Muscles
Chapter 10
Objectives: The Muscular System
• about 600 human skeletal muscles
• constitute about half of our body weight
• three kinds of muscle tissue
– skeletal, cardiac, smooth
• specialized for one major purpose
– converting the chemical energy in ATP into the
mechanical energy of motion
• myology – the study of the muscular system
• Learn major groupings of Skeletal
muscles
• Understand how movements occur at
joints
• Learn the origin, insertion, function of
some major muscles
• Functions? Movement, stability, control of body
openings, heat production
10-2
11-1
Fascicle Orientation of Muscles
Attachment Sites: Origin and Insertion
Unipennate
Triangular
Parallel
Bipennate
Multipennate
Fusiform
Tendon
Circular
Belly
Tendon
Direct & indirect muscle attachment
• Origin = bone that does not move when muscle shortens
(normally proximal)
• Insertion = movable bone (usually distal)
10-3
11-4
Hints: Names of Skeletal Muscle
• Most movements = several muscles
working
• Most muscles are arranged in opposing
pairs at joints
– prime mover or agonist - contracts to
cause desired action
– antagonist stretches and yields to
prime mover
– synergists & fixators stabilize joints &
origin of the prime mover
• Direction fibers run, size, shape, action,
number of origins/locations
• E.G.
- Direction: Rectus femoris
- Size: gluteus maximus
- Shape: serratus anterior
- Action: Flexor carpi radialis
- Number of origins: Triceps brachii
11-5
11-6
1
11-7
Muscles in Facial Expression
Superficial
11-8
Muscles in Facial Expression
Deep
Galea aponeurotica
Frontalis
Galea aponeurotica
Frontalis (cut)
Temporalis
Corrugator supercilii
Corrugator supercilii
Orbicularis oculi
Occipitalis
Orbicularis oculi
Nasalis
Nasalis
Levator labii superioris
Levator labii superioris
Levator anguli oris
Zygomatic arch
Zygomaticus minor
Zygomaticus minor
Zygomaticus major
Masseter
Risorius
Buccinator
Zygomaticus major
Orbicularis oris
Modiolus
Depressor anguli oris
Depressor labii inferioris
Orbicularis oris
Masseter
Mentalis (cut)
Platysma
Modiolus
Risorius (cut)
Mentalis
Within superficial fascia
Arise (origin) ??? Insetion?
Depressor labii
inferioris
Depressor anguli oris
Buccinator
Muscles that Move the Mandible
• Masseter,
temporalis, &
pterygoids
• Origin=skull
• Insert = mandible
• Masseter elevate
the mandible
(biting)
• Temporalis retracts
& elevates
• Pterygoid muscles
Muscles of Chewing and Swallowing
• extrinsic muscles of the tongue
• intrinsic muscles of tongue
– vertical, transverse, and longitudinal fascicles
Styloid process
Palatoglossus
Styloglossus
Mastoid process
Posterior belly of digastric (cut)
Superior pharyngeal constrictor (cut)
Inferior longitudinal
muscle of tongue
Stylohyoid
Middle pharyngeal constrictor
Genioglossus
Hyoglossus
Mylohyoid (cut)
Hyoid bone
Geniohyoid
Larynx
Inferior pharyngeal constrictor
Trachea
Esophagus
11-11
2
Muscles Used in Breathing
Muscles that Move the Head
• Inspiration: thoracic cavity
increases in size
– external intercostals lift
ribs
– diaphragm contracts:
dome is flattened
• During expiration, thoracic
cavity decreases in size
– internal intercostal mm
used in forced
expiration
Digastric
• Sternocleidomastoid muscle
– arises from sternum & clavicle & inserts onto mastoid
process
– contraction of one, laterally flexes the neck and rotates
face in opposite direction
Scalenes – Cervical Vert. to Ribs 1 & 2
Quadratus lumborum fills in space
between 12th rib & iliac crest to
create posterior body wall
11-13
11-14
Muscles of Abdominal Wall
• 4 layers of muscle in the abdominal wall
Muscles of the Anterior Abdominal Wall
•Inguinal canal = passageway from pelvis
• four pairs of sheetlike
muscles
–
–
–
–
•Inguinal ring = opening
external abdominal oblique
internal abdominal oblique
transverse abdominal
rectus abdominis
Posterior
External abdominal oblique
Anterior
Internal abdominal oblique
Peritoneum
Transverse abdominal
Rectus abdominis
Subcutaneous fat
Rectus sheath
Linea alba
Skin
Aponeurosis
Figure 10.14
10-15
11-16
Deep Muscles of the Back
Superficial Muscles of Back
• erector spinae:
Superficial
– iliocostalis, longissimus,
spinalis
– from cranium to sacrum
– extension and lateral flexion
of vertebral column
Deep
Semispinalis capitis
Sternocleidomastoid
Splenius capitis
Trapezius
Levator scapulae
Splenius capitis
Supraspinatus
Splenius cervicis
Infraspinatus
Teres minor
Erector spinae:
Semispinalis capitis
Semispinalis cervicis
Semispinalis
thoracis
Iliocostalis
Longissimus
Teres major
Erector spinae
Longissimus capitis
Serratus posterior
superior
Rhomboideus minor
Rhomboideus major
Deltoid
Superior nuchal line
Spinalis
Serratus anterior
Serratus posterior
inferior
Latissimus
dorsi
Serratus posterior inferior
External abdominal
oblique
External abdominal
oblique
Thoracolumbar
fascia
Internal abdominal
oblique
Gluteus medius
Gluteus minimus
Internal abdominal
oblique
Multifidus
Quadratus lumborum
External abdominal
oblique (cut)
Gluteus maximus
Lateral rotators
10-17
Figure 10.18
10-18
3
Anterior Group of Muscles of
Pectoral Girdle
• pectoralis minor
Male
Ischiocavernosus
Bulbospongiosus
• serratus anterior
– ribs 1-9 to scapula
– abducts and rotates or
depresses scapula
– ribs 3-5 to scapula
Female
Ischiocavernosus
Urethra
Bulbospongiosus
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Vagina
Anus
Gluteus maximus
Subclavius
Gluteus maximus
Pectoralis minor (cut)
(a) Superficial perineal space, inferior view
Pectoralis minor
Internal intercostals
Serratus anterior
External intercostals
Rectus abdominis (cut)
Rectus sheath
• three muscles found just deep to the skin
• ischiocavernosus –
• bulbospongiosus –
External abdominal
oblique (cut)
Internal abdominal
oblique (cut)
Internal abdominal
oblique
Posterior wall of rectus sheath
(rectus abdominis removed)
Inguinal ligament
Transverse abdominal (cut)
10-19
(b) Deep
Stabilizing the Pectoral Girdle
10-20
Figure 10.15b
Stabilizing the Pectoral Girdle
• Anterior thoracic
muscles
– Subclavius extends
from 1st rib to
clavicle
– Pectoralis minor
extends from ribs to
coracoid process
– Serratus anterior
extends from ribs to
inner surface of
scapula
Posterior thoracic muscle
– Trapezius extends from
skull & vertebrae to
clavicle & scapula
– Levator scapulae
extends from cervical
vertebrae to scapula
– Rhomboideus extends
from thoracic vertebrae
to vertebral border of
scapula (major and
minor)
11-21
11-22
Muscles Acting on Arm
Muscles Acting on Arm
• nine muscles cross the shoulder joint and insert on humerus
• two are axial muscles because they originate on axial
skeleton
1. pectoralis major –
2. latissimus dorsi –
• 7 scapular muscles
originate on scapula
1. deltoid
• rotates and abducts arm
• intramuscular injection site
• extension and medial
rotation of humerus
Supraspinatus
Clavicle
Spine of scapula
Sternum
Greater tubercle
of humerus
Infraspinatus
Pectoralis major
Triceps brachii:
Lateral head
Long head
Medial head
Coracobrachialis
Biceps brachii
Brachialis
Figure 10.24a
(a) Anterior view
Humerus
Pectoralis major
Supraspinatus
3. coracobrachialis
Teres minor
Teres major
Triceps brachii:
Sternum
Brachioradialis
2. teres major
Deltoid
Clavicle
Deltoid
Spine of scapula
Greater tubercle
of humerus
Infraspinatus
• flexes and medially rotates
arm
Triceps brachii:
Lateral head
Long head
Coracobrachialis
Lateral head
Long head
Medial head
Humerus
Teres minor
Teres major
Biceps brachii
Latissimus dorsi
Brachialis
Brachioradialis
Triceps brachii:
Lateral head
Long head
4 – 7 remaining four form
the rotator cuff
(a) Anterior view
Figure 10.24a
Latissimus dorsi
(b) Posterior view
Figure 10.24b
10-23
Figure 10.24b
10-24
(b) Posterior view
4
Rotator Cuff Muscles
Rotator Cuff Muscles
• tendons of the remaining four scapular muscles form the
rotator cuff
• “SITS” muscles – for the first letter of their names
– supraspinatus
– infraspinatus
– teres minor
– subscapularis
Anterior
Posterior
Clavicle
Rotator cuff (SITS)
muscles:
Acromion
Supraspinatus
Coracoid
process
Glenoid cavity
Infraspinatus
Teres minor
Subscapularis
Inferior angle
Figure 10.26
10-25
Anterior View of Cadaver Chest
10-26
Back Muscles of Cadaver
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Levator scapulae
Rhomboideus
minor
Rhomboideus
major
Deltoid
Infraspinatus
Deltoid
Teres minor
Pectoralis major
Medial border
of scapula
Biceps brachii:
Long head
Teres major
Short head
Serratus anterior
Triceps brachii:
Lateral head
Long head
External
abdominal
oblique
Latissimus dorsi
(a) Anterior view
(b) Posterior view
© The McGraw-Hill Companies, Inc./Rebecca Gray, photographer/Don Kincaid, dissections
10-27
Flexors of the Forearm (elbow)
• Cross anterior surface of
elbow joint & form flexor
muscle compartment
• Biceps brachii
– scapula to radial
tuberosity
– flexes shoulder & elbow
& supinates hand
• Brachialis
– humerus to ulna
11-29
Figure 10.25b
10-28
Extensors of the Forearm (elbow)
• Cross posterior
surface of elbow joint
& forms extensor
muscle compartment
• Triceps brachii
– long head arises
scapula
– medial & lateral
heads from humerus
inserts on ulna
11-30
5
Cross Section of Upper Limb
Biceps brachii
Deltoid
Triceps brachii
Pectoralis major
Biceps brachii:
Short head
Long head
Brachialis
Common flexor
tendon
Common flexor tendon
(a)
Coracobrachialis
Supinator
Pronator teres
Humerus
Aponeurosis of biceps
brachii
Anterior view
Latissimus dorsi tendon
(b)
Interosseous
membrane
Teres major
Brachioradialis
Triceps brachii:
Lateral head
Long head
(c)
Flexor carpi radialis
Palmaris longus
(a)
Flexor
digitorum
superficialis
Flexor
digitorum
profundus
Flexor
pollicis longus
Flexor
pollicis
longus
Flexor carpi ulnaris
Extensor carpi radialis
longus and brevis
Anterior
Biceps brachii
Lateral
Flexor digitorum
superficialis
Medial
Brachialis
Flexor
retinaculum
Posterior
Triceps brachii:
Medial head
Long head
Lateral head
Key
Anterior (flexor)
compartment, superficial
Anterior (flexor)
compartment, deep
(b)
Posterior (extensor)
compartment
Palmar
aponeurosis
Other muscles
Supinator
Pronator teres
Flexor carpi radialis
Palmaris longus
Radius
Flexor digitorum superficialis
Brachioradialis
(a) Superficial flexors
Extensor carpi radialis longus
Flexor
digitorum
superficialis
tendons
Flexor
digitorum
superficialis
tendons
Flexor
digitorum
profundus
tendons
Flexor
digitorum
profundus
tendons
(b) Intermediate flexor
(c) Deep flexors
Flexor pollicis longus
Flexor carpi ulnaris
Extensor carpi radialis brevis
Extensor digitorum
Flexor digitorum profundus
Ulna
Anconeus
Extensor digiti minimi
10-31
Figure 10.28
Extensor carpi ulnaris
(c)
Intrinsic Hand Muscles
• Retinaculum
Triceps brachii
Brachioradialis
• dorsal interosseous muscles
• palmar interosseous muscles
• lumbricals
Olecranon
Anconeus
Extensor carpi
radialis longus
Anconeus
Supinator
Extensor carpi
radialis brevis
Posterior view
Flexor carpi
ulnaris
Abductor pollicis
longus
Extensor digiti
minimi
Extensor pollicis
brevis
First dorsal
interosseous
Tendon of flexor
digitorum profundus
Adductor
pollicis
Tendon of flexor
digitorum superficialis
Extensor pollicis
brevis
Extensor pollicis
longus
Tendon of flexor
pollicis longus
Lumbricals
Extensor indicis
Opponens
digiti minimi
Extensor pollicis
longus
Tendon of
extensor indicis
Tendon sheath
Abductor pollicis
longus
Extensor digitorum
Extensor carpi
ulnaris
Flexor pollicis
brevis
Flexor digiti
minimi brevis
Tendons of extensor
carpi radialis longus
and brevis
Abductor pollicis
brevis
Abductor digiti
minimi
Tendons of extensor
digitorum
Opponens pollicis
Flexor retinaculum
Tendons of:
Tendons of:
Abductor pollicis
longus
Flexor carpi ulnaris
Flexor carpi
radialis
Flexor digitorum
superficialis
Flexor pollicis
longus
Palmaris longus
(a) Palmar aspect, superficial
(b) Deep extensors
(a) Superficial extensors
Posterior Muscles Acting on Hip
and Femur
Muscles Acting on the Hip and Femur
• anterior muscles of the
hip
– iliacus
• flexes thigh at hip
• iliacus portion arises from
iliac crest and fossa
– psoas major
• flexes thigh at hip
• arises from lumbar
vertebrae
– they share a common
tendon on the femur
• lateral and posterior
muscles of the hip
Iliopsoas:
Iliacus
Psoas
major
– tensor fasciae latae
– gluteus maximus
Piriformis
• prime hip extensor
Pectineus
Adductor
magnus
Adductor
brevis
Adductor
longus
Obturator
externus
– gluteus medius and
minimus
• abduct and medially rotate
thigh
• 6 under gluteus minimus!!
Gracilis
Superficial
Deep
Iliac crest
Gluteus
medius
Sacrum
Gluteus
maximus
Coccyx
Ischial
tuberosity
Gluteus
minimus
Lateral rotators:
Piriformis
Gemellus
superior
Obturator
internus
Obturator
externus
Gemellus
inferior
Quadratus
femoris
Insertion of
gracilis on
tibia
Figure 10.33
10-35
10-36
6
Muscles Crossing the Hip Joint
Muscles Acting on Hip and Femur
• medial (adductor)
compartment of thigh
• primary adductors of the
thigh
–
–
–
–
Iliopsoas:
Iliacus
Psoas
major
Piriformis
Pectineus
Obturator
externus
Adductor
magnus
Adductor
brevis
Adductor
longus
adductor longus
adductor magnus
gracilis
pectineus
Adductor muscles
– bring legs together
– cross hip joint
medially
• Pulled groin muscle
Gracilis
Insertion of
gracilis on
tibia
Figure 10.33
10-37
11-38
Anterior Thigh Cadaver Muscles
Muscles Acting on the Knee and Leg
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Lateral
Iliac crest
Quadriceps femoris has
4 heads
1. Rectus femoris
crosses hip (biggie)
2. Vastus lateralis
3. Vastus intermedius
4. Vastus medialus
Iliopsoas:
Iliacus
Psoas major
Medial
L5
Anterior superior
iliac spine
Tensor fasciae latae
Tensor fasciae
latae
Femoral vein
Iliopsoas
Femoral artery
Medial compartment:
Adductor magnus
Pectineus
Pectineus
Sartorius
Adductor brevis
Iliotibial band
Adductor longus
Gracilis
Adductor longus
Iliotibial band
Anterior compartment:
Sartorius
Quadriceps femoris:
Vastus
intermedius
Rectus femoris
Vastus lateralis
Vastus medialis
• Sartorius!!!!!!
Gracilis
Quadriceps femoris:
Rectus femoris
Vastus lateralis
Vastus medialis
Quadriceps
femoris tendont
Patella
Quadriceps tendon
Patellar
ligament
Patella
(a) Superficial
(b) Deep
© The McGraw-Hill Companies, Inc./Rebecca Gray, photographer/Don Kincaid, dissections
Figure 10.36
10-39
10-40
Figure 10.35
Anterior Compartment of Leg
Muscles Acting on the Knee and Leg
Patella
Patellar
ligament
• posterior (flexor)
compartment of the
thigh
– hamstring muscles
Gluteus medius
Gluteus maximus
Tibia
Gastrocnemius
Fibularis
longus
Soleus
Fibularis
brevis
Gracilis
– from lateral to medial;
biceps femoris
semitendinosus
semimembranosus
Adductor magnus
Tibialis
anterior
Extensor
digitorum longus
Tibialis
anterior
Iliotibial band
Extensor
hallucis
longus
Extensor
digitorum
longus
Vastus lateralis
Extensor retinacula
Fibularis
tertius
Hamstring group:
Biceps femoris
Long head
Short head
Extensor
hallucis
brevis
Semitendinosus
Extensor
digitorum
brevis
Semimembranosus
(a)
Figure 10.37
10-41
(b)
(c)
(d)
10-42
7
Posterior Compartment of Leg
Superficial Group
Intrinsic Muscles of Foot
Lumbricals
Plantaris
Heads of
gastrocnemius
(cut)
Flexor digiti
minimi brevis
Popliteus
Fibularis
longus
Abductor digiti
minimi
Flexor hallucis
longus tendon
Gastrocnemius:
Soleus
Medial head
Lateral head
Flexor digitorum
longus tendon
Abductor hallucis
(cut)
Abductor hallucis
Flexor digitorum
brevis
Quadratus plantae
Plantar aponeurosis
(cut)
Flexor digitorum
brevis (cut)
Calcaneus
Tendon of
plantaris
(a) Layer 1, plantar view
(b) Layer 2, plantar view
Gastrocnemius
(cut)
Fibularis
longus
Tendon of
gastrocnemius
Fibularis
brevis
Flexor
digitorum
longus
Flexor
hallucis
longus
Adductor hallucis
Flexor hallucis brevis
Flexor digiti
minimi brevis
Flexor hallucis
longus tendon (cut)
Calcaneal tendon
Plantar
interosseous
Dorsal
interosseous
Abductor hallucis (cut)
Calcaneus
(a)
Quadratus plantae
(cut)
Flexor digitorum
longus tendon (cut)
(b)
10-43
(c) Layer 3, plantar view
(d) Layer 4, plantar view
(e) Layer 4, dorsal view
10-44
8