Upper limb Flashcards
Which of the following nerves is a branch of the medial cord of the brachial plexus?
A Dorsal scapular
B Medial pectoral
C Lateral pectoral
D Lower subscapular
B
Explanation
The lateral pectoral nerve is a branch of the lateral cord. The dorsal scapular nerve (which supplies the rhomboids and levator scapulae) belongs to the C5 root. The lower subscapular nerve is a branch of the posterior cord. The medial pectoral nerve arises from the medial cord C8 T1 behind the first part of the axillary artery
Regarding the Brachial plexus, which of the following statements is incorrect?
A Branches of the cords surround the third part of axillary artery
B Divisions form behind the clavicle and enter the anterior triangle
C Cords embrace the 2nd part of the axillary artery
D Cords enter the axilla above the first part of the axillary artery
B
Explanation
The 5 roots lie behind the scalenus anterior muscle and emerge between it and scalenus medius to form the trunks which cross the lower part of the posterior triangle of the neck. Each of the three trunks divides into an anterior and a posterior division behind the clavicle. Here, at the outer border of the first rib, the upper two anterior divisions unite to form the lateral cord, the anterior division of the lower trunk runs on as the medial cord, while all three posterior divisions unite to form the posterior cord. These three cords enter the axilla above the first part of the axillary artery, approach and embrace its second part, and give off their branches around its third part.
Thus the roots are between the scalenus muscles, trunks in the posterior triangle, divisions behind the clavicle, and the cords in axilla.
The information about the axillary artery comes from Last’s anatomy. I know it is an older textbook. I have also left the question as is.
The first part of the axillary artery and the cords of the brachial plexus are enclosed within the axillary sheath, which is projected down from the prevertebral fascia in the neck. The lateral and posterior cords are superolateral, and the medial cord posterior, to the artery.
The second part of the artery has the three cords of the plexus lateral, posterior and medial to it, as their names indicate.
The third part has the branches from the cords of the brachial plexus, having in general the same relation to the artery as their parent cords. The medial root of the median nerve crosses in front of the artery to join the lateral root and form the nerve lateral to the artery,
From the current TB
The brachial plexus is formed by the union of the anterior rami of the last four cervical (C5-C8) and the first thoracic (T1) nerve, which constitute the roots of the brachial plexus.
The roots of the plexus usually pass through the gap between the anterior and the middle scalene muscles with the subclavian artery. In the inferior part of the neck, the roots of the brachial plexus unite to form three trunks. A superior, middle and inferior trunk. Each trunk of the brachial plexus divides into anterior and posterior divisions as the plexus passes through the cervico-axillary canal posterior to the clavicle. Anterior divisions of the trunks supply anterior (flexor) compartments of the upper limb and posterior divisions of the trunks supply (extensor) compartments. The division of the trunks form three cords of the brachial plexus. Anterior divisions of the superior and middle trunks untie to form the lateral cord. Anterior division of the inferior trunk continues as the medial cord. Posterior divisions of all three trunks unite to form the posterior cord. The cords bear relationship to the second part of the axillary artery that is indicated by their names. The lateral cord is lateral to the axillary artery etc, The products of the plexus formation are multisegmental , peripheral nerves. The brachial plexus is divided into supraclavicular and infraclavicular parts.
Regarding the brachial plexus, which of the following statements is correct?
A Injury proximal to the trunks will not affect the supraspinatus nor infraspinatus muscles
B Erb’s palsy results in a medially rotated arm with elbow flexion
C Ulnar nerve palsy results in weakness of the interossei and numbness over the radial part of the hand
D Pectoralis major is the only muscle that can test all roots
D
Explanation
Erb’s palsy results in a medially rotated arm with the elbow in extension. The nerve supply to supra and infraspinatous comes from the trunks and will be affected if the injury to the BP is at the level of the trunks or proximal to them. Ulnar nerve injury will give weakness to the ulnar part of the hand
In relation to serratus anterior, which of the following statements is correct?
A Is supplied by the dorsal scapular nerve
B Is formed by 7 slips
C Protracts the scapula
D Is not covered by fascia
C
Explanation
Serratus anterior is supplied by the long thoracic nerve and is formed by 8 slips/ digitations (The muscle arising by a series of digitations from the upper eight ribs). The first digitation arises from the first and second rib. All other digitations arise from their corresponding ribs. It is covered by fascia. The whole muscle contracting en masse, protracting the scapula, effectively elongates the upper limb for activities such as punching and pushing.
Note: old textbooks mentions 8 ror 9 slips. Internet search give 8-10 slips. The current textbook does not explicitly state.
Which of the following statements in relation to pectoralis major is correct?
A Only the costal part has a bony attachment
B Abducts the arm
C Attaches to the glenoid tuberosity
D Is an accessory muscle of respiration
D
Explanation
Both the clavicular and sternocostal heads of pectoralis major have bony attachments. It adducts the arm with lattisimus dorsi. It is not attached to the glenoid tuberosity. The muscle is a medial rotator and powerful adductor of the arm. The sternocostal fibres are the chief adductors. The clavicular head assists in flexion at the shoulder joint. With the upperlimb fixed in abduction the muscle is a useful accessory muscle of inspiration, drawing the ribs up towards inspiration.
Which of the following does not pass through the clavipectoral fascia?
A Cephalic vein
B Thoracoacromial artery
C Lymphatics
D Medial pectoral nerve
D
Explanation
Lymphatics (infraclavicular to apical nodes) and the cephalic vein pass inwards through the clavipectoral fascia. The thoracoacromial artery (or its branches: pectoral, acromial, deltoid and clavicular) and the lateral pectoral nerve pass outwards.
Note: the question might read, Which of the following does not pass through the costacoracoid membrane?, this membrane is part of the clavipectoral fascia between the pectoralis minor and the subclavius. The answer is still the same though.
Extra:
A good mnemonic for structures passing through the clavipectoral fascia - CALL: Cephalic vein A -thoracoAcrominal artery Lymphatics Lateral pectoral nerve.
Regarding the radial nerve which of the following statements is INCORRECT?
A It crosses the lower border of the posterior axillary wall lying on the tendon of lattisimus dorsi
B The radial nerve is a continuation of the posterior cord of the brachial plexus
C The radial nerve is the largest branch of the brachial plexus
D It passes through the quadrangular space into the upper arm
D
Explanation
The radial nerve is the largest branch of the brachial plexus. It is the continuation of the posterior cord (C5, 6, 7, 8, T1). It crosses the lower border of the posterior axillary wall lying on the tendon of lattisimus dorsi. It passes out of site through the triangular interval below the lower border of this tendon as it lies in front of teres major, between the long head of triceps and the humerus.
The radial nerve gives off the posterior interosseous nerve in between brachialis and brachioradialis. It has a posterior cutaneous branch. It only occupies the lower part of the radial grove
Contents passing through the quadrangular space: axillary nerve and the posterior circumflex humeral artery
Triangular space
Boundaries
Inferior: superior border of teres major
Lateral: long head of triceps
Superior: teres minor (or subscapularis)
Contents:
Scapular circumflex vessels
Unlike the quadrangular space or the triangular interval, NO major nerve passes through the triangular space
Quadrangular space
Boundaries
Superior: teres minor (inferior margin)
Inferior: teres major (superior margin)
Medially: long head triceps brachii (lateral margin)
Laterally: Surgical neck of the humerus
Anteriorly: subscapularis
Contents:
Axillary nerve and posterior circumflex humeral vessels (artery and vein)
Triangular interval
Boundaries
Superior: teres major
Medial: long head of triceps brachii
Lateral: humerus (some sources say lateral head of triceps)
Contents
Radial nerve passes through on its way to the posterior compartment of the arm. Profunda brachii also passes from anterior to posterior.
With regard to the lumbricals, which of the following statements is correct?
A Are all supplied by the ulnar nerve
B Oppose the actions of the interossei
C Arise from flexor digitorum superficialis
D Form a proprioceptive bridge between flexors and extensors
D
Explanation
The lumbricals flex the fingers at the MCP joints and extend the interphalangeal joints.
Note in previous textbook, the action at the MCP was disputed and any flexor action here was deemed to be weak
They are supplied by both the median nerve and the ulnar nerve. They attach to the extensor expansion. They arise from the flexor digitorum profundus tendons, and attach to the extensor expansion.
The interossei: the 4 dorsal interossei abduct the fingers (DAB) and the 3 palmar interossei adduct them (PAD)
All the following muscles directly attach the pectoral girdle to the thorax except?
A Subclavius
B Pectoralis major
C Pectoralis minor
D Rhomboids
B
Explanation
Direct attachment of the pectoral girdle to the trunk is provided by muscles which insert into the clavicle or scapula from the axial skeleton. These muscles are pectoralis minor, subclavius, trapezius, the rhomboids, levator scapula and serratus anterior. Indirect attachment to the axial skeleton is secured by the great muscles of the axillary folds, pectoralis major and latissimus dorsi
Note: this question is form Last’s anatomy.
Extra: The pectoral girdle and bones of the free part of the upper limb form the superior appendicular skeleton. The superior appendicular skeleton articulates with the axial skeleton only at the sternoclavicular joint, allowing great mobility. The clavicles and scapulae of the pectoral girdle are supported, stabilised, and moved by the axioappendicluar muscles that attach to the relatively fixed ribs, sternum and vertebrae of the axial skeleton.
Anterior axioappendicular muscles:
Pectoralis major, pectoralis minor, subclavius and serratus anterior.
Posterior axioappendicular muscles:
Trapezius, latissimus dorsi (superficial), levator scapulae, Rhomboids (deep)
Clinical orientated anatomy (Moore)
The scaphoid articulates with all the following except?
A Triquetral
B Capitate
C Trapezium
D Trapezoid
A
Explanation
Answer is triquetral. The scaphoid articulates with the lunate medially, and distomedially with the capitate. The distal convex surface articulates with the trapezium and trapezoid. The scaphoid is the most commonly fractured carpal bone
Which muscle initiates shoulder abduction?
A Supraspinatous
B Deltoid
C Subscapularis
D Teres minor
A
Explanation
From 0-15 degrees of abduction, the supraspinatous is the initiating muscle
To initiate movement during the first 15 degrees of abduction, the deltoid is assisted by the supraspinatus. The deltoid becomes fully effective as an abductor following the initial 15 degrees.
Which of the following is not a branch of the axillary artery?
A Subscapular
B Medial thoracic
C Thoracoacromial
D Superior thoracic
B
Explanation
Note: the lateral thoracic, posterior and anterior circumflex humeral arteries are also branches
1st part of axillary artery gives off (1) the superior thoracic artery. 2nd part gives off (2) the thoraco-acromial trunk and lateral thoracic artery. 3rd part gives off (3) sub-scapular artery and anterior/posterior humeral circumflex artery.
mnemonic’s:
SALSAP or Sometimes Times Life Seems A Pain
(Or even better) Screw The Laywer, Save A Patient
Which muscle is supplied by the posterior interosseous nerve in the posterior compartment of the forearm?
A Anconeus
B Supinator
C Extensor carpi radialis longus (ECRL)
D Brachioradilais
B
Explanation
Note: the question appears to be from the old textbook (as has been left as such). The explanation contains the old textbook as well as the current textbook information.
Older textbook
Posterior compartment of the forearm
Muscles supplied by the posterior interosseous nerve (C7, C8)
Extensor carpi radialis brevis
Extensor digitorium
Extensor digiti minimi
Extensor carpi ulnaris
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis
Supinator
Muscles supplied by the radial nerve (C5, C6)
Brachioradialis
Extensor carpii radialis longus
Anconeus
Current textbook
Posterior compartment of the forearm
Superficial layer
Brachioradialis- Radial nerve (C5, C6, C7)
Extensor carpii radialis longus- Radial nerve (C6, C7)
Extensor carpi radialis brevis- Deep branch of radial nerve (C7, C8)
Extensor digitorium- Deep branch of radial nerve (C7, C8)
Extensor digiti minimi- Deep branch of radial nerve (C7, C8)
Extensor carpi ulnaris- Deep branch of radial nerve (C7, C8)
Deep Layer
Supinator- Deep branch of radial nerve (C7, C8)
Extensor indicis- Posterior interosseous nerve (C7, C8)-continuation of deep branch of radial nerve
Outcropping muscles of deep layer
Extensor pollicis longus- Posterior interosseous nerve (C7, C8)-continuation of deep branch of radial nerve
Abductor pollicis longus- Posterior interosseous nerve (C7, C8)-continuation of deep branch of radial nerve
Extensor polices brevis- Posterior interosseous nerve (C7, C8)-continuation of deep branch of radial nerve
Extra: Supinator is innervated by the deep branch of the radial nerve. The deep branch then becomes the posterior interosseous nerve upon exiting the supinator muscle. Supinator’s nerve roots are primarily from C6 (with some C5 involvement). There are other questions in this question bank which ask specifically about this.
Regarding the anatomical snuff box, which of the following statements is FALSE?
The cephalic vein begins in the roof of anatomical snuffbox is confusing. I have checked Last’s and Moore only mentioned as a content of Anatomical snuffbox
A The bones palpable are the radial styloid, scaphoid, trapezium and the base of the first metacarpal
B Branches of the radial nerve can be palpated over the tendons
C The cephalic vein begins in the roof of the anatomical snuffbox
D The tendons of abductor pollicis longus and extensor pollicis longus form one boundary
D
Explanation
The trapezium and scaphoid can be felt in the floor of the snuffbox between the radial styloid process and the first metacarpal. Note: In Last’s anatomy it says that the bony points readily palpable in the snuff box are from proximal to distal, radial styloid, scaphoid, trapezium and the base of the thumb metacarpal (RSTT).
It contains the radial artery, cephalic vein and cutaneous branches of the radial nerve. It is most obvious with the thumb fully extended; this draws the tendons up and produces a triangular hollow between them. It is the abductor pollicis longus and the extensor policis brevis that form one boundary on the radial or thumb side, and the extensor pollices longus forms the other boundary on the ulnar side. The cutaneous branches of the radial nerve cross these tendons and can be rolled on the tight tendon of EPL. The cephalic vein begins in the roof
Extra: From Last’s anatomy
From the radial side of this arch the cephalic vein begins in the roof of the anatomical snuffbox and runs up along the lateral border of the limb. It runs in the upper arm lateral to biceps, to the deltopectoral groove, and perforates the clavipectoral fascia to drain into the axillary vein. From the ulnar side of the dorsal venous arch the basilic vein runs up the medial border of the limb. It pierces the deep fascia halfway between elbow and axilla and becomes the axillary vein at the lower border of teres major.
Regarding the interossei in the hand, which of the following is true?
A They abduct the fingers only
B They arise from the tendons of Flexor digitorum superficialis
C Palmar interossei have two heads
D They aid in flexion of metacarpo-phalangeal joints & extension of interphalangeal joints
D
Explanation
They arise from the metacarpal bones. Only dorsal interossei have two heads (bipennate). Interossei muscles abduct and adduct the fingers- Remember PAD and DAB - Palmar interossei ADduct and Doral interossei ABduct. The interossei are indispensable for the combined movement of flexion of the MCP joint and the simultaneous extension of the interphalangeal joints. The lumbricals extend both interphalangeal joints. Their action at the MCP joint is disputed and any flexor action here is likely to be weak
Note: The above explanation is taken form the former prescribed textbook. In the current one it states that the interossei and lumbricals act together to provide MCP flexion and IP extension. One muscle does not appear to be more important than the other.
Regarding the acromio-clavicular joint, which of the following statements is correct?
A The coracoid and the trapezoid ligaments make up the coracoclavicular ligamment
B AC joint is innervated by the lateral supraclavicular, medial pectoral and axillary nerve
C No muscles connect the articulating bones to move the AC joint
D AC joint is supplied by the subscapular and thoracoacromial arteries
C
Explanation
The AC joint is an atypical synovial joint. The articular surfaces are covered by fibrocartilage and seperated by an incomplete wedge shaped articular disc. The coracoclavicular ligament (made up by the conoid and trapezoid ligament) is extremely strong and the principal factor in providing stability to the joint. Movements are passive; muscles which move the scapula cause it to move on the scapula. No muscles connect the articulating bones to move the AC joint. Nerve supply: see below-
NOTE: THIS QUESTION POSES SOME CONFUSION. IN OLDER ANATOMY BOOKS (A PREVIOUS RECOMMENDED TEXT), THE NERVE SUPPLY OF THE AC JOINT IS THE SUPRACLAVICULAR NERVE. IN THE CURRENT ANATOMY (THE NEW TEXT), THE NERVE SUPPLY OF THE AC JOINT IS THE LATERAL PECTORAL AND AXILLARY NERVE AND THE LATERAL SUPRACLAVICULAR NERVE (ACCORDING TO HILTON’S LAW)
Arterial supply: suprascapular and thoracoacromial arteries
Shoulder stability in abduction is due to which of the following?
A The musculotendinous cuff of the rotator cuff muscles
B The glenoid labrum
C The glenohumeral ligaments
D The pectoralis major muscle insertion
A
Explanation
Subscapularis, supraspinatous, infraspinatous, teres minor all attach very near the joint, but also fuse with the lateral part of the capsule . This is an indispensable factor in adding stability to the joint.
Which of the following is true regarding the quadrangular and triangular spaces?
A The triangular space transmits the median nerve
B The circumflex scapular artery passes through the quadrangular space
C Long head of triceps forms a border of both spaces
D Teres minor does not form a boundary of either space
C
Explanation
Triangular space
Boundaries
Inferior: superior border of teres major
Lateral: long head of triceps
Superior: teres minor (or subscapularis)
Contents:
Scapular circumflex vessels
Unlike the quadrangular space or the triangular interval, NO major nerve passes through the triangular space
Quadrangular space
Boundaries
Superior: teres minor (inferior margin)
Inferior: teres major (superior margin)
Medially: long head triceps brachii (lateral margin)
Laterally: Surgical neck of the humerus
Anteriorly: subscapularis
Contents:
Axillary nerve and posterior circumflex humeral vessels (artery and vein)
Triangular interval
Boundaries
Superior: teres major
Medial: long head of triceps (brachii)
Lateral: humerus (some sources say lateral head of triceps)
Contents
Radial nerve passes through on its way to the posterior compartment of the arm. Profunda brachii also passes from anterior to posterior.
Regarding the lymphatic drainage of the upper limb, which of the following is correct?
A Superficial lymphatics follows the arteries
B Superficial lymphatic drainage occurs form lymphatic plexuses in the skin of the fingers, palm and dorsum of the hand
C Deep lymphatics travel follows the superficial veins
D Lymphatics of the hand drains into the central lymph nodes in the axilla
B
Explanation
The superficial lymphatics follow the veins and the deep lymphatics follow the arteries (note: this statement is form older sources and differs from the new textbook-see below). Superficial lymphatic vessels originate from the digital lymphatic vessels and the lymphatic plexus of the palm. Most drainage from the palm passes to the dorsum of the hand. Most superficial lymphatics accompanying the cephalic vein enter the apical axillary lymph nodes. The superficial lymphatics accompanying the basilic vein enter the cubital lymph nodes and then drain into the lateral axillary lymph nodes. The axillary lymph nodes drain into the subclavian lymphatic trunk
I have not however changed the stems to the question
In the current TB there is a better explanation of the superficial lymphatic drainage: superficial lymphatic vessels arise from lymphatic plexuses in the skin of the fingers, palm & dorsum of the hand & ascend mostly with superficial veins, such as cephalic & basilic. Some vessels accompanying the basilic vein enter the cubital lymph nodes and terminate in the humeral (lateral) axillary lymph nodes. Those accompanying the cephalic vein enter into the apical axillary lymph nodes and some in to the more superficial deltopectoral lymph nodes. Deep lymphatic vessels, accompany the major deep veins in the upper limb and terminate in the humeral axillary lymph nodes
Regarding the subclavius muscle, which statement is false?
A It is supplied by its own nerve
B It assists in stabilising the clavicle during shoulder movement
C It inserts into the first costochondral joint
D It is small and unimportant
C
Explanation
It is supplied by its own nerve. Its origin is the first costochondral joint. It inserts into the subclavian groove on the inferior surface of the clavicle. It is a small and unimportant muscle. It assists in stabilising the clavicle in movements of the shoulder
Important NOTE
The statement of small and unimportant muscles comes from older anatomy sources. The new TB does not reflect this. In fact, the subclavius muscle The anchors and depresses the clavicle, stabilising it during movements of the upper limb, It also helps resist the tendency of the clavicle to dislocate at the sternoclavicular (SC) joint - for example, when pulling hard during a tug-of-war game. These functions are important.
I have however left the question as is
Which of the following muscles is not supplied by the posterior interosseus nerve?
A Abductor pollicis longus
B Supinator
C Brachioradialis
D Extensor carpi ulnaris
C
Explanation
The muscles of the posterior compartment of the forearm supplied by the posterior interosseous nerve (C7, C8) are:
Extensor carpi radialis brevis, extensor digitorium, extensor digiti minimi, extensor carpi ulnaris, supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis. (old text book)
Note: in the current textbook-extensor carpi radilais brevis,supinator, extensor digitorium, extensor digiti minimi, extensor carpi ulnaris are supplied by the deep branch of the radial nerve
Brachioradialis and anconeus is supplied by the radial nerve (C5, C6)
Extensor carpi radialis longus by the radial nerve (C6, C7)
Anconeus is supplied by the radial nerve (C7, C8)
Regarding the interossei of the hand, which of the following statements is incorrect?
A When they act together, the MCP joints flex and the interphalangeal joints extend
B They insert into dorsal expansion
C They insert into proximal phalanges
D The palmer interossei abduct and the dorsal interossei adduct.
D
Explanation
Both the dorsal and palmer interossei insert into the bases of the proximal phalanges and the extensor expansion of the 2,4 and 2,4,5 digits respectively. When they act together, they give stability as far as adduction and abduction are concerned. The palmer muscles adduct (PAD) and the dorsal abduct (DAB). They also cause flexion at the metacarpo-phalangeal joint and extension at both inter-phalangeal joints.
Current TB
Dorsal interossei 1-4th
Proximal attachment: adjacent sides of to metacarpals (as bipennate muscles)
Distal attachment: base of proximal phalanges; extensor expansions of the 2-4th digits
Palmar interossei 1-3rd
Proximal attachment: palmer surface of 2nd, 4th and 5th metacarpals (as unipennate muscles)
Distal attachment: base of proximal phalanges; extensor expansions of 2nd, 4th and 5th digits
Loss of the greater tuburcle (can be called tuberosity) of the humerus leads to loss of which movement?
A Abduction and medial rotation
B Abduction and lateral rotation
C Adduction and medial rotation
D Adduction and lateral rotation
B
Explanation
The rotator cuff inserts at the greater tuberosity and provides abduction and lateral rotation.
A further complete explanation
Supraspinatus, infraspinatus and teres minor all insert on facets of the greater tubercle. Supraspinatus initiates abduction through the first 15 degrees of the arc. Infraspinatus and teres minor are both involved in lateral rotation of the shoulder. The final rotator cuff muscle, subscapularis, which inserts on the lesser tubercle / tuberosity is a medially rotator of the shoulder. There are no muscles inserting on the greater tuberosity which adduct the shoulder.
Which myotome/myotomes is/are associated with shoulder abduction?
A C5, 6
B C6, 7
C C5, 6, 7
D C5
D
Explanation
Shoulder abduction and lateral rotation=C5
Shoulder adduction and medial rotation=C6 C7 and C8
Which is false with respect to the lateral intermuscular septum?
A Pierced by radial nerve
B It is the origin of medial head of triceps
C Pierced by middle collateral branch of profunda brachii artery
D Brachioradilais and extensor carpi radialis longus attach to the septum
C
Explanation
The septum extends along the lateral supracondylar line and fades out behind the insertion of the deltoid. Brachioradilais and extensor carpi radialis longus extend out from the humerus to gain attachment to the septum in front, and posteriorly the medial head of tricpes arises form it. It is pierced by the radial nerve and the profunda brachii artery (the radial collateral branch). The middle collateral branch of the profunda brachii artery descends in the medial head of triceps
Extra: the medial intermuscular septum is pierced by the ulnar nerve and the superior ulna collateral artery.
Note: in Lasts anatomy: the medial head arises from both intermuscular septa. A web search writes: The medial head arises distally from the groove of the radial neck; from the dorsal surface of the humerus; from the medial intermuscular septum; and its distal part also arises from the lateral intermuscular septum
It is not clearly written in the latest textbook
Which of the following statements is false in relation to latissimus dorsi?
A Internally rotates the humerus
B Arises from the posterior third of the iliac crest
C Arises from spinous processes of T5 to L5
D Inserts into intertubecular groove of humerus
C
Explanation
Proximal attachments: spinous process of the inferior 6 thoracic vertebrae, thoraco-lumbar fascia, posterior 1/3 of illiac crest, last three to four ribs and inferior angle of scapula.
Insertion: floor of intertubecular groove (sulcus) of the humerus
Actions: Extends the shoulder joint, internally rotates the humerus and is a powerful adductor in combination with pectoralis major. It is especially used in restoring the the upper limb from abduction above the shoulder, it is the climbing mucle
Nerve supply: Thoracodorsal N C678
Which of the following statements is correct in relation to teres major?
A Is supplied by the axillary nerve
B Forms the lateral border of the triangular space
C Forms the lower border of the quadrangular space
D Arises from the medial border of the scapula
C
Explanation
Teres Major forms the lower border of both the quadrangular space and triangular space. It is supplied by the subscapular nerve. It arises form the infero-lateral border of the scapula
With regard to the sternoclavicular joint, which of the following statements is true?
A Is the fulcrum of movements of the sterno-clavicular joint
B Is supplied by nerve branches from C8 and T1
C Contains two fibrocartilaginous discs
D Is mostly stabilised by the costoclavicular ligament
D
Explanation
The joint is supplied by the medial supraclavicular nerves of C3 and C4 form the cervical plexus. It contains only one fibrocartilaginous joint. The costoclavicular ligament is the fulcrum of movements at the joint. Stability of the joint is maintained by ligaments , especially the costoclavicular ligament. It takes all the strain off the joint, transmitting stress from he clavicle to the first costal cartilage. The costoclavicular ligament is very strong and is the major stabilising factor of the sternoclavicular joint.
The current TB: The strength of the sternoclavicular joint depends on its ligaments and disc. The main strength seems to be from the anterior and posterior sternoclavicular ligaments and the interclavicular ligament. The costoclavicular ligament acts as an anchor and limits elevation. It doesn’t specify one ligament as strongest.
Old question- have not changed it- see it as a learning experience.
Which muscle is the prime initiator of lateral rotation of the shoulder?
A Deltoid
B Infraspinatus
C Teres major
D Serratus anterior
B
Explanation
All the other muscles are only synergists.
Teres major causes internal rotation of the humerus as well as adduction
Which of the following features protects against inferior dislocation of the abducted shoulder?
A Gleno-humeral joint
B Glenohumeral ligament
C Coraco-acromial arch
D Long head of triceps
A
Explanation
Joint capsule of the glenohumeral joint
The inferior part of the joint capsule, the only part not reinforced by the rotator cuff muscles, is it weakest area. Here the capsule is particularly lax and lies in folds when thew arm is adducted; however, it becomes taut when the arm is abducted.
Rotator cuff muscles stabilise the joint in abduction.
Extra
The long head of triceps is the most important factor in stabilizing the abducted shoulder joint to counteract gravity
Note: in Lasts anatomy it states that the long head of triceps supports the capsule of the shoulder joint when the arm is ABDucted, and it aids in extending the shoulder joint
CM: It states that the muscle action is the chief extensor of the forearm and long head resists dislocation of humerus especially important during ADDuction
Extra: Note: In previous textbooks- the action of the triceps: the extensor of the elbow joint. The long head supports the capsule of the shoulder joint when the arm is ABDucted, and it aids in extending the shoulder joint. This is wrong In the prescribed text: chief extensor of the forearm. The triceps brachii is a large fusiform muscle in the posterior compartment of the arm. As indicated by its name, the triceps has three heads: long, lateral, and medial. The triceps is the main extensor of the forearm. Because its long head crosses the glenohumeral joint, the triceps helps stabilize the aDDucted glenohumeral joint by serving as a shunt muscle, resisting inferior displacement of the head of the humerus. The long head also aids in extension and adduction of the arm, but it is actually the least active head. (follow the current source)
Regarding biceps brachii which of the following statements is correct?
A The short head arises from the acromion
B It is supplied by the median nerve
C It is a supinator of the forearm
D The long head arises from the greater tuberosity of the humerus
C
Explanation
Origin: The long head arises from the supraglenoid tubercle. The short head arises from the coracoid process.
Insertion: Tuberosity of radius and fascia of forearm via bicipital aponeurosis.
Innervation: It is supplied by the musculocutaneous nerve C567.
Action: Supinate forearm, flexible forearm when in supine, short head resistance shoulder dislocation
In relation to the brachial artery, which of the following statements is correct?
A Is a continuation of the subclavian artery
B It passes anterior to the medial supra-epicondylar ridge at the elbow joint
C The largest branch of the brachial artery is the radial artery
D It crosses over the median nerve during its course through the arm
B
Explanation
It is a continuation of the axillary artery. The median nerve lies lateral to it and then crosses over to lie medially in the cubital fossa. Its largest branch is the deep artery of the arm (L. arteria prifunda brachii). It passes anterior to the medial supraepicondylar ridge at the elbow joint
Which of the following is caused by Injury to the middle trunk of the brachial plexus?
A Affects the long thoracic nerve
B C8 sensation will be affected
C Will manifest in the medial cord
D Affects the median nerve
D
Explanation
The middle trunk gives rise (contributes) to the lateral cord which forms the median nerve. The middle trunk receives only the C7 nerve root (C8 is not affected). The medial cord arises only from the inferior trunk. The long thoracic nerve arises from the roots of C5-7, before the formation of the trunks.
Muscles of the rotator cuff include all the following, with the exception of?
A Infraspinatus
B Teres major
C Teres minor
D Supraspinatus
B
Explanation
Muscles comprising the rotator cuff are: teres minor, infraspinatus, suraspinatus and subscapularis. The rotator cuff is the group of muscles and their tendons that act to stabilize the shoulder. The four muscles of the rotator cuff, along with the teres major and the deltoid make up the six scapulohumeral muscles which connect to the humerus and scapula, and act on the glenohumeral joint.
Note: Supraspinatus is actually the only muscle that does not rotate the humerus
In the cubital fossa, which of the following is lateral to the tendon of biceps?
A Radial nerve
B Brachial artery
C Median nerve
D Median cubital vein
A
Explanation
The contents of the fossa, from medial to lateral side are the median nerve, brachial artery, tendons of the biceps and farther laterally the radial nerve and its posterior interosseus branch. The cubital fossa is the triangular area between pronator teres, brachioradialis and a line joining the humeral epicondyles. The ulnar artery passes deep to the deep head of pronator teres. The brachial artery enters the cubital fossa in the midline. Halfway down the fossa it divides into the radial and ulnar arteries. The radial artery usually appears to be direct continuation of the brachial artery and the bigger ulnar artery branches off at an angle
An easy way to remember the order of structures in the cubital fossa is: Really Need (radial nerve) Beer To (biceps tendon) Be At (brachial artery) My Nicest (median nerve). (from lateral to medial)
In terms of the relationship of structures within the cubital fossa, which of the following is correct?
A The radial artery is a direct continuation of the brachial artery
B The radial nerve is medial to biceps tendon
C The ulnar artery lies superficial to the pronator teres
D The median nerve lies lateral to the brachial artery
A
Explanation
The contents of the cubital fossa, from medial to lateral are median nerve, brachial artery, tendon of biceps bracii, radial nerve, and posterior interosseous nerve. The cubital fossa is the triangular area between pronator teres, brachioradialis and a line joining the humeral epicondyles. The ulnar artery passes deep to the deep head of pronator teres. The brachial artery enters the cubital fossa in the midline. Halfway down the fossa, it divides into the radial and ulnar arteries. The radial artery usually appears to be the direct continuation of the brachial artery, and the bigger ulnar artery branches off at an angle.
Regarding triceps, which of the following statements is correct?
A It stabilises the shoulder in abduction resisting inferior dislocation.
B The blood supply is from the posterior interosseous artery
C It is supplied by the radial nerve
D It has two heads
C
Explanation
The triceps is supplied by the profunda brachii artery. It has 3 heads and stabilizes the shoulder in adduction.
In the prescribed text: chief extensor of the forearm. The triceps brachii is a large fusiform muscle in the posterior compartment of the arm. As indicated by its name, the triceps has three heads: long, lateral, and medial. The triceps is the main extensor of the forearm. Because its long head crosses the glenohumeral joint, the triceps helps stabilize the aDDucted glenohumeral joint by serving as a shunt muscle, resisting inferior displacement of the head of the humerus. The long head also aids in extension and adduction of the arm, but it is actually the least active head.
It is supplied by the radial nerve (C6, C7, C8)
The above is from the new textbook. Interesting in Last anatomy: Action of the triceps- “the muscle is the extensor of the elbow joint. The long head supports the capsule of the shoulder joint when the arm is ADBucted, and it aids in extending the shoulder joint”
Note: this explanation is often queried. The statement “the triceps helps stabilize the aDDucted glenohumeral joint” is directly out of the textbook latest edition. Many users feel it should be ABDucted (as per Lasts Anatomy). Therefore, not much more can be done.
Which of the following is the deepest mid-forearm structure?
A Radial artery
B Flexor pollicis longus (FPL)
C Median nerve
D Ulnar nerve
B
Explanation
Usually, the FPL is deeper to the rest of these structures.
Extra:
Forearm structures superficial to deep: 4x superficial flexor/pronator muscles (PT/FCR/PL/FCU)
Ulnar nerve: running down between the axillary artery and vein, behind the medial cutaneous nerve of the forearm, the ulnar nerve pierces the medial intermuscular septum and descends in the groove on the back of the base of the medial epicondyle. It passes between the two heads of the FCU and enters the flexor compartment of the forearm.
Median Nerve at the elbow it lies medial to the artery beneath the bicipital aponeurosis. It passes between the two heads of pronator teres and deep to the fibrous arch of flexor digitorium superficialis. Enters hand via carpal tunnel.
3x Deep flex/pronators: FDP/ FPL/ PQ. Radial artery runs lateral to FCR tendon under cover of brachioradialis and marks the boundary between the anterior and posterior compartments.
In relation to the brachial plexus, which statement is correct?
A The roots pass between the middle and posterior scalene muscles
B The nerve to subclavius is a branch form the trunks
C There are 7 divisions of the trunks
D The axillary nerve is derived from the lateral cord
B
Explanation
The brachial plexus has 6 divisions. The nerve to subclavius arises from the trunks. The suprascapular nerve arises form the trunks. The axillary nerve is derived from the posterior cord. The 5 roots lie behind the scalenus anterior muscle and emerge between it and scalenus medius to form the trunks that cross the lower part of the posterior triangle of the neck. The divisions form behind clavicle and subclavicular, the cords in the axilla and branches in the brachium
Please be aware that old sources differ from the current. The current prescribed text it says that the nerve to subclavius originates from superior trunk (not the roots). However, in older sources, it states that the nerve to subclavius is one of the three branches from the roots. The other two are dorsal scapular and long thoracic. Suprascapular nerve arises form the trunks. (Follow the current source)
Which of the following statements is false in relation to the carpal tunnel?
A Flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons lie within the same sheath at the tunnel
B Flexor carpi ulnaris (FCU) lies in its own synovial sheath as it passes through the tunnel
C The tendon of palmaris longus (PL) lies above the retinaculum and is only partially attached to it
D Flexor carpi radialis (FCR) tendon runs in a subcompartment of the flexor tunnel
B
Explanation
Flexor carpi ulnaris (FCU) tendon inserts into pisiform, pisohamate ligament, pisometacarpal ligament, hamate and 5th metacarpal bone
The carpal tunnel lies between the flexor retinaculum and the carpal bones. The median nerve and the flexor tendons of the fingers and thumb pass through this tunnel. The four tendons of the superficial flexor are separate and lie in two rows, with the middle and ring finger tendons in front of the index and little finger tendons. The tendons of the flexor digitorium profundus lie deeply in one plain, with only the tendon to the index finger being separate from the others, which remain attached together till they reach the palm. All eight tendons of the superficial and deep flexors share a common tendon sheath, which does not invest them completely but is reflected from their radial sides, where arteries gain access. The tendon of flexor pollices longus lies in its own synovial sheath as it passes through the fibro-osseous tunnel. At the lateral end of the tunnel a deep lamina from the flexor retinaculum is attached to the medial lip of the grove of the trapezium. The tendon of flexor carpi radialis, enclosed in its own synovial sheath runs in the groove in this subcompartment of the carpal tunnel. The median nerve passes deep to the flexor retinaculum between the flexor digitorium superficialis tendon to the middle finger and the flexor carpi radialis tendon. The ulnar nerve lies on the front of the reticulum lateral to the pisiform bone, with the ulnar artery lateral to the nerve (in the canal of Guyon)
Extra:
Carpal Tunnel lies bounded by distal carpus and transverse carpal ligament.
Contains 9 tendons (4x FDS, 4xFDP, 1xFPL) and 1 nerve (Median)
Note that palmaris longus tendon sits superficial to ligament centrally, as do FCR and FCU laterally and medially. The ulnar artery and nerve pass through Guyon’s canal superficial and lateral to transverse carpal ligament.
Which of the following is correct in relation to the radial nerve?
A Contains only fibers of C 5,6,7
B Runs with the profunda brachii in the radial groove
C Gives off the posterior interosseus in the spiral groove
D Occupies the entire length of the radial groove
B
Explanation
It runs with the profunda brachii artery in the radial groove of the humerus. The radial nerve divides into the posterior interosseus (aka deep) and superficial branches at the level of the lateral epicondyle. The radial nerve contains fibres from C5-T1. Between the origins of the the medial and lateral heads of triceps, the radial nerve and profunda brachii artery lie in the radial groove.
Regarding pectoralis major, which of the following statements is correct?
A Is supplied by all 5 segments of the brachial plexus
B Is quadrilateral in shape
C Inserts to the medial lip of bicipital groove
D Has a head arising from the posterior surface of the clavicle
A
Explanation
It is triangular in shape. It inserts into the lateral lip of the bicipital sulcus. The clavicular head arises from the medial surface portion of the anterior surface of the clavicle
In the older TB it reads: the muscle is the only one in the upper limb to be supplied by all 5 segments (roots) of the brachial plexus
Current TB: innervation: lateral and medial nerves; clavicular head (C5C6), sternocostal head (C7C8T1). The bold numbers indicate the main segmental innervation
Regarding the quadrangular space, triangular interval and triangular space, which of the following statements is false?
A Triangular space transmits the radial nerve
B Long head of triceps forms the medial border of the quadrangular space
C Quadrangular space admits the axillary nerve
D Teres minor forms a border of both the triangular space and quadrangular space
A
Explanation
Triangular space or medial triangle
Boundaries
Inferior: superior border of teres major
Lateral: long head of triceps
Superior: teres minor (or subscapularis)
Contents:
Scapular circumflex vessels (axillary artery, subscapular artery and scapular circumflex artery)
Triangular interval or lateral triangle
Boundaries
Superior: teres major
Medial: long head of biceps brachii
Lateral: humerus (some sources say lateral head of triceps)
Contents
Radial nerve passes through on its way to the posterior compartment of the arm.
Profunda brachii also passes from anterior to posterior.
Quadrangular space
Boundaries
Superior: teres minor (inferior margin)
Inferior: teres major (superior margin)
Medially: long head triceps brachii (lateral margin)
Laterally: Surgical neck of the humerus
Anteriorly: subscapularis
Contents:
Axillary nerve
Posterior circumflex humeral vessels (artery and vein)
Which of the following is correct in relation to flexor digitorum profundus?
A Is the strongest muscle of the forearm
B Assists pronator quadratus (PQ) in pronation
C Is supplied, 10% of the time, purely by the median nerve
D Has its action enhanced by wrist flexion
A
Explanation
It does not assist PQ in pronation. It is supplied in 60% primarily on its lateral portion by the anterior interosseus branch of the median nerve. The medial portion is supplied by the ulnar nerve. It is the strongest and bulkiest muscle of the forearm. Its action is enhanced by wrist extension
Note: answer from Last’s anatomy
Which is not a branch of the axillary artery?
A Posterior circumflex humeral, 3rd part
B Thoraco-acromial, 2nd part
C Superior thoracic, 1st part
D Circumflex scapula, 3rd part
D
Explanation
Circumflex scapula is a branch of the subscapular artery
Branches of the Axillary Artery:
1 branch of the 1st part (between lateral border of 1st rib and medial border of pectoralis minor) - superior thoracic artery
2 branches of the 2nd part (posterior to pectoralis minor) - thoracoacromial artery - lateral thoracic artery
3 branches of the 3rd part (between the lateral border of pectoralis minor and the inferior border of teres major) - subscapular artery - anterior circumflex humeral artery - posterior circumflex humeral artery
Regarding the ulnar artery, which of the following is correct?
A It disappears from the cubital fossa by passing above the fibrous arch of flexor digitorium superficialis
B The ulnar nerve lies lateral to it
C Has the common interosseus as its major branch
D Forms the deep palmar arch
C
Explanation
The ulnar nerve lies on the medial/ulnar side of the ulnar artery. it supplies the superficial arch, It disappears from the cubital fossa by passing beneath the fibrous arch of flexor digitorum superficialis (FDS). Old and current TBs, say that the superficial palmer arch is formed by the direct continuation of the ulnar artery. The deep palmer arch is formed by the deep branch of the ulnar artery. (not a direct continuation)
Extra:
Deep palmar arch is formed by direct continuation of radial art. with contribution by deep branch of ulnar art. on medial side
The flexor retinaculum attaches to all bones except which of the following?
A Pisiform
B Trapezium
C Hamate
D Capitate
D
Explanation
Lateral attachment: scaphoid (tubercle) and trapezium (ridge)
Medial attachment: pisiform and hook of hamate
Which of the following bones is attached to both flexor and extensor retinaculum?
A Pisiform
B Scaphoid
C Hamate
D Triquetral
A
Explanation
The Flexor retinaculum attached to the scaphoid and trapezium (radially) to the pisiform and hamate (ulnar). Extensor retinaculum originated from the radius to the triquetral and pisiform bones
Which of the following regarding the anatomical snuffbox is correct?
A Contains the posterior interosseus artery
B Has trapezoid palpable in the floor of the snuff box
C Has extensor pollicis longus on its ulnar side and the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) on the radial side
D Is most obvious with the thumb abducted and extended
C
Explanation
The trapezium and scaphoid can be felt in the floor of the snuff box between the radial styloid process and the first metacarpal. It contains the radial artery, cephalic vein and cutaneous branches of the radial nerve. It is most obvious with the thumb fully extended; this draws the tendons up and produces a triangular hollow between them. It is the abductor pollicis longus and the extensor policis brevis that form one boundary on the radial or thumb side, and the extensor pollices longus forms the other boundry on the ulnar side
Which of the following statements is correct in relation to the radial artery?
A Passes between the tendons of extensor pollicis brevis (EPB) and abductor pollicis longus (APL)
B In its middle third, the radial nerve lies medial to it
C Lies on brachioradialis in the upper arm
D Forms both the anterior and posterior carpal arches with the ulnar artery
D
Explanation
The radial nerve (the superficial branch of the radial nerve) lies lateral to the radial artery. It lies deep to brachioradialis. It passes deep to both tendons which form the palmer border of the anatomical snuff box. The anterior and posterior carpal arches supply the articulations of the wrist and carpus
Regarding the acromio-clavicular joint, which of the following statements is false?
A All movements are passive
B It is a complex joint with an incomplete wedge shaped articular disc
C The coraco-clavicular ligament is not a joint stabilising factor
D Is innervated by the lateral pectoral nerve, axillary nerve and lateral supraclavicular nerve
C
Explanation
The AC joint is an atypical synovial joint. The articular surfaces are covered by fibrocartilage and separated by an incomplete wedge shaped articular disc. The coracoclavicular ligament (made up by the conoid and trapezoid ligament) is extremely strong and the principal factor in providing stability to the joint. Movements are passive; muscles which move the scapula cause it to move on the scapula. No muscles connect the articulating bones to move the AC joint. Nerve supply: see below-
NOTE: THIS QUESTION POSES SOME CONFUSION. IN A PREVIOUS RECOMMENDED TEXT, THE NERVE SUPPLY OF THE AC JOINT IS THE SUPRACLAVICULAR NERVE. IN THE PRESCRIBED TEXT, THE NERVE SUPPLY OF THE AC JOINT IS THE LATERAL PECTORAL AND AXILLARY NERVE AND THE LATERAL SUPRACLAVICULAR NERVE (ACCORDING TO HILTON’S LAW)
Arterial supply: suprascapular and thoracoacromial arteries
Regarding the brachial plexus, which of the following statements is correct?
A Suprascapular nerve comes off the posterior cord
B Serratus anterior is supplied by C6/7/8
C All branches originate from roots, divisions or cords
D Dorsal scapular nerve comes off C5
D
Explanation
Serratus anterior is supplied by the long thoracic (C5, C6, C7) nerve. The nerve to subclavius comes off the superior trunk. The suprascapular nerve comes off the anterior division of the superior (upper) trunk. Divisions do not give branches, they come off roots, trunks and cords.
Extra:
“C5,C6,C7 raise your wings up to heaven”: C5,C6,C7 injury causes inability to raise arm past 90 degrees up to heaven, and results in a winging of the scapula. Long thoracic nerve roots (C5,C6,C7) innervate Serratus anterior.
Regarding lymphatic drainage of the upper limb, which of the following statements is INCORRECT
A Deep lymphatics follow the vein
B Superficial lymphatic drainage passes from the palm to the dorsum of the hand
C Superficial lymphatics follow arteries
D Some lymphatics of the hand drain into cubital lymph
C
Explanation
OLD source: The superficial lymphatics follow the veins and the deep lymphatics follow the arteries. Most of the drainage from the palm passes to the dorsum of the hand. Most superficial lymphatics accompanying the cephalic vein to enter the apical axillary lymph nodes.
IMPORTANT NOTE: The current textbook writes: deep lymphatic vessels, less numerous then superficial vessels, accompany the major deep veins in the upper limb (basilic and cephalic) and terminate in the numeral axillary lymph nodes. Superficial lymphatic vessels originate from the digital lymphatic vessels of the digits and lymphatic plexus of the palm. Most drainage from the palm passes to the dorsum of the hand. Some vessels accompanying the basilic vein enter the cubital lymph nodes, proximal to medial epicondyle and medial to basilica vein.
I have added a user provided explanation. It may help: In clinically oriented anatomy (6th Ed) states “deep lymphatic vessels, less numerous than superficial vessels, accompany the major deep veins in the upper limb” BUT it then proceeds to call the deep veins of the upper limb the basilic and cephalic veins - but these are actually the SUPERFICIAL veins of the upper limb. So the explanation in the book doesn’t make sense. I think the answer should read: Deep lymphatic vessels, less numerous than superficial vessels, accompany the major deep veins in the upper limb (radial, ulnar and brachial veins) and terminate in the humeral axillary lymph nodes.
Below is from teach anatomy:
Superficial Lymphatic Vessels—– The superficial lymphatic vessels of the upper limb initially arise from lymphatic plexuses in the skin of the hand (networks of lymphatic capillaries beginning in the extracellular spaces). These vessels then travel up the arm in close proximity to the major superficial veins: The vessels shadowing the basilic vein go on to enter the cubital lymph nodes. These are found medially to the vein, and proximally to the medial epicondyle of the humerus. Vessels carrying on from these nodes then continue up the arm, terminating in the lateral axillary lymph nodes. The vessels shadowing the cephalic vein generally cross the proximal part of the arm and shoulder to enter the apical axillary lymph nodes, though some exceptions instead enter the more superficial deltopectoral lymph nodes. —Deep Lymphatic Vessels— The deep lymphatic vessels of the upper limb follow the major deep veins (i.e. radial, ulnar and brachial veins), terminating in the humeral axillary lymph nodes. They function to drain lymph from joint capsules, periosteum, tendons and muscles. Some additional lymph nodes may be found along the ascending path of the deep vessels.
Which of the following is incorrect regarding the lateral intermuscular septum?
A It is pierced by the median nerve
B Medial head of triceps arises from it
C It has brachioradialis as an anterior relation
D It extends along the lateral suprachondylar line and fades out behind the insertion of the deltoid
A
Explanation
The RADIAL nerve and the profunda brachii artery (radial collateral branch) pierce the lateral intermuscular (IM) septum. The MEDIAN nerve runs with the brachial artery, anterior to the medial intermuscular septum. Medial head of triceps arises from the posterior surface of humerus, inferior to radial groove. It has brachioradialis and extensor carpi radialis longus as anterior relations. The lateral IM septum extends along the lateral supracondylar line and fades out behind the insertion of the deltoid
Note: supracondylar and supraepicondylar are synonymous. The lateral suprachondylar ridge is the same as the lateral supraepicondylar ridge
Regarding brachialis, which of the following statements is correct?
A Inserts into the coronoid process of the ulna
B It’s main innervation is by the radial nerve
C Inserts into the upper 1/3 of the humerus
D It is an extensor of the elbow joint
A
Explanation
It is innervated by the musculocutaneous nerve (C5, C6), and some of the lateral part of the muscle is innervated by a branch of the radial nerve (C5, C7).
Proximal attachment: distal half of anterior surface of humerus
Distal attachment: coronoid process and tuberosity of ulna
(Note: in Last’s it says a small part of brachialis is supplied by the radial nerve) It arises from the lower 2/3 of the humerus. It is a flexor of the elbow joint.
Which statement regarding forearm muscles is correct?
A Flexor pollicis longus (FPL) is unipennate
B Pronator teres (PT) is the most powerful muscle for pronation
C Palmaris longus (PL) is absent in 30% of cases
D Flexor carpi radialis (FCR) runs over whole length of flexor retinaculum
A
Explanation
Pronator quadratus is the most powerful pronator, palmaris longus is absent in 10% of cases. FCR does not run over the entire length of the flexor retinaculum
A patient is stabbed in his axilla; it results in damage to the lateral cord of the brachial plexus. Which muscle will be denervated?
A Coracobrachialis
B Flexi carpi ulnaris
C Supinator
D Anconeus
A
Explanation
Injury to the lateral cord of the brachial plexus results in injury to the musculocutaneous nerve (MC), the lateral pectoral nerve and the lateral root that forms part of the median nerve of the median nerve (MN).
Muscles affected
MC: coracobrachialis, biceps brachii and brachialis (note that brachialis is innervated by some fibres of the radial nerve)
Lateral pectoral nerve: pectoralis major and some part of the pectoralis minor (via branches which connect to the medial pectoral nerve)
MN: muscles of the anterior forearm compartment (except flexi carpi ulnaris and ulnar half of flexor digitorium profundus), five intrinsic muscles in thenar half of the palm and palmer skin
Which muscle causes flexion of the distal phalanges?
A Flexor digitorum profundus
B Palmaris longus
C Flexor pollices longus
D Flexor digitorum superficialis
A
Explanation
The FDP makes up the deep (third) layer of the forearm. It has a medial part which inserts into the bases of the distal phalanges of the 4th and 5ht digits. A lateral part which inserts into the bases of the distal pahalanges of the 2nd and 3rd digits. Its main action is the flexion of the diatal phalanges at the distal interphalangeal joints. Nerve supply of the medial part is the ulnar nerve. Lateral part by the anterior interosseous nerve (form the median nerve). Note: unlike the FDS, the FDP can flex only the index finger independently, thus the fingers can be independently flexed at the proxinal but not the distal interphalangeal joints
Which of the following long bones is the first to ossifiy?
A Clavicle
B Radius
C Femur
D Fibula
A
Explanation
According to Moore- the clavicle is the first long bone to ossify (via intramembranous ossification), beginning during the 5th and 6th embryonic weeks.
Which of the following long bone is the last to completely ossify?
A Femur
B Radius
C Fibulae
D Clavicle
D
Explanation
The current textbook states that the clavicle is the first long bone to ossify (via intramembranous ossification), beginning during the 5th and 6th week embryonic weeks. A secondary ossification centre appears at the sternal end and forms a scale like epiphysis that begins to fuse with the shaft (diaphysis) between 18-25yrs of age and is completely fused to it between 25-31Yrs of age. This is the last of the epiphysis of long bones to fuse
Regarding upper limb dermatomes. Which is the correct dermatome-sensory innervation
A C6-lateral forearm and thumb
B C4-lateral shoulder and upperarm
C C8-little finger, medial side of hand and arm
D T1-lateral aspect of arm and forearm
A
Explanation
Dermatomes as per clinical Moore:
C3,C4 region at base of neck, extending laterally over shoulder.
C5 lateral aspect of arm
C6 lateral forearm and thumb
C7 middle three finger and centre of posterior aspect of forearm
C8 little finger, medial side of hand and forearm
T1 medial aspect of forearm and inferior arm
T2 medial aspect of superior arm and skin of axilla
both last two options are correct in this question.
You are examining a patient with an injury/cut to the wrist. He is unable to abduct his thumb. Other deficits which may be present include the following EXCEPT?
A Loss of sensation over the thumb
B Loss of thumb opposition
C Loss of fine control of 2-3 digits
D Complete loss of thumb flexion
D
Explanation
Laceration of the wrist often causes median nerve injury because the nerve is relatively close to the surface. The median nerve is commonly injured just proximal to the flexor retinaculum
This results in paralysis of the muscles of the thenar eminence. (except the adductor pollicis and deep head of the flexor polices brevis) and the first two lumbricals. Hence opposition of the thumb is not possible, and fine control movements of the 2nd and 3rd digits are impaired. Sensation is also lost over the thumb and adjacent two and a half fingers on the palmer side and only finger tips on the dorsal side. The radial nerve supplies the dorsal radial aspect of the hand and the first web space via its superficial branch.
If the median nerve is severed in the forearm or at the wrist, the thumb cannot be opposed. However, the APL and adductor policis (supplied by the posterior interosseous and ulnar nerves, respectively) may imitate opposition, although ineffective.
You do not loose complete loss of thumb flexion if the median nerve is cut at the wrist as Flexor Pollicis longus originates and is innervated above the wrist. You may have weakened flexion because of the absence of innervation of Flexor pollicis brevis, but you will not have complete loss of flexion.
Extra: a user asked a valid question; What if the laceration cut the FPL tendon too? Then there would be total loss of thumb flexion. The question doesn’t specify the extent of the cut/injury. I agree, the question doesn’t specify, however, an injury/cut, I think, would mean superficial. If the word deep is used, this may change things.
Extra: another user remarked- they are saying he is unable to abduct the thumb. (Haven’t said total or partial) I would have thought he has severed his APL as well. That makes me think it is a deep cut. Not a good question at all.
Remember, the questions are based on recall. Having knowledge of the type of question is just as important as having the original question (which may not be possible)
Flexor Digitorum Superficialis (FDS), which is CORRECT
A The FDS flexes the distal phalanges of the medial four fingers
B The muscle arises from the medial ligament of the elbow joint and the tubercle on the medial border of the coronoid process of the ulnar
C The Tendons pass beneath the flexor retinaculum, the middle and ring finger tendons lie deep to those to the index and little finger
D It is considered the largest muscle of the deep layer of the forearm
B
Explanation
The muscle arises from the common origin, the medial ligament of the elbow joint and the tubercle on the medial border of the coronoid process of the ulna. It is considered the largest muscle of the superficial layer in the forearm. However, the FDS actually forms an intermediate layer between the superficial and deep groups of the forearm muscles. The tendons pass beneath the flexor retinaculum, the middle and ring finger tendons lie superficial to those to the index and little finger. The tendons are enclosed in a common synovial flexor sheath. In the forearm the muscle has the median nerve plastered to its deep surface by areolar tissue. The FDS flexes the middle phalanges of the medial four fingers at the proximal interphalangeal joints. It also flexes the proximal phalanges at the metacarpophalangeal joints and the wrist joint. It is supplied by the median nerve only.
Note: This question is from the old textbook. Still worthwhile to leave in the bank
Carpal tunnel syndrome is proved by all except?
A Loss of sensation over the medial three and a half digits
B Relief of symptoms after surgical incision of the flexor retinaculum
C Loss of sensation over the thenar eminence but not the central palm
D Weakness of the thenar muscles
A
Explanation
Carpal tunnel results from any lesion which reduces the size of the tunnel. The median nerve is the most sensitive structure in the tunnel. The median nerve also has two terminal sensory branches that supply the skin of the hand; hence paraesthesia, hypoaesthesia or anaesthesia may occur in the lateral three fingers of the hand. The median nerve also has one terminal motor branch- the recurrent branch, which serves the three thenar muscles. Progressive loss of coordination and strength in the thumb (due to weakness of APB-abductor pollices brevis and OP- opponens pollices) may occur if the compression is not alleviated. The palmer cutaneous branch passes above the carpal tunnel, thus sensation to the central palm remains unaffected
The dorsal scapular nerve, which is correct?
A Supplies the rhomboids and occasionally subclavius
B Arises from the C6 root
C Pierces scalenus medius
D It is a branch from the trunks of the brachial plexus
C
Explanation
The dorsal scapular nerve is a branch of the roots of the brachial plexus. It arises from the posterior aspect of anterior ramus of C5 with a frequent contribution form C4. It supplies the rhomboids and occasionally levator scapulae. It pierces the middle scalene and descends deep to levator scapulae and rhomboids.
Regarding the deltoid muscle, which is correct?
A It has anterior and middle unipennate parts and a multipennate posterior part
B It initiates abduction
C It attaches to the spine of scapula, acromion, clavicle and deltoid tuberosity
D It is supplied by the axillary nerve (C4,C5)
C
Explanation
The deltoid muscle is divided into unipennate anterior and posterior parts and a multipennate middle part; the parts of the deltoid can act separately or as a whole. It attaches proximally to the lateral third of the calvicle, acromion and spine of scapula. Distally it attaches to the deltoid tuberosity of the humerus. It is supplied by the axillary nerve (C5, C6). Muscle action includes flexion and medial rotation of the arm (anterior part), abduction of the arm (middle part) and extension with lateral rotation of the arm (posterior part). Supraspinatus initiates abduction.
Which is true about the axillary artery?
A Is a continuation of the subclavian as it passes under the medial 1/3 of clavicle
B The axillary vein lies distally on the anterolateral side of the artery
C The thoraco-acromial branch is the largest of the branches of the axillary artery
D Becomes the brachial artery at the inferior border of teres major
D
Explanation
The axillary artery begins at the lateral border of the first rib as the continuation of the subclavian artery and ends at the inferior border of the teres major. It passes posteriorly to the pectoral minor into the arm and becomes the brachial artery when it passes the inferior border of the teres major. It is divided into three parts by the pectoralis minor. The subscapular artery is the largest branch of the axillary artery. The axillary vein lies distally on the anteromedial side of the artery, with its terminal part anteroinferior to the artery.
Extra: Additionally branches of axillary artery can be memorised with mnemonic “Screw The Lawyer, Save A Patient”: Sup Thoracic; Thoracoacromial; Lateral Thoracic; Subscapular; Anterior Circumflex Humeral; Post Circumfelx Humeral.
The deep branch of the radial nerve supplies all the following EXCEPT?
A Supinator
B Extensor carpi ulnaris
C Extensor pollicis longus
D Extensor carpi radialis longus
D
Explanation
The deep branch of the radial nerve (also called the posterior interosseous nerve C7, C8) supplies motor innervation to all the muscles with fleshy bellies located entirely in the posterior compartment of the forearm-distal to the lateral epicondyle of the forearm.
Extra:
The deep branch of radial/posterior interosseous nerve. Its origin is the motor terminal branch of radial nerve, in cubital fossa. Course in the forearm: deep branch exists cubital fossa winding around neck of radius, penetrating and supplying supinator; emerges in posterior compartment of forearm as posterior interosseous; descends on membrane with artery of same name.
Muscles include- extensor carpi radialis brevis, extensor digitorum, extensor carpi ulnaris, extensor digiti minimi, supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis.
Bachioradialis and extensor carpi radialis longus are supplied by the radial nerve C6, C7, by a branch arising above the elbow joint. Anconeus is supplied by the radial nerve as well (C7C8)
Fascia and compartments of the palm, which is INCORRECT?
A The palmer aponeurosis septa that forms the spaces arises from the flexor retinaculum
B The central compartment contains the flexor tendons and the lumbrical muscles
C The second metacarpal bones divides the thenar space from the midpalmer space
D The deepest muscular plane of the palm is the adductor compartment containing the adductor pollicis.
C
Explanation
The palmer aponeurosis fans out form the distal border of the flexor retinaculum. From each of its two sides a septum dips deeply into the palm. That from the ulnar border is attached to the palmer border of the fifth metacarpal bone. The space so formed medial to it is the hypothenar space. The remaining part of the palm is divided into two spaces by the septum that dips in from the radial border of the palmer aponeurosis to the palmer surface of the third metacarpal bone. This septum lies obliquely and separates the thenar space on its radial side from the midpalmer space or beneath the palmer aponeurosis. The septum usually passes deeply between the flexor tendons of the index and middle finger
The spaces can be called compartments as well. The midpalmer/central compartment contains the flexor tendons and their sheaths, lumbricals, superficial palmer arterial arch and the digital vessels and nerves. The hypothenar space/compartment contains the hypothenar muscles and fascia and the thenar muscles and fascia re contained in the thenar space.
The deepest muscular plane of the palm is the adductor compartment containing the adductor pollicis
Myotome C6 performs all upper limb movements EXCEPT?
A Pronation of forearm
B Medial rotation of upper limb
C Wrist extension
D Elbow extension
A
Explanation
C6 does not perform forearm pronation but rather supination. Other movements include shoulder extension and upperlimb adduction, elbow flexion and extension, wrist extension and medial rotation of the upper limb.
Note: although the upper limb is commonly called the arm, it is actually referring to the upper part of the limb between the shoulder and the elbow. The forearm is that part between the elbow and the wrist.
Extra: https://www.kenhub.com/en/library/anatomy/myotomes
C5-C6 Flexion of the arm at the shoulder joint C6 Supination at the shoulder joint C6-C7 Extension of the forearm at the elbow jointFlexion and extension of the hand at the wrist joint C6-C8 Medial rotation, adduction, and extension of the arm at the shoulder joint C7-C8 Pronation at the shoulder jointFlexion and extension of the digits of the hand at the metacarpophalangeal and interphalangeal joints
Which is the incorrect dermatome description of the upper arm?
A C8= little finger, medial side of hand and forearm
B C3, C4= region at base of neck, extending laterally over the shoulder
C C5= lateral aspect of the arm
D T1= medial aspect of forearm and superior arm
D
Explanation
C3, C4= region at base of neck, extending laterally over the shoulder
C5= lateral aspect of the arm,
C6= lateral forearm and thumb
C7= Middle and ring fingers, and centre of the posterior aspect of the forearm
C8= little finger, medial side of hand and forearm
T1= medial aspect of forearm and inferior arm
T2= medial aspect of superior arm and skin of axilla
Which part of bone is a correct match?
A Radial notch of the radius
B Coronoid fossa of the ulna
C Coronoid process of the humerus
D Trochlear notch of the ulna
D
Explanation
Quite a “bony” type of question Coronoid fossa of the humerus and a coronoid process of the ulna. Trochlear of the humerus and a trochlera notch (or fossa) of the ulna. The radial notch is found on the ulna. The radial tuberosity is found on the radius
Regarding the axillary vein which of the following is FALSE?
A The axillary vein receives anastomoses from the superficial veins of the inguinal region
B The axillary vein is formed by the union of the brachial vein and the cephalic vein
C The axillary vein ends at the lateral border of the first rib and becomes the subclavian vein
D The axillary vein lies initially (distally) on the anteromedial side of the axillary artery, with its terminal part anteroinferior to the artery
B
Explanation
The axillary vein is formed by the union of the brachial vein and the basilic vein at the inferior border of the teres major. The axillary vein ends at the lateral border of the first rib and becomes the subclavian vein. The axillary vein lies initially (distally) on the anteromedial side of the axillary artery, with its terminal part anteroinferior to the artery. It is made up of three parts that correspond to the three parts of the axillary artery. It is important to remember that the axillary vein receives the thoracoepigastric vein(s) which are formed by the anastomosis of the superficial veins from the inguinal region with tributaries of the axillary vein. These veins constitute a collateral route that enables venous return in the presence of IVC obstruction
The axillary sheath is an extension of which of the following fascia ?
A Axillary fascia
B Cervical fascia
C Brachial fascia
D Deltoid fascia
B
Explanation
The axillary sheath is a sleeve like extension of the cervical fascia. Neurovascualr structures ensheathed are axillary blood vessels (axillary artery, vein and its tributaries), lymphatic vessels and several axillary lymph nodes, the cords and branches of the brachial plexus and axillary fat
Injury to the median nerve at the flexor retinaculum produces the following deficits EXCEPT?
A Paralysis of the first two lumbricles
B Sensation loss of the skin of the central palm
C Sensation loss over the thumb and adjacent two and a half fingers
D Paralysis of the thenar muscles
B
Explanation
Injury to the median nerve at the flexor retinaculum will result in paralysis of the thenar muscles and the first two lumbricles. Hence opposition of the thumb and fine control movements of the 2nd and third digits are impaired. Sensation is lost over the thumb and adjacent two and a half fingers. Because the palmer cutaneous branch of the median nerve arises just proximal to the flexor retinaculum and travels into the palm superficial to the flexor retinaculum, the skin of the central palm will be spared.
Extra
If the median nerve is severed in the forearm or at the wrist, the thumb cannot be opposed; however the APL and the adductor pollicis (supplied by the posterior interosseous and ulnar nerves, respectively) may imitate opposition, although ineffective
Which of the following statements is incorrect regarding the consequence of a midshaft fracture of the humerus?
A Paralysis may be transient
B Extension of the interphalangeal joints are possible
C Sensory loss occurs distal to the wrist
D There is loss of elbow extension
D
Explanation
When the midshaft of the humerus is fractured, the radial nerve may be injured in the radial groove. Under such circumstances, the triceps is usually not completely paralysed but only weakened because only the medial head is affected. The other two heads’ (lateral and long) nerve supply have a higher origin and are not affected. The muscles in the posterior compartment of the forearm that are supplied by the more distal branches of the nerve are paralysed. The classical wrist drop appears, caused by the inability to extend the wrist and the fingers at the metacarpophalangeal joints. There is sensory loss distal to the wrist but it is minimal (on account of the overlapping median and ulnar nerve supply) and is confined to a small area of skin over the first dorsal interosseous space.
Note: If the radial nerve is injured superior to the origin of its branches to the triceps brachii results in paralysis of the triceps, brachioradialis, supinator and extensor muscles of the wrist and fingers. Loss of sensation in areas of the skin supplied by the nerve also occurs.
The superficial branch of the radial nerve is entirely cutaneous in its distribution, supplying sensation to the dorsum of the hand and fingers. It originates as a branch of the radial nerve in the forearm.
Note: The interphalangeal joints can still be extended weakly through the action of the intact lumbricals and interossei, which are supplied by the median and ulnar nerves.
In the Radial Groove
The radial nerve is tightly bound within the spiral groove of the humerus. Thus, it is most susceptible to damage with a fracture of the humeral shaft.
Motor functions
The triceps brachii may be weakened, but is not paralysed (branches to the long and lateral heads of the triceps arise proximal to the radial groove).
Muscles of the posterior forearm are affected. The patient is unable to extend at the wrist and fingers. Unopposed flexion of wrist occurs, known as wrist-drop.
Which of the following statements is false regarding the bony scapula?
A The thick medial border lies adjacent to the coracoid
B The scapula has three angles and three borders
C The lateral angles bears the glenoid cavity
D The subscapular fossa is found on the costal surface
A
Explanation
The scapula is a triangular, flat bone which has a medial, lateral and superior border. It also has a superior, lateral and an inferior angle. The superior border joins the base of the coracoid process. The concave costal surface of most of the scapula forms a large subscapular fossa. The lateral border terminates in the truncated lateral angle of the scapula, the thickest part of the bone that bears the broadened head of the scapula. The glenoid cavity is the primary feature of the head
Regarding digital nerves, which is CORRECT?
A Palmar nerves only supply palmar surface
B Digital nerve lie posterior to digital artery
C Digital nerves are only sensory
D Common digital nerves lie superficial to superficial palmer arch
C
Explanation
The common digital nerves lie deep to the superficial palmar arch. Palmar nerves supply palmar surface and they end dorsally by supplying the dorsal nail beds. The digital artery lies dorsal to the nerve.
Digital nerves are purely sensory. If a digital nerve is cut, the patient feels numbness on the corresponding side of the finger. Motor function in the finger should be normal, because it is controlled by the tendons, whose muscles are innervated more proximally in the forearm. Impairment of motor function (other than pain with movement) suggests that tendon injury also is present.
Note: lumbrical muscles-arise from the each of the four profundus tendon and passes along the radial side of the corresponding metacarpophalangeal joint, on the palmer surface of the deep transverse metacarpal ligament, to be inserted by a tendon into the extensor expansion on the dorsum of the first phalanx. The two unicapital lumbricals (1,2) are supplied by the median nerve and the two biciputal lumbricals (3,4) are supplied by the ulnar nerve.
Which myotome(s) is responsible for adduction of the fingers
A C8
B T1
C C8 T1
D C7 C8
B
Explanation
Adduction of the fingers= T1
Digital flexion=C7 C8
Digital extension=C7 C8
Pronation=C7 C8
Which is not true regarding the carpal tunnel?
A The ulnar nerve lies on the front of the reticulum lateral to the pisiform bone
B All eight tendons of the superficial and deep flexors share a common tendon sheath, which completely invests the tendon
C The tendon of flexor pollices longus lies in its own synovial sheath as it passes through the fibro-osseous tunnel.
D The median nerve and the flexor tendons of the fingers and thumb pass through this tunnel
B
Explanation
The carpal tunnel lies between the flexor retinaculum and the carpal bones. The median nerve and the flexor tendons of the fingers and thumb pass through this tunnel. The four tendons of the superficial flexor are separate and lie in two rows, with the middle and ring finger tendons in front of the index and little finger tendons. The tendons of the flexor digitorium profundus lie deeply in one plain, with only the tendon to the index finger being separate from the others, which remain attached together till they reach the palm. All eight tendons of the superficial and deep flexors share a common tendon sheath, which does not invest them completely but is reflected from their radial sides, where arteries gain access. The tendon of flexor pollices longus lies in its own synovial sheath as it passes through the fibro-osseous tunnel. At the lateral end of the tunnel a deep lamina from the flexor retinaculum is attached to the medial lip of the grove of the trapezium. The tendon of flexor carpi radialis, enclosed in its own synovial sheath runs in the groove in this subcompartment of the carpal tunnel. The median nerve passes deep to the flexor retinaculum between the flexor digitorium superficialis tendon to the middle finger and the flexor carpi radialis tendon. The ulnar nerve lies on the front of the reticulum lateral to the pisiform bone, with the ulnar artery lateral to the nerve (in the canal of Guyon)
Which is FALSE regarding supination and pronation movements of the upper limb?
A The movements of supination and pronation occur at the superior and inferior radioulnar joints
B The ulnar is entirely stationary during pronation and supination
C About 140 degrees of rotation occurs at the radioulnar joints during pronation and supination
D During supination and pronation the axis of movement of the radius relative to the ulnar passes through the radial head and ulnar styloid
B
Explanation
The movements of supination and pronation occur at the superior and inferior radioulnar joints. In full supination, the anatomical position, the radius lies lateral and parallel to the ulna. During pronation the distal radius rotates in front of and around the head of the ulna, carrying the hand with it. In full pronation the shaft of the radius lies across the front of the ulna with the distal end of the radius lateral to the ulnar head (this statement comes from the old resource.It is wrong, the radius in full pronation lies medial to the ulnar head and not lateral to it)
During supination these movements are reversed. The axis of movement of the radius relative to the ulna passes through the radial head and ulnar styloid. The ulnar is not usually entirely stationery during pronation and supination. The distal end of the ulna moves slightly posterolaterally in pronation and anteromedially in supination, these movements being effected by anconeus and the bicepital aponeurosis respectively. Supination is more powerful inaction, carried out by biceps and supinator muscles. Pronation is produced by pronator quadratus and pronator teres. About 140 degrees of rotation occurs at the radioulnar joints during pronation and supination.
Injury to the median nerve will result in this muscle’s dysfunction
A Extensor carpi radialis longus
B Palmaris brevis
C Palmer interossei 1st-3rd
D Abductor pollicis brevis
D
Explanation
Abductor pollicis brevis-recurrent branch of median nerve (C8, T1)
Palmaris brevis-superficial branch of the ulnar nerve
Palmer interossei 1st-3rd-Deep branch of the ulnar nerve (C8, T1)
Extensor carpi radialis longus-Radial nerve (C6, C7)
Extensor carpi radilias brevis- Deep branch of the radial nerve (C7, C8)
55-year-old woman has an axillary lymph node dissection for breast cancer. Following this, she is unable to medially rotate her arm. Which nerve has most likely been damaged?
A Nerve to subclavius
B Dorsal scapular nerve
C Thoracodorsal nerve
D Long thoracic nerve
C
Explanation
The latissimus dorsi muscle is responsible for medial rotation of the humerus, as well as extension and adduction. It is supplied by the thoracodorsal nerve.
The dorsal scapular nerve supplies the rhomboids, which retract the scapula.
The long thoracic nerve supplies the serratus anterior muscle, which rotates and protracts the scapula.
The nerve to subclavius supplies the subclavius muscle, which depresses the clavicle.
Which of the following nerves has roots from C6, C7 and C8?
A Nerve to subclavius
B Thoracodorsal nerve
C Long thoracic nerve
D Suprascapular nerve
B
Explanation
The thoracodorsal nerve arises from the posterior cord of the brachial plexus. Other branches include the upper and lower subscapular nerves, and axillary nerve, before continuing as the radial nerve. The long thoracic nerve arises from the C5, C6, and C7 nerve roots. The nerve to subclavius arises from the C5 and C6 nerve roots. The suprascapular nerve arises from the upper trunk of the brachial plexus (C5, C6)
A 22-year-old male suffers an injury to the medial side of his wrist after his arm passes through glass. There is profuse bleeding. Which muscle is likely damaged?
A Flexor carpi ulnaris
B Flexor digitorum profundus
C Flexor digitorum superficialias
D Extensor carpi ulnaris
A
Explanation
The FCU tendon attaches to the pisiform, hook of hamate and 5th MC. The ulnar artery enters the and via the ulnar canal, between the pisiform and hook of hamate. Profuse bleeding suggests arterial involvement and thus this is the likely affected muscle structure
Which muscle is responsible for flexion of the DIPJ of the 4th and 5th digits?
A Lumbricals
B Flexor digitorium profundus
C Dorsal interossei
D Flexor carpi ulnaris
B
Explanation
FCU: flexes and aDDucts wrist.
Lumbricals: flex MCPJ and extend IPJ (act with interossei)
Dorsal interossei: abduct digits 2-4 from the axial line
FDP: the medial and lateral parts are responsible for the flexion of the distal phalanges 4/5 and 2/3 at the DIPJ respectively
A patient presents with a sensory disturbance to the dorsal aspect of their first inter-digital space of the hand has a lesion of which nerve?
A Radial nerve
B Median nerve
C Medial cutaneous nerve
D Ulnar nerve
A
Explanation
The radial nerve supplies sensation to the lateral 3.5 digits and associated hand area of the dorsum of the hand.
The thoraco-acromial artery is a branch of which artery?
A Axillary
B Subclavian
C Vertebral
D Superior intercostal
A
Explanation
The axillary artery has three parts located relative to the pec minor muscles. The 1st part is proximal to the pec minor and gives off the superior thoracic artery. The 2nd part is posterior to the pec minor and gives off the thoracoacromial artery and lateral thoracic artery. The 3rd part is distal and gives off the subscapular, and anterior and posterior circumflex arteries.
In a patient with Carpel Tunnel Syndrome, weakness will be evident in testing of which of the following muscles on examination?
A Flexor Pollicis Longus
B Abductor Pollicis Brevis
C Abductor Pollicis Longus
D Extensor Pollicis Longus
B
Explanation
Carpal Tunnel Syndrome affects the median nerve, which supplies the thenar muscles (opponens pollicis, abductor pollicis brevis, flexor pollicis brevis), and the lateral two lumbricals.
Which myotome is responsible for adduction of the fingers?
A C8
B C6
C C7
D T1
D
Explanation
Myotomes:
C5 - shoulder abduction
C6 - elbow flexion
C7 - elbow extension
C8 - finger flexion
T1 - finger abduction & adduction
A patient is unable to abduct or flex their shoulder, and has sensory loss over the lateral aspect of their shoulder. Which nerve root is likely affected?
A C7
B C5
C C6
D C8
B
Explanation
C5 is responsible for shoulder flexion, abduction and lateral rotation; as well as sensation over the lateral shoulder/arm
A patient is unable to flex their shoulder or elbow. Which nerve is likely affected?
A Suprascapular nerve
B Musculocutaneous nerve
C Axillary nerve
D Lower subscapular nerve
B
Explanation
The major muscles involved in shoulder flexion are the pec major and deltoid, with the deltoid being supplied by the axillary nerve. The musculocutaneous nerve supplies the coracobrachialis, biceps brachii and brachialis (both elbow flexion). The coracobrachialis muscles assists shoulder flexion.
Flexion of the shoulder
Pectoralis major (medial and lateral pectoral nerve)
Deltoid (axillary nerve)
Assisted by coracobrachialis (musculocutaneous nerve)
Flexion of the elbow
Brachialis (musculocutaneous nerve)
Biceps Brachii (musculocutaneous nerve)
In anterior shoulder dislocation, which ligaments are most likely damaged?
A Glenohumeral ligaments
B Transverse humeral ligament
C Coracohumeral ligaments
D Acromioclavicular ligament
A
Explanation
Glenohumeral ligaments stabilize the anterior parts of the shoulder joint. Coracohuneral and acromioclavicular ligaments provide superior stability. The transverse humeral ligament bridges intertubercular sulcus, between two tubercles, holding the head of biceps in groove
Between which muscles does the musculocutaneous nerve run after piercing the coracobrachialias?
A Brachioradialis and supinator
B Biceps and brachialis
C Biceps and brachioradialis
D Biceps and Flexor Digitorum Profundus
B
Explanation
The musculocutaneous nerve begins opposite the inferior border of the pec minor, pierces the coracobrachialis, and continues distally between the biceps and the brachialis.
Which structure crosses the floor of the anatomical snuff box?
A Median nerve
B Deep branch of radial nerve
C Ulnar nerve
D Superficial radial nerve
D
Explanation
Structures crossing the floor of the snuff box include the radial artery, superficial branch of the radial nerve, and cephalic vein.
Injury to the radial nerve at the elbow will affect function of which of the following muscles?
A Extensor carpi radialis longus
B Brachioradialias
C Flexor pollicis longus
D Supinator
D
Explanation
The radial nerve gives off branches to the brachioradialis and ECRL from the arm, proximal to the elbow. The FPL is supplied by the median nerve. The radial nerve pierces the supinator in the forearm, supplying it before becoming the posterior interosseous nerve and supplying muscles of the posterior compartment of the forearm.
Which nerve is affected by fracture of the surgical neck of the humerus?
A Radial nerve
B Median nerve
C Musculocutaneous nerve
D Axillary nerve
D
Explanation
The deltoid and teres minor atrophy when the axillary nerve (C5, C6) is severely damaged. Because it passes inferior to the humeral head and winds around the surgical neck of the humerus, the axillary nerve is usually injured during fracture of this part of the humerus. It may also be damaged during anterior dislocation of the glenohumeral joint and by compression from incorrect use of crutches.
The radial nerve courses in the radial groove of the humerus shaft and thus is susceptible to injury with midhumeral fracture.
What is the largest branch of the posterior cord of the brachial plexus?
A Ulnar Nerve
B Median nerve
C Radial nerve
D Musculocutaneous nerve
C
Explanation
The Radial Nerve (n. radialis; musculospiral nerve), the largest branch of the brachial plexus, is the continuation of the posterior cord of the plexus. Its fibres are derived from the fifth, sixth, seventh, and eighth cervical and first thoracic nerves.
source: https://www.imaios.com › e-Anatomy › Anatomical-Parts
Which muscle would be expected to be innervated by median recurrent nerve?
A 1-2nd lumbricals
B Extensor pollicis longus
C 1-2nd palmar interossei
D Abductor pollicis brevis
D
Explanation
Recurrent branch of median nerve supplies opponens pollicis, abductor pollicis brevis and the superficial head of flexor pollicis brevis. Interossei are innervated by the deep branch of the ulnar nerve, the 1st-2nd lumbricals by the median nerve, and extensor pollicis longus by the posterior interosseous nerve
A patient sustains an injury to the lateral cord of the brachial plexus. Which movement of the upper limb is least likely to be affected?
A Rotation
B Flexion
C Extension
D Supination
C
Explanation
The musculocutaneous nerve is derived from the lateral cord of the brachial plexus and innervates the biceps brachii, brachialis, and coracobrachialis muscles (C5–C6), terminating as the lateral cutaneous nerve of the forearm. Injuries to the musculocutaneous nerve are associated with weakness of arm flexion and sensory loss along the lateral forearm. In children, musculocutaneous neuropathies are rare and generally caused by compressive or overuse injuries.
Musculocutaneous nerve innervates the muscles in the anterior compartment of the arm: Biceps brachii, Brachialis, Coracobrachialis. These muscles flex the upper arm at the shoulder and the elbow. In addition, the biceps brachii also supinates the forearm. A useful mnemonic to help you remember these muscles is BBC.
A patient has sustained a shark bite to the proximal forearm and there is profuse bleeding. Where is the best place to occlude the brachial artery?
A Axilla
B Cubital fossa just proximal to the skin fold
C Mid-arm medial to the humerus
D Just distal to axilla, at the medial top part of the humerus
C
Explanation
The best place to compress the brachial artery (manually or with a tourniquet) to control haemorrhage is medial to the humerus near the middle of the arm. Because the arterial anastomoses around the elbow provide a functionally and surgically important collateral circulation, the brachial artery may be clamped distal to the origin of the deep artery of the arm without producing tissue damage. The anatomical basis for this procedure is that the ulnar and radial arteries will still receive sufficient blood through the anastomoses around the elbow.
Arm-extends form the shoulder to the elbow
Forearm-is the distal unit of the articulated strut (extension of the upper arm). It extends form the elbow to the wrist.
Where does the right bronchial artery generally arise from?
A Right 2nd posterior intercostal artery
B Right 3rd posterior intercostal artery
C Right 1st posterior intercostal artery
D Right 4th posterior intercostal artery
B
Explanation
The two left bronchial arteries usually arise directly from the thoracic aorta. The single right bronchial artery may also arise directly from the aorta; however, it commonly arises indirectly, either by way of the proximal part of one of the upper posterior intercostal arteries (usually the right 3rd posterior intercostal artery) or from a common trunk with the left superior bronchial artery.
Where is the best place to palpate the radial artery at the wrist?
A Between the flexor carpis radialis and adductor pollicis longus tendons
B Lateral to the flexor carpis radialis tendon
C Medial to the abductor pollicis longus tendon
D Anatomical snuffbox
B
Explanation
The common place for measuring the pulse rate is where the radial artery lies on the anterior surface of the distal end of the radius, lateral to the tendon of the FCR. Here the artery is covered by only fascia and skin. The artery can be compressed against the distal end of the radius, where it lies between the tendons of the FCR (flexor carpi radialis) and APL (abductor pollicis longus). A radial pulse can also be felt by pressing lightly in the anatominal snuffbox.
