The muscular system (part b), This chapter presents the following content: Muscles of the thorax, muscles of the abdominal wall, muscles of the pelvic floor, muscles of the perineum, superficial muscles of the thorax, superficial muscles of the posterior thorax.
PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal College CHAPTER 10 The Muscular System: Part B 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 Copyright © 2010 Pearson Education, Inc External intercostal (a) Copyright © 2010 Pearson Education, Inc Internal intercostal Figure 10.10a Muscles of the Thorax PLAY A&P Flix™: External intercostals PLAY A&P Flix™: Internal intercostals Copyright © 2010 Pearson Education, Inc Foramen for inferior vena cava Central tendon of diaphragm Foramen for aorta 12th rib (b) Copyright © 2010 Pearson Education, Inc Xiphoid process of sternum Foramen for esophagus Costal cartilage Diaphragm Lumbar vertebra Quadratus lumborum Psoas major Figure 10.10b Muscles of the Abdominal Wall • Four paired muscles; their fasciae and aponeuroses form the lateral and anterior abdominal wall • Internal obliques • External obliques • Transversus abdominis • Rectus abdominis Copyright © 2010 Pearson Education, Inc Pectoralis major Serratus anterior Linea alba Transversus abdominis Internal oblique External oblique Aponeurosis of the external oblique (a) Copyright © 2010 Pearson Education, Inc Tendinous intersection Rectus abdominis Inguinal ligament (formed by free inferior border of the external oblique aponeurosis) Figure 10.11a 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 Copyright © 2010 Pearson Education, Inc Rectus abdominis Internal oblique Pubic tubercle External oblique IIiac crest Transversus abdominis Inguinal ligament Lumbar fascia Lumbar fascia (b) Copyright © 2010 Pearson Education, Inc Figure 10.11b Muscles of the Abdominal Wall PLAY A&P Flix™: External obliques PLAY A&P Flix™: Internal obliques PLAY A&P Flix™: Rectus abdominis PLAY A&P Flix™: Transversus abdominis 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 Copyright â 2010 Pearson Education, Inc Muscles of the Pelvic Floor • 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 Copyright © 2010 Pearson Education, Inc Muscles of the Perineum • Urogenital diaphragm • Anterior half of perineum, inferior to pelvic floor • Deep transverse perineal muscle • External urethral sphincter (voluntary control of urination) Copyright © 2010 Pearson Education, Inc Levator ani Pubococcygeus IIiococcygeus Anterior Obturator internus Coccyx Levator ani Coccygeus Piriformis (a) Copyright © 2010 Pearson Education, Inc Symphysis pubis Urogenital diaphragm Urethra Vagina Anal canal Posterior Pelvic diaphragm Figure 10.12a Urethral opening External urethral sphincter Inferior pubic ramus Deep transverse perineal muscle Central tendon Vaginal opening Anus External anal sphincter (b) Male Copyright © 2010 Pearson Education, Inc Female Figure 10.12b Muscles of the Perineum • Muscles of superficial perineal space • Ischiocavernosus • Bulbospongiosus • Superficial transverse perineal muscles • External anal sphincter (in posterior half of perineum) Copyright © 2010 Pearson Education, Inc Urethral opening Vaginal opening Clitoris Anus Penis Midline raphe Ischiocavernosus Bulbospongiosus Superficial transverse perineal muscle Levator ani Gluteus maximus (c) Male Copyright © 2010 Pearson Education, Inc Female Figure 10.12c 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 PLAY PLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (a) A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (b) Copyright © 2010 Pearson Education, Inc Superficial Muscles of the Thorax • Anterior extrinsic shoulder muscles • Pectoralis minor • Serratus anterior • Subclavius • (Pectoralis major considered later with muscles that act on the humerus) PLAY A&P Flix™: Muscles of the pectoral girdle (a) PLAY A&P Flix™: Muscles of the pectoral girdle (b) Copyright © 2010 Pearson Education, Inc Sternocleidomastoid Subclavius Clavicle Subscapularis Pectoralis minor Deltoid Pectoralis major Sternum Coracobrachialis Serratus anterior Biceps brachii Humerus (a) PLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview (b) Copyright © 2010 Pearson Education, Inc Figure 10.13a Superficial Muscles of the Thorax PLAY A&P Flix™: Pectoralis minor PLAY A&P Flix™: Serratus anterior Copyright © 2010 Pearson Education, Inc Superficial Muscles of the Posterior Thorax • Posterior extrinsic shoulder muscles • Trapezius • Levator scpulae • Rhomboids (major and minor) • (Latissimus dorsi considered later with muscles that act on the humerus) PLAY A&P Flix™: Muscles of the pectoral girdle (c) PLAY A&P Flix™: Movement of the pectoral girdle Copyright © 2010 Pearson Education, Inc Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Rhomboid minor Rhomboid major Spine of scapula Infraspinatus Teres minor Teres major Humerus Latissimus dorsi (c) Copyright © 2010 Pearson Education, Inc Figure 10.13c Superficial Muscles of the Posterior Thorax PLAY A&P Flix™: Trapezius PLAY A&P Flix™: Levator scapula PLAY A&P Flix™: Rhomboid major PLAY A&P Flix™: Rhomboid minor Copyright © 2010 Pearson Education, Inc ... Quadratus lumborum Psoas major Figure 10.10b Muscles of the Abdominal Wall • Four paired muscles; their fasciae and aponeuroses form the lateral and anterior abdominal wall • Internal obliques • External... of the Pelvic Floor • 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... rotation, lateral and medial movements, protraction, and retraction • Two groups of muscles: anterior and posterior PLAY PLAY A&P Flix™: Muscles that act on the shoulder joint and humerus: An overview