The Musculature of the Head


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The Musculature of the Head

  2. 2. The Two Groups of the Muscles of the Head <ul><li>Craniofacial muscles </li></ul><ul><li>- related mainly to the orbital margins and eyelids, the external nose and nostrils, the lips, the cheeks and mouth, the pinna, scalp, and cervical skin. These are collectively referred to as the muscles of facial expression. </li></ul>
  3. 3. Common Characteristics of the Muscles of Facial Expression <ul><li>All are inserted into the skin of the face; </li></ul><ul><li>All are supplied by the muscular branches of the facial nerve </li></ul>
  4. 4. <ul><li>2. Masticatory muscles- </li></ul><ul><li>- concerned primarily with the movements of the temporomandibular joint. </li></ul>
  5. 5. The Musculature of the Head
  6. 6. The craniofacial muscles
  7. 7. The CraniofacialMuscles <ul><li>The craniofacial muscles receive their innervation from the branches of the facial nerve. </li></ul><ul><li>They are grouped as: </li></ul><ul><li>1. epicranial </li></ul><ul><li>2. circumorbital and palpebral </li></ul><ul><li>3. nasal </li></ul><ul><li>4. buccolabial </li></ul>
  8. 8. 1. The Epicranial Muscles
  9. 9. <ul><li>The epicranius is made up of two main parts: </li></ul><ul><li>1. Occipitofrontalis </li></ul><ul><li>2. Temporoparietalis </li></ul>
  10. 10. The Epicranius <ul><li>1. Occipitofrontalis </li></ul><ul><li>- covers the dome of the skull from the highest nuchal lines to the eyebrows. It is a broad, musculofibrous layer consisting of four thin, quadrilateral parts- two occipital and two frontal- connected by the galea aponuerotica. </li></ul>
  11. 11. The Epicranius <ul><li>2. Temporoparietalis </li></ul><ul><li>- variably developed sheet of muscle that lies between the frontal parts of the occipitofrontalis and the anterior and superior auricular muscles. </li></ul>
  12. 12. Superficial fascia of the scalp <ul><li>- is firm, dense and fibro adipose, and adheres closely to bothe skin and the underlying epicranius, including its epicranial aponeurosis, the galea aponuerotica. Posteriorly it is continuous with the superficial fascia of the back of the neck. Laterally it is prolonged into the temporal region, where it is looser in texture. </li></ul>
  13. 13. The Muscles of the Scalp Muscle Action Frontalis Pulls the scalp up and back Occipitalis Pulls the scalp backward and forward
  14. 14. 2. Circumorbital and Palpebral Muscles
  15. 15. <ul><li>This group of muscle if composed of the following: </li></ul><ul><li>1. orbicularis oculi, </li></ul><ul><li>2. corrugator supercilii, </li></ul><ul><li>3. and levator palpebrae superioris. </li></ul>
  16. 18. Orbicularis Oculi <ul><li>- is a broad, flat elliptical muscle which surrounds the circumference of the orbit and spreads into the eyelids, anterior temporal region, infraorbital cheek, and superciliary region. It has three main parts: </li></ul><ul><li>1. Orbital </li></ul><ul><li>2. Palpebral </li></ul><ul><li>3. Lacrimal </li></ul>
  17. 19. Muscle Action Orbital part Closes eyes forcefully Palpebral part Closes the eye gently Lacrimal part Squeezes lubricating tears against the eyeball
  18. 20. Corrugator Supercilii <ul><li>- a small pyramidal muscle located at the medial end of each eyebrow, deep to the frontal part of the occipitofrontalis and orbicularis oculi, with which it is partially blended. </li></ul>Muscle Action Corrugator supercilii Vertical wrinkling of the bridge of the nose as in frowning
  19. 21. 3. Nasal Muscles
  20. 22. <ul><li>The nasal muscle group is composed of the following muscles: </li></ul><ul><li>1. Procerus </li></ul><ul><li>2. Nasalis </li></ul><ul><li>3. Depressor septi </li></ul>
  21. 23. Procerus <ul><li>- is a small pyramidal slip close to, and often partially blended with, the medial side of the frontal part of the occipitofrontalis muscle. </li></ul>
  22. 24. Nasalis <ul><li>- consists of transverse and alar parts which may be continuous at their origins. The transverse part is also known as the compressor nares and the alar part is the dilator nares. </li></ul>
  23. 25. Depressor Septi <ul><li>- is often regarded to as part of the dilator naris. </li></ul>Muscle Action Depressor septi Draw the septum downwards to narrow the nostrils
  24. 26. Muscle Action Procerus Transverse wrinkling of the bridge of the nose Nasalis Compressor Nares Compresses the nostrils Dilator Nares Dilates or flares the nostrils
  25. 27. 4. Buccolabial Muscles
  26. 28. <ul><li>The shape of the buccal orifice and the posture of the lips are controlled by a complex three-dimensional assembly of muscular slips. These include: </li></ul>
  27. 29. <ul><li>Elevators, retractors, and evertors of the upper lip </li></ul><ul><li>Depressors, retractors, and evertors of the lower lip </li></ul><ul><li>A compound sphincter </li></ul>
  28. 30. I. elevators, retractors, and evertors of the upper lip : <ul><li>levator labii superioris alaque nasi, </li></ul><ul><li>levator labii superioris, </li></ul><ul><li>zygomaticus major and minor, </li></ul><ul><li>levator anguli oris, </li></ul><ul><li>and risorius </li></ul>
  29. 31. Depressors, retractors, and evertors of the lower lip <ul><li>depressor labii inferioris, </li></ul><ul><li>depressor anguli oris, and </li></ul><ul><li>mentalis </li></ul>
  30. 32. A compound sphincter: <ul><li>orbicularis oris, </li></ul><ul><li>accessory muscles to the orbicularis oris </li></ul><ul><li>incisivus superior, and </li></ul><ul><li>incisivus inferior </li></ul>
  31. 33. Muscle Action Levator labii superioris alaque nasi Elevate the ala of the nose and the upper lip Zygomaticus major Draws the angle of the mouth up and back as in smiling or laughing Zygomaticus minor Deepen the nasolbial groove as in sorrow
  32. 34. Muscle Action Levator labii superioris Elevates the upper lip and flares the nostrils Gives the expression of sadness Contraction of the whole muscle gives the expression of disdain or doubt
  33. 35. Muscle Action Levator anguli oris or caninus Elevates the angle of the mouth (muscle of happiness) Mentalis Elevate the chin. It also causes trembling of the chin. It wrinkles the skin of the chin as in disdain or doubt.
  34. 36. Muscle Action Risorius Draw the anglef the mouth laterally, giving an expression of strain or tenseness Depressor labii inferioris Depresses the lower lip as in “irony” Depressor anguli oris or Triangularis Depresses the angle of the mouth
  35. 37. Muscle Action Buccinator Or Bugler’s or Trumpeter’s muscle Draw the angle of the mouth laterally and to press the cheeks against the teeth while chewing. Useful in mastication, swallowing, whistling, sucking, and blowing
  36. 38. Muscle Origin Insertion Action Cranial Nerve Orbicularis oris Extrinsic fibers: From insertions of circumoral muscles Intrinsic fibers: From the incisive fossae of the mandible and maxilla Pass around the mouth within the lips as a sphincter Pass obliquely forward and insert into the skin of the lip Compresses the lips against the anterior teeth, closes the mouth, and protrudes the lips VII - zygomatic, buccal and mandibular branches
  37. 39. Muscle Origin Insertion Action Cranial Nerve <ul><li>Platysma </li></ul><ul><li>thin, sub- </li></ul><ul><li>cutaneous quadrilateral muscular sheet covering the upper part of the chest, side of the neck and lower part of the face </li></ul>Skin and superficial fascia of the pectoral and deltoid regions The fibers are directed upward and forward to be inserted into the lower border of the mandible Retract and depress the angle of the mouth VII - cervical branch
  38. 41. Muscles of the External Ear
  39. 42. Muscles of the External Ear Muscle Action Anterior auricular Pulls the ear forward Posterior auricular Pulls the ear backward Superior auricular Pulls ear superiorly
  42. 57. <ul><li>The muscles of mastication includes: </li></ul><ul><li>1. Masseter </li></ul><ul><li>2. Temporalis </li></ul><ul><li>3. Medial Pterygoid </li></ul><ul><li>4. Lateral Pterygoid </li></ul>
  43. 58. Functions of the Muscles of Mastication <ul><li>To move the mandible </li></ul><ul><li>To secure then stabilize the mandibular positions </li></ul><ul><li>To determine the direction of mandibular movements </li></ul>
  44. 61. The Masseter Muscle <ul><li>The masseter muscle is a small quadrilateral muscle that covers most of the lateral aspect of the ramus of the mandible. Lying superficial to this muscle is a portion of the parotid gland, the parotid duct, the transverse facial artery, and the various branches of the facial nerve. </li></ul>
  45. 62. The Masseter Muscle
  46. 63. Muscle Action Masseter Superficial head Elevation (bilateral) Ipsilateral excursion (unilateral) Protrusion (bilateral superficial head) Deep head Retrussion (bilateral)
  47. 64. The Masseter Muscle
  48. 65. The Temporalis Muscle <ul><li>The temporalis muscle is fan-shaped, with the periphery of the fan attached to the side of the skull and the handle of the fan attached to the coronoid process of the mandible. The muscle is covered by a strong membranous sheet of fascia, which attaches superiorly to the superior temporal line. Below, the fascia splits to attach to the medial and lateral aspects of the zygomatic arch. </li></ul>
  49. 66. The Temporalis
  50. 67. Muscle Action Temporalis Elevation (bilateral) Ipsilateral excursion (unilateral) Retrussion (bilateral)
  51. 68. The Temporalis
  52. 69. The Medial Pterygoid <ul><li>The medial and the lateral pterygoids are the occupants of the infratemporal fossa. </li></ul><ul><li>The medial pterygoid muscle is almost a mirror-like image of the masseter muscle. It is rhomboidal and runs practically in the same direction on the inner surface of the mandible. </li></ul>
  53. 70. The Medial Pterygoid
  54. 71. Muscle Action Medial Pterygoid Elevation (bilateral) Protrussion (bilateral) Contralateral excursion (unilateral
  55. 72. The Medial Pterygoid
  56. 73. The Lateral Pterygoid Muscle <ul><li>The lateral pterygoid is almost triangular in shape with two distinct heads, inferior and superior head, each with contrasting functions. It is the only muscles of the four muscles of mastication to occupy primarily a horizontal position. </li></ul>
  57. 74. The Lateral Pterygoid
  58. 75. Muscle Action Lateral pterygoid Inferior head Depression (bilateral) Protrussion (bilateral) Contralateral excursion (unilateral) Lateral pterygoid Superior head Elevation -particularly during power stroke
  59. 76. The Lateral Pterygoid
  60. 77. The Accessory Muscles of Mastication <ul><li>Othes muscles that active in mastication include the suprahyoid and infrahyoid muscles of the neck. Both groups of muscles are active in helping to depress the mandible. </li></ul>
  61. 78. Summary of Actions of the Muscles of Mastication <ul><li>Elevation: </li></ul><ul><li>1. the right and left temporalis </li></ul><ul><li>2. the right and left masseter </li></ul><ul><li>3. the right and left medial pterygoid muscles </li></ul>
  62. 79. Summary of Actions of the Muscles of Mastication <ul><li>Depression: </li></ul><ul><li>1. the inferior head of the right and left lateral pterygoid muscles </li></ul><ul><li>2. the right and left suprahyoid muscles of the neck </li></ul><ul><li>3. the right and left infrahyoid muscles of the neck </li></ul>
  63. 80. Summary of Actions of the Muscles of Mastication <ul><li>Protrusion </li></ul><ul><li>1. the right and left lateral pterygoid muscles </li></ul><ul><li>2. the right and left medial pterygoid muscles </li></ul><ul><li>3. the right and left superficial heads of the masseter muscles </li></ul>
  64. 81. Summary of Actions of the Muscles of Mastication <ul><li>Retrussion </li></ul><ul><li>1.The posterior fibers of the right and left temporalis muscles </li></ul><ul><li>2. deep heads of the right and left masseter muscles </li></ul>
  65. 82. Summary of Actions of the Muscles of Mastication <ul><li>Right Lateral Excursion </li></ul><ul><li>1. the right masseter </li></ul><ul><li>2. the right temporalis </li></ul><ul><li>3. the left medial pterygoid </li></ul><ul><li>4. the left lateral pterygoid </li></ul>
  66. 83. Summary of Actions of the Muscles of Mastication <ul><li>Left Lateral Excursion </li></ul><ul><li>1. the left masseter </li></ul><ul><li>2. the left temporalis </li></ul><ul><li>3. the right medial pterygoid </li></ul><ul><li>4. the right lateral pterygoid </li></ul>
  67. 84. The muscles of the eyeball
  68. 85. The Eye Muscles <ul><li>- Composed of the 7 muscles of the eye </li></ul><ul><li>- Lateral rectus is supplied by the Abducent N. </li></ul><ul><li>- Superior oblique is supplied by the Trochlear N. </li></ul><ul><li>- The rest is supplied by the Oculomotor N. </li></ul>
  69. 90. The muscles of the tongue
  70. 91. The Muscles of the Tongue <ul><li>Extrinsic muscles are responsible for changing position of the tongue. </li></ul>Muscle Action Genioglossus Retract and depress the tongue Hyoglossus Depress the tongue Styloglossus Pull the tongue upwards and backwards
  71. 93. The Muscles of the Tongue <ul><li>The Intrinsic Muscles: </li></ul><ul><ul><li>1. Superior and inferior longitudinal muscles </li></ul></ul><ul><ul><ul><li>Located close to the dorsum of the tongue </li></ul></ul></ul><ul><ul><ul><li>Shorten the length of the tongue and to curl the tip of the tongue and back. </li></ul></ul></ul><ul><ul><li>Transverse muscles </li></ul></ul><ul><ul><li>- narrows the tongue. </li></ul></ul><ul><ul><li>Vertical muscles </li></ul></ul><ul><ul><li>- flattens the tongue. </li></ul></ul>
  72. 95. A Summary of the Actions of the Tongue <ul><li>Protrussion : genioglossus </li></ul><ul><li>Retrussion : hyoglossus, styloglossus, genioglossus </li></ul><ul><li>Depression : genioglossus, hyoglossus </li></ul><ul><li>Elevation : styloglossus </li></ul><ul><li>Shortening : longitudinal intrinsic fibers </li></ul><ul><li>Narrowing : transverse intrinsic fibers </li></ul><ul><li>Flattening : vertical intrinsic fibers </li></ul>
  73. 96. The muscles of the soft palate
  74. 97. Muscles of the Soft Palate
  75. 98. Muscles of the Soft Palate Muscle Action Palatopharyn-geus Elevates the pharynx and larynx Closes the oropharyngeal isthmus Palatoglossus Closes the oropharyngeal isthmus Uvular Raises the uvula to help seal oral from nasal pharynx
  76. 99. Muscles of the Soft Palate Muscle Action Levator veli palatini Elevates palate during swallowing, yawning Tensor veli palatini Tenses the palate and opens the mouth of auditory tube during swallowing and yawning
  77. 100. Muscles of the Soft Palate
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