Untitled Flashcards Set

Chapter 11: Axial Musculature

Introduction

• The skeletal muscles of the body can be subdivided into:

– Axial musculature

▪ Muscles that position the head and vertebral column

▪ Muscles that move the rib cage

– Appendicular musculature

▪ Muscles that stabilize or move the appendicular skeleton

• The muscles are innervated by nerves

The Four Groups of Axial Muscles

• The axial muscles can be placed into four groups based on location or function

– Muscles of the head and neck

– Muscles of the vertebral column

– Muscles of the rib cage and lateral walls of the abdominal and pelvic cavities

– Muscles of the pelvic floor

Muscles of the Head and Neck 

• Several groups of muscles of the head and neck are:

– Muscles of facial expression

– Extra-ocular muscles

– Muscles of mastication

– Muscles of the tongue

– Muscles of the pharynx

– Anterior muscles of the neck

• Muscles of Facial Expression

– Facial expression muscles are divided into five groups

▪ Mouth/eyes/scalp/nose/neck

▪ All are innervated by CN VII

– Orbicularis oris

– Buccinator

– Temporoparietalis

– Occipitofrontalis

– Platysma

• Extra-ocular Muscles

– Extrinsic eye muscles (muscles that control eye movement)

▪ Medial and lateral rectus muscles

▪ Superior and inferior rectus muscles

▪ Superior and inferior oblique muscles

▪ Inferior rectus/medial rectus/superior rectus/Inferior oblique: innervated by CN III

▪ Lateral rectus: innervated by CN VI

▪ Superior oblique: innervated by CN IV

– Eye movements

▪ Lateral rectus: rotates the eye laterally

▪ Medial rectus: rotates the eye medially

▪ Superior rectus: rotates the eye upward

▪ Inferior rectus: rotates the eye downward

▪ Superior oblique: rotates the eye downward and laterally

▪ Inferior oblique: rotates the eye upward and laterally

• Muscles of Mastication

– Masseter

– Temporalis

– Pterygoids

– All are innervated by CN V

• Muscles of the Tongue

– Genioglossus

– Hyoglossus

– Palatoglossus

– Styloglossus

– Genioglossus/Hyoglossus/ Styloglossus: innervated by CN XII

– Palatoglossus: innervated by CN X

• Muscles of the Pharynx

– Pharyngeal constrictors: Superior/Middle/Inferior constrictors

– Laryngeal elevators: Palatopharyngeus/ Salpingopharyngeus/ Stylopharyngeus

– Palatal muscles: Tensor veli palatini/ levator veli palatini

– Constrictors are innervated by CN X

– Elevators are innervated by CN IX and CN X

– Palatals are innervated by CN V and CN X

• Anterior Muscles of the Neck

– Digastric: Anterior belly (CN V)/ Posterior belly (CN VII)

– Mylohyoid: CN V

– Geniohyoid: CN XII

– Stylohyoid: CN VII

– Sternocleidomastoid: CN XI

– Omohyoid: Cervical nerve C 1–C 3

– Sternothyroid: Cervical nerve C 1–C 3

– Sternohyoid: Cervical nerve C 1–C 3

– Thyrohyoid: CN XII

Muscles of the Vertebral Column

• The muscles of the back form three distinct layers

– Superficial layer (extrinsic back muscles): move the neck

– Intermediate layer (extrinsic back muscles): move the vertebral column

– Deep layer (intrinsic back muscles): interconnect the vertebrae

• The Superficial Layer of the Intrinsic Back Muscles

– Splenius capitis

– Splenius cervicis

– Both are innervated by cervical nerves

• The Intermediate Layer of the Intrinsic Back Muscles

– Erector spinae (group of three muscles)

▪ Spinalis (most medial of the three)

▪ Longissimus

▪ Iliocostalis (most lateral of the three)

• The Deep Layers of the Intrinsic Back Muscles

– Transversospinales (a group of five muscles)

▪ Semispinalis

▪ Multifidus

▪ Rotatores

▪ Interspinales

▪ Intertransversarii

• Spinal Flexors

– Longus capitis

– Longus colli

▪ The above two muscles rotate or flex the neck

– Quadratus lumborum

▪ Flexes the vertebral column laterally

Oblique and Rectus Muscles

• These muscles can be grouped in this manner:

– Cervical muscles

▪ Scalene muscles

– Thoracic muscles

▪ Intercostals/transversus muscles/serratus

– Abdominal muscles

▪ Oblique/Transversus abdominis

• Cervical muscles

– Scalene muscles

▪ Anterior

▪ Middle

▪ Posterior

– All scalenes will elevate the ribs (inhalation)

• Thoracic muscles

– Intercostal muscles

▪ External intercostal: elevates the ribs

▪ Internal intercostal: depresses the ribs

– Transversus thoracis: depresses the ribs

– Serratus posterior muscles

▪ Superior: elevates the ribs

▪ Inferior: depresses the ribs

• Abdominal muscles

– External oblique

▪ Compresses the abdomen/depresses ribs/laterally flexes the torso

– Internal oblique

▪ Compresses the abdomen/depresses ribs/laterally flexes the torso

• Rectus muscles

– Cervical region

▪ Geniohyoid/Omohyoid

▪ Sternohyoid/Sternothyroid

– Thoracic region

▪ Diaphragm

– contracts and expands thoracic cavity

– Abdominal region

▪ Rectus abdominis

– Depresses ribs/flexes vertebral column

– Consists of linea alba and tendinous inscriptions

• The Diaphragm

– Major breathing muscle

– When it contracts, the diaphragm lowers to increase the volume of the thoracic cavity

▪ Inspiration

– When it relaxes, the diaphragm rises to lower the volume of the thoracic cavity

▪ Expiration

Muscles of the Perineal Region and the Pelvic Diaphragm 

• The perineal region (pelvic floor)

– Divided into two triangles

▪ Urogenital triangle (anterior triangle)

▪ Anal triangle (posterior triangle)

– Pelvic diaphragm: forms the foundation

– The two triangles are separated by:

▪ Superficial transverse perineal muscle

• Muscles of the urogenital triangle

– Superficial urogenital triangle muscles

▪ Superficial transverse perineal

▪ Ischiocavernosus

▪ Bulbospongiosus

– Deep urogenital triangle muscles

▪ Deep transverse perineal

▪ External urethral sphincter

• Muscles of the anal triangle

– Coccygeus

– Levator ani

▪ Iliococcygeus

▪ Pubococcygeus

– External anal sphincter

Chapter 11: Appendicular Muscles

Appendicular muscles are responsible for:

▪ Stabilizing the pectoral and pelvic girdles

▪ Moving the upper and lower limbs

▪ Absorbing shocks and jolts as you walk, run, or jump

▪ Aiding in strengthening the joint area

• Two major groups of appendicular muscles

– The muscles of the pectoral girdle and upper limbs

– The muscles of the pelvic girdle and lower limbs

Factors Affecting Appendicular Muscle Function 

• Action lines of the shoulder joint

– Direction of pull

– Flexion and extension at the shoulder joint

– Adduction and abduction at the shoulder joint

– Medial and lateral rotation at the shoulder joint

• Spurt and shunt muscles

– Flexors and extensors

– Spurt

▪ Muscle that inserts close to the joint

– Shunt

▪ Muscle that inserts far away from the joint

• Action lines at the hip joint

– Flexion and extension

– Abduction and adduction

– Medial rotation and lateral rotation

Muscles of the Pectoral Girdle and Upper Limbs 

• Muscles associated with the pectoral girdle and upper limbs can be divided into four groups

– Muscles that position the pectoral girdle

– Muscles that move the arm

– Muscles that move the forearm and hand

– Muscles that move the hand and fingers

• Muscles That Position the Pectoral Girdle

– These muscles also coordinate with the muscles that move the arm

▪ Trapezius: Rotates scapula and extend the neck

▪ Rhomboid: Adducts the scapula

▪ Levator scapulae: Elevates the scapula

▪ Pectoralis minor: Protracts the shoulder

▪ Serratus anterior: Protracts the scapula

▪ Subclavius: Protracts the scapula

Muscles of the Pectoral Girdle and Upper

Limbs (3 of 10)

• Muscles That Move the Arm

– Deltoid: Abducts the arm

– Supraspinatus: Abduction

at the shoulder

– Infraspinatus: Lateral

rotation at the shoulder

– Subscapularis: Medial

rotation at the shoulder

– Teres major: Extension and

medial rotation at shoulder

– Teres minor: Lateral

rotation and adduction at

shoulder

9

Muscles of the Pectoral Girdle and Upper

Limbs (4 of 10)

• Muscles That Move the Arm

– Coracobrachialis: Adduction

and flexion at shoulder

– Pectoralis major: Adducts,

flexes, and medially rotates

the arm

– Latissimus dorsi: Extension,

adduction, medial rotation at

shoulder

• Rotator cuff: consists of the

following muscles: supraspinatus,

infraspinatus, subscapularis, and

teres minor

Muscles of the Pectoral Girdle and Upper

Limbs (5 of 10)

• Muscles That Move the Forearm and

Hand

– Triceps brachii: Extension at

the elbow

– Biceps brachii: Flexion at the

elbow and supinates the forearm

– Brachialis: Flexion at the elbow

– Brachioradialis: Flexion at the

elbow

– Anconeus: Extension at the

elbow

– Pronator teres: Pronates the

forearm

– Supinator: Supinates the

forearm

11

Muscles of the Pectoral Girdle and Upper

Limbs (6 of 10)

• Muscles That Move the Forearm

and Hand

– Flexor carpi ulnaris: Flexion

and adduction at wrist

– Flexor carpi radialis:

Flexion and abduction at

wrist

– Palmaris longus: Flexion at

wrist

Muscles of the Pectoral Girdle and Upper

Limbs (7 of 10)

• Muscles That Move the

Forearm and Hand

– Extensor carpi ulnaris:

Extension and adduction

at wrist

– Extensor carpi radialis:

Extension and abduction

at wrist

▪ Extensor carpi

radialis longus

▪ Extensor carpi

radialis brevis

– Pronator quadratus:

Pronates forearm and

hand

13

Muscles of the Pectoral Girdle and Upper

Limbs (8 of 10)

• Muscles That Move the Hand and Fingers

– Extrinsic Muscles of the Hand

▪ These muscles are found mostly in

the forearm

– Abductor pollicis longus

– Extensor digitorum

– Extensor pollicis brevis

– Extensor indicis

– Extensor digiti minimi

– Flexor digitorum superficialis

– Flexor digitorum profundus

– Flexor pollicis longus

Extensor retinaculum

(not a muscle)

Flexor retinaculum (not

a muscle)

Muscles of the Pectoral Girdle and Upper

Limbs (9 of 10)

• Muscles That Move the Hand and Fingers

– Extrinsic Muscles of the Hand

▪ Tendons of the muscles listed on

the previous slide pass through

synovial tendon sheaths,

located within the wrist area

15

Muscles of the Pectoral Girdle and Upper

Limbs (10 of 10)

• Muscles That Move the Hand and Fingers

– Intrinsic Muscles of the Hand

▪ These muscles are found mostly

in the palm or the dorsum of the

hand

– Adductor pollicis

– Opponens pollicis

– Palmaris brevis

– Abductor digiti minimi

– Abductor pollicis brevis

– Flexor pollicis brevis

– Flexor digiti minimi brevis

– Opponens digiti minimi

– Lumbrical

– Dorsal interossei

– Palmar interossei

Compartments and Sectional Anatomy of

the Arm and Forearm (1 of 2)

• The deep fascia extends between the bones and the superficial fascia and

separates the soft tissues of the limb into separate compartments

– Lateral intermuscular septum

– Medial intermuscular septum

– Both septa create compartments within the upper arm

Compartment Muscles Blood Vessels Nerves doublecross

Anterior

compartment

Biceps brachii

Brachialis

Coracobrachialis

Brachial artery

Inferior ulnar collateral artery

Superior ulnar collateral

artery

Brachial veins

Median nerve

Musculocutaneous

nerve

Ulnar nerve

Posterior

compartment

Triceps brachii Deep brachial artery Radial nerve

17

Compartments and Sectional Anatomy of

the Arm and Forearm (2 of 2)

• The forearm

– Divided into four compartments

Compartment Muscles Blood Vessels Nerves

Anterior

compartment

Superficial

Flexor carpi radialis

Flexor carpi ulnaris

Flexor digitorum superficialis

Palmaris longus

Pronator teres

Radial artery

Ulnar artery

Anterior interosseous artery

Anterior ulnar recurrent artery

Posterior ulnar recurrent artery

Median nerve

Ulnar nerve

Anterior interosseous nerve

Ulnar nerve

Median nerve

Deep Flexor digitorum profundus

Flexor pollicis longus

Pronator quadratus

Blank

Lateral

compartment

Brachioradialis

Extensor carpi radialis brevis

Extensor carpi radialis longus

Radial artery Radial nerve

Posterior

compartment

Abductor pollicis longus

Anconeus

Extensor carpi ulnaris

Extensor digitorum

Extensor digiti minimi

Extensor indicis

Extensor pollicis brevis

Extensor pollicis longus

Supinator

Posterior interosseous artery

Posterior ulnar recurrent artery

Posterior interosseous

nerve

Muscles of the Pelvic Girdle and Lower

Limb (1 of 16)

• The muscles of the lower limbs are larger

and more powerful than those of the upper

limbs

• These muscles can be divided into three

groups

– Muscles that move the thigh

– Muscles that move the leg

– Muscles that move the foot and toes

19

Muscles of the Pelvic Girdle and Lower

Limb (2 of 16)

• Muscles That Move the Thigh

– Originate on the pelvis; many are

large and powerful

– Four groups

▪ Gluteal group

▪ Lateral rotator group

▪ Adductor group

▪ Iliopsoas group

Muscles of the Pelvic Girdle and Lower

Limb (3 of 16)

• Muscles That Move the Thigh

– The gluteal muscles

▪ Gluteus maximus

– Extension and lateral

rotation at the hip

– Inserts within the tensor

fasciae latae via the

iliotibial tract to the tibia

▪ Gluteus medius

– Abduction and medial

rotation at the hip

▪ Gluteus minimus

– Abduction and medial

rotation at the hip

▪ Tensor fasciae latae

– Extension of the knee

and lateral rotation of the

leg

21

Muscles of the Pelvic Girdle and Lower

Limb (4 of 16)

• Muscles That Move the Thigh

– The lateral rotator group

▪ Obturator muscles

– Lateral rotation and

abduction of hip

▪ Piriformis

– Lateral rotation and

abduction of hip

▪ Gemelli muscles

– Lateral rotation and

abduction of hip

▪ Quadratus femoris

– Lateral rotation of hip

Muscles of the Pelvic Girdle and Lower

Limb (5 of 16)

• Muscles That Move the Thigh

– The adductor group

▪ Adductor brevis

– Adduction and flexion at the hip

▪ Adductor longus

– Adduction and medial rotation at the

hip

▪ Adductor magnus

– Adduction at the hip

▪ Pectineus

– Flexion and adduction at the hip

▪ Gracilis

– Flexion and medial rotation at the

knee

– Adduction and medial rotation at the

hip

23

Muscles of the Pelvic Girdle and Lower

Limb (6 of 16)

• Muscles That Move the Thigh

– The iliopsoas group

▪ Iliacus

– Flexion at the hip

▪ Psoas major

– Flexion at the hip

Muscles of the Pelvic Girdle and Lower

Limb (7 of 16)

• Muscles That Move the Leg

– Extensors of the knee

(collectively called the

quadriceps femoris). The first

three in this list are the vastus

muscles

▪ Vastus intermedius

– Extends the leg

▪ Vastus lateralis

– Extends the leg

▪ Vastus medialis

– Extends the leg

▪ Rectus femoris

– Extends the leg

– Flexion at the hip

25

Muscles of the Pelvic Girdle and Lower

Limb (8 of 16)

• Muscles That Move the Leg

– Flexors of the knee (collectively

called the hamstrings)

▪ Biceps femoris

– Flexes the leg

– Extension at the hip

▪ Semimembranosus

– Flexes the leg

▪ Semitendinosus

– Flexes the leg

Muscles of the Pelvic Girdle and Lower

Limb (9 of 16)

• Muscles That Move the Leg

– Flexors of the knee

▪ Sartorius

– Allows crossing of the

lower leg

– Flexes, abducts, and

laterally rotates the hip

– Not a part of the

quadriceps

▪ Popliteus

– Medially rotates the hip

– Not a part of the

hamstrings

27

Muscles of the Pelvic Girdle and Lower

Limb (10 of 16)

• Muscles That Move the Foot and

Toes

– Extrinsic Muscles of the Foot

▪ Muscles that originate on the

distal end of the femur or on

the tibia or fibula but yet move

the foot and toes

– Intrinsic muscles of the foot

▪ Muscles that originate on

some aspect of the foot but yet

move the toes

Muscles of the Pelvic Girdle and Lower

Limb (11 of 16)

• Muscles That Move the Foot and

Toes

– Extrinsic Muscles of the Foot

▪ Tibialis anterior: Dorsiflexion

and inversion of the foot

▪ Gastrocnemius: Plantar flexion

▪ Fibularis brevis: Plantar flexion

and eversion of the foot

▪ Fibularis longus: Plantar

flexion and eversion of the foot

▪ Plantaris: Plantar flexion

▪ Soleus: Plantar flexion

▪ Tibialis posterior: Plantar

flexion and inversion of the foot

29

Muscles of the Pelvic Girdle and Lower

Limb (12 of 16)

• Muscles That Move the Foot and

Toes

– Extrinsic Muscles of the Foot

▪ The gastrocnemius and

soleus insert onto the

calcaneal tendon, which

inserts onto the calcaneus

(calcaneal bone)

▪ The superior extensor

retinaculum and inferior

extensor retinaculum

stabilize the tendons in the

tarsal area

Muscles of the Pelvic Girdle and Lower

Limb (13 of 16)

•Muscles That Move the

Foot and Toes

– Extrinsic Muscles of

the Foot

▪ Flexor digitorum

longus: flexion of toes

2–5

▪ Flexor hallucis

longus: flexion of the

hallux

▪ Extensor digitorum

longus: extension of

toes 2–5

▪ Extensor hallucis

longus: extension of

the hallux

31

Muscles of the Pelvic Girdle and Lower

Limb (14 of 16)

• Muscles That Move the Foot and Toes

– Intrinsic Muscles of the Foot

▪ Abductor hallucis: abduction of the

hallux

▪ Flexor digitorum brevis: flexion of

toes 2–5

▪ Abductor digiti minimi: abduction

of the little toe

▪ Lumbricals: extension of toes 2–5

▪ Flexor hallucis brevis: flexion of

the hallux

▪ Flexor digiti minimi brevis: flexion

of the little toe

▪ Plantar aponeurosis is superficial fascia tissue of the plantar surface of the foot

– Intrinsic Muscles of the Foot

▪ Quadratus plantae: flexion of toes 2–5

▪ Adductor hallucis: adducts the hallux

▪ Plantar interossei: adduction of toes 3–5

Muscles That Move the Foot and Toes

Intrinsic Muscles of the Foot

▪ Extensor digitorum brevis

– Extension of the toes of digits 1–4

▪ Dorsal interossei

– Abduction of toes 3 and 4

– Extension of toes 2 through 4

Compartments and Sectional Anatomy of the Thigh and Leg

– Medial and lateral intermuscular septa

– Thigh is divided into compartments:

▪ Anterior

▪ Posterior

▪ Medial

– Lower leg is divided into compartments:

▪ Anterior

▪ Lateral

▪ Superficial posterior

▪ Deep posterior