#8 35 ANATOMY MUSCLES OF THE HEAD. Nermeen Sweiti & Sua'dad Al-Ani 8/10/2015. Nabeel Khouri. Page 0 of 24

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1 #8 35 ANATOMY MUSCLES OF THE HEAD Nermeen Sweiti & Sua'dad Al-Ani 8/10/2015 Nabeel Khouri Page 0 of 24

2 Today we will start a new topic: MUSCLES o How should we study the muscles: a. Tables (I will add them in the sheet). b. Figures from the atlas or google. c. Study them as group (muscles of the head, neck, facial, etc) terminology ( just read them and try to memories them ) : Page 1 of 24

3 These two tables summarize, the terminology of the muscles, this terminology is mainly Latin and it was put by great anatomists back then and passed to us. Pay good attention to the terminology, for it serves you good in studying, memorizing and understanding them, these names reflect their locations by including the bones and parts of the body which they cover, also their actions. it will make identifying structures easier for you in the lab as well. For example: When we say Abdominis means (abdominal), Anconeus (elbow joint), Auricularis (auricle of ear), Brachialis (brachium this is Page 2 of 24

4 the arm). Examples for the action : (Adductor, Abductor, Depressor, Extensor, Flexor, Levator,. Etc. ) Conclusively, the name of the muscle usually consists of two parts, one describes its action functional name- and the other describes its location. for example : a. Adductor Magnus. b. Adductor Medius. c. Adductor Minimus. They are located within the region of the medial aspect of the thigh, but Adductor Policis for is in the forearm. We won t be able to explain the action and origin of all the muscles, because this might take more 20 lectures, and some are too obvious to be explained. Muscle of the facial expression These are the muscle that change the expression of the face; they originate partially from the bone and mainly from the skin, and insert into the skin of the face, that s why they will produce modification of the shape or the figure of the face. These muscles are arranged in different structures or shapes, they could be sphincters, dilators, elevators or depressors. These muscles are the most anterior, extending from the occipitofrontalis muscle to the hyoid bone. Page 3 of 24

5 The nomenclature of these muscles will depend on their function, shape or location. For example, Depressor Labii inferioris: Its function lip location This muscle arises from the oblique line of the mandible, there at its origin its fused with the fibers of the Platysma muscle (located in the neck) and inserts on the skin of the inferior lip when its contracted it will depresses it. Orbicularis Oculi and Orbicularis Oris they are circular in shape and they surround an opening and their function is closing it; they will help in closing the eye and mouth respectively. Page 4 of 24

6 This muscle originates from a raphe, called the median raphe 1, this raphe is attached to maxilla, nasal and frontal bone, in conclusion it originates from the median wall of the orbit. This muscle covers the superior and the inferior parts of the eye, therefore helps in closing it Orbicularis Oris this has two raphes; one on the left and one on the right, these raphes are a point of origin of other muscles that act on the mouth, such as Depressor Angulii Oralis. Depressor Angulii Oralis and levator Angulii Oralis They act on the lateral angles of the mouth, and the superiors lip, respectively. Because the angle of the mouth is deep, this deepened structure like when you look at the face you will see that there is a depression in the lateral aspect of the mouth >> this depression is because of this structure that is made of tendons (raphe tendons) that is located in the left and right aspects of the mouth angle, we have one is depressor and one is levator of the Angulii Oralis. Zygomaticus major and Zygomaticus minor They originate from the zygomatic bone. they will go to the substances of the Superior Labii (Lip) and those are elevators; they draw the angles of mouth superiorly and laterally. Levator Labi Superioris and Depressor Labi Inferioris. Angle= Angulii Oralis = mouth 1 the Dr. pronounced it as the ralph but raphe is the correct word. Page 5 of 24

7 Levatory Labii Superioris Alaeque Nasi of the nose, is another elevator of the ala of the nose (some people might move their nose upward and backward). This muscle is attached to the upper frontal process of the maxilla and inserts into the skin of the lateral part of the nostril and upper lip. wiki mnemonic to remember its name is, "Little Ladies Snore All Night." Corrugator supercilli, which is also considered one of the facial expression muscles. The corrugator draws the eyebrow downward and medially, producing the vertical wrinkles of the forehead. It is the "frowning" muscle wiki Procerus, a very small muscle located in between the eyes, this muscle together with the corrugator they will elevate the piece of nose upward. **Zygomaticus major and Zygomaticus minor, we consider them the only muscles of the facial expression muscles which originate from bones the other ones don t. **this point is debatable ** All the facial expression muscles practically act on something either they will act on the nose, eye, lips or mouth, most of those have different action but they have mainly similar origin and insertion they will go from the skin. Platysma muscle This muscle contributes in facial expression (draws outer part of the lip inferiorly), depresses the chin with the mentalis- and might be considered a respiratory muscle! It is a very thin muscle embedded within the fascia of the skin, if you dissect it you will be able to see that it has just bands of skeletal muscles Page 6 of 24

8 diversified here and there, these bands will help in facial expresser muscle. This muscle goes all the way up and sometimes reaches the structure that covers this Masseter muscle and the Buccinators muscle, so it will go all the way passing the inferior border of the mandible and go within the face and blend with the other muscles such as the facial expresser muscle and as well as the Masticatory muscle. ** These are the muscles of facial expresser. Fronto Occipitalis 1 (one of the facial expresser muscle) it is a continuous muscle, it has two bellies that are connected with the Gala Aponeurotica. If you look at the gala aponeurotica (epicranial aponeurosis) this muscle practically begins from it, and blends with the Orbicularis Oculi and begins from the upper part of the brows regions and going all the way back into the 1 commonly known as occipitofrontalis. Page 7 of 24

9 Occipitalis and insert in the skin and originated in the skin, and that will move the skull of the head backward and upward by contraction. Facial expression muscles, are very important for those who are concerned about their beauty and having a perfect wrinkleless face :P females mostly. usually in the midline there is a fusion of those muscles and there is an aponeurosis, this muscle(platysma) practically make the wrinkles on the forehead, so to get rid of these wrinkles you have to paralyze the muscle and when you want to paralyze the muscle you put Botox over there. Page 8 of 24

10 1) All these muscle are innervated by the facial nerve. 2) They are very important clinically for the facial paralysis. ( when we do paralysis by Botox we do it for the fiber not the nerve) 3) Facial palsy is one of the diseases that is common, this facial palsy usually occurs at the peripheral aspect of the nerve within the parotid gland because the nerve goes through the parotid gland. One half of the facial expression muscles will be paralyzed partially, (all of them, the ones which elevate and depress), it will result in: a. Open eye, it will not close so we will have lacrimation. Page 9 of 24

11 b. Open mouth with the angel depressed down and that we will have salivation. It will affect the ability if talking and pronouncing words properly. The second group of muscles are: muscles of mastication. Those muscles from their name they will help in the masticatory action, *the chewing muscles* They are two muscles, the most important one is the masseter muscle (which is the most powerful in the human being, The power of the muscle is almost 25 kg) There is also temporalis, lateral and medial pterygoid muscle and the buccinators muscle. Buccinators muscle is considered as both : 1- Masticatory muscle 2- Partially, facial expression muscle But we will consider it as masticatory muscle (buccinators), because buccinators muscle going into skin and it will coming from anterior border of mandible (ramus). Now, this muscle will allow the bollus of the food to go from one side to another, and this muscle again will allow the cheeks and face to be inflated. Persistent use of the buccinators and the masseters, will cause them hypertrophy; they will be bigger. After that if this use is reduced significantly, they will get very weak, and go downward, causing what is called a bulldog face. This happens for people who play an instrument like the saxophone, and stop playing it, after few years their hypertrophied muscles will weaken. Page 10 of 24

12 Origin : Alveolar process of maxilla and mandible and pteromandibularraphe Insertion : Fiber of OrbicularisOris Innervation :Facia lnerve (VII) Action : draws the angle of the mouth laterally and superiorly ( also the book says Presses cheeks against teeth) source: pulse s made easy, the Dr didn t mention these. Temporalis muscle it originate from the entire temporal lines in the squamous part of the temporal fossa therefore, it has two origins (one from superior and inferior temporal line). it's Diverging Fibers go and form tendons, this tendons go into the coronoid process of the mandible it will elevate the mandible and retract it backwards (and those are two actions of the temporalis muscle, it is very big muscle). ** this is the end of my part, I hope you find it easy to study ** if these is any mistake please right in the correction zone. Your college Nermeen Sweiti ^^ The masseter: The masseter muscle originates from the zygomatic arch, goes all the way down into the angle of the mandible and the posterior border of the mandibular rami, and a small part of the inferior border of the body of the mandible. (So it s a very important elevator of the mandible inferiorly) Page 11 of 24

13 *There are two other muscles considered to be masticatory muscles, they are deep to the temporalis; The Lateral Pterygoid muscle, and the Medial Pterygoid. The Lateral Pterygoid It has an upper head and a lower head, it is a very important muscle because it originates from the lateral pterygoid plate and inserts into the part that goes into the capsule of the Temporomandibular joint,so it blends with the capsule of the temporomandibular joint (TMJ) and this blending will give stability to this joint. In addition to that it will protrude the mandible forward, so practically this is very important muscle and a very strong muscle. The Medial pterygoid muscle It has two heads; a superficial and a deep one. It originates from the medial surface of the lateral portion of the pterygoid plate, and inserts into the inferior aspect of the medial surface of the mandiblular ramus. They will have to elevate and protrude the mandible, so they have two actions : (elevation and protrusion) and those are the muscles of mastication. Page 12 of 24

14 A summary of the masticatory muscles. Muscles Of The Tongue They are two types: Intrinsic muscles Extrinsic muscle 1) The Intrinsic muscles : from their name,those are muscles that run from a part of the tongue to another, their action is to change the shape of the tongue and they don't originate from a bone, instead they originate and Page 13 of 24

15 insert within the substance of the tongue. They are of three types: Oblique; will change the shape in a transverse way together with the transversalis. Transverse; runs from one side to another. longitudinal, runs along the side of the tongue, it will roll up the tongue backwards and so on. 2) The extrinsic muscles: These muscles originate from the bone and insert into the tongue, and those will move the entire tongue in various directions; such as anteriorly, posteriorly, and laterally, they also will protrude and retract the tongue. So the extrinsic muscles together with the intrinsic, they will manage the function of the tongue, like rolling and extending along with shape altering. The extrinsic muscles are: Genioglossus muscle : originates from the posterior aspect of the mandible, specifically from the Geniohyoid line which is in medial aspect of the mandible. Genio: mandible Hyoglossus: originates from the hyoid bone and inserts Glossus: tongue into the side of the tongue. Styloglossus: originates from the styloid process and inserts into the tongue. Those three muscles are very important; 1 they move food around the mouth, 2 along with the buccinator, they hold the food while teeth are grinding and they 3 push the food up toward the palate so it can be swallowed, 4 change the shape and modify the sound during speech altogether with the intrinsic muscles. Page 14 of 24

16 Summary of tongue muscles: Muscles of the pharynx: If we go deeper within the aspect of the neck we will find the pharyngeal muscles: 1) Pharyngeal constrictor muscles, they are superior, middle and inferior pharyngeal constrictors, they are very important in holding the food and pushing the bolus of food downward. They originate from different parts like the hyoid, the mandible and the substance of the larynx. They insert into a tent shaped raphe; which is the raphe aponeurosis; the constrictor muscles aponeurosis, located in the posterior aspect from the pharyngeal and continues down with the esophagus. 2) Laryngeal elevator muscles Page 15 of 24

17 3) Palatal muscles - Tensor veli palatini - Levatory veli palatini These practically occur in the posterior aspect of the mouth in the oropharynx and they will elevate the palate and depress it, as well as they will put the palate in tension. * the Palate made of two parts ===> hard and soft palate which is the roof of the tongue, this part of palate,which is the posterior aspect is made of these muscles (palatal muscles). Page 16 of 24

18 Muscles of the neck : They can be divided into two parts : 1) Muscles that are superior to the hyoid bone ===> suprahyoid 2) Muscles that are inferior to the hyoid bone ===> infrahyoid **most of these muscles will take their names from the part that they originate from and they will insert into the hyoid bone mainly except the (digastric muscle that have a different name). The suprahyoid muscles: elevate the hyoid bone, they help in swallowing and speaking. 1) Mylohyoid muscle : extends from the mandible; the inferior border to one third to the hyoid bone. 2) Stylohyoid muscle : goes from the styloid process into the hyoid bone 3) Digastric muscle : has 2 bellies,anterior and posterior belly. The Anterior belly comes from the mandible; from the posterior edge of the lower border of the mandible, specially in the midline and it goes all the way into the hyoid bone. The Posterior belly from the mastoid of the temporal bone, to the hyoid bone. **this muscle has a raphe or belly of fixation on the hyoid bone,it will be fixed in the hyoid bone by aponeurosis gate and this gate allows this tendon to continue backwards,superiorly and became again another part of this digastric,which is the posterior belly. So the two belly are made of muscles and the connection between the two bellies is a tendon,this tendon goes into a raphe and this raphe is surrounded by the stylohyoid aponeurosis. Stylohyoid aponeurosis will help in forming a tunnel for this tendon to allow passage from one belly to another, they both insert into this raphe Page 17 of 24

19 and this raphe goes into providing insertion for the stylohyoid muscle. The infrahyoid muscles: they divide the neck into two triangles,specially the (sternocleidomastoid). **these two triangles practically are very important clinically to locate and determine the organs, the arteries and the structures that belong to the neck. **These muscles are named for their position inferior to the hyoid bone. 1) The omohyoid: originates from suprascapular notch, to the body of hyoid 2) The sternohyoid: originates from the sternum to the body of the hyoid. 3) The thyrohyoid: originates from the thyroid cartilage to the hyoid bone. So these muscles, they come from the sternum or the clavicle all way to the inferior aspect of the hyoid bone; the cornio of the hyoid bone. so these are the muscles that are located within the midline and they cover most of the deepest part or the middle part of the anterior triangle of the neck. The sternocleidomastoid: Sternocelido >> the sternum and the clavicle>> the origins of this muscle Mastoid>> its insertion; the Mastoid process of temporal bone. It has 2 heads, one from sternum,one from the clavicle and then go to the mastoid. It's a very powerful muscle that; both heads contract in both sides; left and right. Right side: rotation to left & lateral flexion to right Left side: rotation to right & lateral flexion to left Both sides: extension of head at atlantooccipital joint & flexion of side will rotate the head into the lateral sides and also contraction. Page 18 of 24

20 The respiratory muscles: We have two types of respiratory muscles, primary and accessory; the primary are: - The diaphragm - Intercostal muscles The accessory: - Scalenus anterior and scalenus medial muscles Scalenus anterior and scalenus medial **They are located in the neck, they will go to the first rib and they are deep within the posterior triangle of the neck and deeper to the sternocleidomastoid, so they are covered by the sternocleidomastoid. **They have a gab between them; Scalenus triangle or scalenus gab it allows the brachial plexus to pass from the neck to the upper extremities. Origin and Insertion: The scalenus anterior and medius have a wide origin at the transverse processes of the cervical vertebra. Scalenus Anterior : It arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebrae. Scalenus medial: arises from the posterior tubercles of the transverse processes of the lower six cervical vertebrae. most of the transverse processes of the cervical vertebrae provide insertion for those muscles because they need power for elevating the first rib upward in order to increase the size of the thoracic cavity, and they insert on the upper surface of the 1 st rib. There are ridges over the superior surface of the first rib, two ridges ---> one for the anterior scalene and one for the medial scalene. Page 19 of 24

21 The posterior scalene, the third muscle in that group, it doesn't reach the first rib so it's not one of the respiratory muscles. Deeper muscles of the neck: they are in the anterior aspect of the neck and have nothing to do with the respiration but the Dr. thought that we should know them :* they are deeper to the respiratory ones and deeper to the pharynx* - Longus colli muscle - The longus capities muscle you can see them only from the anterior aspect of the neck,immediately anterior to the body of the cervical rib. The primary muscles of the respiration : - The diaphragm - The intercostal muscle The intercostal muscles They are located intercostal spaces, the spaces between the ribs;there we have the: External oblique + internal oblique The typical rib usually has a head,neck and tubercle,and the angle that goes into the groove,it has a costal groove, it has a costal cartilage that extends to the sternum anteriorly and inserts into the lateral border of the sternum. Page 20 of 24

22 The atypical rib as you can see,it's the 1 st rib,it has a head, neck and tubercle but it has a little bit of an angle,it has 2 grooves for the scaleni (anterior + middle). You can also see it has a medial and a lateral border with smaller costal cartilage that extends to the inferior surface of the clavicle as well as the lateral border of the sternal manubrium. The 11 th and 12 th ribs are mainly called the Floating Ribs, there is a debate about calling them Atypical or typical ribs, since they are short and have no cartilage. You might want to take a look on these photos illustrating the thoracic vertebrae, the Dr. mentioned them fuzzily :P Page 21 of 24

23 In the intercostal space we have 3 types of muscles: The internal oblique muscles and the external oblique, those which fill the intercostal space anteriorly. The third type is the innermost intercostals which are located within a very thin fashion and have small fibers. The external oblique practically extends all the way from the back into the anterior aspect, it begins posteriorly, its direction is downward medially, and practically this muscle is cut after two third of its distance and replaced by an aponeurosis,so you will see aponeurosis with the same fiber direction inferiorly and medially. The internal oblique is the opposite, it will begin from the anterior with a direction downward laterally and it begins with muscle and before it reaches the posterior aspect of the intercostal space, it will be replace by aponeurosis,so the aponeurosis here is different and will help in respiration. The innermost muscles, the muscles which immediately behind them the parietal plural can be seen. Supcostalis muscles, those muscles are very small, you can see them only from the medial or the inner aspect of the thorax anteriorly and they originate from the inner surface of one rib, and are inserted into the inner surface of the second or third rib below, near its angle. Transversus thoracis muscle They are either the horizontal or vertical, located in the posterior between the transverse processes and the part of the rib. Page 22 of 24

24 (slide 46) *These are the intercostal arteries and nerves and how the neurovascular bundle is located in the groove, they will wind around and irrigate most of the intercostal muscles. (slide 48) *This is how the pleural effusion tap is done; the needle is guided by the superior border not by the inferior border of the rib, to prevent injuring the neurovascular bundle. **check the slides for more pictures, illustrations, and tables :D The End This part done by your colleague : Suadad Al-Ani اعتذر عن اي خطأ مسبقا.. رجاءا اذا الحظتوا اي معلومة خاطئة.. يا ريت يتم تبليغي على كروب الدفعة موفقين جميعا Page 23 of 24