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Copyright © 2010 Pearson Education, Inc. Chapter 10 The Muscular System Part B Shilla Chakrabarty, Ph.D.

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Presentation on theme: "Copyright © 2010 Pearson Education, Inc. Chapter 10 The Muscular System Part B Shilla Chakrabarty, Ph.D."— Presentation transcript:

1 Copyright © 2010 Pearson Education, Inc. Chapter 10 The Muscular System Part B Shilla Chakrabarty, Ph.D.

2 Copyright © 2010 Pearson Education, Inc. Muscles of the Thorax Muscles of respiration External intercostals—more superficial muscles that elevate ribs for inspiration Internal intercostals—deeper muscles that aid forced expiration Diaphragm Partition between thoracic and abdominal cavities Most important muscle in inspiration Innervated by phrenic nerves

3 Copyright © 2010 Pearson Education, Inc. Figure 10.10a External intercostal (a) Internal intercostal

4 Copyright © 2010 Pearson Education, Inc. Figure 10.10b Foramen for esophagus Costal cartilage Lumbar vertebra Xiphoid process of sternum Diaphragm Quadratus lumborum Psoas major Foramen for inferior vena cava Central tendon of diaphragm Foramen for aorta 12th rib (b)

5 Copyright © 2010 Pearson Education, Inc. Muscles of the Abdominal Wall Four paired muscles; their fasciae and aponeuroses form the lateral and anterior abdominal wall Muscles that flex vertebral column and compress abdominal wall are: Internal obliques External obliques Transversus abdominis Rectus abdominis Origin Pubic crest and symphysis Insertion Xiphoid process and costal cartilage of ribs 5-7 Function Flex and rotate lumbar region of vertebral column

6 Copyright © 2010 Pearson Education, Inc. Figure 10.11a Transversus abdominis Internal oblique External oblique Aponeurosis of the external oblique (a) Pectoralis major Linea alba Tendinous intersection Rectus abdominis Inguinal ligament (formed by free inferior border of the external oblique aponeurosis) Serratus anterior

7 Copyright © 2010 Pearson Education, Inc. Muscles of the Abdominal Wall Fascicles of these muscles run at angles to one another, providing added strength All are innervated by intercostal nerves Actions of these muscles Lateral flexion and rotation of the trunk Help promote urination, defecation, childbirth, vomiting, coughing, and screaming

8 Copyright © 2010 Pearson Education, Inc. Figure 10.11b Transversus abdominis Inguinal ligament Lumbar fascia Lumbar fascia Internal oblique Pubic tubercle Rectus abdominis External oblique (b) IIiac crest

9 Copyright © 2010 Pearson Education, Inc. Muscles of the Pelvic Floor Pelvic floor (pelvic diaphragm) is composed of two paired muscles Levator ani Coccygeus Both are innervated by sacral nerves Functions of the pelvic diaphragm  Seals the inferior outlet of the pelvis  Supports pelvic organs  Lifts pelvic floor to help release feces  Resists increased intra-abdominal pressure Pelvic diaphragm Symphysis pubis (a) Levator ani Piriformis Posterior Anterior Coccyx Coccygeus Obturator internus IIiococcygeus Levator ani Pubococcygeus Urogenital diaphragm Urethra Vagina Anal canal

10 Copyright © 2010 Pearson Education, Inc. Superficial Muscles of the Thorax Most are extrinsic shoulder muscles  Act in combination to fix the shoulder girdle (mostly the scapula) and move it to increase range of arm movements  Actions include elevation, depression, rotation, lateral and medial movements, protraction, and retraction Two groups of muscles: anterior and posterior

11 Copyright © 2010 Pearson Education, Inc. Superficial Muscles of the Thorax Anterior extrinsic shoulder muscles Pectoralis minor Serratus anterior Subclavius Clavicle Subscapularis Pectoralis minor Coracobrachialis Serratus anterior Humerus Sternocleido- mastoid Deltoid Pectoralis major Sternum Biceps brachii (a)

12 Copyright © 2010 Pearson Education, Inc. Superficial Muscles of the Posterior Thorax Posterior extrinsic shoulder muscles  Trapezius  Levator scapulae  Rhomboids (major and minor) Trapezius (c) Levator scapulae Supraspinatus Clavicle Spine of scapula Infraspinatus Teres minor Humerus Deltoid Teres major Latissimus dorsi Rhomboid minor Rhomboid major

13 Copyright © 2010 Pearson Education, Inc. Muscles Crossing the Shoulder Joint Nine muscles cross the shoulder joint to insert on and move the humerus Some originate off the scapula; others originate off the axial skeleton Three are prime movers of the arm Pectoralis major Latissimus dorsi Deltoid Actions include flexion, extension, adduction, abduction, and rotation of humerus

14 Copyright © 2010 Pearson Education, Inc. Muscles Crossing the Shoulder Joint Four muscles are rotator cuff muscles Supraspinatus Infraspinatus Teres minor Subscapularis Reinforce the capsule of the shoulder Act as synergists and fixators Two additional muscles are synergists: coracobrachialis and teres major Muscles Crossing the Elbow Joint Posterior extensor muscles Triceps brachii—prime mover of forearm extension Anconeus—weak synergist

15 Copyright © 2010 Pearson Education, Inc. Supraspinatus* Spine of scapula (b) Posterior view Deltoid (cut) Greater tubercle of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Latissimus dorsi Humerus Olecranon process of ulna Lateral head Long head Anconeus * Rotator cuff muscles Clavicle Deltoid Sternum Pectoralis major Lateral head Long head Medial head Coracobrachialis Triceps brachii: Biceps brachii Brachialis Brachioradialis (a) Anterior view Muscles Crossing the Shoulder Joint

16 Copyright © 2010 Pearson Education, Inc. Muscles of the Forearm Actions: movements of the wrist, hand, and fingers Most anterior muscles are flexors Some forearm muscles act to produce pronation and supination of the forearm Biceps brachii Tendon of biceps brachii Pronator teres Brachioradialis Extensor carpi radialis longus Flexor pollicis longus Pronator quadratus Flexor retinaculum Medial head of triceps brachii Medial epicondyle of humerus Flexor carpi radialis Palmar aponeurosis Superficial transverse ligament of palm Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis (a)

17 Copyright © 2010 Pearson Education, Inc. Insertion of triceps brachii Anconeus Flexor carpi ulnaris Extensor carpi ulnaris Extensor digiti minimi Extensor indicis Tendons of extensor carpi radialis brevis and longus Extensor expansion (a) Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus Extensor digitorum Extensor carpi radialis brevis Extensor carpi radialis longus Brachioradialis Tendons of extensor digitorum Most posterior muscles are extensors Muscles of the Forearm

18 Antero-medialPostero-lateral

19 Copyright © 2010 Pearson Education, Inc. Intrinsic Muscles of the Hand Small weak muscles Lie entirely within the palm of the hand Control precise movements of metacarpals and fingers (e.g., threading a needle) Abductors and adductors of the fingers Produce opposition—move the thumb toward the little finger

20 Copyright © 2010 Pearson Education, Inc. Muscles Crossing Hip and Knee Joints Most anterior muscles flex the femur at the hip and extend the leg at the knee (fore swing of walking) Most posterior muscles extend the thigh and flex the leg (backswing of walking) Medial muscles all adduct the thigh All three groups are enclosed by the fascia lata

21 Copyright © 2010 Pearson Education, Inc. Movements of the Thigh Include flexion, extension, abduction, adduction, circumduction, and rotation Thigh flexors pass in front of the hip joint Iliopsoas (iliacus and psoas major): prime mover of flexion Tensor fasciae latae Rectus femoris Assisted by medial adductors and sartorius Psoas minor Iliac crest Psoas major Iliopsoas 12th rib Quadratus lumborum Iliacus Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Quadriceps femoris Rectus femoris Vastus lateralis Vastus medialis (a) Adductor magnus Patella Patellar ligament Tendon of quadriceps femoris 12th thoracic vertebra 5th lumbar vertebra Adductor longus Gracilis

22 Copyright © 2010 Pearson Education, Inc. Movements of the Thigh Thigh extensors Hamstring muscles (prime movers of extension) Biceps femoris Semitendinosus Semimembranosus Gluteus maximus (prime mover during forceful extension)

23 Copyright © 2010 Pearson Education, Inc. Muscles of the Thigh that Move the Knee Joint Quadriceps femoris— sole extensor of the knee Hamstring muscles— flex the knee, and are antagonists to the quadriceps femoris Psoas minor Iliac crest Psoas major Iliopsoas 12th rib Quadratus lumborum Iliacus Anterior superior iliac spine Tensor fasciae latae Pectineus Sartorius Quadriceps femoris Rectus femoris Vastus lateralis Vastus medialis (a) Adductor magnus Patella Patellar ligament Tendon of quadriceps femoris 12th thoracic vertebra 5th lumbar vertebra Adductor longus Gracilis

24 Copyright © 2010 Pearson Education, Inc. Muscles of the Anterior Compartment of the Leg Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Extensor hallucis brevis Extensor digitorum brevis Superior and inferior extensor retinacula (a) Primary toe extensors and ankle dorsiflexors Tibialis anterior Extensor digitorum longus Extensor hallucis longus Fibularis tertius (not always present)

25 Copyright © 2010 Pearson Education, Inc. Muscles of the Posterior Compartment of the Leg Gastrocnemius Plantaris Medial head Lateral head Tendon of gastrocnemius Calcaneal tendon Medial malleolus Lateral malleolus Calcaneus (a) Superficial view of the posterior leg. Flexors of the foot and the toes Gastrocnemius Soleus Plantaris Popliteus Tibialis posterior Flexor digitorum longus Flexor hallucis longus

26 Copyright © 2010 Pearson Education, Inc. AnteriorPosterior MusclesOriginInsertionFunction IlipsoasTransverse processes ofT12-L5; iliac fossa Lesser trochanter of femur Major flexion of thigh SartoriusAnterior superior iliac spineProximal tibiaFlexes and laterally rotates thigh

27 Copyright © 2010 Pearson Education, Inc. LateralMedial


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