Bones of the skull, Part 2: Occipital bone скачать в хорошем качестве

Bones of the skull, Part 2: Occipital bone

One of the main cranial bones, the occipital bone has unique internal and external surfaces that each have important anatomical landmarks. Below is a detailed breakdown of its major parts, surfaces, and important points: 1. Parts of the Occipital Bone The occipital bone consists of four parts that fuse during development: Squamous part (Occipital Squama)—Flat, curved portion forming the back of the skull. Basilar part (Basiocciput)—Thick, anterior portion near the foramen magnum; fuses with the sphenoid bone. Lateral (Condylar) parts (x2)—Contain the occipital condyles and hypoglossal canals. 2. External Surface (Posterior View) The outer surface features muscle attachments and bony landmarks: External Occipital Protuberance—Midline bump; attachment for the ligamentum nuchae. Superior Nuchal Line—Ridge above the EOP; attachment for trapezius and sternocleidomastoid muscles. Inferior Nuchal Line—Ridge below the EOP; attachment for deep neck muscles (e.g., rectus capitis posterior). Occipital Crest – Vertical ridge from EOP to the foramen magnum. Foramen Magnum—Large opening for the spinal cord. Occipital Condyles—Kidney-shaped articular surfaces on either side of the foramen magnum; articulate with C1 (atlas). Hypoglossal Canal – Passage for the hypoglossal nerve (CN XII). Condylar Fossa & Canal – Posterior to condyles; may transmit emissary veins. 3. Internal Surface (Anterior View) The inner surface has grooves and depressions related to the brain: Internal Occipital Protuberance—Midline bump near the confluence of sinuses (venous drainage). Groove for Superior Sagittal Sinus—Superiorly, along the midline. Groove for Transverse Sinus—Horizontally from the protuberance. Cerebellar Fossae—Depressions housing the cerebellar hemispheres. Clivus (formed by the basilar part)—sloped surface supporting the brainstem (pons & medulla). 4. Articulations The occipital bone articulates with: Parietal bones (via the lambdoid suture). Temporal bones (at the occipitomastoid suture). Sphenoid bone (via the basilar part). Atlas (C1 vertebra) (via the occipital condyles). Recorded by : Kambiz Ebrahimi https://t.me/foundation_human_anatomy    / @drkambizebrahimi