Vertebral Canal and Scapular Dissection

Question 1

What is the Vertebral canal?

Answer 1

Vertebral canal: encloses the spinal cord, spinal meninges (membranes), and blood vessels

Question 2

Where does the spinal cord begin and end?

Answer 2

Spinal cord: begins at foramen magnum of occipital bone and ends at L2 (in adult)

Question 3

Where is the cervical enlargement?

Answer 3

Cervical enlargement: C4 to T1

Question 4

Where is the lumbar enlargement?

Answer 4

Lumbar enlargement: L2 to S3

Question 5

How many spinal nerves are there and how are they named?

Answer 5

Spinal nerves: 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal;

spinal nerves are numbered according to the vertebra above them; spinal nerves pass under the vertebra (thoracic, lumbar, sacral only); cervical spinal nerves pass above vertebra; C8 has no vertebra

Question 6

What is the Ligamenta flava?

Answer 6

• Ligamenta flava: connect the laminae of the adjacent vertebrae

Question 7

What is the Posterior internal vertebral venous plexus?

Answer 7

• Posterior internal vertebral venous plexus—N 170
o These veins have no valves allowing blood to flow superiorly or inferiorly depending on blood pressure gradients
o Can be routes for metastasis of cancer from the pelvis to the vertebrae, vertebral canal, and cranial cavity

Question 8

What are the meninges found around the spinal cord from superficial to deep?

Answer 8

Dura mater
Arachnoid space (contains CSF)
Arachnoid mater
Pia Mater

Question 9

What are the regions at and after the end of the spinal cord?

Answer 9

o Conus medullaris (medullary cone): end of spinal cord between L1 and L2

o Cauda equina: (horse tail) collection of ventral and dorsal roots in the lower vertebral canal

o Filum terminale internum: filament continuous with the pia mater; arises from tip of conus medullaris and ends at

Question 10

Where are epidurals given or CSF obtained from and why?

Answer 10

Lumbar puncture: used to obtain CSF from subarachnoid space; CSF is taken from space inferior to conus medullaris; at this level, there is no danger of penetrating the spinal cord with the needle

Question 11

What is the Posterior internal vertebral venous plexus?

Answer 11

• Posterior internal vertebral venous plexus—N 170
o These veins have no valves allowing blood to flow superiorly or inferiorly depending on blood pressure gradients
o Can be routes for metastasis of cancer from the pelvis to the vertebrae, vertebral canal, and cranial cavity

Question 12

What are the shoulder muscles?

Answer 12

6 shoulder muscles: deltoid, supraspinatus, infraspinatus, teres minor, teres major, subscapularis

Question 13

What are the parts of the scapula and find them.

Answer 13

•	Scapula:
o	Acromion
o	Suprascapular notch
o	Supraspinous fossa
o	Spine
o	Infraspinous fossa
o	Supraglenoid tubercle
o	Glenoid cavity
o	Infraglenoid tubercle
o	Coracoid process

Question 14

What are the parts of the humerus and find them.

Answer 14

•	Humerus
o	Head
o	Anatomical neck
o	Greater tubercle
o	Lesser tubercle
o	Intertubercular sulcus (bicipital groove)
o	Surgical neck
o	Deltoid tuberosity
o	Radial groove

Question 15

What is the function, innervation and blood supply for the deltoid muscle?

Answer 15

o Function: abducts humerus N424
o Innervation: Axillary nerve
o Artery: posterior circumflex humeral artery

Question 16

What is the function, innervation and blood supply for the teres minor muscle?

Answer 16

o Function: rotates humerus
o Innervation: axillary nerve
o Artery: circumflex scapular artery; posterior circumflex humeral a.

Question 17

What is the function, innervation and blood supply for • Teres major muscle?

Answer 17

o Function: adducts; medially rotates the humerus
o Innervation: lower subscapularis n.
o Artery: circumflex scapular a.

Question 18

What is the function, innervation and blood supply for the supraspinatus muscle?

Answer 18

o Function: initiates abduction of humerus
o Innervation: suprascapular nerve
o Artery: suprascapular artery

Question 19

What is the function, innervation and blood supply for the infraspinatus muscle?

Answer 19

o Function: laterally rotates humerus
o Innervation: suprascapular nerve (N 426)
o Artery: suprascapular artery

Question 20

What are the borders of the quadrangular space?

Answer 20

o Superior border: teres minor m. (inferior border)
o Lateral border: humerus
o Medial border: long head of triceps brachii m.
o Inferior border: teres major m. (superior border)

Question 21

What are the muscles of the rotator cuff?

Answer 21

(4 muscles)—“SITS”
o	Supraspinatus
o	Infraspinatus
o	Teres minor
o	Subscapularis