Ch.7 Vertebral Column & Rib Cage

Question 1

Functions of Vertebral Column

Answer 1

• provides vertical support
• supports weight of the head
• helps to maintain upright body position
• transfer axial skeleton weight to the appendicular skeleton of the lower limbs
• houses and protects the delicate spinal cord and providing passageway for spinal nerves connecting to the spinal cord

Question 2

Parts of a Typical Vertebra

Answer 2

• body: large and block-like; separated by intervertebral discs; is a weight-bearing structure
• vertebral arch: together with the body, the arch surrounds and protects the spinal cord; pedicles form the lateral walls, and laminae the posterior walls
• processes: transverse process extends laterally where a lamina and pedicle join; spinous process projects posteriorly at the junction of the laminae; paired articular processes articulate with an adjacent superior, and an adjacent inferior, vertebrae

Question 3

Cervical Vertebrae

Answer 3

• have a transverse foramen within the transverse process
• atlas, or C1, is a bony ring with no body; its articulations with the head permit the movement we associate a head-nod (yes)
• axis, or C2, has a peg-like process that articulates with C1 permitting the movement we associate with a head-shake (no)
• C3-C7 have the most features in common of the cervical vertebrae

Question 4

Thoracic Vertebrae

Answer 4

• larger and stronger than cervical and are easily identified by their costal facets which articulate with the tubercles of ribs
• bodies of thoracic vertebrae articulate with the heads of ribs, except for T11 and T12

Question 5

Lumbar Vertebrae

Answer 5

• largest and strongest of the unfused vertebrae in the vertebral column
• readily identified by their large size and an absence of costal articular facets

Question 6

Sacrum

Answer 6

• fusion of the 5 sacral vertebrae result in the formation of the sacrum, process that can last from the age of 16-30 years; transverse lines mark the sites of fusion

Question 7

Coccyx

Answer 7

• triangular bone that forms from the fusion of three to five vertebral bones
• fusion of coccygeal vertebrae also lasts a number of years, usually from 20-30 years of age

Question 8

Muscles of Neck that move the head

Answer 8

anterior triangle: angle is bordered: superiorly by the mandible, medially by the cervical midline, and laterally by the anterior borde of sternocleidomastoid muscle
posterior triangle: bordered interiorly by the clavicle, anteriorly by the posterior border of the sternocleidomastoid muscle, posteriorly by anterior border of the trapezious muscle

Question 9

Anterior Group of Muscles

Answer 9

Sternocleidomastoid: flexes cervical portion, flexes the head at atlanto-axial joint, laterally rotate and flex the head
- manubrium of sternum and the clavicle
- mastoid process and nuchal line of temporal bone
Scalene Muscles: elevates the ribs
- transverse process of ribs 2-7
- first and second ribs

Question 10

Posterior Group of Muscles

Answer 10

splenious cervici: extend, flexes and rotte the head
splenius capitis: extend head, laterally flex and rotate head
erector spinae: largest muscle of back, forming bulge on either side of the vertebral column
- extensor of the vertebral

Question 11

Arterial Blood Flow Through the Head and Neck

Answer 11

heart- brachiocephalic trunk- common carotid artery

• external carotid artery- superior thyroid, occipital, temporal, lingual, maxillary and facial arteries
• internal carotid artery, head and neck region
• • external also goes to head and neck aswell

Question 12

Circle of Willis

Answer 12

• important anastomosis of arteries around the sella turcica
• formed from posterior cerebral arteries and posterior communicating arteries (posterior cerebral arteries), internal carotid arteries, anterior cerebral arteries, and anterior communicating arteries (which connect the two anterior cerebral arteries)
• equalizes blood pressure in the brain and can provide collateral channels should one vessel become blocked

Question 13

Blood Flow Through the Cranium

Answer 13

vertebral artery- basilar arteries- anterior, middle and posterior cerebral arteries- anterior and posterior communicating arteries (circle of Willis)- forms the cerebral arterial circle around the pituitary

Question 14

Blood Flow- Veins

Answer 14

heart- brachiocephalic vein- subclavian vein- external jugular vein and internal jugular vein- head and neck region

Question 15

Venous Return from the Cranium

Answer 15

• blood draining from the head passes into three pairs of veins: internal jugular, external jugular, and vertebral veins
• all veins drain into dural venous sinuses and then into the internal jugular veins
• dural venous sinuses are endothelial-lined venous channels between layers of the cranial

Question 16

Venous Blood Flow (circle of Willis)

Answer 16

• anterior and posterior communicating veins (circle of Willis)- anterior, middle and posterior cerebral veins- basilar veins- vertebral vein- brachiocephalic vein- super vena cava- heart

Question 17

Muscles of the Thorax that Assist in Breathing

Answer 17

• resp. muscles alter the size of the thoracic cavity which affects pressure in the lungs, and determines whether we inhale or exhale
• diaphragm is most important respiratory muscle
• external and internal intercostal muscles

Question 18

Nervoud Supply to Thorax

Answer 18

Ansa Cervicalis: 1. Anterior roots= infrahyoid and genihyoid
2. posterior roots= infrahyoid
Phrenic nerve: diaphragm
Segmental branch: deep muscle of neck, levator scapulae and scalene muscles

Question 19

Blood Supply to Thorax- Thoracic Arota

Answer 19

• begins at the level of intervertebral disc between fourth and fifth thoracic vertbrae
• extends through the arotic hiatus
• sends off numerous small arteries, visceral branches to viscera, and parietal branched to body wall structures

Question 20

Veins of the Thorax

Answer 20

• braciocephalic veins drain most thoracic structures by a network of veins, called the azygos system, that runs on either side of the vertebral column
• system consists of three veins- the azygos, hemiazygos, and accessory hemiazygos veins
• ultimately they empty into the superior vena cave