The Muscular System CH. 10 Part 2

Muscles of the Head and Face Important in facial expressions All but one innervated by CN VII (facial nerve) – Levator palpebrae superioris

Fig. 10.7a

Fig. 10.7b

Bell Palsy Idoipathic facial nerve paralysis Results from disease or injury to CN VII Treatments include steroids and antiviral medication DR P. MARAZZI/SCIENCE PHOTO LIBRARY

Muscles of the Neck forums.tigsource.com crossfitsouthbay.com

Neck Muscles Sternocleidomastoid – O – manubrium and medial part of clavicle – I – Mastoid process and lateral side of nuchal line – Action bilateral, flexion of head Unilateral, tilting head up and to side, rotating head. Digastric – O – mastoid notch of temporal bone, digastric fossa of mandible – I – hyoid bone – Action When hyoid fixed, opens mouth wide When mandible fixed, elevates hyoid Mylohyoid – O – Mylohyoid line near inferior margin of mandible – I – hyoid bone – Action Forms floor of mouth, elevates floor of mouth during initial phases of swallowing

Muscles of the Arm healthtwo.wikispaces.com m.eb.com

Muscles of the Arm Biceps Brachii – O – long head, sup. margin of glenoid cavity; short head, coracoid process – I – tuberosity of radius, fascia – Action Synergist in elbow flexion, supination of wrist Brachialis – O – anterior surface of distal humerus – I – Coronoid process and tuberosity of ulna – Action Prime mover in elbow flexion Triceps Brachii – O – Long head, inf. margin of glenoid cavity; lateral head, posterior surface of proximal end of humerus; medial head, posterior surface of humeral shaft – I – olecranon, fascia of forearm – Action Extends elbow, long head extends and adducts humerus

Muscles of the Forearm makeoverfitness.com britannica.com

Muscles of the Forearm Brachioradialis – O – lateral supracondylar ridge of humerus – I – Lateral surface of radius near styloid process – Action Flexes elbow

www2.brevard.edu

of_the_forearm_photo.htm of_the_forearm_photo.htm

Muscles of the Chest, Abdomen, and Back boddunan.com britannica.com

Muscles of the Back muscleblitz.com

Muscles of the Neck, Chest, and Back Trapezius – O – External occipital protuberance, medial third of superior nuchal line and nuchal ligament, spinous processes of vertebrae C7-T3 or T4 – I – acromion and spine of scapula, lateral third of clavicle – Action Extends and laterally flexes neck Stabilizes scapula and shoulder during arm movements Elevates and depresses apex of shoulders

Muscles of the Neck, Chest, and Back Erector spinae – Function to maintain posture and to help stand erect Bilateral contraction – extend vertebral column Unilateral contraction – lateral flexion of vertebral column – Organized into three groups Iliocostalis – Cervicis, thoracis, lumborum Longissimus – Capitis, cervicis, thoracis Spinalis – Capitis, cervicis, thoracis

Fig

Fig

Muscles of Neck, Chest, and Back Latissimus Dorsi – O – Vertebrae T7 – L5, lower 3-4 ribs, iliac crest, thoracolumbar fascia – I – Floor of intertubercular sulcus of humerus – Action Adducts and medially rotates humerus, extends shoulder joint, produces backward swing of arm Pectoralis major – O – Medial half of clavicle, costal cartilages 1-7, aponeurosis of external oblique – I – Lateral lip of intertubercular sulcus of humerus – Action Flexes, adducts, and medially rotates humerus

Muscles of the Legs ultimatepersonaltrainerstoolbox.com m.eb.com

Muscles of the Legs Rectus Femoris – O – Ilium at anterior inferior spine and superior margin of acetabulum, capsule of hip joint – I – patella, tibial tuberosity, lateral and medial condyles of tibia – Action Extends the knee, flexes thigh at hip, flexes trunk on hip of thigh is fixed Vastus Lateralis – O – greater trochanter and intertrochanteric line, gluteal tuberosity, and linea aspera – I – same as rectus femoris – Action Extends knee, retains patella during knee movements Vastus Medialis – O – Femur at intertrochanteric line, spiral line, linea aspera, and medial supracondylar line – I – Same as rectus femoris – Action Same as vastus lateralis Sartorius – O – on and near anterior superior spine of ilium – I – medial surface of proximal end of tibia – Action Aids in knee and hip flexion, abducts and laterally rotates thigh

Muscles of the Legs Biceps Femoris – O – Long head, ischial tuberosity; short head linea aspera and lateral supracondylar line of femur – I – head of fibula – Action Flexes knee, extends hip, laterally rotates femur when hip is extended Semitendinosis – O – ischial tuberosity – I – Medial surface of upper tibia – Action Flexes knee, medially rotates tibia on femor when knee is flexed, medially rotates femur when hip is extended Semimembranosus – O – Ischial tuberosity – I – medial condyle and margin of tibia, intercondylar line and lateral condyle of femur, ligament of popliteal region – Action Same as semitendinosus

Muscles of the Lower Leg health.com

Compartment Syndrome Limb muscles organized into compartments – Area of functionally related muscles, blood vessels and nerves surrounded by deep fascia If blood vessels damaged – Fluid can accumulate in compartment – Pressure build up results in degenerative events Nerve cell and muscle cell death result from ischemia Treatments – Resting and immobilizing limb – fasciotomy