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Skeletal muscles part 2. A few review questions. Muscles of the face originate in the skull. Where do they insert? The skin What is the strongest muscle associated with chewing? Masseter What muscle action allows you to whistle? Buccinator What muscle closes the eye? Orbicularis oculi.
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A few review questions • Muscles of the face originate in the skull. Where do they insert? • The skin • What is the strongest muscle associated with chewing? • Masseter • What muscle action allows you to whistle? • Buccinator • What muscle closes the eye? • Orbicularis oculi
Muscles of the spine • Covered by superfical back muscles • Erector spinae is chief extensor of vertebral column • Opposed by quadratus lumborum and various abdominal muscles Iliocostalis, spinalis, longissimus
Muscles of the trunk • Protect abdominal viscera • Move vertebral column • Assist in breathing (expiration) • Assist in urination and defection • Assist in childbirth
Muscles of trunk, continued • Muscles associated with breathing • Diaphragm • External and internal intercostals • Other muscles become involved with forced breathing
Diaphragm separates thorax and abdomen • Important for breathing • Returning venous blood to the heart • Three major openings • Aortic hiatus • Esophageal hiatus • Caval opening
Perineum: floor of pelvic cavity • Levator ani • Pubococcygeis, iliococcygeus • Coccygeus • Support organs in pelvic cavity • Resist pressure from coughing, urination, etc. • Sphincters
Female and male perimeum Deep muscles are the same
Appendicular muscles • Shoulders and upper limbs • Pectoral girdle: anterior and posterior thoracic muscles • Pelvic girdle and lower limbs
Muscles that position the pectoral girdle Muscles originate on axial skeleton and insert on clavicle or scapula
Muscles that move the arm Anterior Posterior
Range of movement at shoulder • Elevation of scapula- shrugging • Depression- pull-up • Abduction-push-up • Adduction- pulling something toward you • Upward rotation- lifting arm past horizontal • Downward rotation- supporting weight with hands • Deep muscles (rotator cuff) stabilize shoulder
Muscles that move the arm • Deltoid, supraspinatus-abduction • Rotator cuff-subscapularis, teres major (medial); infraspinatus, teres minor (lateral) • Latissimus dorsi-extension, adduction • Pectoralis major- flexion, adduction
Muscles of the upper limb • Most muscles that insert on the forearm and wrist originate on the humerus • Biceps brachii and triceps brachii originate on scapula • Brachoradialis is opposed on triceps brachii • Flexors of wrist are on anterior and medial surfaces of forearm; extensors are on posterior and lateral surface • Flexor digitorum and extensor digitorum muscles perform flexion and extension of fingers
Muscles that move arm and hand Arm Forearm
Muscles of the hip and lower limb • Muscles that move the thigh (p. 298) • Gluteal group • Lateral rotator group • Adductor group • Iliopsoas group • Muscles that move the leg (p. 303)(flexors, extensors) • Muscles that affect the ankles and feet (p. 312) (flexors, extensors, intrinsic)
Muscles that move the leg (lateral) lateral Major groups Flexors of knee Biceps femoris, semimembranosus, semitendinosus, sartorius, popliteus Extensors of knee Quadriceps (rectus femoris, vastus intermedius, vastus lateralis, vastus medialis)
Organization of leg muscles • Muscles are in compartments, superificial and deep • Anterior- extension • Posterior- flexion • Medial- adductor • Lateral- eversion of foot, flexion (ankle)
Compartments Formed by fascia; allow independent movement
Review compartments of upper limb (p. 314, 315) arm forearm
Summary • Extrinsic and intrinsic muscles in hand are important for fine motor skills • Muscles that move spine are complex in organization • Muscles that move femur and large and powerful • Compartments are associated with types of movement • Intrinsic muscles of foot are limited to support and movement