BIO MED MID SEMESTER EXTENDED

Question 1

Axis

Answer 1

C2
Has body and processes like other vertebrae
* Major feature is knoblike dens that projects superiorly
into anterior arch of atlas –Dens is the “missing” body of atlas
* Dens is a pivot for rotation of atlas
* Movement allows side to side rotation for saying “No”

Question 2

FUNCTIONS OF THE VERTEBRAL COLUMN

Answer 2

Axial support of the trunk
- Supports the skull
- Protects the spinal cord
- Transmits weight of the body to the lower limbs
- Attachment points for ribs and muscles

Question 3

Atlas

Answer 3

(C
1
)
* No body or spinous process
* Consists of anterior and posterior arches, and two lateral
masses
* Superior surfaces of lateral masses articulate with occipital
condyles
– Occipital condyles
“
carry
” skull
* Movement for nodding head “Yes”

Question 4

Thoracic vertebra

Answer 4

T1 to T12 increase in size and articulate with ribs – Unique characteristics:
* Body is heart shaped with two small demifacets that
articulate with ribs – T10 to T12 have only single facet, not two have only single facet, not two
* Vertebral foramen is circular
* Long, sharp spinous process points inferiorly
* Transverse processes have transverse costal facets that
articulate with ribs (except T11, T12)

Question 5

Lumbar vertebrae

Answer 5

L1 to L5 “small of back”; receives most stress, so
bodies are massive – Other characteristics:
* Short, thick pedicles and laminae
* Flat, hatchet-shaped spinous processes point
posteriorly
* Vertebral foramen is triangular
* Orientation of articular facets locks lumbar
vertebrae together to prevent rotation

Question 6

Sacrum

Answer 6

Triangular bone at posterior wall of pelvis; made from five fused
vertebrae (S1–S5) – Superior articular process articulates with L5 – Articulates inferiorly with coccyx and laterally with hip bones
via its via its auricular auricular surfaces surfaces, forming , forming sacroiliac sacroiliac joints – Sacral promontory: antero-superior margin – Transverse ridges mark lines of fusion

Question 7

INTERVERTEBRAL DISCS

Answer 7

Cushion like pad (fibrocartilage) composed of two parts
1. Nucleus pulposus
* Inner gelatinous nucleus that gives the disc its elasticity
and compressibility
2. Annulus fibrosus
* Outer collar composed of collagen and fibrocartilag
e
*
Functions
- Act as shock absorbers during running walking, etc.
- Allow spine to flex and ext

Question 8

Pectoral (Shoulder) Girdle

Answer 8

Consists of clavicles (anteriorly) and scapulae (posteriorly)
– Attach upper limbs to axial skeleton
– Attachment sites for muscles that move upper limbs
– Offer great degree of mobility because:
Scapulae are not attached to axial skeleton
Socket of shoulder joint is shallow and does not
restrict movement

Question 9

Scapulae – Shoulder blade

Answer 9

Three borders:
– Superior, Medial (vertebral), Lateral (axillary)
* Three angles:
– Superior, Lateral, Inferior
Bone markings:
* Supraspinous and infraspinous fossae
* Spine
* Acromion
* Coracoid process
* Suprascapular notch
* Glenoid cavity

Question 10

Gene Locus:

Answer 10

The point on a DNA molecule that controls the inheritance of a
particular trait