Lecture 16: Skeletal Muscles II (Trunk)

Question 1

describe the origin, insertion, and innervation of Trapezius? is it ex or intrinsic

Answer 1

extrinsic (superficial)

origin: EOP& spinous processes of all cervical and thoracic vertebrae

insertion: upper fibres reach clavicle and acromion. lower fibres insert to spine of scapula

fxn: lower fibres depress scapula. middle fibres retract scapula.

nerve supply: CNXI

Question 2

describe the origin, insertion, and innervation of Levator Scapulae?? is it extrinsic or intrinsic

Answer 2

Extrinsic (superifical)

origin: transverse processes of cervical vertebrae
insertion: superior angle scapula
fxn: elevate scapula
nerve supply: brachail plexus

Question 3

describe the origin, insertion, and innervation of rhomboid minor and major? are they extrinsic or intrinsic?

Answer 3

extrinsic (superficial)

origin: spinous processes of upper thoracic vertebrae
insertion: medial border of scapula
fxn: elevation & retraction of scapula
innervated by: brachial plexus

Question 4

what is the difference btw extrinsic and intrinsic muscles?

Answer 4

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

superficial and intermediate layers= extrinsic

deep layers = intrinsic

Question 5

label:

Answer 5

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

Question 6

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

Answer 6

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 7

what muscle is this

Answer 7

lattissimus dorsi

Question 8

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

Answer 8

1. erector spinae
2. transversospinalis
3. segmentals

Question 9

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

Answer 9

3 muscles= spinalis (most medial), longissimus, iliocostalis (most lateral)

fxn: erect/extend spine and stabilize vertebrae
complicated origin/insertion. JUST KNOW they attach to vertebrae and ribs, can extend spine

innervate: posterior rami of spinal nerve

intrinsic (deep)

Question 10

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

Answer 10

muscles: semispinalis, rotatores (smallest, r) and multifidus

intrinsic (deep)

attachment/origin: run obliquely btw transverse and spinous processes

innvervated: dorsal rami of spinal nerves

fxn: rotatino of spine and stabilization of vertebrae

Question 11

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

Answer 11

run btw segments of vertebrae. btw spinous OR transverse processes of adjacent vertebrae

1. intertransversarii: btw 2 adj. transverse
   processes, help with side flexion and stabilizes vertebrae
2. interspinales- run btw 2 spinous process. help with extension and stbailize

innvervated: dorsal rami

intrinsic (deep)

Question 12

label 1-3. what muscle group are these

Answer 12

1. spinalis
2. longissimus
3. iliocostalis

= erector spinae

Question 13

what muscle group are these
1. semispinalis
2. rotatores
3. multifidus

Answer 13

1. semispinalis
2. rotatores
3. multifidus

= transversospinalis

Question 14

label 1 and 2. what muscle group are they from?

what is 3? what group?

Answer 14

1. intertransversarii
2. interspinales
   = segmentals
3. rotatores (part of transversospinalis)

Question 15

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

Answer 15

origin: clavicle, sternum, upper 6 costal cartilaes
insertion: lateral tip of intertubercular groove (shoulder)
fxn: medial rotation, horizontal adduction (prime mover)
nerve supply: brachial plexus

extrinsic

Question 16

what muscle is this

Answer 16

pectoralis major

Question 17

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

Answer 17

origin: first 8/9 ribs. fibres wrap around torso
insertion: medial border scapula
fxn: press scapula against thorax (stabilizes scapula) and prime mover for upward rotation of shoulder

nerve supply: brachial plexus

extrinsic

Question 18

what muscle is this

Answer 18

serratus anterior

Question 19

describe the intrinsic intercostal muscles?

Answer 19

3 layers: external, internal, innermost intercostal
run btw adjacent ribs
contract = bring ribs together
involved in forced inspiration

innervated by intercostal nerves (ventral rami of thoracic spinal nerves)

Question 20

label

Answer 20

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

Question 21

what are the origins of diaphragm

Answer 21

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

Question 22

fxn diaphragm

Answer 22

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

Question 23

nerve supply diaphragm

Answer 23

phrenic nerve

Question 24

insertion diaphragm

Answer 24

central tendon

Question 25

what are the 3 openings labelled in diaphragm

Answer 25

1. inferior vena cava 2. esophagus 3. aorta

Question 26

label

Answer 26

1. central tendon (insertion ) 2. xiphoid process (origin) 3. costal cartilage (origin) 4. lumbar vertebrae (origin)

Question 27

what muscles are in the anterolateral group?

Answer 27

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

Question 28

fxn/insertion/innervation External oblique

Answer 28

origin: lower ribs. fibres continuous with aponeurosis tendon. lower border turns into ingeunal ligament. aponeurosis attaches muscle to insertion, which is linea alba tendon. fxn: *** MOVES ORIGIN, not insertion. moves ribs/torso toward midline "contralateral rotation nerve: lower 6 intercostal nerve

Question 29

fxn/insertion/innervation internal oblique

Answer 29

origin: ilium insertion: lower ribs and linea alba fxn: moves linea alba and ribs toward origin (ilium) = ipsilateral rotation nerve: lower 6 intercostal nerves

Question 30

fxn/insertion/innervation transversus abdominus

Answer 30

origin: lower ribs and ilium, turns into aponeurosis insertion: linea alba fxn: compress abdo viscera, increase pressure nerve: lower 6 intercostal nerves

Question 31

fxn/insertion/innervation rectus abdominis

Answer 31

origin: pubic bone insertion: xiphoid process and costal cartilage fxn: flexion torso, priem mover divided into tendinous intersections nerve: lower 6 intercostal nerves

Question 32

label

Answer 32

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

Question 33

label

Answer 33

A. Levator Ani B. Perineal Muscles

Question 34

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

Answer 34

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

Question 35

fxn of Levator ani muscles

Answer 35

= part of pelvic diaphragm lift anal canal and support weight of pubic viscera innervated by sacral plexus

Question 36

what are the 3 muscle groups of the pelvic region and their components?

Answer 36

1. Pelvic Wall Muscles 2. Pelvic Diaphragm: levitor ani and coccygeus 3. perineal muscles

Question 37

fxn of perineal muscles

Answer 37

reinforce diaphragm innervated by pudendal nerve (sacral plexus) make anus and urethra sphincters

Question 38

what is the pelvic diaphragm defect?

Answer 38

L and R half cannot touch anteriorly bc of the three openings therefore we have one more layer of muscles = perineal