Muscles

2. Muscles

6. Muscle = Latin Musculus = “Little Mouse” Function of Muscles – 1. Movement of Skeleton 2. Control of Openings ex: mouth, anus 3. Stabilize Joints & Maintain Posture 4. Produce Heat when cold 5. Facial Expressions ex: happy, sad, fearful 6. Protection ex: eyes, mouth, internal organs

7. Nomenclature – Naming of Muscles 1. Shape ex: deltoid upside-down delta 2. Number of Heads or points of attachment ex: bicep = 2 heads 3. Length Short = Brevis, Long = Longus ex: extensor carpus radalis longus 4. Location ex: biceps brachei – arm biceps femoris – thigh intercostal – between ribs temporalis – over temporal bone 5. Attachments ex: sternocleidomastoid (sternum-clavicle-mastoid)

8. Function of Muscles – 1. Flexor & Extensor - fold and straighten 2. Adductor & Abductor – bring together and take away 3. Supinator & Pronator – palm up and palm down Prime function of a muscle is to move or contract. The Antagonist function is to relax Attachment to Limbs – Origins – proximal (nearest to midline) region of limb Insertion – Distal (distance end away from midline) region of limb Ex: Origin Coracoid Process & Acromium Biceps brachii Insertion Proximal Radius

10. Histology of Muscles – 3 types 1. Smooth or Visceral – around hollow organs or tubes 2. Cardiac – heart 3. Skeletal or Striated – Attached to bones These differ in structure, function and location. Smooth or Visceral or Involuntary Muscle – Made of single cells with a central nucleus and found in sheets held together by connective tissue. Largest Smooth Muscles = Uterus and Digestive tract – peristalsis - slow rhythmic contractions Greatest endurance = Pupil of eye, it is always working Two muscles – radial and circular muscles

11. Smooth Muscle

12. Cardiac Muscle – Tubular cells with central nuclei. They are branched and have intercalated discs along the fibers that help facilitate the spread of the contraction and have striations. Intercalated disc Nuclei Intercalated discs also increase the strength of the connection between cardiac muscle cells.

13. Cardiac Muscle

14. Skeletal Muscle – Longest Muscle cells in the Sartorius 35cm or 14” long Smallest Muscles in the Inner Ear 10u Peripherally Multinucleated Cells make up fibers stronger than steel Terms: Sarcolemma“flesh” Cell membrane of a muscle cell Sarcoplasmis the cytoplasm of muscle cells Sarcomere is the functional unit of muscle contraction. Actin and Myosin (sarcomere) Myofilaments Myofibrils Muscle contract due to nerve impulse coming to sarcolema Impulse Sarcolema Sarcolemic Reticulum Ca++ released This causes the actin and myosin to slide together “ Sliding Filament Theory”

19. Figure 08.07

20. Figure 08.08

21. Figure 08.09a

22. Figure 08.09b

23. Muscles of the Body How many muscles do you have? It was 638 until 1996 when a new muscle was found that connects from the orbit to the mandible so now it is 639.

24. Muscle of Head LevatorPalpabra Splenius Capitis Trapezius

25. Muscles of Head Muscles of the Jaw – 7. Temporalis O – Squamous portion of Temporal Bone I – Coronoid process of Mandible A – Close Jaw 8. Masseter – “chewer” O – Zygomatic Arch I – Angle and Ramus of Mandible A – Close Jaw

27. LevatorPalpabra Splenius Capitis Trapezius

28. Big Muscles of Trunk • Trapezius – tapezoid shaped found superior posterior O – Occipital Bone & Ligamentum Nuchae (attaches to all the spines of Thoracic & Cervical vertebrae) I – Spine of Scapula & Lateral 1/3 of Clavicle A – Adduct scapula, depress scapula, raise scapula & extend head Clavicle Head Ligamentum Nuchae Scapula

29. 2. Latissimus Dorsi –”Broad” lower back - Inferior Posterior O – Thoraco Lumbar Faccia I – Anterior Intertubercular Groove of Humerus A – Medial Rotate Humerus, Adduct Humerus, Depress Humerus 3. Rotator Cuff - Connects Scapula to Humerus Four Muscles – 1. Supraspinous Muscle 2. Infraspinous Muscle 3. Subscapularis Muscle 4. Teris Minor O – Scapula I – Proximal Humerus A – Adduct & Abduct Humerus, rotate Humerus medial & lateral Acromium Scapula Humerus

30. Rotator Cuff Ligamentum nuchae Aponeurosis

31. Arm & Forearm – Muscles of the arm are for strength Muscles of the forearm are for dexterity Arm Muscles – Between shoulder and elbow Biceps – 2 heads or points of origin (short and long head) O – 1. Coracoid Process short head 2. Lip of Glenoid Fossa long head I – Radial Tuberosity A – Powerful Supinator (Hold a bowl of soup) Flexor

32. Figure 08.21

33. Triceps – 3 heads – Posterior arm 1 on Scapula , 2 on proximal end of Humerus O – Infra Glenoid Tubercle Proximal Humerus stretching from medial to lateral I – Olecranon Process of the Ulna (Elbow) A – Extends forearm & stabilizes elbow joint Forearm Muscles - Brachio Radialis Muscles – Gives shape to forearm Anterior Muscles flexor of wrist and fingers Posterior Muscles Extensor of wrist and Fingers Thenar Eminence – Large muscle at the base of the thumb

34. Figure 08.22

35. Anterior Superior Trunk Muscles - • Pectoralis Major – Chest Muscles O – Sternum, Medial Clavicle, 2-6 Costal Cartilage I – Outer lip of Intertubercular Groove of Humerus A – Adduct & Medial Rotate Humerus 2. Deltoid – Gives shape to the shoulder O – Lateral Clavicle & spine of Scapula I – Deltoid Tuberosity of Humerus A – Abduct Humerus and assist Bicep and Tricep

37. Abdominal Muscles – All anterior muscles for the support and protection of abdominal & pelvic viscera. Contraction of these muscles flexes vertebral column. • Rectus Abdominus – Rectus = “straight” – major visible abdominal muscles known as a “six-pack”. O – 5,6 & 7 Costal Cartilage and Xiphoid Process I – Pubic Bone & Pubic Symphysis Linea Alba – “white line” No blood vessels just connective tissue Costal Cartilage Sternum Wrapped in aponeurosis of the External Obliques, Internal Obliques & Transverse Linea Alba Linea Alba E.O. Rectus Abdominus Trans I.N. Rectus Abdominus Pubic Bone

38. External Obliques – Very important muscles and aponeurosis O – Lower Ribs I - Linea Alba Action - • Support & Potect Pelvic Viscera • Flex Vertebral Column • Aids in Breathing • Aids in Vomiting • Aids in Defecating • Aids in Childbirth • Used for laughing, coughing and sneezing Folded bottom of aponeuroces forms Inguinal Canal. Testes descend through this canal after birth in males. Inguinal Hernia – Intestines can get stuck in canal and get squeezed

40. Muscles of the Hip - 19 muscles in hip Function - Flex & Extend, Adduct & Abduct, Circumduct Two Groups of Muscles – 1. Gluteal Muscles – Posterior Pelvis / Buttock Give shape to posterior pelvis Humans have the largest Gluteal Muscles Females have fat pads on top of the muscle 3 Muscles – Gluteal Maximus, Gluteal Medius and Gluteal Minimus O – Ilium I – Posterior Ilium, Ileotibal band & Greater Trochanter of Femur

41. Figure 08.26

42. 2. Anterior Thigh Muscles – 1. Sartorius – called the “Taylor’s Muscle” – Let you sit cross legged. O – Anterior Iliac Spine I – Medial Proximal Tibia A – Flex Hip Joint & Flex Knee Joint 2. Quadricep – 4 muscles They are held together by Faccia Lata a tough fibrous wrapping 1. Rectus Femoris 2. Vastus Lateralis 3. Vastus Intermedus 4. Vastus Medialis O – Ilium & Proximal Femur I – Quadriceps Tendon to Patella Tendon and Tibial Tuberosity. A – Extends Leg

43. Figure 08.25 iliotibial band

44. Medial Thigh Muscle – Grailis “slender” O – Pubic Bone I – Medial Proximal Tibia A – Adduct Thigh & Flex Knee Posterior Thigh Muscles – Hamstring - 1. Biceps Femoris 2. Semimembranosus 3. Semitendenosus O – ischium I - Proximal Medial Tibia A - Extend Hip & Flex knee

45. Figure 08.27

46. Anterior Leg – Front of Tibia has no muscles just periosteum containing nerves that’s why is hurts so much when you hit you shin. Tibilas Anterior – Along sides of tibia connects to Dorum “top” of foot so you can pull you foot up. Posterior Leg – • Gastrocnemius – superficial - gives shape to calf, large in humans O – epicondyles of Femur I – Calcaneus (heel) via the Achilles Tendon A – Extends foot called Plantar Flexon “plant on ground” 2. Soleus – deep muscle – O – Proximal Fibia & Fibula I – Achilles Tendon A – Plantar Flexon

47. Figure 08.28

48. Figure 08.30

49. Figure 08.15

50. Figure 08.16