Lecture 16: Skeletal Muscles II (Trunk)

Question 1

What is the origin, insertion, and innervation of Trapezius? Is it extrinsic or intrinsic?

Answer 1

-origin: occipital lobe+spinus process of cervical vertebrate
-insertion: upper fibres reach clavicle and acromion. lower fibres insert to spine of scapula
-CNXI
extrinsic
-superficial

Question 2

What is the function of trapezius?

Answer 2

-upper/lateral fibers elevates shoulder
-horizontal fiber retracts scapula/adduction
-lower fibers depress scapula

Question 3

What is the origin, insertion, and innervation of levator scapula? Is it extrinsic or intrinsic?

Answer 3

-origin: transverse processes of cervical vertebrae
-insertion: superior angle scapula
-brachial plexus
-f(x)= elevate scapula
-extrinsic
-superficial

Question 4

What is the origin, insertion, and innervation of rhomboid minor+major? Is it extrinsic or intrinsic?

Answer 4

origin: spinous processes of upper thoracic vertebrae

insertion: medial border of scapula

f(x): elevation +retraction of scapula

innervation: brachial plexus

Question 5

What is the difference btw extrinsic and intrinsic muscles?

Answer 5

ex: origin and insertion in different regions
in: origin and insertion in same region

superficial and intermediate layers= extrinsic

deep layers = intrinsic

Question 6

label

Answer 6

1: trapezius
2:levator scapulae
3: rhomboid minor
4: rhomboid major

Question 7

describe the origin, insertion, and innervation of latissimus dorsi?? is it extrinsic or intrinsic

Answer 7

origin: spinous processes of lower thoracic & all lumbar vertebrae & sacrum & ileum

insertion: intertubercular groove

fxn: prime mover for extension of shoulder.
can do medial rotation and adduction of shoulder

innervated: brachial plexus

extrinsic (sueprficial)

Question 8

what muscle is this

Answer 8

latissimus dorsi

Question 9

what are the 3 groups of deep layer muscles in the trunk

Answer 9

1. erector spinae
2. transversospinalis
3. segmentals

Question 10

describe the origin, insertion, and innervation of erector spinae muscles?? is it extrinsic or intrinsic
list the 3 muscles in this group

Answer 10

1. spinalis (most medial)
2. longissimus (longest muscle fibers)
3. iliocostalis (most lateral)

origin/insertion: complicated: attach at vertebrae and ribs

fxn: erect/extend spine and stablize vertebrae

innervation: posterior rami of spinal nerse
intrinsic(deep)

Question 11

describe the origin, insertion, and innervation of transversospinalis?? is it extrinsic or intrinsic
list the 3 muscles in this group

Answer 11

1. semispinalis
2. rotatores (smallest+shortest))
3. multifidus

origin/attachment: runs obliquely btw transverse and spinous process

innervation: dorsal rami of spinal nerves

fxn: stabilization of vertebrae, rotates vertebral column

Question 12

describe the origin, insertion, and innervation of Segmentals?? is it extrinsic or intrinsic
list the 2 muscles in this group

Answer 12

1. intertransversarii: btw 2 adjacent transverse processes, helps with side flexion and stabilizes vertebrae
2. interspinales: runs btw 2 spinous process. helps with extension and stabilization

innervation: dorsal rami
-(intrinsic)deep

Question 13

label muscle groups

Answer 13

1. spinalis
2. longissimus
3. iliocostalis
   = erector spinae

Question 14

label muscle groups

Answer 14

1. semispinalis
2. rotatores
3. multifidus
   = transversospinalis

Question 15

label the muscles and what groups are they from?

Answer 15

1. intertransversarii
2. interspinales
   = segmentals
3. rotatores
   =transversospinalis

Question 16

describe the origin, insertion, and innervation of pectoralis major?? is it extrinsic or intrinsic

Answer 16

o: clavicle, sternum (upper 6 costal cartilages)
i: lateral tip of the inter-tubercular groove(shoulder)

fxn: medial rotation, horizontal adduction

innervation: brachial plexus
extrinsic

Question 17

Answer 17

pectoralis major

Question 18

describe the origin, insertion, and innervation of serratus anterior?? is it extrinsic or intrinsic

Answer 18

o: first 9 ribs, fibers wrap around thorax
i: medial border of ribs+medial border of scapula

fxn: protraction + stabilization of scapula
innervation: bracial plexus

extrinsic

Question 19

Answer 19

serratus anterior

Question 20

describe the intrinsic intercostal muscles?

Answer 20

3 layers: external, internal, innermost
-run btw adjacent ribs

fxn: involved in forced inspiration

innervation: ventral rami of thoracic spinal nerves

Question 21

Answer 21

1. external intercostal
2. internal intercostal
3. innermost intercostal

Question 22

what are the origins of the diaphragm

Answer 22

1. xiphoid process
2. lumbar vertebrae
3. costal cartilage

Question 23

fxn of diaphragm

Answer 23

contraction brings down central tendon during inhalation, compresses abdominal viscera (increases pressure)

-respiratory muscle

Question 24

innervation of diaphragm

Answer 24

phrenic nerve

Question 25

insertion of diaphragm

Answer 25

central tendon

Question 26

what are the 3 openings labelled in diaphragm

Answer 26

1. inferior vena cava 2. esophagus 3. aorta

Question 27

Answer 27

1. central tendon (i) 2. xiphoid process (o) 3. costal cartilage (o) 4. lumbar cartilage (o)

Question 28

what muscles are in the anterolateral group?

Answer 28

1. external oblique 2. internal oblique 3. transversus abdominus 4. rectus abdominis

Question 29

fxn/origin+insertion/innervation External oblique

Answer 29

o: lower ribs i: linea alba, aponeurosis(flat connective tissue) is the bridge for external oblique -lower borders becomes the ingeunal ligament fxn:***moves origin, not insertion; moves ribs towards midline "contralateral rotation" innervation: lower 6 intercostal nerves

Question 30

fxn/origin+insertion/innervation Internal oblique

Answer 30

o: ilium i: lower ribs and linea alba fxn: ipsilateral rotation innervation: lower 6 intercostal nerves

Question 31

fxn/origin+insertion/innervation transversus abdominus

Answer 31

o: lower ribs+ilium, turns into aponeurosis i: linea alba fxn: increases abdominal pressure innervation: lower 6 intercostal nerves

Question 32

fxn/origin+insertion/innervation rectus abdominus

Answer 32

o: pubic bone i: ribs 5,6,7 fxn: flexion of torso innervation: lower 6 intercostal nerves

Question 33

Answer 33

1. linea alba 2. tendinous intersection 3. external oblique 4. aponeurosis 5. inguinal ligament 6. internal oblique 7. transversus abdominus 8.rectus abdominis

Question 34

what is the inguinal ligament

Answer 34

thickening of aponeurosis extends from the anterior superior iliac spine to public tubule

Question 35

Answer 35

A. levator ani B. perineal muscles

Question 36

what muscle groups comprise the pelvic floor

Answer 36

pelvic diaphragm + perineal muscles

Question 37

what makes up the pelvic diaphragm

Answer 37

levator ani + coccygeus

Question 38

what is this triangle called? what are the upper and lower divisions? what do the 4 blue dots represent?

Answer 38

= perineum top triangle= urogenital bottom: anal triangle top blue dot= pubic symphysis bottom= coccyx sides= ischial tuberosity

Question 39

fxn/origin+insertion/innervation levator ani

Answer 39

o: pubic bones + ilium i: coccyx fxn: supports weight of pelvic viscera innervation: sacral plexus

Question 40

fxn of perineal muscles

Answer 40

innervated by pudendal nerve sits below the diaphragm to support the pelvic viscera, bc the muscles close to midline are weak due to openings. make anus and urethra sphincters.