AXIAL MUSCULOSKELETAL SYSTEM

Question 1

What are the 80 bones of the axial skeleton

Answer 1

Skull: cranium, mandible and auditory ossicles (28 bones)

Hyoid bone (1 bone)

Vertebral column: vertebrae, sacrum, coccyx (26 bones)

Thoracic cage: sternum, ribs (25 bones)

Question 2

What are the functions of the vertebral column

Answer 2

protects the spinal cord and spinal nerves

supports body weight

provides a partly rigid and flexible axis for the body and a pivot for the head

posture and locomotion

Question 3

What is the general anatomy of a vertebra

Answer 3

anterior body

posterior vertebral arch (pair of pedicles and laminae)

4 articular, 2 transverse, 1 spinous processes

vertebral foreamen

inferior processes articulate with superior processes of more caudal vertebra

Question 4

Explain unique anatomy of a cervical vertebra

Answer 4

small, wide body

short/bifid spinous process

triangular foreamen

2 transverse foramen

nearly horizontal articular facets

flexion/extension/rotation of head and neck

Question 5

Explain the anatomy of atlas C1

Answer 5

articulates with occipital condyles of cranium with superior articular facets

largest foramen

no vertebral body

no spinous processes

long transverse processes

atlanta-occipital joint allows flexion/extension

Question 6

Explain the anatomy of Axis C2

Answer 6

Tooth like odontoid process (called Dens) projects superiorly from body and articulates with articular facets of atlas

Atlatoaxial joint allows rotation

Question 7

Explain the unique anatomy of thoracic vertebra

Answer 7

articulate with ribs

spinous processes are long and project inferiorly

Vertebral body is heart shaped

T1-10 articulate twice with ribs, once being at body

T11-12 articulate only once with ribs at body

forward flexion, lateral flexion, rotation

Question 8

Explain the unique anatomy of Lumbar vertebra

Answer 8

Very large, kidney shaped body

short spinous processes project posteriorly

triangular foramen

long, slender transverse processes

allows forward flexion, lateral flexion, prohibits rotation

Question 9

Outline the sacral and coccygeal vertebrae

Answer 9

sacral vertebrae fuse during adolescence into one immobile wedge shaped bone, 5 segments, strength and stability of pelvis, 4 pairs of foramina for exit of posterior and anterior rami of spinal nerves

coccyx high variable 3-5 segments, articular and transverse processes but lack pedicles, laminae and spinous processes, anchors pelvic muscles and ligaments

Question 10

what are the 3 abnormal curvatures of the vertebral column

Answer 10

kyphosi: excessive posterior curving, osteoporosis, neuromuscular disorders
lordosis: excessive anterior curving, obesity, pregnancy, weakness of abdominal wall
scoliosis: abnormal lateral curvature, developmental problems of muscular paralysis on 1 side of back

Question 11

when are secondary curves developed

Answer 11

in association with lifting the head and assuming upright sitting

shifts weight of trunk over legs as child begins to stand

centre of gravity closer to hips, not in front of feet

Question 12

What effects does ageing having on the vertebral column

Answer 12

increased curvature

decrease in bone density

intervertebral discs dehydrate and compress

loss of muscle tone

Question 13

Explain the anatomy and function of intervertebral discs

Answer 13

act as shock absorbers

nucleus pulposus: gelatinous inner sphere, absorbs compressive stress

annulus fibrosus: outer collar of ligaments and fibrocartilage, binds vertebrae together, resists spine tension

Question 14

what are the 5 intervertebral ligaments

Answer 14

anterior and posterior longitudinal: anterior and posterior surfaces of vertebrae bodies

interspinous: tips of spinous processes

ligamentum flavium: laminae

supraspinous: spinous processes from C7 to sacrum

ligamentum niche: supraspinous ligament that extends from C7 to base of skull

Question 15

Explain the ribs of the thoracic cage

Answer 15

1-7: true ribs, vertebrosternal, connect to sternum by costal cartilages

8-12: false ribs, vertebrochondral ribs

8-10: fuse together with cartilage before reaching the sternum

11-12: floating ribs, no connection to sternum

Question 16

Outline the sternum

Answer 16

manubrium: articulates with clavicles and costal cartilage of first ribs

sternal body: articulates with first seven cartilage of true ribs

xiphoid process: cartilaginous, ossifies later in life, attachment for diaphragm and rectus abdominis

Question 17

What are the three muscles types of the vertebral column

Answer 17

superficial: spinous processes of cervical and thoracic, extend/laterally flex/rotate neck
intermediate: erector spinal lie in grooves of each side of column, extends column, iliocostalis, longissimus, spinalis
deep: transversospinalis 3 groups found in groove between transverse and spinous processes, semispinalis, multifidi and rotatores muscles, slight extension and rotation of column

Question 18

What are the intervertebral muscles

Answer 18

transverse with spinous processes of adjacent superior vertebrae

rotatores thoracis

multifidi

intraversarii

Question 19

Outline the oblique and rectus muscles

Answer 19

vertebral column flexion, compresses abdomen, depresses ribs

external and internal abdominal obliques

rectus and transverse abdominis