⬅ Home
16# Cervical & Brachial Plexus
1. The cervical plexus is formed by the anterior rami of which spinal nerves?
C1–C3
C1–C4 with contribution from C5
C2–C5
C3–C6
Explanation:
The cervical plexus is formed from C1–C4 anterior rami with contribution from C5.
2. All cutaneous branches of the cervical plexus emerge at which point?
Angle of mandible
Anterior border of SCM
Root of neck
Midpoint of posterior border of SCM
Explanation:
All four cutaneous branches emerge at the midpoint of the posterior border of SCM (nerve point of neck).
3. Which nerve supplies the skin over the angle of the mandible?
Great auricular nerve
Lesser occipital nerve
Transverse cervical nerve
Supraclavicular nerve
Explanation:
The great auricular nerve (C2–C3) supplies skin over the angle of the mandible.
4. Which statement about C1 fibers is CORRECT?
They give a cutaneous branch
They form the great occipital nerve
They travel with hypoglossal nerve
They supply trapezius directly
Explanation:
C1 fibers travel with the hypoglossal nerve and contribute to ansa cervicalis and geniohyoid/thyrohyoid.
5. The ansa cervicalis supplies all infrahyoid muscles EXCEPT:
Omohyoid
Thyrohyoid
Sternohyoid
Sternothyroid
Explanation:
Thyrohyoid is supplied by C1 fibers via hypoglossal nerve, not by ansa cervicalis.
6. The phrenic nerve is formed by which spinal roots?
C3, C4, C5
C2, C3, C4
C4, C5, C6
C5 only
Explanation:
Phrenic nerve arises from C3–C5 (“C3,4,5 keep the diaphragm alive”).
7. The phrenic nerve enters the thorax by passing:
Behind subclavian artery
Behind subclavian vein
Through the esophageal hiatus
In front of the subclavian artery
Explanation:
The phrenic nerve enters the thorax anterior to the subclavian artery.
8. The brachial plexus is formed by anterior rami of:
C4–T1
C5–T1
C6–T2
C5–T2
Explanation:
The brachial plexus is formed by C5 to T1 anterior rami.
9. The roots of the brachial plexus lie between which muscles?
SCM and trapezius
Pectoralis major and minor
Scalenus anterior and medius
Subclavius and serratus anterior
Explanation:
Roots pass between scalenus anterior and scalenus medius muscles.
10. Which trunks form the lateral cord?
Posterior divisions of all trunks
Anterior division of lower trunk
Posterior divisions of upper and middle trunks
Anterior divisions of upper and middle trunks
Explanation:
The lateral cord is formed by anterior divisions of upper and middle trunks.
11. The cords of the brachial plexus are named according to their relation to:
Second part of axillary artery
Axillary vein
Clavicle
First rib
Explanation:
Cords are named by their relation to the second part of the axillary artery.
12. Which nerve is a direct terminal branch of the posterior cord?
Median nerve
Radial nerve
Musculocutaneous nerve
Ulnar nerve
Explanation:
Posterior cord divides into axillary and radial nerves.
13. Which nerve pierces the coracobrachialis muscle?
Median nerve
Radial nerve
Musculocutaneous nerve
Ulnar nerve
Explanation:
Musculocutaneous nerve pierces coracobrachialis muscle.
14. The musculocutaneous nerve ends as:
Posterior cutaneous nerve of forearm
Medial cutaneous nerve of forearm
Radial sensory branch
Lateral cutaneous nerve of forearm
Explanation:
It continues as the lateral cutaneous nerve of the forearm.
15. The median nerve is formed by:
Lateral and medial cords
Posterior cord only
Upper trunk
Lower trunk
Explanation:
Median nerve is formed by contributions from both lateral and medial cords.
16. In the arm, the median nerve crosses the brachial artery:
From medial to lateral
Does not cross it
From lateral to medial
Behind it
Explanation:
Median nerve crosses the brachial artery from lateral to medial halfway down the arm.
17. Which nerve passes behind the medial epicondyle of the humerus?
Median nerve
Ulnar nerve
Radial nerve
Musculocutaneous nerve
Explanation:
The ulnar nerve becomes superficial behind the medial epicondyle.
18. The ulnar nerve supplies which forearm muscles?
All flexors
No forearm muscles
All intrinsic hand muscles
FCU and medial half of FDP
Explanation:
Ulnar nerve supplies flexor carpi ulnaris and medial half of flexor digitorum profundus.
19. The ulnar nerve enters the hand:
Superficial to flexor retinaculum
Through carpal tunnel
Between thenar muscles
Deep to palmar aponeurosis only
Explanation:
Ulnar nerve enters the hand superficial to flexor retinaculum (Guyon’s canal).
20. Which nerve is the sole motor nerve to the posterior compartment of the arm?
Ulnar nerve
Median nerve
Radial nerve
Axillary nerve
Explanation:
Radial nerve supplies all muscles of the posterior compartments of arm and forearm.
21. Which nerve provides extensive cutaneous innervation to the posterior upper limb?
Median nerve
Ulnar nerve
Musculocutaneous nerve
Radial nerve
Explanation:
Radial nerve provides cutaneous innervation to most of posterior limb.
22. The axillary sheath encloses:
Axillary artery, vein, and cords
Axillary vein only
Only terminal branches
Subclavian vessels
Explanation:
Axillary sheath encloses artery, vein, and cords of brachial plexus.
23. Which trunks of the brachial plexus have NO branches?
Upper trunk only
Upper and middle trunks
Middle and lower trunks
All trunks
Explanation:
Middle and lower trunks do not give branches.
24. Injury to the phrenic nerve most directly affects:
Intercostal muscles
Diaphragm
Scalene muscles
Sternocleidomastoid
Explanation:
Phrenic nerve is the sole motor supply to the diaphragm.