Lec 4

Question 1

Pectoralis Major

Answer 1

MA: Aducts and medially rotates humerus, felxion (think putting on seatbelt), HADD, draws scapula anteriorly and inferiorly

• Clavicular head flexes humerus and sternocostal head extends from flexed position

PA:
- Clavicular head: clavicle
- sternocostal head; sternum, superior six costal cartilages, external oblique muscle

DA: Lateral lip of intertubercular sulcus of humerus (PLATE)

N: lateral and medial pectoral nerves; clavicular head (C5, C6), sternocostal head (C7, C8, T1)

Question 2

Deltoid

Answer 2

MA:
- Clavicular (anterior) part; *flexes and medially rotates arm (mostly flexes)
- Acromial (middle); abducts arm
- Spinal (posterior); *extends and laterally rotates arm

PA: (WHERE TRAP ENDS), clavicle, acromion, spine of scapula

DA: Deltoid tuberosity of humerus

N: Axillary nerve (C5, C6)

Question 3

Pec Minor

Answer 3

MA: Stabilizes scapula by drawing it inferiorly and anteriorly against the thoracic wall (forward posture)
- with scap fixed, assist to elevate the thorax during forced inhalation

PA: 3rd, 4th and 5th ribs near the costal cartilage

DA: coracoid process

N: medial pectoral nerve (C8, T1); lateral pectoral nerve (variable)

Question 4

Infraspinatus

Answer 4

MA: externally rotate the shoulder, stabilize humerus head in glenoid fossa (with rotator cuff)

PA: infraspinatus fossa

DA: greater tubercle of humerus

N: Suprascapular nerve (C5, C6)

Question 5

Teres Major

Answer 5

Lats little brother

MA: Adduct, internally rotate (and extend) GHJ

PA: Posterior surface of inferior angle of the scapula

DA: Medial lip of intertubercular sulcus of the humerus

N: Lower subscapular nerve (C5, C6)

starts on back side and inserts on front side so (IR)

Question 6

Supraspinatous

Answer 6

MA: Initiates and assits deltoid in abduction of the arm
- stabilize humerus head

PA: supraspinatus fossa of scap

DA: greater tubercle of scapula

N: suprascapular nerce C4, C5, C6

Question 7

Teres Minor

Answer 7

MA: Externally rotate (GHJ), stabilize humerus head

PA: Lateral border of scap

DA: greater tubercle of humerus

N: Axillary nerve (C5, C6)

Question 8

Subscapularis

Answer 8

MA: Internally rotate GHJ, stabilize humerus head

PA: subscapular fossa

DA: Lesser Tubercle of humerus

N: Subscapular Nerve

Question 9

What kinds of joints are the AA and OA joints?

Answer 9

AA: pivot (synovial)

OA: condyloid (synovial)

Question 10

What is the process of CNS development called? What vitamin is really important?

Answer 10

Neurulation

Folate (B vitamin)

Question 11

Describe the process of neurulation

Answer 11

1. Neuroectodermal tissues differentiate from the ectoderm and thicken into neural plate. Neural plate borders on each side divide neural plate from ectoderm
2. Neural plate bends dorsally and two ends come together at their neural plate borders creating the neural crest
3. Neural tube closes from the bending into circle and the neural crest becomes PNS
4. Notochord degenerates and becomes nucleus pulposus of intervertebral discs, mesoderm cells differentiate into somites (become axial and skeletal muscle)

Question 12

How does Spina Bifida occur?

Answer 12

When the two vertebral arches do not fully fuse during development, leaving the vertebral canal open

Typically in lower vertebrae

Question 13

Spina Bifida Occulta

Answer 13

• SB Occulta; defect in vertebral arch of L5 or S1, asymptomatic with hair tuft

Question 14

Severe Spina Bifida

Answer 14

• Severe when there is a large bubble of the meninges (spinal cord covers, dura/arch/pia)
• can include cerebrospinal fluid (meningocele) or a portion of spinal cord (myelomeningocele)
• causes neurological deficits, problems with ambulation (walking) and Ball and Bladder

Question 15

How many spinal nerves are there? Where do they come from?

Answer 15

31 pairs

• 8 cervical
• 12 thoracic
• 5 lumbar
• 5 sacral
• 1 coccygeal

Spinal nerves originate at spinal cord and connect CNS to PNS

Question 16

Where does C1 spinal nerve leave the spinal cord? What does it innervate?

Answer 16

• goes between skull and C1 vertebrae
• innervates suboccipitals
• so under C7 is C8 spinal nerve

Question 17

What is significant about the spacing in the spinal column?

Answer 17

The thoracic region has more space where spinal nerves exit between vertebrae compared to lumber, so it is more common for discs to compress spina nerves in the lumbar region

Question 18

Where does the Cauda Equina begin?

Answer 18

L1/L2

Question 19

Describe how spinal nerves are organized (roots vs ramis)

Answer 19

The anterior root enters on the front side caring motor information from the body, and the posterior root enters from the back side carrying sensory info from the body.

“a” for action, anterior is motor

They meet in the middle to become the spinal nerve, and then split into ventral rami (extrinsic back) and dorsal rami (deep back muscles and skin of back)

extrinsic back; lat, rhomboids, trap, levator

Question 20

Myotomes

Answer 20

the muscles supplied by an individual spinal nerve

Question 21

What motions are common with C5 innervation?

Answer 21

• external rot and scapation, abduction, flexion

think every movement is moving away from body

Question 22

What motions are common with C6, C7, C8 spinal nerves?

Answer 22

IR, Adduction and Extension

Question 23

What spinal nerves are associated with pronation, supination, digital flexion/extension, and lateral/medial movement of digits

Answer 23

pronation - c8

supination - c6

• digital flexion c8
• digital extension c7
• lateral and medial digits - T1

Question 24

Dermatomes

Answer 24

Area of skin supplied by an individual spinal nerve

Used to assess the level of spinal cord injury (depending on what areas are having sensory issues you know what spinal cord is affected)

if one whole dermatome area is affected then a spinal nerve is injured

if only one peripheral nerve is, might not be spinal level injury

Question 25

Lumbar Cistern

Answer 25

extension of the subarachnoid space below the conus medullaris where the cuada equina begins

contains CSF

L1/L2

Question 26

Where does the spinal dural sac terminate?

Answer 26

S2 (extends slightly from where spinal cord terminates, think about your cadaver)

Question 27

What is at the ending of the spinal cord and beginning of the cauda equina?

Answer 27

Conus Medullaris

cone shaped/tapered end of spinal cord at L1/L2

Question 28

Filum terminale ____ and filum terminale _____

Answer 28

Thread-like extension of pia matter

Internum starts at conus medullaris and goes to end of dural sac where it then becomes externum and goes to coccyx

Question 29

Describe the layering of the spinal meninges from superficial to deep

Answer 29

(Epidural Space)

Dura Matter

(Subdural space)

Arachnoid mater

(subarachnoid space)

CSF Cerebral Spinal Fluid

Pia matter (very connected to spinal cord and hard to see)

Question 30

Where are lumbar spinal punctures given?

Answer 30

Needle goes between L3/4 or L4/5

*Cant go before L1 or L2 because the cord is solid (horse tail begins after)

Question 31

Where is the Nuchal Ligament

Answer 31

external occipital protuberance down the SP of C1-C7

Question 32

Supraspinous ligament

Answer 32

Think ligament on top of nuchal ligament and then interspinous ligament moving down

Question 33

Ligamenta Flava

Answer 33

Runs inside the vertebral column, connects backside (lamina) to the next backside/lamina

Question 34

Interspinous ligament

Answer 34

between spinous processes

Question 35

ALL and PLL

Answer 35

Anterior longitudal ligament covers vertebral body

Posterior longitudal ligament is on back side of vertebral bodies (in the canal)