Anatomy MCQs

Damage to which nerve would result in difficulty initiating abduction of the arm? a) Suprascapular nerve b) Long thoracic nerve c) Lower subscapular nerve d) Upper subscapular nerve

Answer a) Supraspinatus is innervated by supra scapular nerve (C5,6) and assists the deltoid in the first 15 degrees of abduction. Long thoracic nerve innervates serratus anterior. Limits abduction above horizontal. Upper subscapular nerve innervates subscapularis and lower subscapular nerve innervate teres major and subscapularis. Would impair adduction and medial rotation.

Which muscles does the clavicopectoral fascia enclose? a) pectoralis major and pectoralis minor b) serratus anterior and pectorals major c) subclavius and pectoralis minor d) pectorals major and subclavius

Answer c) Encloses subclavius and pec minor. Lies deep to the pectoral fascia and pectorals major. The part of the fascia between the subclavius and pec minor is the costocoracoid membrane and it is pierced by the lateral pectoral nerve which supplies pec major.

Which is the false statement in relation to the sub scapular artery? a) It divides into the circumflex scapular artery and the thoracodorsal artery b) It descends along the lateral border of the subscapularis on the posterior axillary wall c) It is the largest branch of the axillary artery d) It arises from the second part of the axillary artery

Answer d) The subscapular artery arises from the third part of the axillary artery along with the anterior and posterior circumflex humeral artery. 1st part: 1 branch = superior thoracic artery 2nd part: 2 branches = thoracoacromial and lateral thoracic artery

Damage to the long thoracic nerve would cause? a) Inability to shrug against resistance. b) Inability to abduct the arm above the horizontal position. c) Inability to raise the trunk with upper limb as occurs when rock climbing. d) Atrophy of the deltoid muscle

Long thoracic nerve injury ( C5, C6, C7) = innervates serratus anterior; winged scapula (moves posteriorly and laterally) and inability to rotate the glenoid cavity superiorly therefore can't abduct arm above the horizontal. Thoracodorsal nerve injury (C6,7,8) = innervated latissimus dorsi; unable to climb. Accessory (CN XI) nerve injury = inability to shrug against resistance Axillary nerve injury (C5,6) = deltoid atrophy