Presentation on theme: "Muscles and regional anatomy of the head and neck and the back"— Presentation transcript:
1 Muscles and regional anatomy of the head and neck and the back Lecturer: Dr. M. SamsamUniversity of Central Florida, Orlando,Pictures from Platzer atlas and textbookof human anatomy and K. Moore anatomyAnd Tortora principles of anatomy, 10th edition
3 Skull continued**Fontanels in the skull are the unossified remnants of the membranes in newborns.Major fontanels are: anterior (ossified within months), posterior,mastoid and sphenoid which are ossified within 6 month or more
10 Muscles of the head These are mimetic muscle: radiate into the skin of the face and the head, and their contractioncauses displacement of the skin.4 groups:A- Muscles of the ScalpB- Muscles in the region of eyelidC- Muscles in the Nasal regionD- Muscle of the Mouth regionA- Muscles of the Scalp:Epicranius Muscle: (Occipitofrontalis)Has 2 bellies: Frontal (3), Occipital (2), and inbetween, the Galea Aponeurotica (1).Temporoparietalis M. (5)Epicranius Function:produces wrinkles in forehead and gives facialexpression of Astonishment.Innervation: All mimetic muscles by Facialnerve (cranial nerve CNVII) .
11 Muscles in the region of eyelid or palpebral fissure: Orbicularis Oculi muscle:Has 3 parts: Orbital (1), Palpebral (2) andLacrimal (3).Function: produces folds in lateral angle of theeye, expression of Worry and concern (C).Corrugator supercilli (7):Pulls the skin and eyebrow down and medially.Produces vertical folds. Protects against light.Pathetic pain muscle.Thinker’s brow expression (D)Innervation:All mimetic muscles by Facial (CNVII) N.
12 Mimetic muscles in the region of the mouth 1- Orbicularis Oris M.: Function: its contraction closes the mouth.Strong contraction gives a sucking shape.Expression of reserve (D).2- Buccinator M.: Quadrilateral in shape.Origin: mandible at 1st or 2nd molar region.Forms the pterygomandibular raphe (3).Extends to angle of the mouth and forms thelateral wall of its vestibule.Function: enables air to be blown out of themouth. Pulls angle of the mouth laterally.Keeps the mucous membrane of the cheekfree of folds.Contraction gives expression of satisfaction (E).
13 Mimetic muscles in the region of the mouth 4- Zygomaticus Major: Origin: zygomatic bone.Insertion: angle of mouth.Function: lifts the corner of the mouth upward,giving expression of laughter or pleasure (F).5- Zygomaticus Minor:Origin: zygomatic boneInsertion: nasolabial groove.6- Risorius: (laughing muscle)Function: together woth zygomatic major itproduces the nasolabial folds.Its contraction gives expression of Action (G).7- Levator labii superioris:Origin: Infraorbital margin to skin of upper lip.
14 Mimetic muscles in the region of the mouth 8- Lavator anguli oris: It lifts the angle of the mouth,Giving expression of self confidence (8).9- Depressor anguli oris:Function: pulls the angle of the mouthdownwards and produces expression ofsadness (I).10- Depressor labii inferioris:It pulls the lower lid down, giving expressionof perseverance (K).11- Mentalis:Produces: chin-lip furrow, giving expression ofdoubt and indecision (L).12- PlatysmaAll mimetic muscles are innervatedby facial N. (CNVII)
15 Muscles of Mastication: Masseter (1), temporalis (2),Lateral (3) and medial pterygoid (4)***All Innervated by Mandibular nerve (CNV/3).***Develop from 1st branchial arch.CNV= cranial nerve 5 (trigeminal nerve).It has 3 branches: ophthalmic, maxillaryand mandibular1- Masseter M:Origin: Zygomatic arch (5)Insertion: masseteric tuberosity of mandible (6)Has 2 parts:7- Superficial part (oblique fibers)8- Deep part (vertical fibers)Function: powerfully closes the jaw by elevatingthe mandible. NN: Masseteric N CNV/3.2- Temporalis M:Origin: temporal fossa (9) as far as inf temp line.Insertion: by a strong tendon to coronoidprocess of mandible and mandibular ramus (11).Function: strongest elevator of lower jaw.NN: deep temporal N CNV/3.
16 Muscles of Mastication: Masseter (1), temporalis (2),Lateral (3) and medial pterygoid (4)Lateral pterygoid M (3):Has 2 parts (12 and 14)Function: mandibular movements (guiding muscle).NN: lateral pterygoid N CNV/3.Medial Pterygoid M (4):Runs at right angles to the lateral pterygoid M.Has 2 partsAngle of mandible is between this muscle andthe masseter M.Function: elevates mandible andpushes it forward. Rotational movement.NN; Medial pterygoid N CNV/3.
17 Anterior Facial Regions: First of all, the blood supply of the face ismostly by ext. carotid and partly by int. carotid.Facial artery (2) from ext. carotid passesit anastomose with dorsal nasal A. (4) comingfrom Ophthalmic A.Forehead is supplied by supratrochlear A. (8)and supraorbital (9) A., both from ophthalmic A.Facial vein (10) anastomoses via Angularvein (11) With dorsal nasal vein.***This anastomoses is extremely importantsince this allows a direct connection toCavernous sinus, through which, infectionseg: from a furuncle on the lip, may get into skull.All mimetic muscles are innervated by branchesof facial N: 13- temporal branch, 14- zygomatic15- buccal branch and 16- marginal mandibular.
18 Anterior Facial Regions: Sensory innervation to the face:Is derived from branches ofTrigeminal (V) nerve: Ophthalmic (V/1),Maxillary (V/2) and mandibular (V/3) nerves.Ophthalmic nerve: supplies the forehead:Supratrochlear N (17) and supraorbital (18).Maxillary nerve: supplies lower eyelid,Cheek, lateral nasal, upper lip and anteriorTemporal regions by Infraorbital N. (22).Mandibular N: lower lip over mandible(not angle) and chin by mental N (23).Auriculotemporal N (24) supplies skin onMandible ramus, concha of auricle andMost part of ext. layer of tympanic memb.Sensitivity of the 3 branches of trigeminal Ncan be tested by pressing nerves 18, 22 and 23.This is a vertical line, 2-3 cm lateral to midline.***Trigeminal Neuralgia.
19 Trigeminal neuralgia (Tic Douloureux) A disorder of unknown etiology (cause) associated with intractable pain along the 3branches of trigeminal nerve but especially along maxillary and mandibularnerves. A simple trigger such as touch, cold or hot can start the pain.Therapy: Carbamazepine, radiofrequency destruction of thebranches involved.Alcohol or Glycerin injection around the trigeminal ganglion.Transection of the sensory root.Vascular decompression of the trigeminal ganglion.
20 Hyoid bone: Is in the neck, but, may be included with the bony skeleton of the skull.PARTS:Body (anterior)Greater horns (laterally)Lesser horns (upwards)Stylohyoid ligament
21 Muscles of the neck: Platysma: Is the only cutaneous muscle in human body(under the skin)Attachments: superiorly: inf. borderof mandible and skin, and is attachedto superficial fascia covering pectoralismajor and deltoid muscles inferiorly.*Action: brings down corners of themouth, expressing sadness.*Innervation: Facial N. (VII)(cervical branch)*Injury to this nerve leads toparalysis of platysma (skin fallsaway from the neck by folds).*Careful sutures of the skin should bemade in surgery of the neck region.
22 Cranial muscle inserted on the Shoulder girdle: 1- Trapezius M: Repetition: 2- Descending part3- Transverse part, 4- Ascending partDescending:Origin: from external occipital protuberanceSuperior nuchal line, and Ligamentum nuchaeInsertion: lateral third of clavicleTransverse part: from C7-T3 spinous processInserted to: clavicle and scapula (acromion)Ascending: from T3-T12 spinous processInsertion: spine of the scapula*Function: elevation, retraction androtation of scapula.Helps in adduction and slight elevation of arm*Innervation: spinal root of Accessory nerve(CNXI) and C3-C4 (propioception)14- Sternocleidomastoid MOrigin: sternum (15) and clavicle (16)Insertion: Mastoid process and sup. nuchal lineFunction: unilateral contraction turns the headto opposite side and bends it ipsilaterally.Bilateral contraction: lifts the head.Also functions in respiration.Innervation: Accessory nerve (CNXI) and C2-C3
24 **Congenital and Spasmodic Torticollis (Wry neck) Congenital Torticollis:Most common type of Torticollis.Fibromatosis (fibrous tissue tumor)of Sternocleidomastoid M.Head turns to the side and face awayfrom the affected side.Leads to stifness of the neck due to fibrosisand shortening of the sternocleidomastoid.Injury during delivery may also result in Torticollis.(muscle tear and hematoma leads to fibrosis)Therapy: division of the muscle below XI nerveor from its distal attachment.
25 **Spasmodic Torticollis (Wry neck) Cranial dystonia (abnormal tonicity)Between years of age. Unknown cause.May involve bilateral neck muscles especiallythe Sternocleidomastoid M.Unilateral deviation of the head.(turning, tilting, flexion or extension of the neck)May involve other muscles in the body.Therapy: myotomy or also section of the spinalAccessory N. and upper cervical ant. roots
26 **Infrahyoid muscles: Omohyoid, Sternohyoid,Sternothyroid and Thyrohyoid*2-4) Omohyoid muscleHas an Inferior and a superior bellyInf. Belly:Origin: Upper border of scapula nearthe scapular notch.Sup. Belly: inserted to the lower border ofthe body of the Hyoid bone.A fascial sling connects it to the clavicle.*Action: fascia tensor and dilates internalJugular vein lying beneath it.(this aids to return of blood to the heart)Opens the mouth and helps in lateralflexion of the head.*Innervation: Most Infrahyoid muscles areinnervated by cervical Ansa (C1-C3).
27 Infrahyoid muscles: Continued 1-3) Sternohyoid M.:Origin: Post. Surface of manubrium andSterno-clavicular jointInsertion: Body of hyoid bone (inner surfaceand laterally).4-6) Omohyoid M.7-9) Sternothyroid: deeper to sternohyoidOrigin: post. Surface of manubriumInsertion: oblique line of thyroid cartilageIt covers the thyroid gland.10-11) Thyrohyoid M.:Continuation of Sternothyroid M.Origin: oblique line of thyroid cartilageInsertion: inner surface of body (laterally)and lower margin of greater horn.Innervation: C1, before giving the branch tocervical ansa.*Action: All infrathyroid muscles work togetherto approximate thyroid cartilage to hyoid bone.When mouth is open, they stabilizelaryngeal cartilages and the hyoid bone.
28 Suprahyoid muscles: **Digastric M.: Origin: Insertion: Stylohyoid M.: Digastric, Stylohyoid,Myelohyoid and Geniohyoid MM.**Digastric M.:Origin:Anterior belly: from mandiblePosterior belly:Mastoid notch of temporal boneInsertion:intermediate tendon to body andgreater horn of hyoid bone.Function: Raising hyoid andstabilizing it in speaking andswallowing,depressing the mandible.**Innervation:Ant. Belly: V/3, trigeminal N. (from nerve tomyelohyoid) and post. belly: VII, facial nerve.Stylohyoid M.:Origin: Styloid process of temporal boneInsertion: body of hyoidFunction: elevates and retracts hyoid bone,elongates floor of the mouth.Innervation: VII, facial N. (cervical branch)
29 Suprahyoid muscles: *Myelohyoid M.: *Geniohyoid M.: continuedMyelohyoid, Geniohyoid,Stylohyoid andDigastric muscles.*Myelohyoid M.:Origin: mandible,Insertion: body of hyoidFunction:Elevates hyoid and floor of themouth and tongue in swallowingand speaking.*Innervation:V/3 (myelohyoid N. frominf. Alveolar N.)*Geniohyoid M.:Origin: mandible, Insertion: body of hyoidFunction: pulls the hyoid anterosuperiorly,shortens floor of the mouth and widens pharynx.*Innervation: C1 via hypoglossal nerve
30 Atlas: Submandibular region: Look at the relation between Hyoglossus and Myelohyoid Muscles,the Lingual nerve, Submandibular gland, duct, andganglion and the Hypoglossal nerve
31 Atlas: 12- Geniohyoid M. 10- Myelohyoid M. 15- Ant. Belly of Digastric M.14- Genioglossus (cut)
33 Paravertebral and Scalene muscles Paravertebrals: Rectus Capitis Ant., Logus Capitis andLongus Colli.Rectus capitis: (1-3)Helps to flex the head. NN: Cervical Plex.(C1)Longus Capitis: (4-6)Bend the head forward and unilateral actionturns the head sideways.NN: Cervical Plexus(C1-4).Longus Colli: (7, 8, 9)Action: unilateral contraction bends and turnscervical column to the side.Also bend the cervical spine forwards.NN: cervical and brachial Pl. (C2-C8)
34 Scalene muscles Most important muscles for quiet inspiration They lift the first 2 pairs of ribs (sup part of thorax).Unilateral contraction tilts cervical column to oneside.Scalene Anterior (17):Scalene Medius (20):Scalene Posterior (23):NN: Brachial plexus (C4-C8).Scalenus minimus M. may be present in 30%.26- Scalene opening:brachial plexus and subclavian artery pass through.
35 Occipital (Omotrapezoid) triangle: Floor: Splenius Capitis (17), Lavator Scapulae (16), Post. Scalene (15)and Middle Scalene (14).*Content: Cervical Plexus.Accessory Nerve comes from behind theSternocleidomastoid M.It divides the supraclavicular region to aCare free and careful zone.12- superficial cervical Artery13- Anterior Scalene M.***Scalene gap:Formed between scalene Anterior and Middleand 1st rib, in which run the Brachial plexus (18)and Subclavian Artery (19).21- Phrenic nerve Suprascapular N.23- Long Thoracic N Dorsal Scapular N.25- Cervical lymph nodeAA
37 Triangles of the Neck: Anterior Triangle: Posterior Triangle: Submandibular T.Carotid T.Muscular T.Submental T.Borders:Posterior (lateral) :SternocleidomastoidSuperior: mandibleAnterior: midline of the neckPosterior Triangle:Occipital T.Omoclavicular T.
38 Carotid Triangle: Borders: Content: Super: Post. belly of Digastric Med: Sup. Belly of Omohyoid(2)Lat: Sternocleidomastoid (1)Skin innervat.: cervical plexusContent:External jugular vein andSuperficial cervical fasciaInternal jugular vein (9) andCommon facial vein (6)Common carotid A. (10)Carotid Sinus (11)12- Internal carotid A.13- External carotid A.29- Vagus nerve (behind and inbetween vessels)24- descending branch of XII(upper root of cervical ansa)runs above the carotid sheath.18- Hypoglossal N.
39 Big vessels in the neck: Hypoglossal nerveExternal Carotid A.CommonCarotid A.internal Jugular V.Vagus N.Subclavian A.Brachial plexusCommon facial V.Superior cervicalsympathetic ganglion
41 Thyroid Gland: Body's largest endocrine gland Is deep to sternothyroid and sternohyoid MAt C5-T1 level. It has a capsuleand externally covered by a sheath.Consists of an isthmus (1), whichunites the lobes.A right lobe (2) and a left lobe (3).Pyramidal lobe:A remnant of thyroglossal ductmay persist in the middle partof thyroid (50%).Ectopic Thyroid****Function:Produces Thyroxin which controlsthe rate of metabolism of the body,and Calcitonin controlling Ca++metabolism.Blood supply:Superior (8) and inferior (9) thyroidal artery
42 Goiter: Enlargement of Thyroid gland (nonneoplastic and noninflammatory). Usually not upward shift.Endemic in areas deficient in Iodine in food.Swelling in the neck which may disturb trachea,esophagus and/or laryngeal nerves.Exophthalmic goiter is due to excessive productionof thyroxin.Thyroidectomy:Removal of thyroid due to cancer.Subtotal due to preservation of Parathyroid glandsand recurrent as well as superior laryngeal nerves.Inadvertent removal of parathyroid glands lead totetany, severe convulsion and muscle spasm due todecrease in serum Ca++ and may lead to immediaterespiratory failure.
43 Usually 4, one upper and one lower gland per each thyroid lobe. Parathyroid glands:Usually 4, one upper and one lower gland per each thyroid lobe.They are external to thyroid capsule and internal to the connective tissue sheath.Function: Produce parahormon, controlling the metabolism of P and Ca++.