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
11
12
13
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
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Neurotransmitter
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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
Modiolus
Levator scapulae
Inferior pharyngeal
constrictor
Thyrohyoid
Sternothyroid
Omohyoid
Sternohyoid
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:
Modiolus
Levator scapulae
Inferior pharyngeal
constrictor
Thyrohyoid
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
Internal jugular vein
Thyrohyoid
Sternohyoid
Infrahyoid
group
Omohyoid:
Superior belly
Inferior belly
Sternocleidomastoid
Sternothyroid
Infrahyoid
group
Clavicle
O: Manubrium & medial clavicle;
I: Mastoid process of temporal bone
Action: Flexion in neck against
resistance
21
Lateral view
Trapezius:
O: Occipital bone, spine of C7
& all thoracic vertebrae;
I: Acromion & spinous process of scapula
Action: Extends heads, movement of
scapula
Stylohyoid
Hyoglossus
Mylohyoid
Digastric
(anterior belly)
Hyoid bone
Thyrohyoid
Omohyoid
(superior belly)
Sternothyroid
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
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
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
Common flexor tendon
Anterior view
Pronator teres
Supinator
Aponeurosis of biceps
brachii
Brachioradialis
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
pollicis longus
Flexor digitorum
superficialis
Flexor
retinaculum
Palmar
aponeurosis
(a) Superficial flexors
(b) Intermediate flexor
Flexor
digitorum
superficialis
tendons
Flexor
digitorum
superficialis
tendons
Flexor
digitorum
profundus
tendons
Flexor
digitorum
profundus
tendons
(c) Deep flexors
33
Anterior view of the forearm
Common flexor
tendon
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
superficialis
tendons
Flexor
digitorum
profundus
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
L5
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
Patella
Patellar ligament
Anterior muscles of thigh, superficial view
37
Iliac crest
includes
Iliacus
Psoas major
L5
Anterior superior iliac spine
Tensor fasciae latae
Medial compartment:
Pectineus
Adductor brevis
Anterior compartment:
Origin:
Insertion:
Quadriceps femoris tendon
Action:
Patella
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
Patella
Patellar ligament
39
Gluteal muscles, posterior view
Superficial
Deep
Iliac crest
Gluteus
minimus
Gluteus
medius
Sacrum
Gluteus
maximus
Coccyx
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:
Hamstring group:
Insertion:
Short head
Action:
Practice
42
Patella
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