Muscles of Facial Expression & Muscles of Mastication - Tongue

MUSCLES PART A

2 groups-muscles of facial expression & muscles of mastication/tongue

Muscles of facial expression-insert into skin, nonverbal communication, innervated by cranial nerve 7 (facial nerve)

SCALP-epicranius (occipitofrontalis) has bipartite muscle with galea aponeurotica and a frontal/occipital belly

FACE-corrugator supercili zymomatius, risorius, levator labii superior, depressor labii inferior, depressor labii anguli oris, orbicularis oris, mentalis, buccinaor, platysma

Muscles of mastication-4 pairs, innervated by nerve 5 (trigeminal nerve)

Jaw closure-temporalis and macceter

Grinding-medial and lateral pterygoids

Chewing-buccinator

Muscles of tongue movement-innervated by cranial nerve 12 (hypoglossal)

-genioglossus

-hyoglossus

-styloglossus

Muscles of anterior neck and throat (swallowing)

1. Suprahyoid-4 deep muscles, move hyoid & larynx, form floor-oral cavity,anchor tongue

1. Infrahyoid- straplike muscles, depress hyoid and larynx

*synergists to head flexion*

Muscles of neck & vertebral column (head movement)

-sternocleidomastoid→head flexor, strap muscle of neck region

                              →sternocleidomastiod & scalenes-lateral head movement

                            →semispinalis capitis-synergist w/ sternocleidomastoid

                            →splenius capitis & cervicis portions-head extension, rotation, bending

*tranverse process(bumps on spine)-attachment of muscles

MUSCLES PART B

Muscles of thorax(breathing)

-muscles of respiration

-external intercoastals-superficial, elevate ribs for inspiration

-internal intercoastals-deep, aid forced expiration

-diaphragm→partition b/w thoracic & abdominal cavities, must important muscles in inspiration, innervated by phrenic nerves

Muscles of abdominal wall-4 pairs, fasciae/aponeuroses form lateral & interior abdominal wall

→rectus abdominis

→external oliques

→internal obliques

→transversus abdominis

Muscles of pelvic floor

→pelvis floor(diaphragm) has 2 muscles (levator ani & coccygeus) *both innervated by sacral nerves*

Functions: seals inferior outlet of pelvis, protects pelvis organs, lifes pelvic floor to release feces, resists increased intra-abominal pressure

Muscles of perineum

→urogenial diaphragm

-anterior half of perineium, inferior to pelvic floor

-deep transverse perineal muscle

-contains external urethral schincter(voluntary control of urination)