Muscles of the Head, Neck, and Face

Ppt # 8

10-2

Muscles of Facial Expression• muscles that insert in the dermis and

subcutaneous tissues

• tense the skin and produce facial expressions

• innervated by facial nerve (CN VII)

• paralysis causes face to sag

• found in scalp, forehead, around the eyes, nose and mouth, and in the neck

10-3

Muscles in Facial Expression

Figure 10.7a

Frontalis

Galea aponeurotica

Orbicularis oculi

Platysma

(a) Anterior view

Mentalis (cut)

Orbicularis oris

MasseterZygomaticus minor

Levator labii superioris

Zygomaticus major

Risorius

Depressor anguli oris

Depressor labii inferioris

Nasalis

Corrugator supercilii

Buccinator

Modiolus

Levator anguli oris

Superficial Deep

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10-4

Muscles in Facial Expression

Frontalis (cut)Galea aponeurotica

Orbicularis oculi

Sternohyoid

Orbicularis oris

Occipitalis

OmohyoidSternothyroid

Inferior pharyngealconstrictor

Sternocleidomastoid

Masseter

Thyrohyoid

Zygomatic archLevator labii superioris

Zygomaticus minor

Zygomaticus major

Depressor labiiinferiorisDepressor anguli orisBuccinator

Risorius (cut)

Nasalis

Corrugator supercilii

Mentalis

Levator scapulae

(b) Lateral view

Modiolus

Temporalis

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Figure 10.7b

10-5

Muscles of Chewing and Swallowing• extrinsic muscles of the tongue

– tongue is very agile organ– pushes food between molars for chewing (mastication)– forces food into the pharynx for swallowing (deglutition)– crucial importance to speech

• intrinsic muscles of tongue– vertical, transverse, and longitudinal fascicles

Figure 10.8

Genioglossus

Styloglossus

Palatoglossus

Posterior belly of digastric (cut)

Stylohyoid

Superior pharyngeal constrictor (cut)

Middle pharyngeal constrictor

Inferior pharyngeal constrictor

Hyoglossus

Hyoid bone

Styloid process

Mastoid process

Mylohyoid (cut)

Geniohyoid

Esophagus

Inferior longitudinalmuscle of tongue

Larynx

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Trachea

10-6

Muscles of Chewing• four pairs of muscles produce the

biting and chewing movements of the mandible– depression – to open mouth– elevation – biting and grinding– protraction – incisors can cut– retraction – make rear teeth meet– lateral and medial excursion – grind

food

• temporalis, masseter, medial pterygoid, lateral pterygoid

• innervated by mandibular nerve which is a branch of the trigeminal (V)

Figure 10.9

Temporalis

Orbicularis oris

Masseter (cut)

(a) Lateral view

Buccinator

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(b) Posterior view

Medial pterygoid muscle

Medial pterygoid plate

Lateral pterygoid plate

Interior of oral cavity

Lateral pterygoid muscle

10-7

Hyoid Muscles – Suprahyoid Group• aspects of chewing, swallowing, and vocalizing• eight pairs of hyoid muscles associated with hyoid bone • digastric - opens mouth widely• geniohyoid – depresses mandible• mylohyoid – elevates floor of mouth at beginning of swallowing• stylohyoid – elevates hyoid

Figure 10.10a

Levator scapulae

Sternocleidomastoid

Digastric:Anterior bellyPosterior belly

StylohyoidMylohyoid

SternohyoidOmohyoid:

Suprahyoidgroup

Infrahyoidgroup

(a) Anterior view

Hyoid boneCommon carotid arteryInternal jugular vein

Clavicle

Thyrohyoid

Superior bellyInferior belly

Superficial Deep

InfrahyoidgroupSternothyroid

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10-8

Hyoid Muscles – Infrahyoid Group• fix hyoid bone from below…allowing suprahyoid muscles to open

mouth • omohyoid – depresses hyoid after elevation• sternohyoid – depresses hyoid after elevation• thyrohyoid – depresses hyoid and elevates larynx• sternothyroid – depresses larynx after elevation

Figure 10.10a

Levator scapulae

Sternocleidomastoid

Digastric:Anterior bellyPosterior belly

StylohyoidMylohyoid

SternohyoidOmohyoid:

Suprahyoidgroup

Infrahyoidgroup

(a) Anterior view

Hyoid boneCommon carotid arteryInternal jugular vein

Clavicle

Thyrohyoid

Superior bellyInferior belly

Superficial Deep

InfrahyoidgroupSternothyroid

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10-9

Muscles of Pharynx

• three pairs pharyngeal constrictors – encircle pharynx forming a muscular funnel– during swallowing drive food into the esophagus

Figure 10.8

Genioglossus

Styloglossus

Palatoglossus

Posterior belly of digastric (cut)

Stylohyoid

Superior pharyngeal constrictor (cut)

Middle pharyngeal constrictor

Inferior pharyngeal constrictor

Hyoglossus

Hyoid bone

Styloid process

Mastoid process

Mylohyoid (cut)

Geniohyoid

Esophagus

Inferior longitudinalmuscle of tongue

Larynx

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Trachea

Muscles Acting on the Head• originate on the vertebral column, thoracic cage, and pectoral girdle• insert on the cranial bones• actions

– flexion (tipping head forward)– extension (holding the head erect)– lateral flexion (tipping head to one side)– rotation (turning the head to the left and right)

• may cause contralateral movement – movement of the head toward the opposite side

• may cause ipsilateral movement – movement of the head toward the same side

• neck flexors– sternocleidomastoid– scalenes

• neck extensors– trapezius– splenius capitis– semispinalis capitis

10-10

10-11

Triangles of the Neck

Figure 10.11Sternocleidomastoid

Anterior trianglesA1. MuscularA2. CarotidA3. SubmandibularA4. Suprahyoid

Posterior trianglesP1. OccipitalP2. Omoclavicular

A2A3A4

A1P1

P2

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© The McGraw-Hill Companies, Inc./Joe DeGrandis, photographer