Download presentation
Presentation is loading. Please wait.
1
Chapter 10 The Muscular System
2
Skeletal Muscles: Functional Groups
Prime movers Provide the major force for producing a specific movement Antagonists Oppose or reverse a particular movement Synergists Add force to a movement Reduce undesirable or unnecessary movement Fixators Synergists that immobilize a bone or muscle’s origin
3
Naming Skeletal Muscles
Location—bone or body region associated with the muscle Shape—e.g., deltoid muscle (deltoid = triangle) Relative size—e.g., maximus (largest), minimus (smallest), longus (long) Direction of fibers or fascicles—e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis)
4
Naming Skeletal Muscles
Number of origins—e.g., biceps (2 origins) and triceps (3 origins) Location of attachments—named according to point of origin or insertion Action—e.g., flexor or extensor, muscles that flex or extend, respectively
5
Muscle Mechanics: Arrangement of Fascicles
Circular Fascicles arranged in concentric rings (e.g., orbicularis oris) Convergent Fascicles converge toward a single tendon insertion (e.g., pectoralis major) Parallel Fascicles parallel to the long axis of a straplike muscle (e.g., sartorius) Fusiform Spindle-shaped muscles with parallel fibers (e.g., biceps brachii) Pennate Short fascicles attach obliquely to a central tendon running the length of the muscle (e.g., rectus femoris)
6
(a) (g) (b) (f) Circular (orbicularis oris) (b) Convergent
(pectoralis major) (c) (e) (c) Parallel (sartorius) (d) Unipennate (extensor digitorum longus) (d) (e) Bipennate (rectus femoris) (f) Fusiform (biceps brachii) (g) Multipennate (deltoid) Figure 10.1
7
Major Skeletal Muscles of the Body
Grouped by function and location Information for each muscle Name and description—note information in the name Origin and insertion—there is usually a joint between the origin and the insertion Action—insertion moves toward origin; best learned by acting out muscle movement on one’s own body Innervation—name of major nerve that supplies the muscle
8
Epicranius, frontal belly Orbicularis oculi Masseter Zygomaticus
Head Facial Temporalis Epicranius, frontal belly Orbicularis oculi Masseter Zygomaticus Shoulder Orbicularis oris Trapezius Neck Deltoid Sternohyoid Arm Platysma Triceps brachii Sternocleidomastoid Biceps brachii Thorax Brachialis Forearm Pectoralis minor Serratus anterior Pronator teres Pectoralis major Brachioradialis Intercostals Flexor carpi radialis Palmaris longus Abdomen Pelvis/thigh Rectus abdominis Iliopsoas Internal oblique Pectineus Transversus abdominis Thigh External oblique Rectus femoris Thigh Vastus lateralis Tensor fasciae latae Vastus medialis Sartorius Adductor longus Leg Gracilis Fibularis longus Leg Extensor digitorum longus Gastrocnemius Tibialis anterior Soleus Figure 10.4
9
Epicranius, occipital belly Sternocleidomastoid Arm Trapezius
Neck Epicranius, occipital belly Sternocleidomastoid Arm Trapezius Triceps brachii Shoulder Brachialis Deltoid Forearm Infraspinatus Brachioradialis Teres major Extensor carpi radialis longus Rhomboid major Latissimus dorsi Flexor carpi ulnaris Hip Extensor carpi ulnaris Gluteus medius Gluteus maximus Extensor digitorum Iliotibial tract Thigh Adductor magnus Hamstrings: Leg Biceps femoris Gastrocnemius Semitendinosus Soleus Semimembranosus Fibularis longus Calcaneal (Achilles) tendon Figure 10.5
10
Muscles of the Head Two groups Muscles of facial expression
Muscles of mastication and tongue movement
11
Muscles of Facial Expression
Insert into the skin Important in nonverbal communication All innervated by cranial nerve VII (facial nerve)
12
Muscles of Facial Expression
Epicranius (occipitofrontalis) Bipartite muscle consisting of the Frontalis Occipitalis Galea aponeurotica—cranial aponeurosis connecting above muscles The two muscles have alternate actions of pulling the scalp forward and backward
13
Epicranius Galea aponeurotica Corrugator supercilii Frontal belly
Orbicularis oculi Occipital belly Levator labii superioris Zygomaticus minor and major Temporalis Buccinator Masseter Risorius Sternocleidomastoid Orbicularis oris Trapezius Mentalis Splenius capitis Depressor labii inferioris Depressor anguli oris Platysma Figure 10.6
14
Muscles of Mastication and Tongue Movement
Four pairs involved in mastication Prime movers of jaw closure Temporalis and masseter Grinding movements Medial and lateral pterygoids
15
Muscles of Mastication and Tongue Movement
All are innervated by cranial nerve V (trigeminal nerve) Buccinator muscles (of facial expression group) also help by holding food between the teeth Three muscles anchor and move the tongue All are innervated by cranial nerve XII (hypoglossal nerve)
16
Temporalis Orbicularis oris Masseter Buccinator (a) Figure 10.7a
17
Lateral pterygoid Medial pterygoid Masseter pulled away (b)
Figure 10.7b
18
Tongue Styloid process Styloglossus Genioglossus Hyoglossus Stylohyoid
Mandibular symphysis Stylohyoid Hyoid bone Geniohyoid Thyrohyoid Thyroid cartilage (c) Figure 10.7c
19
Muscles of the Anterior Neck and Throat
Most are involved in swallowing Two groups Suprahyoid Infrahyoid
20
Suprahyoid Muscles of the Anterior Neck and Throat
Four deep muscles are involved in swallowing (they move the hyoid bone and larynx) Form the floor of the oral cavity Anchor the tongue Move the hyoid bone and the larynx
21
Median raphe Anterior Mylohyoid belly Digastric Stylohyoid Posterior
Hyoid bone Omohyoid (superior belly) Stylohyoid (cut) Thyrohyoid Sternohyoid Thyroid cartilage of the larynx Sternocleido- mastoid Thyroid gland Omohyoid (inferior belly) Sternothyroid (a) Figure 10.8a
22
Tensor veli palatini Levator veli palatini Styloid process Buccinator
Superior pharyngeal constrictor Mandible Middle pharyngeal constrictor Mylohyoid (cut) Hyoid bone Thyrohyoid membrane Geniohyoid Hyoglossus Inferior pharyngeal constrictor Thyroid cartilage of larynx Esophagus (c) Trachea Figure 10.8c
23
Muscles of the Neck and Vertebral Column
Two functional groups Muscles that move the head Muscles that extend the trunk and maintain posture
24
Muscles of the Neck and Vertebral Column: Head Movement
Sternocleidomastoid—major head flexor Suprahyoid and infrahyoid—synergists to head flexion Sternocleidomastoid and scalenes—lateral head movements Semispinalis capitis—synergist with sternocleidomastoid Splenius (capitis and cervicis portions): head extension, rotation, and lateral bending
25
Base of occipital bone 1st cervical vertebra Mastoid process Middle
scalene Sternocleido- mastoid Anterior scalene Posterior scalene (a) Anterior Figure 10.9a
26
Mastoid process Splenius capitis Spinous processes of the vertebrae
cervicis (b) Posterior Figure 10.9b
27
Muscles of the Neck and Vertebral Column: Trunk Extension
Deep (intrinsic) back muscles Erector spinae (sacrospinalis) group—prime movers of back extension and lateral bending Iliocostalis Longissimus Spinalis Semispinalis and quadratus lumborum—synergists in extension and rotation
28
Iliocostalis cervicis Semispinalis cervicis Longissimus cervicis
Ligamentum nuchae Mastoid process of temporal bone Semispinalis capitis Longissimus capitis Iliocostalis cervicis Semispinalis cervicis Longissimus cervicis Semispinalis thoracis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis Erector spinae Longissimus Spinalis Multifidus Iliocostalis lumborum Quadratus lumborum External oblique (d) Figure 10.9d
29
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
30
External intercostal (a) Internal intercostal Figure 10.10a
31
Xiphoid process of sternum Foramen for inferior vena cava Foramen for
esophagus Costal cartilage Central tendon of diaphragm Diaphragm Foramen for aorta Lumbar vertebra 12th rib Quadratus lumborum (b) Psoas major Figure 10.10b
32
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
33
Transversus abdominis
Pectoralis major Serratus anterior Linea alba Tendinous intersection Transversus abdominis Internal oblique Rectus abdominis External oblique Aponeurosis of the external oblique Inguinal ligament (formed by free inferior border of the external oblique aponeurosis) (a) Figure 10.11a
34
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
35
Rectus abdominis Internal External oblique oblique Lumbar fascia
IIiac crest Pubic tubercle Lumbar fascia Transversus abdominis Inguinal ligament (b) Figure 10.11b
36
Muscles of the Pelvic Floor
Pelvic floor (pelvic diaphragm) is composed of two paired muscles Levator ani Coccygeus Both are innervated by sacral nerves
37
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
38
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)
39
Anterior Pubococcygeus Symphysis pubis Levator ani IIiococcygeus
Urogenital diaphragm Urethra Vagina Anal canal Obturator internus Coccyx Levator ani Piriformis Coccygeus Pelvic diaphragm Posterior (a) Figure 10.12a
40
Urethral opening External urethral sphincter Vaginal opening
Inferior pubic ramus Deep transverse perineal muscle Central tendon Anus External anal sphincter Male Female (b) Figure 10.12b
41
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
42
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)
43
Sternocleido- mastoid Subclavius Clavicle Subscapularis Deltoid
Pectoralis minor Pectoralis major Coracobrachialis Sternum Serratus anterior Biceps brachii Humerus (a) Figure 10.13a
44
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)
45
Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Spine of
Rhomboid minor Infraspinatus Rhomboid major Teres minor Teres major Humerus Latissimus dorsi (c) Figure 10.13c
46
Muscles Crossing the Shoulder Joint
Nine muscles cross the shoulder joint to insert on and move the humerus Three are prime movers of the arm Pectoralis major Latissimus dorsi Deltoid Actions include flexion, extension, adduction, abduction, and rotation of humerus
47
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
48
Clavicle Deltoid Sternum Pectoralis major Coracobrachialis
Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Figure 10.14a
49
Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle
of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view * Rotator cuff muscles Figure 10.14b
50
Table Part 1
51
Muscles Crossing the Elbow Joint
Anterior flexor muscles Brachialis and biceps brachii—chief forearm flexors Brachioradialis—synergist and stabilizer
52
Clavicle Deltoid Sternum Pectoralis major Coracobrachialis
Triceps brachii: Lateral head Long head Medial head Biceps brachii Brachialis Brachioradialis (a) Anterior view Figure 10.14a
53
Muscles Crossing the Elbow Joint
Posterior extensor muscles Triceps brachii—prime mover of forearm extension Anconeus—weak synergist
54
Supraspinatus* Spine of scapula Deltoid (cut) Greater tubercle
of humerus Infraspinatus* Teres minor* Teres major Triceps brachii: Lateral head Long head Latissimus dorsi Humerus Olecranon process of ulna Anconeus (b) Posterior view * Rotator cuff muscles Figure 10.14b
55
Muscles of the Forearm Actions: movements of the wrist, hand, and fingers Most anterior muscles are flexors and insert via the flexor retinaculum Most posterior muscles are extensors and insert via the extensor retinaculum Some forearm muscles act to produce pronation and supination of the forearm
56
Muscles of the Forearm Pronators: pronator teres and pronator quadratus Supinator: a synergist with the biceps brachii Flexors Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum muscles (superficialis and profundus) Flexor pollicis longus
57
Superficial transverse ligament of palm
Palmar aponeurosis Flexor retinaculum Pronator quadratus Flexor digitorum superficialis Flexor pollicis longus Flexor carpi ulnaris Palmaris longus Extensor carpi radialis longus Flexor carpi radialis Brachioradialis Medial epicondyle of humerus Pronator teres Tendon of biceps brachii Medial head of triceps brachii Biceps brachii (a) Figure 10.15a
58
Tendon of flexor digitorum superficialis (cut) Tendon of flexor
digitorum profundus Lumbricals Tendon of flexor pollicis longus Thenar muscles of thumb Tendon of flexor carpi ulnaris (cut) Pronator quadratus Flexor pollicis longus Flexor digitorum profundus Supinator (c) Figure 10.15c
59
Muscles of the Forearm: Posterior Compartment
Extensors Extensor carpi radialis longus and brevis Extensor digitorum Extensor carpi ulnaris Extensor pollicis brevis and longus Extensor indicis Abductor pollicis longus
60
Tendons of extensor carpi radialis brevis and longus Extensor pollicis
expansion Tendons of extensor digitorum Tendons of extensor carpi radialis brevis and longus Extensor pollicis longus Extensor indicis Extensor pollicis brevis Extensor digiti minimi Abductor pollicis longus Extensor carpi ulnaris Extensor digitorum Flexor carpi ulnaris Extensor carpi radialis brevis Anconeus Extensor carpi radialis longus Insertion of triceps brachii Brachioradialis (a) Figure 10.16a
61
Extensor pollicis brevis
Interossei Extensor indicis Extensor pollicis brevis Extensor pollicis longus Abductor pollicis longus Supinator Anconeus Olecranon process of ulna (b) Figure 10.16b
62
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
63
Finger and Thumb Movements
Flexion Thumb—bends medially along the palm Fingers—bend anteriorly Extension Thumb—points laterally Fingers—move posteriorly
64
Intrinsic Muscles of the Hand
Three groups Thenar eminence (ball of the thumb) Hypothenar eminence (ball of the little finger) Each of the above groups has a flexor, an abductor, and an opponens muscle Midpalmar muscles: lumbricals and palmar and dorsal interossei extend the fingers Interossei muscles also abduct and adduct the fingers
65
Muscles Crossing Hip and Knee Joints
Most anterior muscles flex the femur at the hip and extend the leg at the knee (foreswing 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
66
Thigh flexors pass in front of the hip joint
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
67
Anterior superior iliac spine Tensor fasciae latae Pectineus
12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Adductor longus Sartorius Gracilis Quadriceps femoris Adductor magnus • Rectus femoris • Vastus lateralis • Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament (a) Figure 10.19a
68
Hamstring muscles (prime movers of extension)
Movements of the Thigh Thigh extensors Hamstring muscles (prime movers of extension) Biceps femoris Semitendinosus Semimembranosus Gluteus maximus (prime mover during forceful extension)
69
Gluteus medius Gluteus maximus Adductor magnus Gracilis
Iliotibial tract Long head Biceps femoris Short head Hamstrings Semitendinosus Semimembranosus (a) Figure 10.20a
70
Adductors (also medially rotate thigh)
Movements of the Thigh Adductors (also medially rotate thigh) Adductor magnus Adductor longus Adductor brevis Pectineus Gracilis
71
Pectineus (cut) Adductor brevis Adductor magnus Adductor longus Femur
O = origin I = insertion (b) Figure 10.19b
72
Movements of the Thigh Abductors
Gluteus maximus (also laterally rotates thigh) Gluteus medius (also medially rotates thigh) Gluteus minimus (also medially rotates thigh) Piriformis (also laterally rotates thigh) Obturator externus (also laterally rotates thigh) Obturator internus (also laterally rotates thigh) Gemellus (also laterally rotates thigh)
73
Gluteus medius (cut) Gluteus minimus Superior gemellus Piriformis
Obturator internus Obturator externus Inferior gemellus Quadratus femoris Gluteus maximus (cut) (c) Figure 10.20c
74
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
75
Anterior superior iliac spine Tensor fasciae latae Pectineus
12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Adductor longus Sartorius Gracilis Quadriceps femoris Adductor magnus • Rectus femoris • Vastus lateralis • Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament (a) Figure 10.19a
76
Gluteus medius Gluteus maximus Adductor magnus Gracilis
Iliotibial tract Long head Biceps femoris Short head Hamstrings Semitendinosus Semimembranosus (a) Figure 10.20a
77
Fascia of the Leg A deep fascia of the leg is continuous with the fascia lata This fascia segregates the leg into three compartments: anterior, lateral, and posterior Distally, the fascia thickens and forms the flexor, extensor, and fibular retinaculae
78
Muscles of the Leg: Movements
Various leg muscles produce the following movements Ankle—dorsiflexion and plantar flexion Intertarsal joints—inversion and eversion of the foot Toes—flexion and extension
79
Muscles of the Anterior Compartment of the Leg
Primary toe extensors and ankle dorsiflexors Tibialis anterior Extensor digitorum longus Extensor hallucis longus Fibularis tertius (not always present)
80
Extensor digitorum longus
Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis (a) Figure 10.21a
81
Muscles of the Lateral Compartment of the Leg
Plantar flexion and eversion of the foot Fibularis longus Fibularis brevis
82
Extensor digitorum longus
Patella Head of fibula Gastrocnemius Soleus Fibularis longus Extensor digitorum longus Tibialis anterior Extensor hallucis longus Fibularis tertius Fibularis brevis Superior and inferior extensor retinacula Flexor hallucis longus Extensor hallucis brevis Fibular retinaculum Extensor digitorum brevis Lateral malleolus (a) 5th metatarsal Figure 10.22a
83
Muscles of the Posterior Compartment of the Leg
Flexors of the foot and the toes Gastrocnemius Soleus Plantaris Popliteus Tibialis posterior Flexor digitorum longus Flexor hallucis longus
84
(a) Superficial view of the posterior leg.
Plantaris Medial head Gastrocnemius Lateral head Tendon of gastrocnemius Calcaneal tendon Medial malleolus Lateral malleolus Calcaneus (a) Superficial view of the posterior leg. Figure 10.23a
85
Flexor hallucis longus
Plantaris (cut) Gastrocnemius lateral head (cut) Gastrocnemius medial head (cut) Popliteus Soleus (cut) Tibialis posterior Fibula Fibularis longus Flexor digitorum longus Flexor hallucis longus Tendon of tibialis posterior Fibularis brevis Medial malleolus Calcaneal tendon (cut) Calcaneus (c) The triceps surae has been removed to show the deep muscles of the posterior compartment. Figure 10.23c
86
Major Actions of Muscles Acting on the Thigh, Leg, and Foot
View the next five slides for a summary of the major actions of the muscles acting on the thigh, leg, and foot
87
Intrinsic Muscles of the Foot
Help flex, extend, abduct, and adduct the toes Support the arches of the foot along with some leg tendons Extensor digitorum brevis—dorsal foot muscle that helps extend the toes
88
Extensor digitorum longus
Fibularis longus Gastrocnemius Tibia Tibialis anterior Extensor digitorum longus Soleus Extensor hallucis longus Fibularis tertius Superior and inferior extensor retinacula Extensor hallucis brevis Extensor digitorum brevis (a) Figure 10.21a
89
Plantar Muscles The plantar muscles occur in four layers
Superficial layer Flexor digitorum brevis Abductor hallucis Abductor digiti minimi Second layer Flexor accessorius Lumbricals
90
Tendon of flexor hallucis longus
Lumbricals Flexor hallucis brevis Flexor digiti minimi brevis Abductor hallucis Flexor digitorum brevis Flexor accessorius Abductor digiti minimi Calcaneal tuberosity (a) First layer (plantar aspect) Figure 10.24a
91
Flexor hallucis brevis
Lumbricals Flexor hallucis brevis Flexor hallucis longus tendon Flexor digitorum longus (tendon) Flexor digiti minimi brevis Abductor digiti minimi Flexor accessorius Fibularis longus (tendon) Flexor digitorum longus (tendon) Flexor hallucis longus (tendon) (b) Second layer (plantar aspect) Figure 10.24b
92
Plantar Muscles 3. Third layer 4. Deepest layer Flexor hallucis brevis
Adductor hallucis Flexor digiti minimi brevis 4. Deepest layer Plantar and dorsal interossei
93
Adductor hallucis (transverse head)
Adductor hallucis (oblique head) Interosseous muscles Flexor hallucis brevis Flexor digiti minimi brevis Fibularis longus (tendon) Flexor accessorius Flexor digitorum longus (tendon) Flexor hallucis longus (tendon) (c) Third layer (plantar aspect) Figure 10.24c
94
(d) Fourth layer (plantar aspect): plantar interossei
Figure 10.24d
Similar presentations
