Skeletal Muscles: Head, Neck and Trunk Muscles 10-1

Muscles of the Neck 10-2 Fig Anterolateral Neck Muscles Sternocleidomastoid One or both may contract Posterior Neck Muscles Trapezius Fig Mylohyoid Sternocleidomastoid Trapezius Geniohyoid Hyoid bone Clavicle Semispinalis capitis (cut) Splenius capitis (cut) Sternocleidomastoid Splenius capitis Levator scapulaeDeepDeeper

Muscles of Facial Expression 10-3 Fig Elevators Levator labii superioris, Occipitofrontalis, Zygomaticus Depressors Depressor labii inferioris, Platysma Other actions Buccinator, Orbicularis oculi, Orbicularis oris Frontal belly of occipitofrontalis Orbicularis oculi Levator labii superioris Zygomaticus Depressor labii inferioris Platysma Depressor labii inferioris Orbicularis oris Zygomaticus Levator labii superioris Orbicularis oculi Temporalis Masseter Orbicularis oris Buccinator

Muscles of Facial Expression 10-4 Elevators Levator labii superioris, Occipitofrontalis, Zygomaticus Depressors Depressor labii inferioris, Platysma Other actions Buccinator, Orbicularis oculi, Orbicularis oris

Muscles of Facial Expression 10-5 Fig. 11.3

Muscles of Mastication 10-6 Major Muscles Temporalis and Masseter Temporalis: Origin - temporal lines of parietal Insertion - coronoid process Masseter: Origin - zygomatic arch Insertion - lateral side of mandible Fig. 11.5

Hyoid Muscles 10-7 Actions of hyoid muscles: move mandible and hyoid Fig Mylohyoid Digastric Anterior belly Posterior belly Geniohyoid Hyoid bone Clavicle Mylohyoid Digastric Anterior belly Posterior belly

Trunk Muscles - Muscles of Vertebral Column 10-8 Fig Superficial: Erector spinae (Iliocostalis, Longissimus, Spinalis), Semispinalis, and Multifidus Deep: Interspinalis Actions: Extension, rotation, lateral flexion of the back Multifidus Iliocostalis Longissimus Spinalis Erector spinae DeepDeeper Semispinalis

Muscles of Respiration 10-9 Fig Inspiration: Diaphragm is primary muscle of inspiration (depresses floor of thoracic cavity) External intercostals elevate ribs Expiration: Internal intercostals depress ribs

Trapezius Extend Head, Adduct, Elevate or Depress Scapula

Latissimus Dorsi Extend, Adduct & Rotate Arm Medially

Deltoid Abduct, Flex & Extend Arm

Pectoralis Major Flexes, adducts & rotates arm medially

Biceps Brachii Flexes Elbow Joint

Triceps Brachii Extend Elbow Joint

Rectus Abdominus Flexes Abdomen

External Oblique Compress Abdomen

Forearm Muscles Flexor carpi—Flexes wrist Extensor carpi—Extends wrist Flexor digitorum—Flexes fingers Extensor digitorum—Extends fingers Pronator—Pronates Supinator—Supinates

Gluteus Maximus Extends & Rotates Thigh Laterally

Rectus Femoris Flexes Thigh, Extends Lower Leg

Gracilis Adducts and Flexes Thigh

Sartorius Flexes Thigh, & Rotates Thigh Laterally

Biceps Femoris Extends Thigh & Flexes Lower Leg

Tibialis Anterior Dorsiflexes and Inverts Foot

Gastrocnemius Plantar Flexes Foot & Flex Lower Leg

Big Picture Function of all three major types of muscle (skeletal, cardiac, smooth) is integral to function of the entire body All three types of muscle tissue provide the movement necessary for survival Relative constancy of the body’s internal temperature is maintained by “waste” heat generated by muscle tissue 10-26