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Axial Skeleton > Muscles of Thoracic Cage > Flashcards

Muscles of Thoracic Cage Flashcards

1
Q

Describe function of muscles of pharynx and larynx

A

Pathways for air AND for food will converge in pharynx

During swallowing pharynx can only manage flow of food, as a result will close of the airway

Epiglottis (leaf-like lid) shuts over the larynx during swallowing to prevent any form of aspiration - so patient does not inhale food or foreign bodies into lungs

Phalangeal muscles prevent collapse of upper airways by creating some -ve pressure during inspiration

muscular impairment from neurological disorder, i.e. CVA, where swallow is affected this can have knock on effect to respiratory status

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2
Q

State muscles of respiration

A

Muscles of the pharynx and larynx

Muscles of the ribcage, thoracic spine and neck

Muscles of the abdominal wall, and lumbar spine

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3
Q

Give muscles of ribcage

A

4 muscles

diaphragm
external intercostals
internal intercostals
innermost intercostals

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4
Q

Give main functions of muscles of ribcage

A

Increase thoracic dimensions during inspiration - pump, bucket handles

Support the thoracic cage - keep in good position

Intercostal muscles prevent any recession or bulging of the intercostal spaces

Inhibit the lungs natural tendency to collapse - help to splint airways open

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5
Q

Give position of diaphragm

A

Unpaired, domed (parachute) shape skeletal muscle situated in the trunk.

Separates abdominal and thoracic cavities by filling the inferior thoracic aperture

Short anterior fibres and longer posterior fibres give the appearance of an inverted letter J when viewed from the side. When viewed from the front, two small domes (cupolae) on either side of the central tendon can be seen, that on the right being at a slightly higher level than the left: the central part lies opposite the xiphisternal joint

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6
Q

Give attachments of diaphragm

A

Origin -
Lumbar part: upper three lumbar vertebrae as right crus and upper two lumbar vertebrae as left crus and adjacent IV discs; Medial arcuate lig (spans between vertebral body L2 and TP L1 ) and Lateral arcuate lig (spans TP L1 to tip of Rib 12)

Costal part - inner surface of lower 6 ribs and CCs

Sternal part - post surface Xiphoid process

Insertion: Fibres converge and arch superomedially to insert into central tendon situated towards the front of the muscle; fibrous pericardium enclosing the heart is firmly attached to the middle central tendon

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7
Q

Give action of diaphragm

A

Major muscle of inspiration

Core stability

Active contraction in labour (parturition), miticurtation, vomiting

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8
Q

Give innervation of diaphragm

A

Left and right phrenic nerves C3,4,5

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9
Q

Describe zone of apposition (ZoA)

A

Refers to a vertical area of the diaphragm that begins at their insertion point on the inside of the lower ribs and extends to the top of the diaphragms.

Important for proper diaphragmatic function - will affect diaphragmatic tension
Abdominal surgery or distended abdomen - will have an impact on diaphragmatic function

Controlled by abdominal muscles

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10
Q

What are the structures passing between thorax and ribcage via diaphragm

A

major tubular structures = inferior vena cava, oesophagus and aorta

these structures do so by named openings; they may be accompanied by nerves and/or other vessels.

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11
Q

Describe the structures passing through caval opening

A

Caval opening is in the central tendon to the right of the midline and transmits the inferior vena cava and right phrenic nerve

It is level with the lower border of T8.

Consequently, the inferior vena cava is constantly held open.

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12
Q

Describe structures of oesophageal opening

A

At the level of T10, is to the left of the midline surrounded by fibres of the right and left crura

The oesophagus, the trunks of the vagus nerves (now known as the gastric nerves) and the oesophageal branches of the left gastric vessels pass through the opening.

The left phrenic nerve pierces the muscular part of the diaphragm near the oesophageal opening in front of the left part of the central tendon.

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13
Q

Describe structures passing through aortic opening

A

Lies behind the diaphragm, in front of T12, as the two crura cross each other.

The aorta and thoracic duct pass into and out of the abdomen, respectively.

The azygos vein is partly covered by the right crus, whereas the greater and lesser splanchnic nerves pierce the crura to enter the abdomen passing towards the coeliac ganglion.

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14
Q

Describe structures passing behind medial and lateral arcuate ligaments

A

Sympathetic trunk passes behind medial arcuate lig

Subcostal nerve passes behind lateral arcuate lig.

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15
Q

Describe structures passing between sternal and costal attachments of the diaphragm

A

Anteriorly between the sternal and costal attachments of the diaphragm, the superior epigastric artery enters the rectus sheath to supply the upper part of rectus abdominis

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16
Q

Describe other important features of the diaphragm

A

Surface area = 900cm2

Muscle fibres can reduce in length by up to 40%

Lots of functional reserve

Damage to C3,4,5 = issues with breathing

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17
Q

Describe position of external intercostals

A

Outer layer of muscles within intercostal spaces

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18
Q

Give attachments of external intercostals

A

Origin: Inferior border of the rib above

Insertion: Fibres pass obliquely inferomedially to superior border of the rib below

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19
Q

Give action of external intercostals

A

Most active during inspiration - causing elevation of the rib below towards the rib above

Stabilise chest wall - so diaphramatic change can cause drop in intrathoracic pressure

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20
Q

Give position of internal intercostals

A

Middle layer of muscles within intercostal spaces

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21
Q

Give attachments of internal intercostals

A

Origin: Inferior border of the costal cartilage and costal groove of the rib above

Insertion:
Fibres pass obliquely inferolaterally (90o to external intercostal) to superior border of the rib below; deep to corresponding external intercostal

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22
Q

Give action of internal intercostals

A

Most active during expiration - causing depression of rib above to rib below

Support intercostal space

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23
Q

Give position of innermost intercostals

A

Inner layer of muscles within intercostal space

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24
Q

Give attachments of innermost intercostals

A

Origin: Inferior borders and internal surfaces CC of ribs 2-6

Insertion:
Fibres pass obliquely inferolaterally (similar to internal intercostals) to inferior and deep surface of body of sternum, Xiphoid process and CC of ribs 4-7

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25
Q

Give action of innermost intercostals

A

Act within internal intercostals

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26
Q

Give innervation of intercostals

A

anterior primary rami of adjacent intercostal (thoracic) nerves

27
Q

Give main muscles of inspiration

A

2 muscles:
Diaphragm

External intercostals

(Serratus posterior superior)

28
Q

Give position of Serratus posterior superior

A

Thin flat muscle lying anterior to the rhomboids

29
Q

Give attachments of Serratus posterior superior

A

Origin:
Inferior part of the ligamentum nuchae and spinous processes of C7- T3 and adjacent supraspinous ligaments

Insertion:
Fibres pass inferolaterally to attach superior borders of ribs 2-5, lateral to angles

30
Q

Give action of Serratus posterior superior

A

Attachment to the ribs 2-5 causes them to be elevated, thus assisting inspiration

31
Q

Give accessory muscles of inspiration

A 
Sternocleidomastoid
Scaleni
Serratus Anterior
(Serratus Posterior Superior)
Pectoralis Major
Pectoralis minor
Latissimus Dorsi
32
Q

Give position of sternocleidomastoid

A

Long straplike muscle arising from two heads running obliquely around the side of the neck close to the midline anteriorly

33
Q

Give attachments of sternocleidomastoid

A

Origin:
Sternal head: superior part of anterior surface of manubrium sterni

Clavicular head: superior surface of medial third of the clavicle

Insertion:
Sternal head: Lateral half of superior nuchal line of the occipital bone

Clavicular head: Lateral surface of mastoid process of the temporal bone

34
Q

Give action of sternocleidomastoid

A

Unilateral contraction: cervical spine: neck ipsilateral flexion, neck contralateral rotation

Bilateral contraction:
Inferior cervical vertebrae: neck flexion

Reversed origin: elevation of clavicle and manubrium of sternum in forced inspiration

35
Q

How to palpate sternocleidomastoid

A

laterally flex the neck to the same side and then rotate the head to the opposite side against resistance.

Both sternal and clavicular heads can be gripped between the fingers, with the gap between them easily identifiable.

The round muscle belly is palpable throughout its length, as is the flat tendon attaching to the mastoid process.

36
Q

Give position of scaleni muscles

A

Anterior: deep to sternomastoid in front of scalenus medius

Medius: middle and largest of the scalene muscles

Posterior: smallest and most posterior scalene muscle

37
Q

Give attachments of scaleni muscles

A

Anterior: anterior tubercles of TP C3-6 to scalene tubercle inner border of rib 1

Medius: TP C1-2 and posterior tubercles of TP C3-7 to impression on superior surface rib 1, posterior to subclavian groove

Posterior: posterior tubercles of TP C4-6 to outer surface rib 2, posterior to serratus anterior attachment

38
Q

Give actions of Scaleni muscles

A

Reversed origin:
Elevate ribs 1-2 in forced inspiration

All 3 unilateral= ipsilateral side flexion

Two anterior bilateral = neck flexion

39
Q

Give position of Serratus anterior

A

Large, flat, muscular sheet covering the side of the thorax lying between the ribs and scapula

Sandwiched between pectoralis major, anteriorly, and latissimus dorsi posteriorly

40
Q

Give attachments of serratus anterior

A

Origin:
fleshy digitations just anterior to the midaxillary line to the outer surfaces of the upper eight or nine ribs and intervening intercostal fascia

Insertion:
Costal surface of entire medial border of scapula

41
Q

Give actions of serratus anterior

A

Protraction, retraction of scapula

Respiratory distress: elevate upper 8-9 ribs to increase AP diameter of thorax

42
Q

How to palpate serratus anterior

A

muscular subject, the digitations of serratus anterior can be felt and often seen running forwards in the region of the midaxillary line, especially when performing ‘press-ups’.

43
Q

Give position of pectoralis major

A

Thick, triangular muscle located on the upper half of the anterior surface of the thoracic wall; forms anterior fold of axilla

44
Q

Give attachments of pectoralis major

A

Clavicular fibres: anterior surface of medial 1/2 clavicle

Sternocostal fibres: anterior surfaces of manubrium, body of sternum, upper 6 CCs, rib 6 and aponeurosis of EO

Insertion:
Lateral lip of intertubercular sulcus of humerus

45
Q

Give action of pectoralis major

A

Shoulder ADD, MR (against resistance)

Clavicular fibres: shoulder flexion (to 90o flexion)

Sternocostal fibres: extension (back to neutral against resistance)

Respiratory distress: elevate upper 7 ribs to increase AP diameter of thorax

46
Q

How to palpate pectoralis major

A

Clavicular part can be readily palpated if the arm is flexed to 60° and held against downward pressure, and the sternocostal part is best palpated if this same position is maintained against upward pressure

47
Q

Give position of pectoralis minor

A

thin, flat, triangular muscle situated on the anterior chest wall deep to pectoralis major

48
Q

Give attachments of pectoralis minor

A

Origin:
Anterior surfaces of ribs 3-5, close to CCs and intervening intercostal fascia

Insertion:
Fibres converge to a short, flat tendon as they pass superolaterally to attach to the upper surface and medial border of the coracoid process of the scapula

49
Q

Give actions of pectoralis minor

A

Assists depression and protraction of scapula (working with serratus anterior)

Assists MR of scapula (against resistance)

Scapula and upper limb fixed: Elevate ribs 3-5 during forced inspiration

50
Q

Give position of latissimus dorsi

A

Large, flat, triangular sheet of muscle running between the trunk and humerus

“wing” muscle

51
Q

Give attachments of lattissimus dorsi

A

Origin:
TLF into SP of T7-12, all lumbar and sacral vertebrae and adjacent supraspinous and interspinous ligaments; adjacent iliac crest, lower 3-4 ribs and inferior angle of scapula

Insertion:
Fibres converge, passing superolaterally and rotating to floor of intertubercular sulcus of the humerus

52
Q

Give actions of latissimus dorsi

A

Shoulder extension, ADD, MR (against resistance)

Respiratory distress: assist forced expiration in coughing by attachment to lower 3-4 ribs

Assists in singing

53
Q

How to palpate latissimus dorsi

A

asking the subject to raise the arm to 90° flexion and to hold it steady against an upwardly directed pressure.

The muscle can be felt contracting if the posterior axillary fold is held between finger and thumb while the subject coughs.

Adduction of the abducted arm against resistance also enables latissimus dorsi to be seen and felt

54
Q

What are the muscles of forced expiration

A

Intercostals - internal and innermost

Transversus thoracis

Subcostals

Rectus abdominis

External oblique

Internal oblique

Transversus abdominis

Quadratus lumborum (QL)

Latissimus dorsi

55
Q

Give position of transversus thoracis

A

Inner aspect of the anterior thoracic wall

56
Q

Give attachments of transversus thoracis

A

Origin:
Posterior surface of the xiphoid process , lower 1/2 body of the sternum and 4-7 costal cartilages.

Insertion:
inner surface of the 2-6 costal cartilages

57
Q

Give action of transversus thoracis

A

Depress costal cartilages articulating with the sternum downwards and so contributes to expiration

58
Q

Give position of subcostals

A

Irregular slips of muscle extending across one or two intercostal spaces

59
Q

Give attachments of subcostals

A

Origin:
Internal aspect of lower ribs

Insertion:
Fibres pass inferiorly to inner surface of the rib 1 or 2 levels below near the angle

60
Q

Give action of subcostals

A

depress the ribs and so aid expiration

61
Q

Give position f serratus posterior inferior

A

Lying deep to latissimus dorsi

62
Q

Give attachments of serratus posterior inferior

A

Origin:
SP T11- L2, adjacent supraspinous ligts via TLF

Insertion:
fibres run horizontally to attach to the lower four ribs at their angles

63
Q

Give action of serratus posterior inferior

A

pull the lower four ribs inferoposteriorly and so may assist expiration

Axial Skeleton (11 decks)

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