What Is the Parietal Bone?

It is a pair of brain and skull bones. The flattened and flattened quadrangular bones are located on both sides of the cranial crest. A little below the middle of the outside, there are two arched lines from front to back. The upper part is called the upper temporal line, which is where the temporal fascia is attached. There is a bulge in the middle of the outside, called the top nodule, and the distance between the two nodules is the maximum width of the head, which is the landmark point for measuring the widest skull.

It is a pair of brain and skull bones. The flattened and flattened quadrangular bones are located on both sides of the cranial crest. A little below the middle of the outside, there are two arched lines from front to back. The upper part is called the upper temporal line, which is where the temporal fascia is attached. There is a bulge in the middle of the outside, called the top nodule, and the distance between the two nodules is the maximum width of the head, which is the landmark point for measuring the widest skull.

Chinese name

Parietal bone

Pinyin

dng g / g

Attributes

Skull one

Shape

Slightly oblate, at the top of the head

Features

One on each side.

Brief introduction

Refers to the skull

Zhuyin

Physiological significance of parietal parietal

Participate in the formation of the brain. It is a flat rectangular bone plate with a convex shape facing outwards and is located in the middle of the skull cap. Skull trauma is more common here, and sometimes it can be a sunken or comminuted fracture.

Anatomy of parietal brain skull

The brain and skull include the occipital bone, sphenoid bone, temporal bone, parietal bone, frontal bone, and ethmoid bone.

Occipital bone

The occipital bone is located at the back and lower part of the skull and has a scoop-shaped quadrilateral shape. The anterior part of the occipital bone has a large occipital foramen. The occipital scales are above and behind the foramen. The sides of the hole have sides and the base is in front of the foramen. Pillow scales, the outer center is the occipital protuberance, which extends to the upper line to both sides, and the bulge forward on the midline is the occipital condyle. The inner surface is recessed and divided into four sockets by the cross ridges. The upper two are triangular corresponding to the occipital lobe of the brain and the lower two are square adjacent to the cerebellum. The center of the bulge is the occipital bulge and there is an upward sagittal sinus sulcus. This sulcus passes through the bulge and is mostly connected to the right transverse sinus sulcus. The occipital condyle extends from the bulge to the foramen magnum. The lateral part, the occipital condyle below, is connected to the atlas, and the longitudinal axis of the occipital condyle points to the anterior medial side. There is sometimes a sacral canal in the popliteal fossa that leads to a vein. A sublingual neural tube passes through the upper part of the anterior iliac crest, and the hypoglossal nerve () passes through this tube. The anterior edge of the side is concave, which is called the jugular vein notch. The jugular vein notch and the jugular vein process form a jugular vein hole with the temporal bone on the entire skull. The basal part, facing the upper front, the outer (lower) central small protrusion, which is the pharyngeal nodule, is attached to the pharyngeal suture; the inner surface is slightly concave, called the slope, supporting the pons, medulla, and basilar artery; on both sides is the infrasinus sinus .

Sphenoid

The sphenoid bone is sphenoid, located at the base of the skull, between the occipital bone and the temporal bone. It is divided into a central body, large wings and winglets that extend to both sides, and wing-shaped processes that protrude downward (Figure 1). The body is hollow with sphenoid sinus. The upper part of the body is depressed into a saddle, and the front begins at the anterior sulcus, followed by the transverse saddle nodule, and then backwards to accommodate the depression of the pituitary gland, so it is called the pituitary fossa. The two sides protrude rearwardly, that is, the posterior bed. The longitudinal groove where the body side meets the large wing is passed by the internal carotid artery and is called the carotid groove. The middle protrusion of the front of the body is the chrysalis, and the lower protrusion is the butterfly mouth. The forward opening of the sphenoid sinus is covered by the sphenoid, and the hole left is the sphenoid sinus. The back of the body is connected to the bottom of the occipital bone in osteosynthesis in adulthood (after about 25 years of age). The winglet, the front part of the body protrudes outward, and connects the frontal and ethmoid bones. The posterior margin is free. The medial end is the anterior bed process. The gap between the winglet and the large wing connects the middle cranial fossa and the orbit. Named supraorbital fissure. The winglet starts from two feet, with the optic nerve tube between the two feet, connecting the lateral end of the anterior sulcus to the orbit, and is passed by the optic nerve (II) and the ophthalmic artery. The large wings extend outward from the body, wide and embedded in the whole skull, forming the bottom of the middle cranial fossa, the outer wall of the orbit, the bottom of the temporal fossa, and the upper wall of the infratemporal fossa. The deep depression of its brain surface is adjacent to the temporal lobe of the brain. The anterior medial hole is horizontally forward to the pterygopalatine fossa, and the maxillary nerve (V2) passes. The oval foramen is larger, located on the posterolateral side of the foramen, reaching the infratemporal fossa and passing through the mandibular nerve (V3). The spine hole near the sphenoid spine also leads to the infratemporal fossa, which is the middle meningeal artery into the cranial foramen. The temporal surface of the large wings forms the base of the temporal fossa where the temporal muscles attach. Below the temporal is the apex of the infratemporal fossa. This face and the temporal face are bounded by the temporal inferior condyle. The orbital surface of the large wing is square, facing forward inward, forming the outer wall of the orbit. The junction of the pterygoid and the wing protrudes vertically downward, forming the outer side wall of the nasal cavity, the inner side wall of the infratemporal fossa, and the posterior wall of the pterygopalatine fossa. board. The posterior edge of the medial plate constitutes the lateral edge of the posterior nostril, with a wing hook at the lower end. The pterygoid root is in front of the pterygoid tube to connect the rupture hole and the pterygopalatine fossa, and the pterygoid nerve passes. The sheath process is located at the junction of the medial plate and the body. The upper and lower processes have scabbard furrows and vulva sheath furrows, respectively, forming a tube of the same name in the entire skull.

Figure 1 Sphenoid bone (upper view)

1, sphenoid wing 2, sphenoid wing 3, pituitary fossa 4, dorsal saddle 5, spinous hole 6, oval hole 7, round hole 8, supraorbital fissure

The temporal bone is located between the sphenoid bone and the occipital bone, and forms part of the bottom and side walls of the cranial cavity. It also participates in the composition of the temporal and subtemporal fossa, which is divided into three parts: scales, drums, and rocks (milk) (Figure 2).

The scales are on the upper side, and the scales are vertical. The temporal surface is outside. It is smooth, attached to the temporal muscles, and has a middle temporal artery groove. The condyles protrude from the posterior aspect of the face and point forward to the zygomatic temporal process to form the zygomatic arch. The deep concavity below it is called the mandibular fossa; the joint nodule bulges in front of the mandibular fossa and is the anterior boundary of the fossa. The drum is below the scales and before the mastoid process, it is an incomplete ring-shaped bone mass, which is located below the external ear canal; the medial end of the drum has a sulcus, which is where the tympanic membrane is attached. The outer ear door is surrounded by the drum from the front, the bottom and the back. The rock (cone) is hard and contains the inner ear and tympanum. Its mastoid is on the posterolateral side. The inner side of the mastoid is a deeper mastoid notch, which is the posterior abdominal attachment of the biceps, and the inner side is the occipital artery groove, where the occipital artery passes; the sigmoid sinus groove can be seen on the inside. There is a drum cable between the lower part of the rock and the drum, and the drum cable passes through it. The cone itself is in the shape of a triangular pyramid, extending forward and inward from the inner surfaces of the scales and the drum, embedded between the sphenoid bone and the occipital bone, and divided into anterior, posterior and lower faces. The front of the pyramid is the base of the middle cranial fossa, and the near tip is where the trigeminal ganglion is located, which is slightly depressed to become the trigeminal nerve footprint. The mask has a bow-like bulge, a tympanic cover, a small rock, a large rock neural tube hole, and a small rock, a large rock groove. The upper edge of the rock is between the front and the back, and there is a sinus sulcus on the rock. The back belongs to the posterior cranial fossa, and the anterior ear is divided into the inner ear door, which is the entry and exit site of the facial nerve () and vestibular snail (). Bone fissures on the posterolateral side of the inner ear, that is, the outer opening of the vestibular aqueduct. The lower edge is between the back and the bottom, and the front is the inferior sinus groove. The lower part near the center is the outer mouth of the carotid artery tube, which leads upward to the carotid artery tube. The tube passes from the tip of the rock through the inner mouth of the carotid tube and opens in the posterior wall of the rupture hole. The bone surface depression behind the carotid canal is the jugular vein fossa. The fossa is connected with the occipital jugular vein notch to form the jugular foramen. After the hole, the inferior petrosal sinus, glossopharyngeal nerve (XI), and vagus nerve (X) ), Accessory nerve (XI), sigmoid sinus. The posterior end of the bony septum between the external opening of the carotid tube and the jugular foramen is wide and contains a noticeable dimple, the external opening of the volute. Between the styloid process and the mastoid that protrude forward and inward, the papillary foramen can be seen, which is the cranial foramen for the facial nerve (VII). The tip of the rock and the gap between the sphenoid body and the occipital bone is called a ruptured hole, and its lower mouth is often covered by cartilage in the living body.

Figure 2 External view of temporal bone (right side)

1. Squam 2, Mandibular fossa 3, Condyle 4, Outer ear door 5, Rock 6, Drum 7, Styloid 8, Mastoid

The parietal bone is quadrangular, and the outer bulge is concave, which can be divided into two sides, four edges, and four corners. On the outer posterior part, there are bulging top nodules and apical holes near the sagittal margin, and there are upper and lower temporal lines outside the midline. There is an upper sagittal sinus sulcus along the sagittal margin on the inside; the sigmoid sinus passes at the mastoid angle, forming a sigmoid sinus sulcus.

Frontal

The frontal bone is divided into frontal shell-shaped frontal scales, horizontal orbits and anterior inferior nose; the front wall and bottom of the anterior cranial fossa and the orbital apex. Frontal scales are divided into outer, inner and temporal. The frontal nodules with rounded bulges on both sides of the outer lower part are the sites of primary ossification, which is more pronounced in women and young people. Below it is the eyebrow arch, which is more bulging in men; between the medial ends of the eyebrow arches on both sides, it is called between the eyebrows. At the junction of the medial 1/3 and the lateral 2/3 of the upper orbital edge, there is a supraorbital foramen or supraorbital notch, which is passed by the neurovascular of the same name. The branches of the upper nerve and blood vessels pass by. The lateral end of the upper orbital margin ends at the condyle. The inner brain pressure traces, arterial sulcus, and small granules are all obvious; on the median line, there are upper sagittal sinus grooves, frontal condyles, and blind holes from top to bottom. The temporal surface is located below the temporal line and forms the front of the temporal fossa floor for the attachment of the temporal muscle. The nose is located between the upper edges of the orbits on both sides and narrows down to become a nasal spine. The middle orbit is divided into left and right triangular orbital plates by the ethmoidal notch, separating the anterior cranial fossa and the orbit. The shallow depression or spine on the inner side of the orbital surface is the attachment point of the upper oblique tendon and pulley, and it is called the pulley spine or small depression of the pulley. The lateral division is where the lacrimal glands are located, which is called the lacrimal fossa. The pre- and post-ethmographic holes (tubes) are formed by joining the frontal bone and the sieve plate to communicate the orbit to the nasal cavity. The frontal sinus, one on the left and the right, the septum is often biased to one side, so the left and right sinuses are not the same size and open from the frontal nasal canal to the middle nasal passage.

Ethmoid

The ethmoid is thin and fragile, located between the two orbits, located before the sphenoid bone and below the frontal bone, forming the bottom of the anterior cranial fossa, the top and outer walls of the nasal cavity, and the inner wall of the orbit. Frontal view, ethmoid bone is "scarf" shape, divided into sieve plate, vertical plate and ethmoid labyrinth on both sides. The sieve plate is in a horizontal position and is embedded with a frontal ethmographic notch, which separates the cranial cavity from the nasal cavity. There are more than 20 sieve holes that pass through the olfactory nerve (I) root filaments.

Figure 3 ethmoid bone

A, top view B, front view

1. Orbital plate 2. Sieve plate 3. Cockscomb 4. Vertical plate

The cockscomb protrudes above the plate. The vertical plate divides the nasal cavity into left and right halves, forming the upper part of the bony nasal septum, which is connected to the septal cartilage in front and the vomera in the lower part. The ethmoid labyrinth is a general term for the ethmoid sinus, which is divided into anterior, middle and posterior ethmoid sinus by the two frontal positions. The outer wall of the labyrinth is called the orbital plate, which is made of the inner wall of the orbit. The inner and lateral sides of the labyrinth are irregular, with the upper and middle turbinates curled downward and outward. The lost posterior, middle, and anterior ethmoid sinuses all open in the nasal cavity.