Back Myology Flashcards
Is skeletal muscle striated?
Yes
What are the the 4 general types of striated skeletal muscle?
- Flat (broad) skeletal muscle
- Pennate muscles
- Fusiform muscles
- Digastric muscles
Description of flat skeletal muscles
They are thin and expanive (can stretch alot)
Description of pennate skeletal muscles
Pennate skeletal muscles are feather-like.
There are 3 types:
- Unipennate skeletal muscle
- Bipennate skeletal muscles
- Multipennate skeletal muscles
What is a ligament?
Attaches bone to bone
What is a tendon
Attaches muscle to bone
Description of a fusiform muscle
Fusiform skeletal muscle is spindle shaped with a thick middle and skinny ends. 3 kinds:
- Bicipital muscles–> muscle with two heads
- Tripcipital–> muscle with three heads
- Quadracipital muscle–> muscle with 4 heads
There are 6 layers of back muscles. The first three are _____ and the last three are _____.
6 layers:
The first three are extrinsic and superficial
The last three are intrinsic and deep
What innervates layers 1-3 of the back muscle?
Layers 1-3 are innervated by a branch of the [anterior ramus] of a [cranial nerve].
Layers 4-6 are innvervated by posterior rami.
Layer 1 Muscles
- Trapezius muscle
- Latissimus Dorsi muscle
Trapezius muscle
Action:
What does the whole muscle do, upper fibers, lower fibers, and what does it do when the scapula is fixed?
Innervation:
Action:
1. Whole muscle: Retract the scapula, rotating the gleniod cavity superiorly
2. Upper fibers: elevate the scapula
3. Lower fibers: depress the scapula
4. When the scapula fixed:
Upper fibers will extend the neck bilaterally
Laterally flex the neck
Rotate the face away
Innervation: Spinal accessory nerve 11
Latissimus Dorsi Muscle
Action:
Innervation:
Blood supply?
Action:
Adduct the humerus
Medially rotate the humerus
Rotate the gleniod cavity inferiorly
Innvertion: thorcadorsal N.
Blood supply: thoracodorsal artery
Which is usually above and below: major and minor?
Minor is usually above major
Layer 2 Muscles
- Rhomboid major muscle
- Rhomboid minor muscle
- Levator scapulae muscle
Rhomboid major M.
Layer:
Action:
Innervation:
Blood supply:
Layer: 2
Action: retract & elevate the scapula, rotate the glenoid cavity down (inferiorly)
Innervation: dorsal scapular nerve
Blood supply: dorsal scapular artery
Rhomboid minor m.
Layer:
Action:
Innervation:
Layer: 2
Action: retract and elevate the scapula, rotating the glenoid cavity down
I: dorsal scapular nerve.
Blood supply: dorsal scapular artery
Levator Scapulae M
Layer:
Action:
Innervation:
Levator Scapulae Muscle
Layer 2
Action: elevate the scapula, rotating the glenoid cavity inferiorly
When the scapula is fixed, it will extend and laterally flex the neck
Innervation: Dorsal scapular n.
Layer 3 muscles
- [Serratus Posterior] Superior M.
- [Serratus Posterior] Inferior M.
Serratus Posterior Superior M.
Layer:
Action:
Innervation:
Blood supply:
Layer: 3
Action: Elevate the ribs during forced inspiration (breathing in)
Innervation: 2-5th intercostal N.
Blood supply: intercostal arteries
Serratus Posterior Inferior M
Layer:
Action:
Innervation:
Layer: 3
Action: Depress the ribs during forced expiration (breathing out)
Innervation: Anterior Rami of 9-12 intercostal nerves
Layer 4 muscles
- Splenuis capitis m.
- Splenuis cervicis m.
These are responsible for moving the [HEAD] and [NECK].
Layer, Action and Innervation of:
Splenius Capitis M.
AND
Splenius Cervicus
***They do the same exact thing
Splenius capitus m. - Goes to the skull
Splenius cervicus m. -goes to the neck
Layer: 4
Action:
- Extends the neck bilaterally
- Flex the neck laterally
- Rotate the face toward the muscle
Innervation: posterior rami
which 2 muscles have actions that are [primarily propioceptive]?
- Serratus posterior superior m.
- Serratus posterior inferior m.
Tell me about the layer 5 muscles.
Layer 5 muscles are called the [erector spinae group].
They help to keep the spine straight. There are 3 main groups: I LOVE SEX;
- Iliocostalis muscle (most lateral)
- Longissimus muscle (medial)
- Spinalis muscle(most medial)
Layer 5: Erector Spinae Group
Action:
Innervation:
Erector Spinae Group (spinalis, longissimus and iliocostalis muscles)
Action:
- Help us stand in a erect posture
- Extend the [vertebral column and head] when working bilaterally
- Flex the vertebral column laterally (unilaterally).
Innervation:
posterior rami
Name the 3 Illiocostalis muscles
- Iliocostalis lumborum m.
- Iliocostalis thoracis m.
- Iliocostalis cervicis m.
Name the 3 longissimus muscles
- Longissimus thoracis m.
- longissimus cervicis m.
- Longissimus capitis m.
Longissimus capitis m. action
- Extends the neck
- Flexes the neck
- Rotates the face toward the muscle unilaterally
What are the 3 parts of the spinalis m.
- Spinalis capitis m.
- Spinalis cervicis m.
- Spinalis thoracis m.
The spinalis thoracis m. often blends in with what muscle?
longissimus thoracis m.
This is the only muscle you can probably see.
What spinalis muscles cannot usually be seen or are absent?
- Spinalis cervicis
- Spinalis capitis
What is a back sPRAIN?
A injury to the ligament in between bone, often due to not stretching before activites
What is a back sTRAIN?
A back strain can be caused when you strain a muscle from too much stretching and tearing of a muscle fiber.
As a result, your muscles will spasm (involuntarily contract) and inflame to protect.
What are layer 6 muscles called?
Transversospinalis group.
Layer 6 is called transversospinalis group because they come from a transverse process and go to a spinous sprocess at every level.
What are the layer 6 muscles called?
- Rotatores brevis muscle (goes to the adjacent spinal segment)
- Rotatores longus muscle (2 segments away)
- Multifidis m (extends 3 or 4 spinal segments away)
- Semispinalis group (5+ spinal segments away).
What are the three types of semispinalis muscles?
- Semispinalis capitis muscle
- Semispinalis cervicis muscle
- Semispinalis thoracis muscle
Semispinalis capitis muscle
Action:
- Extends head
- Rotates the face away (makes sense because it is the most superior)
Innervation: Posterior rami
Semispinalis cervicis muscle
Layer:
Action:
Innervation:
Layer: 6
Action:
- Extends the spine
- Rotate spine AWAY
Innervation:
Posterior Rami
Semispinalis Thoracis Muscle
Layer:
Action:
Innervation:
Layer: 6
Action:
- Extends the spine
- Rotates the spine away
Innervation:
Posterior rami
Rotatores brevis muscle
Rotatores longus muscle
Multifidus muscle
—-they all do the same thing—-
Layer:
Action:
Innervation:
Rotatores brevis muscle- extends to the adjacent spinous process
Rotatores longus muscle- extends 2 spinous processes away
Multifidus muscle- extends 3 or 4 spinous processes away
Layer: 6
Action:
- Extend the spine
- Rotate the spine away
- Primarily propioceptive
Innervation:
Posterior Rami
Where is the multifidus muscle best developed?
Lumbar region
Which is the best developed semispinalis muscle?
Semispinalis capitis muscle
There are 4 muscles in the suboccipital region:
- Rectus capitis posterior major muscle
- Rectos
