Cavitas Cranii Anatomy PDF

# Cavitas cranii - **Fortil** in basis cranii interna are the holes in the lamina cribrosa, that lead to the nasal cavity. - **Further back** is foramen opticum and fissura orbitalis superior, they connect the cranial cavity with the eye cavity. - The cranial cavity is directly connected with the...

# Cavitas cranii - **Fortil** in basis cranii interna are the holes in the lamina cribrosa, that lead to the nasal cavity. - **Further back** is foramen opticum and fissura orbitalis superior, they connect the cranial cavity with the eye cavity. - The cranial cavity is directly connected with the eye cavity and nasal cavity. There is no direct connection between the cranial cavity and the oral cavity. - **Directly behind** fissura orbitalis superior is foramen rotundum, that is slanting forward and leads to fossa pterygopalatina. - **Foramen rotundum** contains n. maxillaris. The nerve runs from fossa cranii media to fossa pterygopalatina. It continues through the upper part of fossa pterygopalatina and leaves it through fissura orbitalis inferior. Here the nerve is renamed to n. infraorbitalis. - **Behind and to the side** of foramen rotundum is foramen ovale, a slightly larger hole that connects the cranial cavity, fossa cranii media, with spatium lateropharyngeum. It lies in front of the vertebral column and lateral to the organs of the neck, such as the pharynx, esophagus, larynx and trachea. - **Medially** to foramen ovale is foramen lacerum, a fairly large hole with irregular edges. This hole is closed by a cartilage plate. - **Foramen lacerum**, the 'lacerated' or 'frayed' hole, is aptly named considering the torn edges of the hole, it occupies a unique position amongst the holes in the cranial base. This hole is filled by a cartilage plate. - Other holes like foramen jugulare are filled by connective tissue with vessels and nerves. No vessels or nerves go through foramen lacerum. - **Directly behind** foramen lacerum, at the tip of pars petrosa, is apertura interna canalis carotici. This hole faces forward and medially and marks the exit of canalis caroticus. The channel runs through pars petrosa and contains an important artery to the brain, a. carotis interna. - It is difficult to see apertura interna canalis carotici on the drawing. - **In fossa cranii posterior** is the inner ear canal opening, porus acusticus internus, on the back surface of pars petrosa. The ear canal opening leads to the inner ear canal, meatus acusticus internus. The ear canal ends with a plate with many small holes. These can only be seen when looking directly into the inner ear canal, they mostly lead to the inner ear. - **Between** pars petrosa and the occipital bone, with foramen magnum, is a large opening, foramen jugulare. - This hole connects fossa cranii posterior with spatium lateropharyngeum on the outer surface of the cranium. The circumference of the hole is reminiscent of a figure-eight. - **Foramen jugulare** contains v. jugularis interna and three cranial nerves: IX, X and XI. Foramen jugulare can also be seen clearly on basis cranii externa. - **On the edge** of foramen magnum is the entrance to canalis hypoglossi. The channel is directed horizontally, forwards and laterally and connects fossa cranii posterior with spatium lateropharyngeum. - **Foramen magnum** is an oval hole with the longest axis from front to back. It connects the cranial cavity with the channel in the vertebral column, canalis vertebralis. - **Many holes** in basis cranii open into spatium lateropharyngeum, but this does not apply to foramen magnum. The transition between the spinal cord and the brainstem lies at the lower edge of the hole, i.e., the lowest section of the brainstem, the medulla oblongata, passes through foramen magnum. - The three membranes around the spinal cord and around the brain are connected through foramen magnum, this also applies to the fluid-filled space between the two innermost membranes. - **Spatium lateropharyngeum** connects to the cranial cavity through several holes. Spatium lateropharyngeum is best described as a 'connective tissue column' with the large vessels and nerves of the neck. The 'column' lies in front of the vertebral column and laterally from the viscera of the neck. At this section the esophagus and trachea are visible. Closer to basis cranii externa lies spatium lateropharyngeum laterally to the pharynx. - The 'connective tissue column', spatium lateropharyngeum, runs from basis cranii externa down through the entire neck to the opening towards the chest cavity. The drawing shows that the space facing the skin is covered by three different areas, the uppermost (15), the middle (16) and the lowermost (13). - **The pharynx is shown from the back.** The back wall has been cut open so that we can look at the front wall. Here is the entrance to the larynx and the nasal cavity (4). The white 'columns' on either side of the pharyngeal wall are the upper parts of spatium lateropharyngeum. Here the space correctly bears its name 'lateropharyngeum'