Part 1:
The Head

Topographic Anatomy of the Head

Limits, outer orienteers. The head is separated from the neck with the line which begins on chin elevation - protuberantia mentalis, after that it laterally continues across the lower mandible edge, continues by the lower semicircle of outer aural meatus, goes on to the upper nuchal line, linea nuchae superior, and ends on both sides on outer elevation of occipital bone with protuberantia occipitalis externa. In general, the head is divided into cerebral cranium - cranium cerebrale and facial cranium - cranium faciale.

Cerebral Cranium

Limits: The cerebral cranium is separated from facial cranium with the anatomical formations described below. It is limited by glabella by the middle line. Afterwards this line goes along the brow arch, arcus superciliaris, then - by the rear edge of the processus zygomaticus ossis frontalis and processus frontosphenoidalis ossis zygomatici, then the line goes on by the zygomatic arch, then it continues vertically to the rear edge of the ascending branch of the mandible, and afterwards it continues on the bottom margin where it ends after connecting with a similar line coming from the opposite side - forming protuberantia mentalis.

Area division: The cerebral cranium can be divided into the cranium base, basis cranii, and the cranium fornix (or dome) which is also called calvaria. The cranium base is divided into inner one (basis cranii interna) and external one (basis cranii externa). Calvaria is divided into frontal, parietal, occipital, temporal and mastoid regions (regg. Frontalis, parietalis, occipitalis, temporalis et mastoidea).

Regio frontalis (or the frontal area) is located within the frontal region. Its limiting line begins in the lower part of glabella, spreads to the sides across eyebrow arches, crosses the zygomatic process of the frontal bone, continues upwards across temporal line, and then ascends by the projection line of the coronal suture.

Regio parietalis (parietal region). Limits: anterior limit is the coronal suture, lambdoid suture is the rear limit, temporal line limits it from the sides.

Regio occipitalis (occipital region) is located within the squama of the occipital bone. Limits: lambdoid suture limits it from the top and from the sides and the line drawn horizontally from one apex of mastoid bone to another limits it from below. It's called linea bimastoidea.

Regio temporalis (temporal region). Limits: upper and rear limit is the temporal line, lower limits are zygomatic arch and temporal line above the external aural canal, anterior limit is the zygomatic process of the frontal bone and the outer section of the temporal line. Layer topography of this area has its own complications: skin has less connective tissue septa the lower it is. Aponeurotic helmet becomes thinner and is called here fascia superficialis or superficial fascia. Fascia temporalis propria or proper temporal fascia is formed by the arcus zygomaticus after attaching with its lower margin. You can find its spatium interaponeuroticum, interaponeurotical space, between the plates.

Regio mastoidea or mastoid is an area which is limited with mastoid process. Layer topography of this area has its own complications: skin has no hair and is tightly attached with the mastoid aponeurosis or aponeurosis mastoideus lying below, which is a continuation of galea aponeurotica, but is significantly thinner that its origin. Mastoid process is covered with a thick layer of the periosteum and has attachment points of m. sternocleidomastoideus, mm. splenius capitis et cervicis, venter posterior m. digastrici.

Layers of Regions and their Characteristics:

1. Derma - thick, hair-covered skin, it has a large number of sebaceous and sweat glands. It is firmly attached to the deeper lying subcutaneous fat and supracranial muscle, musculus epicranius, using vertically going connective tissue septa.
2. Panniculus adiposus - it's subcutaneous fat. Blood and lymphatic vessels of this layer are firmly fixed using connective tissue septa. That's why vessels do not collapse when injured.
3. M. epicranius - it's epicranius muscle which consists of the frontal part, m. frontalis, and the occipital part of the m. occipitatis. Both parts have shared tendon helmet, galea aponeurotica, which is located in the parietal region and becomes thinner as it goes laterally during transition to the temporal region. These three layers which were described above form a single layer of tightly interconnected tissues.
4. Stratum fasciaie - it's fascial layer, a layer of incoherent connective tissue.
5. Periosteum is firmly attached to the skull bones only in the sutural areas.
6. Ossa cranii are the bones of the skull of variable thickness. Occipital region bones have the maximum thickness, and the temporal bones have the minimum thickness. The skull bones are composed of three layers. It's the lamina externa or the external plate, substantia diploica or the spongeous matter which has a lot of vessels - especially vv. diploicae, and lamina vitrea or glass-like plate.
7. Spatium epidurale - it's the space above the dura mater.
8. Dura mater is composed of dense fibrous connective tissue. As it goes deeper, this tunica forms the falx cerebri or the crescent of the brain and with its help it divides cerebral hemispheres from each other; falx cerebelli or the crescent of the cerebellum divides the cerebellar hemispheres, and tentonum cerebelli or the tent of the cerebellum separates the occipital lobes of the cerebral hemispheres from the cerebellum. These processes of dura mater form channels for the drainage of venous blood from the cranial cavity which are called venous sinuses.
9. Spatium subdurale is a space beneath the dura mater.
10. Arachnoidea encephali or the arachnoid membrane contains blood vessels and continues from one gyrus to another without going in.
11. Spatium subarachnoidaie or subarachnoid space stores cerebrospinal fluid in its subarachnoid cisterns or cisternae subarachnoidaie.
12. Pia mater or the soft tunica contains a large number of vessels. The tunica finds its way inside all the sutures between the gyruses.
13. Spatium epicerebrale or epicerebral space. Has the most amount of cerebrospinal liquid between all the listened above spaces.
14. Gyri cerebri or brain gyruses.

Regio Frontalis Has the Next Blood Vessels (Fig. 1):

1. a. frontalis is the final branch of the a. ophthatmica and leaves the cranial cavity through the frontal hole, for. frontale. A. frontalis anastomoses with the a. angularis in the corner of the eye;
2. a. suproorbitalis leaves the cranium through the incisura supraorbitalis. Frontal artery lies a little bit more medially than supraorbital. Venous backflow goes through the frontal veins, vv. frontales and after that backflow continues through v. angularis and afterwards it goes on to the system of frontal facial vein. A small amount of blood keeps going to v. ophthatmica superior which pours into the cavernous sinus.

Figure 1 Vessels and nerves of the head.

1 - r. parietalis a. temporalis superficialis, 2 - r. frontalis a. temporalis superficialis, 3 - aa. et nn. temporales profundus, 4 - m. temporalis, 5 - n. auriculotemporalis, 6 - n. auricularis posterior, 7 - a. auricularis posterior, 8 - n. occipitalis minor, 9 - m. sternocleidomastoideus, 10 - n. occipitalis major, 11 - a. occipitalis, 12 - m. trapezius

Innervation: motor nerves of this region descend from ramus frontalis n. facialis; sensitive nerves - from ramus ophthalmicus n. trigemini. Lymph drainage of this area is performed through nodi auriculares anteriores, which are located a little a bit more forward than the tragus of the ear.

Regio parietalis is supplied with blood with r. parietalis a. temporalis superficialis. Venous backflow goes through r. parietalis v. temporalis superficialis. Innervation of the area: front is innervated with n. supraorbitalis and n. frontalis, sides - with n. auriculotemporatis, rear - with n. occipitalis major. Lymphatic backflow is supplied with nodi auriculares posteriores.

Regio occipitalis is supplied with blood through a. occipitalis, which branches off a. carotis externa. A. occipitalis gets under m. sternocleidomastoideus and comes close to v. jugularis interna and n. occipitalis minor. Terminal branches a. occipitalis are located under m. epicranius, where they diverge into rr. mastoidei, auriculares, occpitales. Venous outflow goes through the occipital vein, v. occipitalis which runs together with the artery of the same name.

Innervation of the area:

1. n. suboccipitalis or the suboccipital nerve. Its branches innervate mm. recti capitis posterior major et minor, mm. obliqui capitis superior et inferior.
2. n. occipitalis major or the greater occipital nerve is the posterior branch of the second cervical spinal nerve. It's a sensory nerve.
3. n. occipitatis minor or smaller occipital nerve moves away from the cervical plexus to innervate the skin of the occipital area. Lymphatic backflow goes through nodi occipitales.

Regio temporalis is supplied with blood through aa. temporales anterior et posterior (anterior and posterior temporal arteries). Lymphatic vessels traverse into the fossa pterygopalatina and fall into a...