MUSCLES OF HEAD, NECK & TRUNK

 

I.  MUSCLES OF FACIAL EXPRESSION

A.  Epicranius: two muscles and an aponeurosis (galea aponeurotica)

1.  Frontalis: elevates eyebrows and wrinkles forehead

2.  Occipitalis: draws scalp backward

B.  Orbicularis Oculi:

C.  Orbicularis Oris: closes and puckers lips (kiss)

D.  Zygomaticus Major:
                            

E.  Depressor Anguli Oris: depresses corner of mouth (frown)

F.  Buccinator: pulls cheeks against teeth when chewing

G.  Platysma:

 


 

II.  MUSCLES OF MASTICATION (= Chewing)

A.  Masseter:  elevates mandible

B.  Temporalis: elevates and retracts mandible

C.  Medial and Lateral Pterygoids:


 

III.  MUSCLES OF THE TONGUE       

A.  Genioglossus: protracts (protrudes) and depresses tongue                                               

B.  Styloglossus:

C.  Hyoglossus: depresses sides of tongue

 

 

IV.   NECK MUSCLES

A.  Lateral Neck Muscle

1.  Sternocleidomastoid:




B.  Posterior Neck Muscle

1.  Splenius Capitus: each rotates head to one side, together: extend the neck/head

 

 

C.  Anterior Neck Muscles

1.  Suprahyoid muscles

a.  Digastric: elevates hyoid and depresses mandible

b.  Stylohyoid:

c.  Mylohyoid: elevates hyoid and raises floor of mouth

d.  Geniohyoid:

2.  Infrahyoid muscles

a.  Sternohyoid: depresses hyoid

b.  Omohyoid:

c.  Sternothyroid: depresses thyroid cartilage

d.  Thyrohyoid:

 

 


V.  BACK MUSCLES

A.  Superficial Back Muscles

(These will be covered with the upper extremity!)

B.  Deep Back Muscles (Muscles of the vertebral column)

1.  Quadratus Lumborum:



2.  Erector Spinae

a.  Extend the vertebral column

b.  Consists of:

i.  Iliocostalis:

ii.  Longissimus:

iii.  Spinalis:

 

VI. THORAX MUSCLES

A.  Superficial Thorax Muscles (These will be covered with the upper extremity)


B.  Deep Thorax Muscles

1.  Diaphragm: contraction pulls the central portion down, increasing vertical dimensions of thorax

2.  External Intercostals:

 

3.  Internal Intercostals:

 

4.  Scalenes: elevates ribs during inspiration

 

 

VII. ABDOMINAL MUSCLES

A.  As a group, they compress the abdominal contents and flex the vertebral column

1.  External Abdominal Oblique:

2.  Internal Abdominal Oblique:

3.  Transversus Abdominis:

4.  Rectus Abdominis:

 

VIII.  MUSCLES OF THE PELVIC FLOOR AND PERINEUM

A.  Known as the “pelvic diaphragm” or “urogenital diaphragm”

1.  Closes inferior opening of pelvis

2.  Supports the pelvic organs

 

 

Which of the following elevates the hyoid bone?

a.                 Sternohyoid

b.                 Sternothyroid

c.                  Omohyoid

d.                 Thyrohyoid

e.                  Mylohyoid