Lec 4 Flashcards
Spinal Cord and Dorsal Scap Region
Pectoralis Major
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)
Deltoid
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)
Pec Minor
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)
Infraspinatus
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)
Teres Major
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)
Supraspinatous
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
Teres Minor
MA: Externally rotate (GHJ), stabilize humerus head
PA: Lateral border of scap
DA: greater tubercle of humerus
N: Axillary nerve (C5, C6)
Subscapularis
MA: Internally rotate GHJ, stabilize humerus head
PA: subscapular fossa
DA: Lesser Tubercle of humerus
N: Subscapular Nerve
What kinds of joints are the AA and OA joints?
AA: pivot (synovial)
OA: condyloid (synovial)
What is the process of CNS development called? What vitamin is really important?
Neurulation
Folate (B vitamin)
Describe the process of neurulation
- Neuroectodermal tissues differentiate from the ectoderm and thicken into neural plate. Neural plate borders on each side divide neural plate from ectoderm
- Neural plate bends dorsally and two ends come together at their neural plate borders creating the neural crest
- Neural tube closes from the bending into circle and the neural crest becomes PNS
- Notochord degenerates and becomes nucleus pulposus of intervertebral discs, mesoderm cells differentiate into somites (become axial and skeletal muscle)
How does Spina Bifida occur?
When the two vertebral arches do not fully fuse during development, leaving the vertebral canal open
Typically in lower vertebrae
Spina Bifida Occulta
- SB Occulta; defect in vertebral arch of L5 or S1, asymptomatic with hair tuft
Severe Spina Bifida
- 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
How many spinal nerves are there? Where do they come from?
31 pairs
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
Spinal nerves originate at spinal cord and connect CNS to PNS
Where does C1 spinal nerve leave the spinal cord? What does it innervate?
- goes between skull and C1 vertebrae
- innervates suboccipitals
- so under C7 is C8 spinal nerve
What is significant about the spacing in the spinal column?
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
Where does the Cauda Equina begin?
L1/L2
Describe how spinal nerves are organized (roots vs ramis)
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
Myotomes
the muscles supplied by an individual spinal nerve
What motions are common with C5 innervation?
- external rot and scapation, abduction, flexion
think every movement is moving away from body
What motions are common with C6, C7, C8 spinal nerves?
IR, Adduction and Extension
What spinal nerves are associated with pronation, supination, digital flexion/extension, and lateral/medial movement of digits
pronation - c8
supination - c6
- digital flexion c8
- digital extension c7
- lateral and medial digits - T1
Dermatomes
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
Lumbar Cistern
extension of the subarachnoid space below the conus medullaris where the cuada equina begins
contains CSF
L1/L2
Where does the spinal dural sac terminate?
S2 (extends slightly from where spinal cord terminates, think about your cadaver)
What is at the ending of the spinal cord and beginning of the cauda equina?
Conus Medullaris
cone shaped/tapered end of spinal cord at L1/L2
Filum terminale ____ and filum terminale _____
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
Describe the layering of the spinal meninges from superficial to deep
(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)
Where are lumbar spinal punctures given?
Needle goes between L3/4 or L4/5
*Cant go before L1 or L2 because the cord is solid (horse tail begins after)
Where is the Nuchal Ligament
external occipital protuberance down the SP of C1-C7
Supraspinous ligament
Think ligament on top of nuchal ligament and then interspinous ligament moving down
Ligamenta Flava
Runs inside the vertebral column, connects backside (lamina) to the next backside/lamina
Interspinous ligament
between spinous processes
ALL and PLL
Anterior longitudal ligament covers vertebral body
Posterior longitudal ligament is on back side of vertebral bodies (in the canal)
