Test: Upper Limb - NEET PG MCQ

The fracture clavicle is most often in the middle third (at the junction of lateral 1/3rd and medial 2/3rd) and results in upward displacement of the proximal fragment pulled by the sternocleidomastoid muscle and downward displacement of the distal fragment by the deltoid muscle and gravity.

• The tip of coracoid process can be palpated 2.5 cm below the junction of lateral 1/4 and medial 3/4 of the clavicle (in the infraclavicular fossa).
• Key: A- Infraglenoid tubercle; B- Acromion process; C-Coracoid process; D-Superior angle of scapula.

Serratus anterior is inserted on the medial border of scapula (costal aspect).

Long head of triceps attaches to the infraglenoid tubercle 

• The lateral border separates the attachments of subscapularis and teres minor and major. These muscles project beyond the bone and, with latissimus dorsi below, cover it so completely that it cannot be felt through the skin.
• Even the superior border and angle of the scapula are deep to soft tissue and is not readily palpable.

• Superior angle lies at the junction of superior and medial borders, and lies over the 2nd rib and 2nd thoracic vertebra.
• The inferior angle is opposite the spine of the 7th thoracic vertebra and overlies the inferior border of 7th rib.

Lateral (and medial) epicondyles are outside the capsular ligament. They are traction epiphysis.

• Synovial membrane of shoulder joint forms a tubular sheath around the tendon of biceps brachii where it lies in the bicipital groove of the humerus.
• Anterior circumflex artery sends an ascending branch upwards in the groove.

• Radius articulates with carpal bones to form radiocarpal (wrist) joint. It is the major contributor in the joint.
• The medial bone ulna is excluded from this articulation by an articular disc.
• Radial artery lies medial to styloid process of radius, then winds laterally around the styloid process to enter the anatomical snuff box.
• Radial (spiral) groove is present on humerus bone.

• Distal end of radius has Lister’s tubercle on the dorsal side.
• The tendon of extensor carpi radialis longus (and Brevis) pass lateral to the tubercle.
• The tendon of extensor pollicis longus passes medial to the Lister’s tubercle.

• Lateral (and medial) epicondyles are outside the capsular ligament.
• Tendon of extensor carpi radialis longus pass lateral to the Lister’s tubercle.
• Most common site of fracture clavicle is the junction of medial 2/3rd with lateral 1/3rd. It may also be considered as junction of intermediate 1/3rd with lateral 1/3rd.
• Lateral border of scapula gives origin to teres major & minor muscles.
• Wrist joint is called radio-carpal joint and formed by articulation of the distal end of the radius with the proximal row of carpal bones.

Attachment on greater tubercle is teres minor (not major). Teres major attached to the medial lip of bicipital groove on humerus.

• Pectoralis major muscle is an adductor (and not abductor) at shoulder joint.
• Serratus anterior muscle causes protraction of scapula. Retractors are: Rhomboideus major and minor muscles.
• Flexor pollicis longus do not cross (and act) at elbow joint. It flexes the phalanges and carpometacarpal joint of the thumb.
• Pectoralis minor stabilizes scapula by pulling it anteriorly and inferiorly. It doesn’t participate in shoulder joint movements.
• Flexor carpi ulnaris causes flexion at the wrist joint and ulnar deviation (adduction) as well.

• Both supraspinatus and deltoid are involved throughout the range of abduction, including the initiation of the movement.
• Serratus anterior and trapezius help in overhead abduction.
• The multipennate acromial (not clavicular) fibres of deltoid are the powerful abductors of arm at the shoulder joint.
• Axillary nerve injury paralyses the deltoid; hence abduction is seriously compromised. Musculotendinous rotator cuff stabilizes the shoulder joints posterosuperiorly and partly anteriorly as well (but inferiorly it is deficient).

• Anconeus muscle is an extensor at elbow joint (with triceps) and flexor pollicis longus muscle do not cross (and act) at elbow joint.
• Biceps brachii is a powerful supinator and causes elbow flexion as well.
• Brachioradialis is a flexor at elbow joint especially in mid-prone position. Humeral head of pronator teres crosses elbow joint, hence participate in elbow flexion.
• Chief action of brachialis is elbow flexion

• The wrist (radiocarpal) joint is an ellipsoid type of synovial joint, though some authors consider it as condylar variety.
• Internal pudendal vessels pass through greater and lesser sciatic foramina (not through obturator foramen).

• Abduction of the hand occurs at the wrist joint, carried out by the muscles like Flexor carpi radialis.
• Flexor carpi ulnaris works for adduction of hand at wrist joint.

• Coracoacromial ligaments attaches to bone scapula at different points and is not attached to the previous or next bone in line of weight transmission.
• Ligaments involved in weight transmission connect one bone with the next bone, in line of weight transmission.
• There are numerous ligaments which help in weight transmission of upper limb to the axial skeleton, frequently mentioned is coracoclavicular, attached the conoid tubercle and trapezoid line, transmit the weight of the upper limb to the clavicle.

• Most of the authors mention two branches of from the upper trunk of brachial plexus: Suprascapular nerve and nerve to subclavius.
• Gray’s anatomy mentions that the slender nerve to subclavius (C5, 6) springs from the upper trunk.
• Suprascapular nerve (C5, 6) usually arises as the first branch of the upper trunk but it frequently springs directly from the ventral primary ramus of C5. It innervates supra and infraspinatus muscles.

• Median nerve is contributed by two roots given by lateral cord: C6, 7 and medial cord: C8; T1. It appears to be the best answer.
• Axillary nerve- C5, 6; Ulnar nerve - C (7) 8, T1; Musculocutaneous nerve- C5,6,7.
• Radial nerve (C5, 6, 7, 8, T1) carries fibres from all the roots of brachial plexus.

• Contribution by C4 to brachial plexus is pre-fixed brachial plexus. Post-fixed brachial plexus has contribution by T2
• Upper trunk has C5,6; Middle trunk: C7 and Lower trunk: C8 and T1 root values.
• Lateral cord is formed by anterior divisions of upper and middle trunk.
• Medial cord by anterior division of lower trunk and Posterior cord by posterior divisions of upper, middle and lower trunks.

Posterior cord gives five branches, including axillary nerve which supplies teres minor muscle.

• Injury to upper trunk of brachial plexus results in Erb’s palsy resulting in policeman tip hand deformity: Adduction and medial (internal) rotation at shoulder joint; extension at elbow joint and pronation at radioulnar joint.
• Initiation of shoulder abduction (supraspinatus paralysed) and raising the arm to 90° (deltoid paralysed) is not possible.
• Outer (lateral) surface of the upper limb (C-5, 6 dermatome) has sensory disturbance.
• Decreased sensation on medial side of hand (C-8 dermatome) occurs in Klumpke’s palsy.

• Upper trunk of brachial plexus carries C-5, 6 root values.
• Trunks of brachial plexus pass in the scalene triangle bounded by scalenus anterior and medius muscle, it lies lateral (and not medial) to the scalenus anterior muscle, where a block can be carried out.
• Long thoracic nerve arises directly from the roots of brachial plexus (C-5, 6, 7).
• Lesion of upper trunk of brachial plexus (e.g., Erb’s palsy) leads to partial (C5,6) injury of radial nerve (C-5, 6, 7, 8; T1).

In Klumpke’s palsy there is a lesion in the lower trunk of brachial plexus, leading to claw hand deformity due to paralysis of hand muscles, including intrinsic muscles like lumbrical and interossei. Features of Horner syndrome are evident due to injury of T1 sympathetic fibres.