Fig 1.
3D-reconstruction of cranium and cervical vertebrae of the Neophocaena phocaenoides.
A: dorsal view of the suboccipital region. B: left lateral aspect of the suboccipital region. occi: occiput. △: the fused transverse processe of the first three cervical vertebrae. ▲: the fused spinous processe of the first three cervical vertebrae. ○: the atlanto-occipital interspace.
Fig 2.
The suboccipital muscles of the Neophocaena phocaenoides in the atlanto-occipital interspace.
A: the superficial layer of suboccipital musculature. B: the deep layer of suboccipital musculature. A. C.: articular capsule of the atlanto-occipital joint. LRCD: the lateral rectus capitis dorsal. RCDmi: the rectus capitis dorsal minor. RCDma: the rectus capitis dorsal major. S. C.: semispinalis capitis. occi: occiput.
Fig 3.
Sagittal sectional P45 plastinated sheet of suboccipital region of the Neophocaena phocaenoides.
A: Sagittal section of P45 plastinated sheet of the Neophocaena phocaenoides. a: The magnified area of suboccipital region. RCDmi: the rectus capitis dorsal minor. RCDma: the rectus capitis dorsal major. C4: the fourth cervical vertebra. occi: occiput. ☆: cerebellomedullary cistern. ▲: spinal dura mater. △: cerebral dura mater. ◇: the fused spinous process of the first three cervical vertebrae. ◆: the fused vertebral body of the first three cervical vertebrae. …: the myodural bridge.
Fig 4.
Sagittal sectional histological sheet of suboccipital region of the Neophocaena phocaenoides.
A, a: results of Hematoxylin and eosin staining. B, b: results of VG (picric acid and acid fuchsin) staining. C, c, d, e, f: results of Sirius Red in saturated cabazotic acid staining. A, B, C, a, b, c were under 4× light microscope. d and e were under 5× polarized microscope, and f was under 10× polarized microscope. RCDmi: the rectus capitis dorsal minor. RCDma: the rectus capitis dorsal major. SDM: spinal dura mater. CDM: cerebral dura mater. S. P.: fused spinous process of the first three vertebrae. ▲: the myodural bridge. ★: venous plexus. ◆: the muscle fibers of the RCDmi.