Alright, so this video is going to be about the common carotid and the external carotid artery. So before I start, I just want to inform that the arteries and branches I've put in this video is very schematic, but hopefully they will help you get a complete picture of this topic. I've also put some mnemonics along the way for you to use if you want to.
Now, we will start here, looking at the common carotid ascending along the neck, and as it reaches the upper border of the thyroid cartilage, it will divide into the external carotid, and the internal carotid arteries. There's really not much to say about the common carotid since it doesn't really have any side branches at all, it just ascends and then divides at the upper border of the thyroid cartilage. One special thing with it though is that at the upper part of it, it has some chemoreceptors called the carotid bodies which senses the chemical change in the bloodstream as a part of the homeostasis. Similarly you can find some receptors at the beginning of the internal carotid. called the carotid sinus.
These are one of the major body receptors we have, and they change the diameter of the blood vessel if it senses a stretch. So that's really all I had for the common carotid. Now let's focus on the external carotid artery. The external carotid artery will continue upwards, and then as it reaches the retromandibular fossa, it will divide into two terminal branches, and these are called the maxillary artery and the superficial temporal artery. So let's just remove the internal carotid to clear up space.
Again just keep in mind that the anatomical placements might not be 100% accurate, I've just tried to simplify them so that it gets easier for you to visualize and then hopefully remember them. Now let's look into the side branches of the external carotid. I found a little mnemonic for the side branches that I found quite helpful, it's some anatomists like freaking out poor medical students.
Arranging them like this using the first letter The first one is the superior thyroid, one of the three arteries coming out from the anterior side of the external carotid. It begins at the level of the hyoid bone, and then it will descend to the thyroid cartilage to supply it from the superior side. That's why it's called the superior thyroid. On its way down, it will give off some muscular branches for the straight muscles of the neck.
Remember, these are the thyrohyoid, the sternohyoid, the omohyoid, and the sternohyoid. it also supplies the middle region of the sternocleidomastoid muscle as well. Apart from that, it also gives off the superior laryngeal artery, which supplies the muscles of the larynx. Next up is the ascending pharyngeal, which is the only side branch of the external carotid that leaves towards the medial side. So this one will ascend along the medial side of the external carotid, along the pharynx, and then it will enter through the jugular foramen.
to the posterior part of the cranial cavity as the posterior meningeal artery. So it will supply the pharynx along with the pharyngeal constrictor muscles and also the meninges, the posterior part of the meninges. It also gives off the inferior tympanic artery which supplies the tympanic cavity or the middle ear, you know where the ossicles are. So that's it for this one. Next up is the lingual artery which is also one of the anterior branches of the external carotid.
It branches off at the level of the thyroid bone, and then it pierces through the muscles of the tongue, and then it ends up as a deep lingual artery. So this artery will supply the whole tongue with blood. That's why it's called the lingual artery. So it will give off the dorsolingual artery for the mucus layer of the dorsal part of the tongue, as well as the sublingual artery, supplying both the mucosa, the mucosal, and the mucosal artery. at the floor of the mouth and the sublingual gland.
So that's the lingual artery. Next one, and this is the last one of the anterior branches. This is the facial artery.
It goes out from the external carotid at the region of the mandibular angle and then it will curve towards the face at the base of the mandible and then it will continue upwards to the medial side of the eye as the angular artery. Now to make this artery easier, I've divided the side branches into two groups. I've divided them into the ones that branch out at the cervical region and the ones that branch out at the facial region. And for these, I've got another mnemonic for you guys. They go tags all.
Now for the cervical branches, we've got the tonsillary artery supplying the palate tonsil, the ascending palate which goes to the soft palate and then supplies that. the glandular artery for the submandibular glands and the submen artery which also supply the submandibular gland as well as the floor of the mouth so those are tags the cervical branches for the facial branches we got all a4 angular artery is the first it's not really a side branch it's rather it's a terminal branch which communicates with an artery coming out from the medial corner of the eye called the dorsal nasal which essentially comes from the ophthalmic artery so The facial and the ophthalmic artery and the stamos here, meaning that they connect here at the medial side of the eye. Then there's L for the superior and inferior labial artery supplying the top and bottom lip.
And then the last L stands for the lateral nasal, supplying the dorsum and the nasal wing. So that's mostly it for the facial artery. I use tags all as a way to remember it.
Next up is the occipital artery, branching out posteriorly from the external carotid. as you see here, supplying the occipital region with blood. It has a mastoid branch going into the mastoid foramen, supplying the meninges, and we also have the sternocleidomastoid branch for the sternocleidomastoid muscle. In addition to that, it also has a side branch for the external ear, as well as some descending branches supplying the neck muscles, like the trapezius for example. So really, to remember the occipital artery, just associate it with everything you find in the posterior part of the head and neck.
The other posterior branch of the external carotid artery is the posterior auricle. It will travel towards the backside of the auricle and basically just terminate as the auricular branch. It really just supplies the scalp behind the ear as well as the external ear as well. Apart from that, it also gives off the stilomastoid artery which enters the stilomastoid foramen and supplies all the structures in here like the tympanic cavity, the onterum, the mastoid cells. as well as the semicircular canals.
So basically it supplies the middle ear and parts of the internal ear as well. So that's the posterior auricular artery. Now for the last two, the terminal branches, the maxilla and the superficial temporal artery.
I think it's easier to look at them if we clear things up a little bit. The maxillary artery's origin is behind the neck of the mandible. At first it's embedded into the parotid gland. and then we'll continue towards the pterygopalatine fossa.
Now we divide the maxillary artery into three parts according to its anatomical location. The first one is behind the temporomandibular joints, the second is in the infratemporal fossa, and then the last part is where it terminates the pterygopalatine fossa. So let's start with the branches of the temporomandibular joints. The first branch is the deep auricular artery.
This one will enter the bony wall of the external acoustic meotus to supply the skin of the canal, the external acoustic meotus, and also a part of the tympanic membrane since you know they're both located in the same area. It can sometimes give off some small branches for the tympodomandibular joint as well so keep that in mind since it passes right next to the tympodomandibular joint. Next it has the anterior tympanic artery which passes through the pit through tympanic fissure to supply the middle ear. It also give off the middle meningeal artery, which enters the middle cranial fossa through foramens spinosum to supply quite a huge area of the meninges. Apart from that, it also give off the superior tympanic branch for the middle ear, so there are quite a couple of arteries from the external carotid that supply structures in the ear.
Middle Meningial Artery is actually an artery you will hear quite a lot about when you work in clinics, because most traumas that directly injure the skull will lead to an epidural hematoma or an epidural bleeding due to rupture in the middle meningeal artery, giving a really painful headache. So remember that it originally comes from the maxillary artery behind the temporomandibular joint, entering the skull through foramen spinosum. And Another really important branch is the inferior alveolar artery, which goes along the mandibular canal, and then it will go out through the mental foramen as the mental artery, supplying the skin and muscles of the chin.
The inferior alveolar artery is really important because it provides blood supply to the inferior teeth and gums through the dental and periodental branch, as well as supplying muscles of the floor of the mouth, the myelohyoid muscle. and the anterior belly of the musculus digastricus. Now over to the branches of the infratemporal fossa. This is where the artery pass between the lateral and the medial pterygoid muscles.
And remember, those are part of the the muscles of mastication and the side branches here are also mostly for these muscles of mastication there's the mesoteric artery for the mesoteric muscle there's a deep temporal arteries there's two branches for the temporal arteries the anterior and the posterior temporal arteries we have the pterygoid branch for the pterygoid muscle and then lastly there's the buccal artery for the buccinator that's the muscle that aids in smiling and and pushing the food as you chew as for the pterygoid palatine fossa There's 5 branches, there's the superior posterior alveolar artery, which runs behind the temporal arch along the maxillary tuberosity, and then it will enter the alveolar canals. So the artery will supply the premolar and the molar T, the gums, and also the maxillary sinus, or the mucosa of the maxillary sinus, since it passes through the maxillary sinus as well. Next in the list is the infraorbital artery. It goes into the optic cavity through the inferior optic fissure, and then it will sneak out from the orbita to the anterior region of the face through the infraorbital foramen, supplying the anterior region of the face.
So I guess this went too fast for you, didn't it? I'll go through it again. As you see here, through the inferior optic fissure, into the orbita, and then out through the infraorbital foramen to the anterior region of the face.
And As you see in this picture, on its way it will branch out an artery for the maxillary sinus, the incisors and the canine teeth, and also the gums. And that branch supplying the anterior part of the superior teeth is called the superior anterior alveolar artery. So that's mostly the blood supply of the teeth. For the superior part of the teeth you have the superior anterior alveolar artery, the superior posterior alveolar artery, and for the inferior teeth we have the inferior alveolar artery. So now that the maxillary artery keeps going into the pterygopalatine fossa, it gives off the descending palatine artery.
The descending palatine artery will travel a short distance within the pterygopalatine fossa, and then enter the greater palatine canal. It's a little hard to show it here through a presentation, especially because I'm bad at animation, but it travels down and then exits at around the 2nd-3rd molars, and divide into the lesser palatine and the greater palatine arteries, supplying the hard palate, the soft palate, and also the gums. The greater palatine though, it will continue and enter the nasal cavity through the incisive canal, to anastomose with the other branch of the maxillary artery, the sphenopalatine artery. So the sphenopalatine artery will pass through the sphenopalatine foramen, that's why it's called the sphenopalatin artery, it passes through the sphenopalatin foramen into the nasal cavity. Now, these two arteries, together with the anterior and posterior admiral arteries and the superior labial artery, will anastomose at the nasal septum and form this area called Little's area or Kisselbach's area.
And in the majority of times when you nose bleed, it's because you've ruptured some of the vessels in Little's area. in the septum of the nose. So that's these two.
Lastly there's the artery of the pterygoid canal. It may have various origin points but mainly it's in the pterygoid canal and supply the auditory tube and a little bit of the tympanic cavity as well. Now finally the last one of the external carotid is the superficial temporal artery.
So after the external carotid divides into maxillary and the superficial temporal artery. It will continue upwards in front of the ear and then divide into two terminal branches. There's gonna be a lot of terminal branches when we talk about the external carotid artery. The two terminal branches are the frontal branch and the parietal branch.
The frontal branch will run tutorialsly upwards and forward to the forehead to supply the muscles, the skin and bones, basically everything you find in this region. and then it will anastomose with the supraorbital artery of the ophthalmic artery in the orbita which you know originally comes from the internal carotid so this is also where the internal carotid and the external carotid um communicate so that's the frontal branch the piratal branch of the superficial temporal artery will curve upwards and then backwards to the side of the head lying very superficially to supply the parital region with blood As well as connecting with the two arteries back here, the posterior auricle and the occipital arteries of the external carotid. Also keep in mind that it communicates with the parietal branch of the other side of the head. In terms of side branches, they are very limited to the region of the superficial temporal arteries, and they are the anterior auricular branch, supplying the auricle and the external acoustic mottus. There's the transverse facial artery, which passes transversely across the face, and supplies the parotid gland, the masseter muscle, as well as the skin of the side of the face.
It do anesthetize with the arteries you'll find in this region like the facial arteries, the infraorbital artery, the mesoteric artery of the maxilla and you know so forth. And then lastly the middle temporal supplying the temporal muscles. So that's all I had for the common carotid and the external carotid arteries. I really hope this video helped you in any way to understand these arteries. Just remember as long as you make sure to go through it several times, it will eventually stick into your memory.