlas. EOP, external occipital protuberance; ICA, internal carotid artery; IJV, internal jugular vein; Inf ob, inferior oblique; RCLa, rectus capitis lateralis; RCPMi, rectus capitis posterior minor; RCPMo, rectus capitis posterior major; SNL, superior nuchal line; Sm cap, semispinalis capitis; Sp cap, splenius capitis; Sup ob, superior oblique; VA, vertebral artery