1 Myology Muscles of the Head

2 NAMING OF MUSCLES 1. Direction of muscle fibers: a. Rectus: fibers run parallel to the midline (rectus abdominis) b. Transverse: fibers run perpendicular to the midline (transverse abdominis) c. Oblique: fibers run diagonally to the midline (external oblique) 2. Location: a. named for a nearby bone: (frontalis) frontal bone b. position relative to a bone: (tibialis anterior) tibia c. section of a muscle having more than one part (anterior deltoid)

3 NAMING OF MUSCLES (cont) 3. Size: a. large muscle (gluteus maximus) b. small muscle (gluteus minimus) c. long muscle (extensor digitorum longus) d. short muscle (peroneus brevis) 4. Number of origins: a. two origins: biceps femoris b. three origins: triceps brachii c. four origins: pronator quadratus

4 NAMING OF MUSCLES (cont) 5. Shape: a. triangular: deltoid b. trapezoid: trapezius c. saw-toothed: serratus d. rhomboid or diamond shaped: rhomboids 6. Origin and Insertion: a. sternum, clavicle, and mastoid process: SCM

5 NAMING OF MUSCLES (cont) 7. Action: a. decreases an angle of a joint: flexor digitorum b. increases an angle of a joint: extensor carpi ulnaris c. moves bone away from midline: abductor pollicis brevis d. moves bone closer to midline: adductor longus e. upward movement: levator scapulae f. downward movement: depressor labii g. turns palm up or anteriorly: supinator h. turns palm down or posteriorly: pronator i. decreases size of an opening: external anal sphincter j. makes a body part more rigid: tensor fascia latae k. moves a bone around its longitudinal axis: rotator

6 Muscles of Head Overview Divided into 3 groups Muscles of the Scalp Muscles of the Face ( Eyes, Nose, and Mouth ) Muscles of Mastication

7 Muscles of the Head Overview Muscle of head are located superficially in the fascia and therefore move the fascia of the scalp and/or face. –Muscles of scalp move scalp, ears, eyebrows –Muscles of facial expression subdivided into muscles that move: Skin around eyes Skin around nose Skin around mouth –Muscles of mastication attach to mandible which is necessary for chewing i.e. mastication.

8 Muscles of Head Overview Innervation: –Muscles of scalp innervated by facial nerve (CNVII). –Muscles of facial expression innervated by facial nerve (CN VII) –Muscles of mastication innervated by trigeminal nerve (CN V).

9 Muscles of the Scalp Occipitofrontalis : – Can be considered 2 separate muscles the occipitalis and frontalis – Both attach into the galea aponeurotica Galea aponeurotica is broad flat tendon also known as the epicranial aponeurosis Temporoparietalis : – Also attaches into galea aponeurotica. – Degree of development varies; some people it is thin other it is non- existent. –Occipitofrontalis and temporoparietalis are known as the epicranius Auriculares : –One, two, or all three are nonfunctional in many people –Smallest is anterior auricularis, largest is posterior auricularis

10 O: Occipital & temporal bones I: Galea aponeurotica A: draws scalp posteriorly I: CN VII (Facial nerve) Occipitalis Palpation: page 15

11 O: Galea aponeurotica I: Fascia and skin superior to the eye and nose A: draws scalp anteriorly and elevates the eyebrows I: CN VII (Facial nerve) Frontalis Palpation: page 15

12 Temporoparietalis O: Fascia superior to ear I: Lateral border of galea aponeurotica A: Elevates ear and Tightens the scalp N: CN VII (Facial nerve) Palpation: page 18

13 Auricularis O: Anterior: anterior fascia of the ear Superior: lateral margin of the galea aponeurotica Posterior: temporal bone I: Anterior: Spine of helix Superior: Superior aspect of cranial surface of the ear Posterior: Posterior ear A: Anterior: draws ear anteriorly Superior: elevates ear Posterior: draws ear posteriorly N: CN VII (Facial nerve) Palpation: page 20