Muscles & Nerves Flashcards

1
Q

How is a longitudinal view of skeletal muscle identified?

A
  • Heavy striations
  • Quite straight fibres
  • Nuclei pushed to edge of fibres
  • fibres seperated by endomysium
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2
Q

How is a cross-section of skeletal muscle recognised?

A
  • Nuclei pushed to the edge of fibres
  • Each fibres surrounded by endomysium
  • bundled into fascicles surroudned by perimysium
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3
Q

What is different about smooth muscle histology?

A

images can show cross-sectional areas & longitudinal areas

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4
Q

How is smooth muscle longitudinal section recognised?

A

Longitudinal:

  • Spindle shaped nuclei
  • Dense & “blurry”
  • no striations
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5
Q

How is smooth muscle cross-sections recognised?

A

Central nuclei
Not as clearly bundled
Fibres wrapped in endomysium

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6
Q

How is cardiac muscle recognised?

A
  • Branching with gaps
  • Intercalated discs (hard af to see)
  • light striations
  • Largely (but not entirely) mononucleate.
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7
Q

What are axial muscles?

A

Muscles that attach entirely to the trunk

e.g. rectus abdominis & intercostal muscles

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8
Q

What are appendicular msucles?

A

Muscles that attach partly or wholly to the limbs

e.g. deltoids, pectoralis & biceps brachii

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9
Q

How do muscles atach to bones?

A

Via rounded tendons made from dense regular connective tissue

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10
Q

What is the origin of a muscle?

A

The proximal/superior/medial attachment

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11
Q

What are insertions of a muscle?

A

The distal/inferior/lateral attachments

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12
Q

Which end of a muscle is moving?

A

The insertions

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13
Q

What end of the muscle is stationary?

A

The origin

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14
Q

What is an aponeurosis?

A

A smooth, flat & broad tendon.

E.g. the tendons of Obliques

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15
Q

What do ligaments do?

A

Attach bones to adjacent bones across joints to stabilize them

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16
Q

How do muscles connect to joints?

A

They connect to the bones on either side by tendons on either side

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17
Q

Function/location

Biceps Brachii:

A

Biceps Brachii connects to the scapula (short & long head) & the radius.
It causes flexion of elbow & shoulder. Also effects supination

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18
Q

Function/Location

Brachioradialis:

A

Attaches to distal humerus & distal radius.
Causes elbow flexion
Also involved in pronation/supination

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19
Q

Location

Triceps Brachii:

A

Attaches to the scapula, proximal humerus & proximal radius.

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20
Q

What are diaphragms?

A

Skeletal muscles that span the mid-sagittal plane (medial plane).

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21
Q

Whats special about a diaphragms tendon?

A

Its large & centrally located

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22
Q

What does the thoracic diaphragm do?

A

Seperates the thorax &abdomen.

It increases thoracic volume during breathing. (dome shaped)

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23
Q

What are antagonistic pairs?

A

2 muscles that combine to carry out a single function

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24
Q

Example of an antagonistic pair

A

Biceps Brachii & Triceps Brachii

biceps contracts & triceps relaxes to allow elbow flexion

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25
Q

What is a synergist?

A

Synergists help perform the same motion as an agonist. They stabilize movement & contain it within safe/desired level.

26
Q

What do fixator muscles do?

A

They fix a joint in place to allow another joint to move. e.g. roatator cuff muscles lock shoulder joint so biceps can contract to cause elbow flexion

27
Q

What do stabilizing muslces do?

A

Stabilize a joint
Often around shouler/hip
e.g. rotator cuff muscles that stabilize the shoulder so it can move without dislocation

28
Q

How are muscle compartments seperated?

A

Deep fascial intermuscular septa.

A lateral one between the humerus & lateral side and vice versa on the medial side.

29
Q

How are muscles in a compartment innervated?

A

A common nerve innervates all the muscles in a compartment

30
Q

What nerves supply all arm muscle compartments?

A

The brachial plexus (C5-T1 vertebrae)

31
Q

What nerves supply all leg muscle compartments?

A

The lumbosacral plexus (T12-S4)

32
Q

How is direction used in muscle naming?

A

Obliques are named because they arnt parallel or at 90degrees to any plane.
Also rectus means straight musces (rectus abdominis)

33
Q

How is location used in muscle naming?

A

E.g. Tibialis Posterior
Tells us the bone (Tibia) & the location (to the back)
Also converse muscles tell us thers usually an opposite.
E.g. seratus anterior tells us theres probably a serratus posterior

34
Q

What are the 8 areas used for msucel naming?

A

Location, Attachments, sphincter, action, shape, no of heads, size & direction.

35
Q

How is size used for muscle naming?

A
  • Major & minor
  • Minimus, Medius & maximus
  • Longus & Brevis
36
Q

No. of heads in muscle naming

A
See triceps (3 heads) & biceps (2 head)
In biceps they connect to scapula
37
Q

Shape in muscle naming

A

“Teres” refers to rounded muscle.

E.g. Teres Major is a thick & rounded muscle connecting to the proximal humerus & inferior angle of scapula

38
Q

Action in muscle naming?

A

Extensor, abductor, pronator etc

e.g. extensor digitorum in posterior forarm extends fingers.

39
Q

Sphincter in muscle naming?

A

A sphincter tells us the muscles are arranged circularly & thickened.
Generally involuntary smooth muslce but some voluntary skeletal (e.g. external snal & urinary sphincters)

40
Q

Attachemnts in muscle naming?

A

E.g. Sternocleidomastoid muscle

Attaches to sternum, clavicle & mastoid process of temporal bone.

41
Q

How do somatic nerves exit the spinal cord?

A

By ventral & dorsal roots.
Ventral - Anterior & motor
Dorsal - Posterior & sensory

42
Q

What is the mixed spinal nerve?

A

When the dorsal & ventral roots converge after exiting the spinal cord

43
Q

Where is the mixed spinal nerve?

A

In the intervertebral foramen

44
Q

How do somatic nerves exit the mixed spinal nerve?

A

As a ventral (anterior) ramus & dorsal (psterior) ramus.

Both contianing sensory & motor nerves.

45
Q

What does the ventral ramus spply?

A

The anterolateral sides of the trunk & limbs

46
Q

What does the dorsal ramus supply?

A

The posterior side of the body & not the limbs

47
Q

What kinds of tissue are supplied by rami?

A

Skeletal muscle
Cartilage
Bones
Skin

48
Q

What supplies the erector spinae?

A

The dorsal Ramus

49
Q

What are the nerves supplying intercostal muscles & how are they numebred?

A

Intercostal nerves

Numbered by the rib above them

50
Q

Whats different about the lower half of the intercostal nerves?

A

The lower 6 (T7-T12) also supply the muscles of the anterior abdominal wall.

51
Q

What are cutaneous nerves?

A

Branches of nerves from the brachial and lumbosacral plexus’ supplying the skin.

52
Q

Whats a dermatome?

A

An area (strip) of skin supplied by cutaneuous branches of a single spinal nerve

53
Q

Why is a dermatome smaller than the area supplied by its cutaneuous nerve?

A

Cutaneuous nerves contain fibres from multiple spinal nerves.

54
Q

What is the efect of dermatomal overlap?

A

nerve fibres supplying adjacent dermatomes would have to fail to lose sensation & function in a dermatome

55
Q

What spinal nerves from the segmental dermatomes of the trunk?

A

T1-T12 & L1

They relate to the intercostal spaces & msulces

56
Q

How is longitudinal sections of nerve fibres recognised?

A
  • Wavy
  • lighter pink than surrounding tissue
  • Many purple nuclei
57
Q

How are cross-sections of nerve fibres reconised?

A
  • Nuclei of scwann cells at the edge of fibres (PNS)
  • endoneurium surrounding every fibres myelin sheaf
  • fascicles surrounded by perineurium
58
Q

What is the main anterior rotator cuff muscle?

A

The subscapularis muscle

59
Q

What is the rotator cuff muscle on top?

A

Supraspinatous Muscle

60
Q

What is the roatator cuff muscles on the back/

A

Infraspinatous muscle

Much smaller & inferior teres minor muscles

61
Q

What joints the humerus to the deep fascia?

A

The intermuscular septum (radial & medial)

62
Q

What are the layers betwen the surface & the muscle compratmentS?

A

Skin, superfical fascia, deep fascia