Lecture 15: Muscular System I (Head+Neck)

Question 1

How are muscles names?

Answer 1

Shape: rhomboid, deltoid, trapezius

Location: pectoralis, intercostal

Attachments: SCM

Heads: biceps brachii, quadriceps femoris

Fxn: extensor, erector

Direction of fibres: transversus abdominis

Size: gluteus maximus

Question 2

what is origin vs insertion of muscle

Answer 2

Origin-attachment of muscle that remains stationary

Insertion- attachment of muscle that moves

Question 3

what are the superficial muscles of head

Answer 3

3 divisions- orbital, nose, oral

Occipital belly: skin back of head. attached to other belly by Epicranial Aponeurosis

Occipitifrontalis (epicranius)- made of occipital and frontal belly. frontal lifts eyebrows

orbicularis oculi: surrounds orbit, closes eyelids. keeps nasolacrimal duct open

Nasalis: joins contraleateral muscle, forms bridge. compresses onse/widen nostrils (for breathing)

orbicularis oris: oral cavity. attachs to upper and lower jaw. makes core of lips.

Question 4

masseter

Answer 4

deep muscle of face

originates from zygomatic arch.
inserts to lateral ramus of mandible.

CNV (mandibular division)

Question 5

label and explain

Answer 5

ALL DEEP MUSCLES

middle: temporalis. coronoid process of mandible is insertion point

bottom left: medial pterygoid. deep in mandible, arise from pterygoid process of sphenoid. inserts into medial surface of ramus. vertical fibres, therefore elevats mandible

right: lateral pterygoid. pulls mandible forward (protractio). horizontal fibres

Question 6

label and explain

Answer 6

left=optic nerve

middle= levator palpebrae superioris. lifts upper eyelid. ***only muscle with dual nerve supply: CNIII and Sympathetic. fibres from TI

right: extraoccular muscles (innervated by CNIII, IV, VI)

Question 7

label and explain

Answer 7

A: Palatal Muscles: sit in soft palate. contract & elevate palate to prevent food getting into nose (aid in swallowing). supplied by CNX

B: Laryngeal elevators: lift up pharynx (attached to larynx) to prevent food entering

C: Pharyngeal constrictors: push down bolus

Question 8

which nerve supplies muscles of pharynx?

Answer 8

CNX

Question 9

what is the pharynx

Answer 9

muscular tube, 10 cm

base of skull to 6th cervical vertebrae, where it is continuous with esophagus

Question 10

what is the larynx

Answer 10

airway passageway

Question 11

label and explain

Answer 11

A: Styloid Process
B: Intrinsic tongue muscle: both attachments in tongue
C: Mandible
D: Extrinsic tongue muscles: originate outside tongue (i.e. mandible, temporal)
E: Hyoid bone

Question 12

how many muscles are in tongue? which CN are they innervated by?

Answer 12

19
CNXII

Question 13

what is the fxn of intrinsic laryngeal muscles?

Answer 13

change tension of vocal cords
change pitch by changing position of cartilage

CNX

Question 14

Answer 14

intrinsic laryngeal muscles

Question 15

label and explain innervation

Answer 15

A: Suprahyoid muscles: innervated by CNV, VII

B: hyoid bone

C: infrahyoid muscles: innervated by Ansa Cervicalis

D: SCM: Innervated by CNXI

Question 16

what are the superficial muscles of the neck? fxn

Answer 16

suprahyoid: btw hyoid and mandible. opens jaw, only hpapens if hyoid is stable

infrahyoid: stabilizes hyoid by pulling it down. btw sternum, scapula, and hyoid

SCM: bends neck to shoulder (unilateral contractioN) and rotates head contraleterally

Question 17

SCM fxn

Answer 17

unilateral contraction- turns face contralaterally

bilateral contraction= flexion of neck

(SCM injured in whiplash)

Question 18

what muscles are these? are they deep or superficial

Answer 18

scalenes

deep muscles

3 pairs.
original insertion is transverse process of cervical vertebrae. insert into rib 1 and 2

fxn= elevate first two ribs.
“accessory respiratory muscles”. helps with inspiration

innervated by brachial plexus branches