Muscles of Facial Expression & Muscles of Mastication – Tongue
MUSCLES PART A2 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 bellyFACE-corrugator supercili zymomatius, risorius, levator labii superior, depressor labii inferior, depressor labii anguli oris, orbicularis oris, mentalis, buccinaor, platysmaMuscles of mastication-4 pairs, innervated by nerve 5 (trigeminal nerve)Jaw closure-temporalis and macceterGrinding-medial and lateral pterygoidsChewing-buccinatorMuscles of tongue movement-innervated by cranial nerve 12 (hypoglossal) -genioglossus-hyoglossus-styloglossusMuscles of anterior neck and throat (swallowing)Suprahyoid-4 deep muscles, move hyoid & larynx, form floor-oral cavity,anchor tongueInfrahyoid- 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 BMuscles 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 nervesMuscles of abdominal wall-4 pairs, fasciae/aponeuroses form lateral & interior abdominal wall→rectus abdominis→external oliques→internal obliques→transversus abdominisMuscles 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 pressureMuscles of perineum→urogenial diaphragm -anterior half of perineium, inferior to pelvic floor-deep transverse perineal muscle-contains external urethral schincter(voluntary control of urination)