1. Which muscle is inserted into the floor of
the intertubercular sulcus of the humerus?
a) Latissimus dorsi
b) Teres major
c) Pectoralis major
d) Deltoid
Correct Answer - A
Ans. is 'a' i.e., Latissimus dorsi
The shaft of humerus is cylindrical in the upper half and triangular on
cross-section in the lower half. The upper part has intertubercular
sulcus (bicipital groove) anteriorly. Bicipital groove contains long
head of biceps with its synovial sheath and an ascending branch of
anterior circumflex humeral artery. Middle third of posterior surface
of shaft of the humerus has a spiral groove (radial groove) which
contains radial nerve and profunda brachi vessels.
Attachment to shafts are ?
* Insertions of pectoralis major (on lateral lip of bicipital groove),
latissimus dorsi (on floor of bicipital groove), teres major (on deltoid
tuberosity) and coracobrachialis (medially on mid shaft).
* Origin of brachialis (anterior surface); Lateral and medial head of
triceps (posterior surface); pronater teres (from medial
supracondylar ridge); brachioradialis (from lateral supracondylar
ridge) and ECRL (from lateral supracondylar ridge).
,2. At what level does the trachea bifurcates
?
a) Upper border of T4
b) Lower border of T4
c) 27.5 cm from the incisors
d) Lower border of T5
Correct Answer - B
Ans. is 'b' i.e., Lower border of T4 [Ref BDC Sth/e Volume 1 p.
267]
Trachea bifurcates at carina, at the level of lower border of T, or T4 -
T5 disc space.
,3. Cricoid cartilage lies at which vertebral
level ?
a) C3
b) C6
c) T1
d) T4
Correct Answer - B
Ans. is 'b' i.e., C6 [Ref BDC 5I'Ve Vol. III, p. 237]
, 4. Which of the following is true about
vertebral development -
a) The notochord forms the annulus fibrosus
b) The sclerotome forms the nucleus pulposus
c) The sclerotome surrounds the notochord only
d) The sclerotome surrounds the notochord and the neural tube
Correct Answer - D
Ans. is 'd' i.e., The sclerotome surrounds the notochord and the
neural tube [Ref Langman's embryology 10th/e p. 140]
Development of vertebral column
The human nervous system develops from neuroectoderm.
During development, behind the neuroectoderm lies the mesoderm
(paraxial mesoderm) that encloses the notochord (a derivative of
endoderm).
This paraxial mesoderm give rise to somites.
Somites further differentrated into :
Dermatomyotome :- Give rise to skeletal muscles and dermis.
Sclerotomes :- Give rise to vertebral column.
Sclerotornes which surround notochord starts projecting posteriorly
(dorsally) to surround neural tube and forms.
Ventral sclerotomes :- Give rise to vertebral body and annulus
fibrosus, Lateral sclerotomes :- Give rise to vertebral arch (pedicle
and lamina).
Dorsal sclerotomes :- Give rise to spinous process. The notochord
forms the nucleus pulposus.
the intertubercular sulcus of the humerus?
a) Latissimus dorsi
b) Teres major
c) Pectoralis major
d) Deltoid
Correct Answer - A
Ans. is 'a' i.e., Latissimus dorsi
The shaft of humerus is cylindrical in the upper half and triangular on
cross-section in the lower half. The upper part has intertubercular
sulcus (bicipital groove) anteriorly. Bicipital groove contains long
head of biceps with its synovial sheath and an ascending branch of
anterior circumflex humeral artery. Middle third of posterior surface
of shaft of the humerus has a spiral groove (radial groove) which
contains radial nerve and profunda brachi vessels.
Attachment to shafts are ?
* Insertions of pectoralis major (on lateral lip of bicipital groove),
latissimus dorsi (on floor of bicipital groove), teres major (on deltoid
tuberosity) and coracobrachialis (medially on mid shaft).
* Origin of brachialis (anterior surface); Lateral and medial head of
triceps (posterior surface); pronater teres (from medial
supracondylar ridge); brachioradialis (from lateral supracondylar
ridge) and ECRL (from lateral supracondylar ridge).
,2. At what level does the trachea bifurcates
?
a) Upper border of T4
b) Lower border of T4
c) 27.5 cm from the incisors
d) Lower border of T5
Correct Answer - B
Ans. is 'b' i.e., Lower border of T4 [Ref BDC Sth/e Volume 1 p.
267]
Trachea bifurcates at carina, at the level of lower border of T, or T4 -
T5 disc space.
,3. Cricoid cartilage lies at which vertebral
level ?
a) C3
b) C6
c) T1
d) T4
Correct Answer - B
Ans. is 'b' i.e., C6 [Ref BDC 5I'Ve Vol. III, p. 237]
, 4. Which of the following is true about
vertebral development -
a) The notochord forms the annulus fibrosus
b) The sclerotome forms the nucleus pulposus
c) The sclerotome surrounds the notochord only
d) The sclerotome surrounds the notochord and the neural tube
Correct Answer - D
Ans. is 'd' i.e., The sclerotome surrounds the notochord and the
neural tube [Ref Langman's embryology 10th/e p. 140]
Development of vertebral column
The human nervous system develops from neuroectoderm.
During development, behind the neuroectoderm lies the mesoderm
(paraxial mesoderm) that encloses the notochord (a derivative of
endoderm).
This paraxial mesoderm give rise to somites.
Somites further differentrated into :
Dermatomyotome :- Give rise to skeletal muscles and dermis.
Sclerotomes :- Give rise to vertebral column.
Sclerotornes which surround notochord starts projecting posteriorly
(dorsally) to surround neural tube and forms.
Ventral sclerotomes :- Give rise to vertebral body and annulus
fibrosus, Lateral sclerotomes :- Give rise to vertebral arch (pedicle
and lamina).
Dorsal sclerotomes :- Give rise to spinous process. The notochord
forms the nucleus pulposus.
