1.1 Step 5: Suboccipital triangle скачать в хорошем качестве

1.1 Step 5: Suboccipital triangle

These videos have been excerpted from Netter’s Video Dissection Modules on Student Consult.  http://bit.ly/2oEt9CO Step 5 Completely remove the semispinalis capitis from its attachments to the skull. Again note the convergence of the fibers of the semispinalis cervicis to the spinous process of C2. Removal of the semispinalis capitis reveals the suboccipital triangle. The muscles which form this triangle are the rectus capitis posterior major, the obliquus capitis inferior, and the obliquus capitis superior, which takes its origin from the transverse process of C1 and attaches to the skull. In the interval between the right and left rectus capitis posterior major muscles, note the belly of the rectus capitis posterior minor. Also note, emerging from the inferior border of the obliquus capitis inferior, the nerve fibers which form the greater occipital nerve and the accompanying occipital artery. Key Terms • Semispinalis capitis: arises from the transverse processes of the first six thoracic vertebrae and inserts on a broad area of the occipital bone, on either side of the midline and in the interval between the superior and inferior nuchal lines N10. • Semispinalis cervicis: arises from transverse processes of the second to the fifth thoracic vertebrae and attaches to the spinous processes of the second to the fifth cervical vertebrae. The highest fibers are the thickest and converge onto the spinous processes of C2 N175. It is innervated by the dorsal primary rami of the corresponding thoracic and cervical spinal nerves. • Axis: the second cervical vertebra N19. It has a number of characteristic features, including: a relatively large stout spinous process N15 for the attachment of ligaments (ligamentum nuchae, interspinous ligament) and muscles semispinalis cervicis, multifidi, rotators, obliquus capitis inferior, rectus capitis posterior major); a dens, which projects into the vertebral canal of C1 to articulate with the anterior arch ( median atlantoaxial joint) N19; and a pair of relatively large flat superior articular facets N19, which articulate with matching surfaces on the atlas N19. The large flat articular surfaces are designed exclusively for rotation, and the dens, which is anchored by a series of strong overlying ligaments N23 establishes a stable axis for head rotation. • Suboccipital triangle: an area just inferior to the occipital bone that is bounded by the rectus capitis posterior major, the obliquus capitis superior and obliquus capitis inferior. It lies deep to the semispinalis capitis, and within it are the ramifications of the suboccipital nerve N201, the atlantooccipital membrane, the posterior arch of the atlas, and vertebral artery N22. • Rectus capitis posterior major: muscle of suboccipital triangle attaching distally to the spinous process of axis and proximally to the middle of inferior nuchal line of occipital bone N172 N173 N175. It acts to rotate and draw the head backward, and it is innervated by a dorsal branch of first cervical (suboccipital) nerve. • Obliquus capitis inferior: has an attachment to the apex of the spinous process of the axis and to the inferior and dorsal part of the transverse process of the atlas N172 N173 N175. It acts to rotate the atlas, turning the face toward the same side, and it is innervated by a branch of the dorsal primary division of the suboccipital nerve. • Obliquus capitis superior: attaches to the superior surface of the transverse process of the atlas and to the occipital bone, between the superior and inferior nuchal lines, lateral to the semispinalis capitis N172 N173 N175. It extends and laterally flexes the head at the neck, and it is innervated by a branch of the dorsal primary division of the suboccipital nerve. • Rectus capitis posterior minor: attaches to the posterior tubercle of atlas and to the occipital bone N172 N173 N175. It is extends the head and is innervated by the suboccipital and greater occipital nerves. ABOUT: The project was made possible by several very dedicated faculty and staff at University of North Carolina, Chapel Hill--especially O.W. Henson and Noelle A. Granger--and partner schools, and by a grant from the Fund for the Improvement of Post-Secondary Education of the US Department of Education. This channel includes over 400 short videos highlighting the steps in a full-body human dissection in the gross anatomy lab. Each step is narrated and key structures labeled.