Presentation on theme: "Part I: Muscles of the Head and Neck Part II: Muscles of the Trunk"— Presentation transcript:
1 Part I: Muscles of the Head and Neck Part II: Muscles of the Trunk Nestor T. Hilvano, M.D., M.P.H.(Illustrations Copyright by Frederic H. Martini, Pearson Publication Inc., and The McGraw-Hill Companies Inc.)
2 Learning Objectives You should be able to: Describe the various shapes of skeletal muscles and relate this to their functions.Explain what is meant by the origin, insertion, belly, action, and innervation of a muscle.Explain how muscles interact to produce or oppose movements.Identify the major skeletal muscles of the head and neck, and indicate their origins, insertions, actions, and innervation.Discuss common abnormalities and injuries of muscles of the head and neck.Identify and describe the major skeletal muscles of the vertebral column (back).Identify and describe the muscles of the thorax and the diaphragm.Identify and describe the oblique and rectus muscles.Identify and describe the muscles of the pelvic floor.Correlate clinical conditions of the trunk using what you have learned in anatomy and physiology.
3 Part I: IntroductionMuscles are named as to location, attachment, relative position, action, size, number, and shape.Shapes of skeletal muscle fibers:Parallel - have parallel fascicles; stronger pullConvergent - broad at origin and tapering to a narrower insertion; less pull than parallel musclePennate - fascicles insert obliquely on a tendon; produce more tension (more muscle fibers)Circular - ring around body opening
4 Descriptive Term for Muscle Size: Longus = longLongissimus = longestTeres = long and roundBrevis = shortMagnus = largeMajor = largerMaximus = largestMinor = smallMinimus = smallestParts of a Skeletal Muscle:1. ___ - attachment to stationary end of muscle.2. ___ - thicker, middle region of muscle.3. ___ - attachment to mobile end of muscle.a. insertionb. originc. belly
5 Muscle Actions___ - produces a particular movement, prime mover; ex. biceps brachii.___ - aids the prime mover, provide additional pull near the insertion or stabilizes the point of origin (fixators); ex. brachioradialis___ - opposes the prime mover; preventing excessive movement and injury; ex. triceps brachii.a. antagonistb. agonistc. synergist
6 Skeletal Muscle Innervation Cranial nerves arising from the brainexit the skull through foraminanumbered I to XIISpinal nerves arising from the spinal cordexit the vertebral column through intervertebral foramina
7 Muscles of Facial Expression Origin - surface of the skullInsertion - superficial fascia and dermisInnervation – VII C.N.Action – Movements of facial structuresParalysis causes face to sag = ________Include the orbicularis oculi, buccinator, orbicularis oris, mentalis, depressor labi inferioris, levator labi superioris, rizorius, zygomatic, frontalis, platysma
8 Figure 11-4b Muscles of Facial Expression Epicranial aponeurosisFrontal belly ofoccipitofrontalisTemporoparietalis(cut and reflected)Corrugator superciliiTemporalisTemporalis (temporoparietalisremoved)Orbicularis oculiProcerusNasalisLevator labii superiorisZygomaticus minorLevator anguli orisZygomaticus majorOrbicularis orisMasseterRisoriusBuccinatorPlatysmaDepressor anguli orisDepressor labii inferiorisMentalis (cut)Sternal head ofsternocleidomastoidThyroid cartilageof the larynxClavicular head ofsternocleidomastoidTrapeziusClaviclePlatysma(cut andreflected)Procerus- contraction will flare the nostrilsAnterior view
9 Muscles in Facial Expression F_____ elevates eyebrow, wrinkles foreheadC_____ wrinkles eyebrowO_____ closes eyelidsZ_____ elevates corner of mouth, upper lip (smile)R_____ draws corner of mouth to side (smile)B_____ compresses cheek, whistling muscleO_____ closes lips (purses lips)P _____ tightens neck, depresses mandibleWe blink every 2 to 10 seconds. Eachblink lasts for 0.3 to 0.4 seconds.
10 Muscles of Mastication Arise from skull and insert on mandibleM_____ and T_____ elevate the mandibleM_____ and L_____ Pterygoids help elevate, but produce lateral excursion of jaw (side to side grinding)V CN innervationB
11 Extrinsic Eye Musclesa. superior rectus b. inferior rectus c. Medial rectusd. lateral rectus e. inferior oblique f. superior obliqueActions- eye movements; CN innervations- III, IV, & VI___ look up; ___ look down___ look medially; ___ look laterally___ look down and laterally; ___ look up and laterally
12 Muscles of the Tongue Styloglossus- elevate & retract Shifts food onto teeth and pushesit into pharynx; speechIntrinsic Muscle- shapeExtrinsic Muscles- movementPalatoglossus- elevate, XI CNStyloglossus- elevate & retractHyoglossus- down & retractGenioglossus- down & protractAction: Elevate, retract, & protract tongueWhat is the strongest muscle?XII CN
13 Muscles of the Pharynx Action- Initiating the swallowing process Pharyngeal constrictors(superior, middle. inferior)Laryngeal elevatorsPalatal muscles (tensor veli palatini, levator veli palatini)What is dysphagia?
14 Anterior Muscles of Neck Digastric and geniohyoid depress the mandible or elevates larynxMylohyoid provides muscular floor to the mouthStylohyoid elevates larynxOmohyoid and sternohyoid depress hyoid bone and larynxSternocleidomastoid – from clavicle and manubrium to mastoid- Action? __________- Innervation= XI CN
15 HomeworkDefine key terms: origin, insertion, belly, agonist, synergist, antagonist, dysphagia, bell’s palsy, deglutition.Name the action/s of the following: masseter, temporalis, digastric, pterygoids, genioglossus, orbicularis oris, orbicularis oculi, platysma, corrugator supercili, rhizorius, zygomaticus, levator labi superioris, medial rectus, lateral rectus, frontalis, pharyngeal constrictors, and buccinator.
16 Part II: Muscles of the Trunk Nestor T. Hilvano, M.D., M.P.H.
17 Superficial Muscles of Back Trapezius – elevation and medial rotation, retraction (adduction), and depression of scapulaLatissimus dorsi – adduction, extension, and medial rotation of humerusBA
18 Muscles of the Back Erector spinae group Semispinalis group Multifidis 3 columns muscleIliocostalis, longissimus, spinalisExtends ________Semispinalis groupvertebrae to vertebraein neckExtends _________Multifidis- rotates vertebral columnQuadratus lumborumilium to 12th riblateral flexion of vertebral columnSemispinalisErector spinaeMultifidisQuadratus lumborum
19 Muscles of the Back Intervertebral muscles - interspinalis - intertransversalis- rotatoresAction: slightextension orrotation
20 DiaphragmMuscular sheet that forms a wall between thoracic & abdominal cavitiesMuscle fascicles extend to a fibrous central tendonFunction: major muscle of ____; contraction flattens it during ____; recoils (moves up) during ____.a. inspirationb. expirationc. respiration
21 Muscles of Thorax Scalene muscle (anterior, middle, & posterior) - action: elevate the first 2 ribs and assist in flexion of neckExternal intercostalsInternal intercostalsTransversus thoracis
22 Intercostals External intercostals Internal intercostals pull ribcage up and outward during inspirationInternal intercostals- pull ribcage in and downward during forced expirationTransversus thoracis – as above (internal intercostals)
23 Muscles of the Abdomen 4 Pairs of sheetlike muscles Functions external obliqueinternal obliquetransverse abdominisrectus abdominisFunctionssupport the viscerastabilize the vertebral column (flexion of spine)help in respiration (forced expiration), urination, defecation and childbirth
24 Rectus Abdominis and External Oblique External oblique –superficial,downward, anteriorly; action:compresses abdomenRectus abdominis – vertical,straplike; action: compressesabdomen- fibrous compartment enclosing thismuscle is ______.- a median collagenous partition is______.- separated into segments bytransverse lines/bands of collagenfibers named ______.a. linea albab. tendinous inscriptionsc. rectus sheet
26 Muscles of the Pelvic Floor: Perineum The perineum isdiamond-shaped region bounded by pubic symphysis, coccyx and ischial tuberositiespenetrated by anal canal, urethra and vaginaanteriorly = urogenital triangleposteriorly= anal triangleFunctions- support organs of pelvic cavity- flex sacrum and coccyx- control movement of materials thruurethra and anus
27 Superficial Muscles of Urogenital Triangle- support external genitalia Ischiocavernosus = arises ischial and pubic ramusBulbospongiosus = covers bulb of penis or enclosesvaginaFunction during intercourse and voiding of urine
28 Deep Muscles of UG Diaphragm - support pelvic floor and muscles of urethra * Urogenital diaphragm = 2 muscles1. deep transverse perineus m. - supports pelvic viscera2. external urethral sphincter m.- inhibits urination
29 Muscles of Pelvic Diaphragm- support anal triangle PubococcygeusIliococcygeusDeepest compartment of the perineumPelvic diaphragm = 2 muscles- levator ani m. supports viscera and defecation- coccygeus m. supports and elevates pelvic floor
30 HerniasProtrusion of viscera through muscular wall of abdominopelvic cavityInguinal herniamost common type ofhernia in malesviscera enter inguinal canal or even the scrotumHiatal herniastomach protrudes through diaphragm into thoraxoverweight people over 40Umbilical herniaviscera protrude through the navel
31 HomeworkDefine key terms: linea alba, rectus sheath, tendinous transcriptions, herniaName the action/s of the following: trapezius, latissimus dorsi, diaphragm, levator ani, scalene, external intercostals, internal intercostals, erector spinae, external urethral sphincter, rectus abdominis, transversus thoracis, bulbospongiosus.Compare and contrast inguinal hernia, hiatal hernia, and umbilical hernia.