1. Chapter 11 *Lecture Outline
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2. Chapter 11 Outline Muscles of the Head and Neck
Muscles of the Vertebral Column
Muscles of Respiration
Muscles of the Abdominal Wall
Muscles of the Pelvic Floor

3. Axial Muscles
Axial muscles have both their origins and insertions on parts of the axial skeleton.
Axial muscles support the head and spinal column.
Axial muscles are used in facial expression, chewing, and swallowing.
Axial muscles aid in breathing and support and protection of the abdominal and pelvic organs.

4. Five Groups of Axial Muscles
Muscles of the head and neck
Muscles of the vertebral column
Muscles of respiration
Muscles of the abdominal wall
Muscles of the pelvic floor

5. Figure 11.1

6. Figure 11.1

7. Muscles of Facial Expression
These muscles have their origin in the superficial fascia or on the skull. They insert into the superficial fascia of the skin.
When they contract they contort the skin thereby causing changes in facial expression.
Most of these muscles are innervated by cranial nerve VII (CN VII), the facial nerve.

8. Muscles of Facial Expression
Figure 11.2

10. Figure 11.3

11. Muscles of Facial Expression
Buccinator—compresses the cheek against the teeth when we eat to keep food from getting into the vestibule. It is also the muscle of suckling. It is used to compress air in the oral cavity to play a wind instrument.

12. Muscles of Facial Expression
Figure 11.2

13. Muscles of Facial Expression

14. Muscles of Facial Expression—continued

15. Extrinsic Eye Muscles Six muscles move the eye
Originate from a common tendinous ring in the posterior orbit and attach onto the anterior sclera (outer surface) of the eye
Figure 11.4

16. Extrinsic Eye Muscles
The six extrinsic eye muscles, innervation, and movement of the eye are:
Medial rectus (CN III) pulls eye medially
Lateral rectus (CN VI) pulls eye laterally
Inferior rectus (CN III) pulls eye inferiorly
Superior rectus (CN III) pulls eye superiorly
Inferior oblique (CN III) elevates and turns eye laterally
Superior oblique (CN IV) depresses and turns eye laterally

17. Extrinsic Eye Muscles

18. Muscles of Mastication
All are innervated by CN V3.
Temporalis—elevates and retracts the mandible (pulls posteriorly)
Masseter—elevates and retracts the mandible (pulls anteriorly)
Lateral and medial pterygoids—protract and move the mandible from side to side while chewing

19. Muscles of Mastication
Figure 11.5

20. Muscles of Mastication

21. Muscles That Move the Tongue
The tongue is comprised of intrinsic muscles that curl, squeeze, and fold the tongue.
The extrinsic muscles attach to the tongue and cause the tongue to perform other movements such as protraction, retraction, depression, and elevation.

22. Extrinsic Tongue Muscles
Genioglossus—protracts (sticks out) tongue
Styloglossus—elevates and retracts tongue
Hyoglossus—depresses and retracts tongue
Palatoglossus—elevates posterior part of tongue

23. Extrinsic Muscles of the Tongue
Figure 11.6

24. Palatoglossus
Styloglossus
Genioglossus
Hyoglossus 24

25. Extrinsic Muscles of the Tongue

26. Muscles of the Pharynx
The pharynx, commonly called the “throat” is a funnel-shaped tube that lies posterior to and extends inferiorly from the oral and nasal cavities.
Several muscles help form this muscular tube or attach to it and aid in swallowing.
Most of these muscles are innervated by CN X.

27. Muscles of the Pharynx
The primary pharyngeal muscles are the superior, middle, and inferior constrictor muscles.
When a bolus of food enters the pharynx, these three muscles contract sequentially to initiate swallowing.

28. Muscles of the Pharynx
Figure 11.7

29. Muscles of the Pharynx

30. Muscles of the Anterior Neck
Muscles of the anterior neck are divided into the suprahyoid and infrahyoid muscles.
Suprahyoid muscles are superior to the hyoid bone.
Infrahyoid muscles are inferior to the hyoid bone.

31. Suprahyoid Muscles
All of these muscles elevate the hyoid bone during swallowing. They are as follows:
Digastric
Geniohyoid
Mylohyoid
Stylohyoid

32. Suprahyoid Muscles
Figure 11.8

33. Infrahyoid Muscles
All of these muscles depress the hyoid bone during swallowing. They are as follows:
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid

34. Infrahyoid Muscles
Figure 11.8

35. Muscles of the Anterior Neck

36. Muscles That Move the Head and Neck
Anterolateral muscles—flex the head and/or neck
Posterior muscles—extend head and/or neck

37. Anterolateral Neck Muscles
Sternocleidomastoid muscles are the major muscles of this compartment.
Upon bilateral contraction, they cause flexion of neck.
Upon unilateral contraction, they cause lateral flexion and rotation of head to the opposite side.

38. Sternocleidomastoid Muscle
Figure 11.9

39. Posterior Neck Muscles
Posterior muscles extend the head and/or neck when they contract bilaterally. When they contract unilaterally they turn the head and neck to the same side. The major muscles in this compartment are:
Splenius capitis
Splenius cervicus
Semispinalis capitis
Longissimus capitis

40. Posterior Neck Muscles
Figure 11.10

41. Muscles of the Vertebral Column
There are two major groupings of muscles that are responsible for movement of the vertebral column:
Erector spinae—maintain posture, help to stand erect; bilateral contraction extends the spinal column and unilateral contraction flexes the column laterally
Transversospinalis—minor deep back muscles, deep to the erector spinae; connect and stabilize the vertebrae

42. Erector Spinae
The erector spinae muscles are organized into three groups:
Iliocostalis—most lateral group comprised of cervical, thoracic, and lumbar parts
Longissimus—comprised of capitis, cervical, and thoracic parts
Spinalis—most medial group inserting onto the spinous process of vertebrae, comprised of cervical and thoracic parts

43. Erector Spinae Muscles
Figure 11.11

44. Transversospinalis Muscles
Figure 11.12

45. Quadratus Lumborum A muscle that also moves the vertebral column
Bilateral contraction causes extension of spinal column
Unilateral contraction laterally flexes vertebral column

46. Muscles of the Vertebral Column

47. Muscles of the Vertebral Column—continued

48. Muscles of Respiration
These muscles are involved in inhalation and exhalation:
Serratus posterior superior—elevates ribs during inhalation
Serratus posterior inferior—depresses ribs during exhalation
External intercostals—elevates ribs during inhalation
Internal intercostals—depresses ribs during forced exhalation
Transverse thoracis —depresses ribs during exhalation
Diaphragm—the major muscle of respiration

49. Muscles of Respiration
Figure 11.13

50. Diaphragm
Internal dome-shaped muscle that physically separates the thoracic and abdominopelvic cavities
Possesses a central tendon onto which all of its fibers converge
Contraction of diaphragm causes a depression of the muscle thus increasing the vertical dimensions of the thoracic cavity

51. Diaphragm
Figure 11.13

52. Muscles of Respiration

53. Muscles of the Abdominal Wall
Four anterolateral muscles collectively compress and hold the abdominal organs in place. They also flex the vertebral column.
External oblique—most superficial lateral muscle; directed inferomedial
Internal oblique—middle of the three lateral muscles; directed at right angle to the external oblique
Transverse abdominis—deepest of three lateral muscles; directed horizontally
Rectus abdominis—anterior muscle connecting the sternum to the pubic bone; divided into four muscle segments

54. Muscles of the Abdominal Wall
Figure 11.14

55. Muscles of the Abdominal Wall
Figure 11.14

56. Muscles of the Abdominal Wall

57. Muscle Actions on the Axial Skeleton

58. Muscles of the Pelvic Floor
This structure consists of three layers of muscles known as the pelvic diaphragm. These muscles participate in the following functions:
support of the pelvic organs
control of defecation
control of urination
reproductive processes, such as erection and ejaculation

59. Triangles of the Pelvic Floor
The diamond-shaped region between the lower extremities is called the perineum.
If you draw a line between the two ischeal tuberosities, you have divided that diamond-shaped area into two triangles:
Urogenital triangle—anterior triangle; contains external genitalia and urethra
Anal triangle—posterior triangle; contains the anus

60. The Axial Musculature
Muscles of the Pelvic Floor- Perineum (Female)

61. The Axial Musculature
Muscles of the Pelvic Floor- Perineum (Male)

62. Triangles of the Pelvic Floor
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Sacrum
Sacroiliac articulation
Ilium
Coccyx
Piriformis
Coccygeus
Ischial spine
Obturator internus
Anal canal
Iliococcygeus
Levator
ani
Vagina
Pubococcygeus
Urethra
Obturator canal
Urogenital diaphragm
Pubic symphysis
(a) Female, superior view
Raphe
Pubic symphysis
Urogenital
triangle
Bulbospongiosus
Pubic ramus
External urethral
sphincter
Ischiocavernosus
Superficial transverse
Perineal muscle
Urethra
Deep transverse
perineal muscle
Perineal body
Anus
Anal
triangle
Levator ani
External anal
sphincter
Gluteus maximus
Superficial
Deep
(b) Male, inferior view
Pubic symphysis
Urethra
Pubic ramus
Urogenital
triangle
Vagina
sphincter
External urethral
Bulbospongiosus
Ischiocavernosus
Urethra
Vagina
perineal muscle
Superficial transverse
Deep transverse
perineal muscle
Perineal body
Levator ani
Anus
Figure 11.15
Anal
triangle
External anal
sphincter
Gluteus maximus
Superficial
Deep
(c) Female, inferior view

63. Muscles of the Pelvic Floor Triangles

64. Muscles of the Pelvic Floor Triangles—continued