Each bone of the human body is the most important "cog" in a huge mechanism. Head bone elements perform a protective function. These elements include the temporal bone.
Temporal bone: description
An important part of the cranium is the temporal bone, which is located on both sides of the skull, and therefore is paired. More precisely, it belongs to one of the components of the skull covering the brain. Surround her sphenoid, parietal and occipital bones.
This bone element in combination with the lower jaw forms a movable joint. And in tandem with the zygomatic bone, they make up the zygomatic arch.
The temporal element itself is an integral bone: it is represented by a number of parts that form it.
The temporal bone develops by ossification of six points. At the end of the 8th week of embryonic development, the scaly parts are the first to ossify. At the 3rd month, hardening occurs in the drum part. With the advent of the 5th month of fetal development, several sites of ossification appear in the cartilaginous part of the pyramid.
By the period preceding birth, the temporal bone already consists of a scaly part, a drum and a stony part, and in the interval between these parts there are crevices with connective tissue.
Bone structure
The anatomy of the temporal bone is as follows. A pyramid, a drum part and scales are distinguished in it.
The pyramid is also called the rocky part. And for good reason, because this element consists of a very solid bone element. In its shape, the stony part is very similar to a trihedral pyramid (hence the name). The base of the pyramid is displayed in the mastoid process.
The pyramid consists of the following parts: top; frontal, back and lower surfaces; apical, posterior and lower margin.
The front surface of the pyramid has a direction expressed forward and upward. From the side, the pyramid goes into the scales of the temporal bone. Between these two elements of the temporal bone is a stony-scaly hole. In its central part, the front surface of the pyramid has a slight arched elevation. At a distance through these elevations in the form of a scaly hole, there is a flat section that serves as the roof of the tympanic cavity.
The back surface of the pyramid is adjacent to the center. Almost in the central part of this surface of the pyramid there is a small auditory opening that flows into the internal auditory canal. On the lateral side of the auditory foramen, there is the fossa. And on the underside there is a vestibule water opening.
The lower surface of the pyramid is equipped with a complex surface relief. The lower surface flows into the mastoid process.
The upper edge of the pyramid is a boundary line that fastens the front and back surfaces. At its base is a groove of a stony sinus.
The back edge of the pyramid delimits the back and bottom surfaces. Along its surface lies the groove of the lower stony sinus. Near the lateral side of the furrow is a dimple with an external opening of the tubule of the cochlea.
On the inside, the pyramid houses the organs of hearing and balance.
The diagram shows:
- Scaly part or scales. This bone element has a curved shape on the outside of the plate, the upper edge of which is beveled. Its part - scales - got this part due to the fact that it is superimposed in an appropriate (scaly) way on the adjacent end of the parietal bone and the wing of the sphenoid bone. From the lower edge, it closes with the pyramid of the mastoid processes and the tympanic part. The external side, having a smooth structure, forms a temporal fossa. The zygomatic process originates from the scales, heading towards the temporal process of the zygomatic bone and attaches with it with its serrated edge, forming a zygomatic arch. Scaly edges are shown below.
- Zygomatic process. This element serves as a connecting part with the zygomatic bone. At the base of the process are two of its roots: frontal and posterior, and between them there is a fossa intended for attachment with the lower jaw.
- Joint tubercle. It is located on the lower edge of the frontal root of the zygomatic process. Its function is very significant for the jaw - to prevent the displacement of the head of the lower jaw bone forward at the time of wide opening of the mouth.
- Mandibular fossa. It is isolated from the external auditory meatus by a thin plate made of bone substance. This distinction has a good effect on the process of moving the pathological process from the auricle to the articular part and in the opposite direction.
- External auditory cavity. This hole is located on the lateral outer side of the temporal bone. It is covered with scales on top, with the posterior mastoid, with the frontal and lower - the drum part of the temporal bone.
- Glazer's slit, otherwise called stony-drum. This is a narrow cavity that delimits the tympanic part, a portion of the temporal bone and the protruding edge of the roof of the tympanic cavity;
- Drum part. This is a bone plate, not large in size and curved in shape. It attaches to adjacent areas of the temporal bone. The drum part protects the external auditory opening, enveloping it on three sides in combination with scales and the mastoid process. These three sections of the temporal bone are fused with the front end, back and bottom. The place of their intergrowth is called the mastoid-tympanic fissure, it is located behind the auditory opening. The auditory opening passes into the auditory meatus, the end point of which is the tympanic cavity. A drum-scaly crevice runs from the front of the connector.
- Mastoid. This is the posterior fragment of the temporal bone, which is located behind the auditory opening. It is delimited from the scaly part by the parietal notch. From the outside, the muscles of the head are attached to the mastoid process, they are well held due to its convex and rough surface.
- The styloid process. It is represented by a site of connection of muscle tissues and ligaments. The styloid process is a fragment of the temporal bone, which, by the nature of its formation, has a gill nature. It is a residual element of the hyoid arch.
Functions
The temporal bone performs three functions:
- Protective. The temporal bone together with the rest of the bones of the skull protects the brain from various kinds of damage.
- Supporting. The cranial bone of the temporal lobe supports the brain, being its support.
- The temporal bone is the site of attachment of the head muscles.
In addition, this bone contains organs and channels of the auditory apparatus, balance, and also various tubules and vessels lie in it.
The functions performed are completely dependent on the anatomy of the temporal bone. In addition, the location of nearby bones also affects functionality.
Temporal bone canals
The temporal bone is completely striated with various notches, cavities and tubules. Channels and cavities of the temporal bone are used to conduct vessels, nerve branches, arteries. The canals are hollow tubular cords interlacing parts of the temporal bone.
Below is a table of the temporal bone canals.
Temporal bone canals| Bone canals | What cavities connect | What crosses the channels |
| Front channel | The back wall of the pyramid and the awl-mastoid opening | 7th facial nerve, stony artery and awl-mastoid vessels |
| Sleepy channel | The top of the pyramid and the outer base of the skull | Carotid artery and carotid plexus |
| Muscular-tubal canal | Drum cavity and the upper wall of the pyramid | Upper barb artery, auditory tube |
| Drum string tubule | Front channel, tympanic cavity and tympanic fissure | 7th facial nerve and posterior tympanic artery |
| Mastoid tubule | Jugular recess and mastoid fissure | auricular process of the 10th pulmonary gastric nerve |
| Drum tubule | Rocky fossa, lower wall of the pyramid and tympanum | Small stony nerve vessel, tympanic artery running from below |
| Carotid tubules | The edge of the carotid cord and tympanic cavity | Carotid-drum nerve fibers and arteries |
| Snail tubule | The beginning of the internal auditory organ and the lower base of the pyramid | Snail Canal Vienna |
| Inner auditory meatus | Inner ear and cranial fossa extending from behind | 7th facial nerve, 8th cochlear nerve and artery of the inner ear |
| Water supply vestibule | The beginning of the inner ear and the cranial fossa located on the back | Venous water supply vessel |
Facial Nerve Canal
Consider the front canal of the temporal bone. It originates on the underside of the hearing aid located inside the ear. Its orientation is expressed laterally - forward to the cleft channel of the stony nerve fiber. In this area, it forms a coil, which is called the frontal canal ring. The front canal of the temporal bone continues from the knee in the direction from the side and back along the trajectory of the right angle parallel to the axis of the pyramid. Then the direction becomes vertical and ends with a mastoid hole at the rear wall of the tympanic cavity.
Sleepy channel
The carotid canal of the temporal bone begins its path on the underside of the pyramid in the form of an opening (aperture). Its focus is straight and up, but closer to the surface of the pyramid. The channel bends at an angle of 90 and exits with an external hole at the apex of the pyramid. The carotid artery passes through the channel.
Muscular-tubal canal
The muscular-tubal canal of the temporal bone is a fragment of the auditory tube of the apparatus of the inner ear. The channel begins at the top of the pyramid, namely: located between its frontal edge and the scales of the temporal bone.
Drum string tubule
This tubule begins from the canal of the facial nerve, but its beginning is located slightly higher from the styloid opening, and ends in a stony-tympanic fissure. The contents of this temporal bone canal in the table were examined in more detail.
Mastoid tubule
The tubule takes its beginning in the jugular fossa, crosses the lower part of the facial canal and ends in the mastoid-tympanic fissure. The mastoid channel through its cavity conducts the process of the vagus nerve.
Drum tubule
The drum tubule originates from the bottom of a rocky dimple. Continues its way up and straight. Crosses the bottom section of the tympanic cavity and rushes to the top of the cape, but already in the form of a groove. Its end extends through the cleft of a stony nerve located on the front side of the temporal bone pyramid.
The drum channel contains a drum nerve in its cavity.
Sleepy tubules
There are two carotid tubules in total. They begin from the wall of the carotid canal, from where they are then displayed in the tympanic cavity. The function of these channels is conducting.
The temporal bone canals are shown schematically above. They show the complexity of the processes occurring in the bone.