Axial Muscles

Skeletal Muscles Attach directly to bone Exceptions?  diaphragm and tongue How does muscle contraction work? https://www.youtube.com/watch?v=yiWgd-fnp2s

What are the axial muscles? Muscles that attach to the axial skeleton Include: muscles of the head, neck, vertebral column, abdomen, & pelvis Key terms: Action Origin vs. Insertion Agonist vs. Anatagonist Synergists Pulling force ONLY

MUSCLES OF THE HEAD & NECK

Muscles of Facial Expression Associated with mouth, eyes, nose, ears, scalp, and neck Attachments (one or both) or not to bone but to skin!

Scalp – aka Epicranium Epicranial aponeurosis Occipitofrontalis muscle Consists of a frontal belly and occipital belly Separated by a flat sheet of connective tissue: epicranial aponeurosis Actions: Frontal belly – wrinkling forehead, raising the eyebrows, and pulling scalp forward Occipital belly – tenses / relaxes the scalp

Ear Temporoparietalis Action: tense the scalp and move the ear flap

Eye Corrugator supercilii Orbicularis oculi Corrugator supercili Action: closes the eye Corrugator supercili Action: pull the skin downward and wrinkle the forehead into a frown Levator palpebrae superioris Action: “elevates” the upper eyelid Orbicularis oculi

Nose Procerus - vertical Nasalis - horizontal Action: limited movement / muscles change the shape of nostrils

Mouth Buccinator Orbicularis oris Depressor anguli oris Action: compresses the cheeks when you are eating Orbicularis oris Action: shapes the lips for speech, food manipulation, expression Depressor anguli oris Action: depress the corners of the mouth Levator labii superioris Action: elevates the upper lips Depressor labii inferioris Action: depresses the lower lip Mentalis Action: elevates and protrudes the lower lip Risorius Action: produces grimace-like tensing of the mouth Associates with pain expression Clinical applications with tetanus: lockjaw Zygomaticus major / Zygomaticus minor Originate on the zygomatic bone and insert on the corners of the mouth Action: elevate the corners of your mouth when you smile

Identify… Levator labii superioris Zygomaticus minor Orbicularis oris Zygomaticus major Mentalis Depressor labii inferioris Buccinator Depressor anguli oris

Neck Platysma Action: lowers the mandible and results in an expression of horror and digust!

M. L. A. K. J. I. B. H. C. G. F. E. D. Orbicularis oculi Orbicularis oris Platysma Mentalis Depressor labii inferioris Depressor anguli oris Buccinator Risorius Zygomaticus major Zygomaticus minor Levator labii superioris Occipitofrontalis (front belly) Epicranius aponeurosis H. C. G. F. E. D.

Muscles of the Eye Oculomotor / Extrinsic / Extraocular muscles – move the eyeballs Insert on the sclera (the white part of the eye) Intrinsic eye muscles – involved in focusing the eye for vision

Muscles of Mastication – aka “chewing” Muscles depress and elevate the mandible to open and close the jaws Masseter Temporalis Lateral / Medial pterygoid

Muscles of the Tongue Root word for each tongue muscle – glossus, (“tongue” in Greek) Genioglossus Action: depresses and protracts the tongue (e.g. licking ice cream) Hypoglossus Action: depresses and retracts the tongue Palatoglossus Action: elevates the tongue / depresses the palate Styloglossus Action: retracts the tongue / elevates the sides

Muscles of the Neck (Anterior) Principal muscle: sternocleidomastoid Suprahyoid muscles (act to elevate the hyoid bone) Digastric muscle  anterior / posterior belly Mylohyoid Geniohyoid Stylohyoid Infrahyoid muscles (act to depress the hyoid bone and larynx) Omohyoid Sternohyoid Sternothyroid Thyrohyoid

Anterior belly Mylohyoid Stylohyoid Posterior belly Digastric Hyoid bone Superior bely Stylohyoid cut Sternothyroid Thyrohyoid Omohyoid Sternocleidomastoid Inferior belly Sternohyoid

https://www. youtube. com/watch https://www.youtube.com/watch?v=3Z0nbAm2HPw&index=2&list=PLFC6EDFB29AA50FAC

MUSCLES OF THE VERTEBRAL COLUMN, ABDOMEN, AND PELVIS

Muscles of the Vertebral Column Organized into superficial, intermediate, and deep layers Extensor muscle vs. Flexor muscle Terminology to keep in mind: Capitis (skull) Cervicis (neck) Thoracis (thoracic vert.) Lumborum (lumbar vert.)

Superficial Layer – Vert. Column Splenius capitis muscle Splenius cervicis muscle

Intermediate Layer – Vert. Column ERECTOR SPINAE GROUPS Spinalis cervicis Spinalis thoracis Longissimus capitis Longissimus cervicis Longissimus thoracis Iliocostalis cervicis Iliocostalis thoracis Iliocostalis lumborum

Spinalis Longissimus Iliocostalis

Spinal Flexors – Vert. Column (Anterior/Lateral) Longus capitis Longus colli – limit extension Quadratus lumborum

Oblique & Rectus Muscles Slanted relative to the body’s vertical axis Support the vertebral column, move ribs during respiration, make up the abdominal wall Also…increase intra-abdominal pressure during urination, defecation, and childbirth

Oblique Muscles – Vert. Scalene muscles  anterior, middle, and posterior Originate on the transverse process of a C vertebrae and insert on a 1st or 2nd rib Intercostal muscles  external, internal, transversus Muscles of the thoracic region Located between ribs and along diaphragm Change the size of the chest for breathing Serratus muscles  superior, posterior / inferior, posterior Insert on the ribs and assist the intercostal muscles in moving the rib cage Superior: elevates the rib cage Inferior: depresses the rib cage

Oblique Muscles – Vert. Serratus posterior superior Serratus posterior inferior

Oblique Muscles- Abdominal Region Linea Alba Tendinous inscriptions External oblique muscle – compress/flex the abdomen, depress ribs, rotate vertebral column Internal oblique muscle - compress/flex the abdomen, depress ribs, rotate vertebral column Transversus abdominis muscle – compress the abdomen **NOTICE THE ORIENTATION OF THE FIBERS**

Muscles of the Pelvic Region Form bowl that supports the organs of the reproductive and digestive systems Pelvic diaphragm – flex the coccyx muscle and tense the pelvic floor Coccygeus muscle Originates on ischial spine and inserts on lateral / inferior borders of the sacrum Levator ani muscle Originates on the inside edge of the pubis and ischeal spine and inserts on the coccyx Elevates / retracts the anus

REVIEW

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