Ex 12 Skeletal Muscle 1 A Characteristics of

Ex. 12: Skeletal Muscle 1

A. Characteristics of Three Muscle Types 2

1. Skeletal muscle– with striations; each skeletal muscle cell (fiber) has multiple and peripherally located nuclei 3

Location– primarily to bones by tendons (a) Nuclei Striations Muscle fiber (b) 4

2. Cardiac muscle–striations; each muscle cell (fiber) has a single centrally located nucleus, branches, and intercalated discs at both ends 5

Location– the heart 6

3. Smooth muscle– without striations; each cell (fiber), with a single and centrally located nucleus, is thick in the middle and tapered at each end 7

Location– walls of viscera, airways, blood vessels, iris and ciliary body of eye (a) Nuclei Muscle cells (b) 8

B. The Organization of Skeletal Muscle 9

A B C 10

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C. The Neuromuscular Junction 14

The number of muscle fibers controlled by one neuron is called a motor unit. Spinal cord Motor neuron 1 Motor neuron 2 Neuromuscular junction Skeletal muscle fibers 15

Neurotransmitter 16

Ex. 13: Gross Anatomy of the Muscular System Required muscles/tendons are highlighted in green, the same 80 muscles and 3 tendons appeared in the lab manual. When highlighted in red, muscles’ actions, insertions, and origins are also required. 17

Anterior view Superficial Deep Galea aponeurotica Frontalis Corrugator supercilii Orbicularis oculi Levator labii superioris Zygomaticus minor Zygomaticus major Risorius Nasalis Levator anguli oris Masseter Buccinator Modiolus Depressor anguli oris Depressor labii inferioris Orbicularis oris Mentalis (cut) Platysma 18

Lateral view Galea aponeurotica Frontalis (cut) Corrugator supercilii Temporalis Orbicularis oculi Occipitalis Nasalis Levator labii superioris Zygomatic arch O: Zygomatic arch & maxilla; I: Mandibular angle & ramus Action: Closes jaw & elevates mandible Zygomaticus minor Zygomaticus major Orbicularis oris Masseter Sternocleidomastoid Levator scapulae Inferior pharyngeal constrictor Thyrohyoid Sternothyroid Omohyoid Sternohyoid Modiolus Risorius (cut) Mentalis Depressor labii inferioris Depressor anguli oris Buccinator 19

Lateral view Galea aponeurotica Corrugator supercilii Nasalis Levator labii superioris Zygomatic arch Origin: Insertion: Action: Levator scapulae Inferior pharyngeal constrictor Thyrohyoid Modiolus Depressor labii inferioris Depressor anguli oris Practice 20

Anterior view Superficial Deep Digastric: Anterior belly Posterior belly Suprahyoid group Stylohyoid Mylohyoid Hyoid bone Common carotid artery Levator scapulae Sternohyoid Infrahyoid group Omohyoid: Superior belly Inferior belly Sternocleidomastoid Internal jugular vein Thyrohyoid Sternothyroid Infrahyoid group Clavicle O: Manubrium & medial clavicle; I: Mastoid process of temporal bone Action: Flexion in neck against resistance 21

Lateral view Trapezius: Stylohyoid Hyoglossus Mylohyoid Digastric (anterior belly) Hyoid bone Thyrohyoid Omohyoid (superior belly) Sternothyroid O: Occipital bone, spine of C 7 & all thoracic vertebrae; I: Acromion & spinous process of scapula Action: Extends heads, movement of scapula Digastric (posterior belly) Splenius capitis Inferior pharyngeal constrictor Sternocleidomastoid Trapezius Levator scapulae Scalenes Omohyoid (inferior belly) Sternohyoid 22

Lateral view Origin: Insertion: Action: Hyoglossus Splenius capitis Inferior pharyngeal constrictor Hyoid bone Thyrohyoid Levator scapulae Scalenes Sternothyroid Practice 23

Superficial muscles of the anterior abdominal wall Pectoralis major Latissimus dorsi Serratus anterior Tendinous intersections Rectus sheath Umbilicus Linea semilunaris Linea alba Aponeurosis of external abdominal oblique Rectus sheath (cut edges) Transverse abdominal Internal abdominal oblique (cut) External abdominal oblique (cut) Rectus abdominis Inguinal ligament 24

Deep muscles of the anterior abdominal wall Subclavius Pectoralis minor (cut) Pectoralis minor Internal intercostals Serratus anterior External intercostals Rectus abdominis (cut) Rectus sheath External abdominal oblique (cut) Internal abdominal oblique (cut) Posterior wall of rectus sheath (rectus abdominis removed) Inguinal ligament Transverse abdominal (cut) 25

Deep muscles of the anterior abdominal wall Subclavius External intercostals Rectus sheath Posterior wall of rectus sheath (rectus abdominis removed) Inguinal ligament Practice 26

Lateral view of intercostal muscles External intercostals O: Xiphoid process of sternum Inferior vena cava O: Ribs Esophagus Insertion: Central tendon of diaphragm O: Vertebral column Internal intercostals Inferior view of diaphragm Action: Prime mover of inspiration 27

Neck, back, and gluteal muscles Superficial Deep Splenius capitis Sternocleidomastoid Trapezius Deltoid Levator scapulae Rhomboideus major/minor Supraspinatus O: Acromion and spine of scapula I: Deltoid tuberosity Action: Prime mover of arm abduction Erector spinae Infraspinatus Teres minor Teres major Serratus anterior Serratus posterior inferior Latissimus dorsi External abdominal oblique Internal abdominal oblique Thoracolumbar fascia Gluteus medius Gluteus maximus Gluteus minimus Lateral rotators 28

Neck, back, and gluteal muscles Superficial Deep Splenius capitis Origin: Insertion: Action: Erector spinae Serratus posterior inferior Thoracolumbar fascia Lateral rotators Practice 29

Anterior view Clavicle Sternum Deltoid Triceps brachii: Pectoralis major Coracobrachialis Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis 30

Posterior view Supraspinatus Spine of scapula Greater tubercle of humerus Infraspinatus Humerus Teres minor Teres major Triceps brachii: Lateral head Long head Latissimus dorsi O: glennoid cavity I: olecranon process of ulna Action: forearm extensor 31

Anterior view Subscapularis Coracobrachialis Brachialis O: Distal humerus I: coronoid process of ulna Action: Major flexor of forearm 32

Anterior view of the forearm Biceps brachii Triceps brachii Brachialis Common flexor tendon Pronator teres Supinator Aponeurosis of biceps brachii Brachioradialis Anterior view Interosseous membrane Flexor carpi radialis Flexor digitorum superficialis Palmaris longus Flexor carpi ulnaris Extensor carpi radialis longus and brevis Flexor digitorum profundus Flexor pollicis longus Flexor digitorum superficialis Flexor retinaculum Palmar aponeurosis (a) Superficial flexors (b) Intermediate flexor Flexor digitorum superficialis tendons Flexor digitorum profundus tendons (c) Deep flexors 33

Anterior view of the forearm Common flexor tendon Aponeurosis of biceps brachii Anterior view Interosseous membrane Flexor digitorum profundus Flexor retinaculum Palmar aponeurosis (a) Superficial flexors Practice (b) Intermediate flexor Flexor digitorum superficialis tendons Flexor digitorum profundus tendons (c) Deep flexors 34

Posterior view of the forearm Triceps brachii Brachioradialis Olecranon Extensor carpi radialis longus Anconeus Posterior view Anconeus Supinator Extensor carpi radialis brevis Flexor carpi ulnaris Abductor pollicis longus Extensor digitorum Extensor carpi ulnaris Abductor pollicis longus Extensor digiti minimi Extensor pollicis brevis Extensor pollicis longus Extensor pollicis brevis Extensor indicis Extensor pollicis longus Tendon of extensor indicis Tendons of extensor carpi radialis longus and brevis Tendons of extensor digitorum (a) Superficial extensors (b) Deep extensors 35

Supination Pronation Lateral epicondyle Medial epicondyle Supinator Pronator teres Ulna Radius Pronator quadratus Biceps brachii Radius Bursa Supinator Ulna Muscle actions in supination 36

Iliac crest Iliopsoas: includes Iliacus Psoas major L 5 Anterior superior iliac spine Tensor fasciae latae Medial compartment: Adductor magnus Pectineus Adductor brevis Iliotibial band Adductor longus Gracilis Anterior compartment: Sartorius Rectus femoris O: Iliac spine and superior acetabulum I: Tibial tuberosity and patella Action: Extend knee and flexes thigh at hip Vastus lateralis Vastus medialis Quadriceps femoris tendon Patellar ligament Anterior muscles of thigh, superficial view 37

Iliac crest includes Iliacus Psoas major L 5 Anterior superior iliac spine Tensor fasciae latae Medial compartment: Pectineus Adductor brevis Anterior compartment: Origin: Insertion: Action: Quadriceps femoris tendon Patellar ligament Practice Anterior muscles of thigh, superficial view 38

Anterior muscles of the thigh, deep view Quadriceps femoris: Vastus intermedius Vastus lateralis Vastus medialis Quadriceps femoris tendon Patellar ligament 39

Gluteal muscles, posterior view Superficial Deep Iliac crest Gluteus medius Sacrum Gluteus maximus Coccyx Gluteus minimus Lateral rotators: Piriformis Gemellus superior Obturator internus Obturator externus Ischial tuberosity Gemellus inferior Quadratus femoris 40

Posterior muscles of the hip and thigh Gluteus medius Gluteus maximus Gracilis Adductor magnus Iliotibial band Vastus lateralis Biceps femoris, long head: O: Ischial tuberosity I: Head of fibula & lateral condyle of tibia Action: Extends thigh, laterally rotates leg, & flexes knee Hamstring group: Biceps femoris, long head Short head Semitendinosus Semimembranosus 41

Posterior muscles of the hip and thigh Origin: Insertion: Hamstring group: Short head Action: Practice 42

Patellar ligament Tibia Gastrocnemius Fibularis longus Soleus Fibularis brevis Tibialis anterior Extensor digitorum longus O: Lateral condyle of tibia I: First cuneiform and metatarsal 1 Action: Prime mover of dorsiflexion Extensor retinacula (a) 43

Extensor hallucis longus Fibularis tertius (c) 44

Extensor digitorum longus (d) 45

Superficial muscles of the leg, posterior compartment Plantaris Gastrocnemius: Medial head Lateral head Tendon of gastrocnemius Calcaneal tendon Calcaneus 46

Deep muscles of the leg, posterior view Plantaris Popliteus Heads of gastrocnemius (cut) Fibularis longus Soleus Tendon of plantaris Gastrocnemius (cut) Fibularis longus Flexor digitorum longus Fibularis brevis Flexor hallucis longus 47

Plantaris (cut) Gastrocnemius (cut) Popliteus Soleus (cut) Fibula Tibialis posterior Fibularis longus Flexor digitorum longus Flexor hallucis longus Fibularis brevis Calcaneal tendon (cut) Calcaneus (a) 48