Chapter 11 Muscles
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Transcript of Chapter 11 Muscles
Chapter 11 Muscles Muscles of facial expression Muscles of mastication Extrinsic tongue muscles Muscles of the neck and throat Back muscles Deep thorax muscles Abdominal wall muscles Superficial thorax muscles Shoulder muscles Elbow muscles Forearm muscles Hip & knee muscles Leg muscles
Chapter 11 Muscles
You are responsible for muscles described in class– Origin– Insertion– Action– Nerve - innervation (if given)
Be able to recognize muscles in all diagrams of text
Muscles of facial expression
Orbicularis oculi– Sphincter muscle of eyelid– O: frontal & maxillary bones– I: tissue of eyelid– Action: closes eye– Nerve: facial / CN VII
(11.6)
Muscles of facial expression
Zygomaticus – O: zygomatic bone– I: corners of mouth– Action: smiling– Nerve: facial / CN VII
(11.6)
Major and Minor
Muscles of mastication
Masseter – O: zygomatic arch– I: angle & ramus of
mandible– Action: elevate mandible– Nerve: trigeminal nerve /
CN V (foramen ovale)
(11.7a)Masseter
Muscles of mastication
Temporalis – O: temporal fossa– I: coronoid process of
mandible– Action: elevate and
retract mandible– Nerve: trigeminal n. /
CN V
(11.7a)
Extrinsic tongue muscles
Styloglossus – O: styloid process of
temporal bone– I: tongue– Action: retract & elevate
tongue– Nerve: hypoglossal n. /
CN XII
(11.7c)Styloglossus
Extrinsic tongue muscles
Hyoglossus – O: hyoid bone– I: tongue– Action: depresses tongue– Nerve: hypoglossal n. /
CN XII
(11.7c)
Hyoid bone
Muscles of neck & throat
Digastric – two muscle bellies with an
intermediate tendon attached to the hyoid bone
– O: inferior margin of mandible (anterior belly); mastoid process of temporal bone (posterior belly)
– I: hyoid bone– Action: elevate hyoid, stabilize
hyoid, depress mandible– Nerve: trigeminal n. / CN V
(anterior belly), facial n. / CN VII (posterior belly)
(11.8a)Anterior belly Posterior belly
Muscles of neck & throat
Stylohyoid – O: styloid process of
temporal bone– I: hyoid bone– Action: elevate & retract
hyoid, swallow– Nerve: facial n. / CN VII
(11.7c)
Stylohyoid
Muscles of neck & throat
Sternohyoid – O: manubrium &
medial end of clavicle– I: hyoid bone– Action: depress hyoid
(11.8a)
Sternohyoid
Muscles of neck & throat
Pharyngeal constrictors – O: mandible, pterygoid
process, hyoid, laryngeal cartilages
– I: posterior medial raphe of pharynx
– Action: peristaltic contraction / swallow
(11.8b)
Superior
Middle
Inferior
Muscles of neck & throat
Sternocleidomastoid – O: manubrium & medial
clavicle– I: mastoid process of
temporal bone– Action: head & neck
flexion, rotate head contralaterally
– Nerve: accessory n. / CN XI (11.8a)
Muscles of neck & throat
Sternocleidomastoid
Back muscles
Spinalis – O: spines of upper
lumbar and lower thoracic vertebrae
– I: spines of upper thoracic and cervical vertebrae
– Action: extends vertebral column
(11.9d)
Deep thorax muscles
External & internal intercostals – O&I: inferior & superior
border of ribs – Action: inspiration and
expiration
(11.10a)
Internal
Deep thorax muscles
Diaphragm – O: inferior internal
surface of rib cage & sternum, inferior costal cartilages, lumbar vertebrae
– I: central tendon– Action: flattens on
contraction (inspiration)– Nerve: phrenic nerves (11.10b)
Xiphoid process
Abdominal wall muscles Rectus abdominis
– O: pubic crest & symphysis– I: xiphoid process and
costal cartilages of ribs 5-7– Action: flex & rotate lumbar
vertebrae, fix & depress ribs, stabilize pelvis during walking, increase intraabdominal pressure
– Note: 3 tendinous insertions, aponeurosis & linea alba
(11.11ab)
Superficial thorax muscles
Pectoralis minor – O: anterior surface of
ribs 3-5– I: coracoid process of
scapula– Action: with ribs fixed,
pulls scapula anterior & inferior; with scapula fixed, pulls ribs superiorly
– Nerve: Medial and lateral pectoral nerves (C6-C8)
(11.13a)
Superficial thorax muscles
Superificial thorax muscles
Serratus anterior – O: ribs 1-8– I: vertebral border of
scapula– Action: hold scapula
against chest wall, moves inferior angle of scapula lateral & superior (abduction, pushing, punching)
– Nerve: long thoracic nerve (11.13a,8.1a reversed)
Superificial thorax muscles
Trapezius – O: occipital bone,
ligamentum nuchae, C7-T12 spinous processes
– I: acromion, spine of scapula, lateral third of clavicle
– Action: stabilize, elevate, adduct, depress scapula, extend head
– Nerve: Accessory (CNXI), C3 and C4 (11.13b)
Shoulder muscles
Pectoralis major – O: medial clavicle,
sternum, cartilage of ribs 1-6, aponeurosis of external oblique
– I: greater tubercle of humerus
– Action: arm-flexion, medial rotation, adduction, elevation of rib cage
(11.13a)
-Nerve: Medial and lateral pectoral nerves (C6-C8)
Shoulder muscles
Deltoid – O: lateral clavicle,
acromion & spine of scapula (compare to insertion of trapezius)
– I: deltoid tuberosity of humerus
– Action: arm-abduction, flexion, extension, medial & lateral rotation
– Nerve: Axillary nerve(C5-C-6) (11.13ab)
Shoulder muscles
Subscapularis – O: subscapular fossa– I: lesser tubercle of
humerus– Action: medial rotate
arm, stabilize shoulder joint
– Nerve: Subscapular nerves (C5-C7)
(11.14d)
Shoulder muscles
Infraspinatus – O: infraspinous fossa– I: greater tubercle of
humerus– Action: lateral rotate
humerus, stabilized shoulder joint
– Nerve: Suprascapular nerve
(11.14b)
Rotator cuff muscles
Act to stabilize head of humerus in glenoid cavity and prevent dislocation
Supraspinatous (Suprascapular nerve) Infraspinatus (Suprascapular nerve) Subscapularis (Subscapular nerve) Teres minor (Axillary nerve)
Elbow muscles
Triceps brachii – O: long head-
infraglenoid tubercle, lat. & med. heads-posterior shaft of humerus
– I: olecranon process of ulna
– Action: extend forearm, assist adduction of arm
– Nerve: Radial nerve (11.14b)
Elbow muscles
Biceps brachii – O: short head-coracoid
process, long head-tubercle above glenoid cavity and lip of glenoid cavity (intertubercular groove)
– I: radial tuberosity– Action: flex elbow, supinate
forearm, weak arm flexor– Nerve: Musculocutaneous
nerve (C5 & C6)
(11.14c)
Forearm muscles
Flexor carpi (radialis & ulnaris) – O: medial epicondyle
of humerus, ulna– I: metacarpals and
carpals– Action: wrist flexion,
abduct & adduct hand– Carpal tunnel (Median
nerve) syndrome p. 184
(11.15a)Anterior view
radialisulnaris
Forearm muscles
Extensor carpi– O: lateral epicondyle of
humerus– I: base of metacarpals – Action: extend, abduct,
and adducts wrist– Palpate forearm muscles
Hip & knee muscles
Quadriceps femoris – O: anterior inferior iliac
spine, superior margin of acetabulum, greater trochanter, shaft of femur
– I: patella and tibial tuberosity via patellar tendon
– Action: extend knee, flex thigh
Hip & knee muscles
Gluteus muscles– O: ilium, sacrum, coccyx– I: shaft & greater
trochanter of femur– Action: extend thigh (climb
stairs, running), lateral & medial rotate thigh, abduct thigh, steadies pelvis
Hip & knee muscles
Hamstrings– O: ischial tuberosity, shaft
of femur– I: lateral & medial
condyles and shaft of tibia, head of fibula, lateral condyle femur
– Action: extend thigh, flex knee
– Makes touching toes hard
Leg muscles
Tibialis anterior – O: lateral condyle and
shaft of tibia– I: tarsal and first
metatarsal bones– Action: dorsiflexion
Leg muscles
Gastrocnemius – O: medial & lateral
condyles of femur– I: calcaneus via Achilles
tendon– Action: plantar flexion, flex
knee