W6 HIGH YIELD PT 2

Solutions A and B are separated by a semi-permeable membrane that is permeable to Ca2+ and impermeable to Cl-. Solution A contains 10 mM CaCl2, and solution B contains 1 mM CaCl2. What will be the electrical potential of solution A as compared to solution B? A. +60 mV B. +30 mV C. -60 mV D. -30 mV E. +120 mV F. -120 mV

-30 mV

A 21 year old patient has a lesion of the upper trunk of the brachial plexus (Erb - Duchenne paralysis). Which of the following is the most likely diagnosis? A. Paralysis of the rhomboid major B. Inability to elevate the arm above the horizontal C. Arm tending to lie in medial rotation D. Loss of sensation on the medial side of the arm E. Inability to adduct the thumb

Arm tending to lie in medial rotation The classical signs of Erb Duchenne palsy is an upper limb that is adducted, medially rotated arm, and an extended elbow. This is a result of C5/C6 nerve roots damaged due to shoulder dystocia.

If the middle trunk was severed, which nerve would not be affected? A. Thoracodorsal nerve B. Radial nerve C. Axillary nerve D. Median nerve

Axillary nerve Middle trunk only receives nerve supply from the C7 root. C. is correct. Its roots are C5 and C6. (A) C7, C8, T1 (B) and (D) C5,6,7,8, T1 (E) C6,7,8

A man got stabbed at the back of his arm in an anatomical space between the teres major, teres minor, and the long and lateral heads of the triceps brachii muscles. A nerve has been affected and now he is unable to abduct his arm to the horizontal. Identify what nerve is affected and what nerve roots? A. Axillary nerve, C5-6 B. Radial nerve, C5-T1 C. Suprascapular nerve, C5-6 D. Long thoracic nerve, C5,6,7

Axillary nerve, C5-6 The space described is the quadrangular space and the nerve found in that space is the axillary nerve. None of the other nerves are found in this space. Also, the axillary nerve innervates the deltoid to abduct the arm to the 90 degree position. Supraspinatus which is innervated by suprascapular nerve initiates the motion of arm abduction but it is not in the quadrangular space and does not abduct to the 90 degree position.

Greg, the Gym Rat and Will, the Workout Warrior got into an arm wrestling match, where Greg edged out Will in a close fashion. In the process, Will injured his arm and fell to the ground immediately after the match. He could not flex his arm and also lost sensation on the lateral forearm. MRI and CT scans confirmed that Will has a muscle hypertrophy in the axilla, which have contributed to his injury. A nerve originating from which of the following root(s) is most likely injured? A. C5 B. C5, C6 C. C6, C7, C8 D. C5, C6, C7, C8, T1 E. C8, T1

C5, C6 The nerve most likely damaged is Musculocutaneous n., which originates from spinal nerve roots C5 and C6. Musculocutaneous n. innervates Brachialis m. (Main flexor of arm) and Biceps brachii m. (Supinator & Flexor). Also, it becomes the Lateral cutaneous nerve of forearm and provides cutaneous innervation to the lateral forearm. The hypertrophied muscle is most likely the Coracobrachialis m. which adducts and flexes the humerus (Arm wrestle). Musculocutaneous n. pierces the Coracobrachialis m. on its way to the arm, so hypertrophy would cause a pinching of the Musculocutaneous n. But you should be able to get the right answer just by looking at the deficits!

The nerve found in the triangular interval receives its roots from which spinal nerves? A. C5-C6 B. C8-T1 C. C5-T1 D. C6-C8

C5-T1 The Radial Nerve is found in the Triangular Interval which arises from C5-T1 spinal nerves.

What are the nerve roots of the thoracodorsal nerve? A. C5, C6 B. C6, C7, C8 C. C8, T1 D. C5 - T1 E. C5

C6, C7, C8 Thoracodorsal nerve branches from the posterior cord of the brachial plexus and is from the nerve roots C6-C8. It innervates the latissimus dorsi muscle.

Two important concepts to understand are Dermatomes and Cutaneous innervation. Being able to differentiate the two can help with diagnosis of neurological disorders. What are the supplying dermatomes & cutaneous innervation of the ring finger (Digit IV)? A. C6/C7 & Median B. C6/C7 & Median/Radial C. C7 & Radial/Ulnar D. C7 & Radial/Ulnar/median E. C7/C8 & Radial/Ulnar/Median F. C7/C8 & Radian/Ulnar G. C8 & Radial/Median H. C8 & Radial/Ulnar/Median

C7/C8 & Radial/Ulnar/Median The ring finger is divided down the middle between dermatomes C7 & C8. The cutaneous innervation on the anterior/palmer surface is also split down the middle between Median & Ulnar nerves. The posterior surface of the ring finger is unique in that the medial portion is innervated by Ulnar nerve while the Lateral portion is split with the distal portion innervated by Median and the rest proximal innervated by Radial nerve.

Patient comes into the emergency room because of some pain in his arm and he is unable to make a fist. He tells you that he was on a ladder painting the windows in his home and for some reason the ladder slipped but he managed to grab hold of a handle with his right hand. Now when he tries to make a fist and cannot because his digit 4 and digit 5 do not flex and has lost sensation to this area as well. Knowing that this injury damaged a nerve which nerve roots are most likely damaged? A. C5 and C6 B. C6 and C7 C. C7 and C8 D. C8 and T1

C8 and T1 A. Incorrect. If the patient damaged C5 and C6 roots of the brachial plexus he would present with an erb-duchenne palsy. B. Incorrect. The roots C6 and C7 control the innervations to the later cutaneous part of the forearm. C. Incorrect. C7 and C8 innervate are not low enough in the brachial plexus to cause this type of patients presentation. D. Correct. C8 and T1 nerve root damage causes Klumpke's palsy or Claw hand. The patient is unable to make a fist due to the ulnar nerve innervations to the small finger and ring finger.

A patient presents to your office unable to make a complete fist with his right hand. He said that he was climbing a tree to save a kitten when a branch broke from under him. He tried to hang on for a couple minutes but had to let go. When he tried grabbing the kitten that was about to run away, he noticed his medial two fingers would not bend. What spinal nerve roots were damaged during this accident? A. C5, C6, C7 B. C8, T1 C. C6, C7, C8 D. C1, C2, C3

C8, T1 Choice B is correct, corresponding to the ulnar nerve injury described. Choice A corresponds to the musculocutaneous nerve and does not extend down to innervate muscles in the hand. Choice C does not correspond to the ulnar nerve. Choice D is not in the brachial plexus.

A patient comes into the ER with an elbow injury. The radiologist tells you that the medial epicondyle is fractured. Upon examination the patient presents with "clawing" of the fingers when asked to make a fist. What are the roots of the nerve that is most likely affected? A. C5-C6 B. C5-C7 C. C5-T1 D. C8-T1

C8-T1 The Ulnar nerve is mostly likely affected in a fracture elbow involving the medial epicondyle because the nerve passes just posterior to it. The roots of the ulnar nerve are C8-T1.

While mountain biking at Tom Brown park, your friend Jeff took a nasty fall. You went to help him up and make sure he was okay. Other than a few scrapes on his legs and arms everything seemed okay, but when he tried to grab his handle bars you noticed he could not completely flex his last two fingers. Attempt to make a fist results in a typical "claw hand" presentation. Which nerve roots did Jeff injure on his bicycle accident? A. C5-C6 B. C8 C. C8-T1 D. C7-T1 E. C8-T2

C8-T1 Seeing how Jeff was not able to completely close his last two fingers you know that the ulnar nerve must be damaged. The roots for the ulnar nerve are C8-T1, the most inferior portion of the brachial plexus.

What artery exists in the triangular space? A. Posterior circumflex numeral B. Thoracodorsal C. Circumflex scapular D. Anterior circumflex numeral

Circumflex scapular Posterior circumflex humeral artery exits the quandrangular space with the axillary nerve while the thoracodorsal and anterior circumflex humeral do not travel through any known space or interval.

A 23 year-old male presents to the ER with a painful right shoulder following a sports injury. X-ray shows a fracture to the scapula extending to the base of the coracoid process. Which muscles are mostly affected by this kind of fracture by losing their attachments to this structure? A. Coracobrachialis, Short head of biceps, Pectoralis minor B. Short head of biceps, Teres minor, Sternal head of pectoralis major C. Coracobrachialis, Short head of biceps, Teres minor D. Short head of biceps, Long head of triceps, Teres minor E. Coracobrachialis, Short head of biceps, Pectoralis minor

Coracobrachialis, Short head of biceps, Pectoralis minor The three muscles that occupy the Axilla are Coracobrachialis, Short head of biceps, Pectoralis minor. all of them has an attachment to the coracoid process of the scapula. Fracture to the the coracoid process will affect the action of the three of them.

A man is brought into the Emergency Room after being thrown from a motorcycle. Upon examination, you notice that his left arm hangs by his side with medial rotation. You know this to be an injury to the superior trunk of the brachial plexus. The name of this presentation is called: A. Claw hand B. Horner's syndrome C. Terrible triad D. Erb's palsy E. Bell's palsy

Erb's palsy This can occur when a person is thrown from a motorcycle or horse and lands on the shoulder in a way that widely separates the neck and shoulder causing injury to the superior trunk of the brachial plexus. Claw hand is a clinical presentation of inferior trunk injury to the brachial plexus.

After a complicated delivery, the mother notices that her baby has a waiter's tip deformity. With her nursing background, she knows it means an upper trunk brachial plexus injury. What is the other name for this condition, and what nerve roots are damaged? A. Shoulder dystocia, C8-T1 B. Erb-Duchenne Palsy, C5-C6 C. Klumpke paralysis, C5-C6 D. Prefixed brachial plexus, C4-C8

Erb-Duchenne Palsy, C5-C6 Erb-Duchenne Palsy, C5-C6 is correct. Shoulder dystocia is correct but the roots are wrong. In C, the roots are correct but Klumpke is a lower trunk injury

An ice skater slips and falls directly on his shoulder injuring his superior trunk of his right brachial plexus. Which of the following actions would NOT be compromised? A. Abduction of the humerus B. Adduction of the humerus C. Inferior rotation of scapula D. Lateral rotation of the humerus E. Medial rotation of the humerus

Inferior rotation of scapula Injuring the superior trunk would spare the dorsal scapular nerve innervating the rhomboids muscles and levator scapula. The levator scapulae rotates the scapula inferiorly(Answer C). Answer choices B and E is dealt with by subscapular/ teres minor innervated by subscapularis nerve which is damaged by the fall(C5-C6). Also A and D are the actions of suprascapular innervated muscles which is also damaged by superior trunk damage.

What process is predominantly involved in the generation of the resting membrane potential? A) Transport of sodium out of the cell by Na+/K+ ATP-ase B) Transport of potassium in the cell by Na+/K+ ATP-ase C) A decrease in concentration of chloride ions outside the cell D) K+ exit out of the cell through potassium channels E) Entry of sodium into the cell through ligand gated sodium channels

K+ exit out of the cell through potassium channels

A post-fixed brachial plexus increases the risk for which brachial neuropathy? A. Wrist drop B. Hand of benediction C. Klumpke's palsy D. Erb's palsy E. Ape hand

Klumpke's palsy Post-fixed brachial plexus means T2 and/or T3 contribute to the brachial plexus. This increases the risk of inferior trunk compression - Klumpke's palsy - due to increased risk of compression or stretching of the inferior trunk/roots in the superior thoracic aperture.

Lateral pectoral nerve arises from what part of brachial plexus? A. Medial Cord B. Middle trunk C. Lateral Cord D. Posterior Cord E. Superior Trunk

Lateral Cord The Lateral Pectoral nerve arises directly from the lateral cord of the brachial plexus.

. Lateral pectoral nerve arises from part of the brachial plexus? A. Middle Trunk B. Posterior Cord C. Lateral Cord D. Superior Trunk E. Medial Cord

Lateral Cord The lateral pectoral nerve arises from the lateral cord of the brachial plexus and innervates the pectoralis major muscle.

A cricket player dislocated his shoulder during a game. The displaced humeral head came to rest anterior to the glenohumeral joint, inferior to the coracoid process. Given the most likely nerve injury with this type of dislocation, where would you expect paresthesia in this patient? A. Posterior shoulder B. Anterior shoulder C. Lateral shoulder D. Posterior arm and forearm E. Medial arm and forearm

Lateral shoulder An inferior dislocation (which results in the humeral head moving down then anteriorly from the joint) may injure the axillary nerve, which provides sensation to the lateral shoulder.

Inactivation of the sodium-potassium ATPase pump will cause which of the following to occur? A. Loss of ional gradients across the membrane B. An increase in the intracellular potassium concentration C. Maintenance of membrane potential D. An increase in the flow of sodium out of the cell

Loss of ion gradients across the membrane

A patient present to the clinic after falling off his skateboard while attempting to grind on a rail. He attempted to break his fall by grabbing the rail, but ended up taking the impact in his armpit. You perform a few tests and find out that the patient has paresthesia of the medial aspect of his forearm. Which nerve has been damaged and what are the spinal roots? A. Medial antebrachial cutaneous nerve - C8-T1 B. Median nerve - C5-T1 C. Medial brachial cutaneous nerve - C8-T1 D. Radial Nerve - C5-T1 E. Ulnar nerve - C7-T1

Medial antebrachial cutaneous nerve - C8-T1 Anytime a patient has sustained trauma in the area of the armpit it is vital to check the status of the brachial plexus. The medial antebrachial cutaneous nerve provides cutaneous innervation to the medial aspect of the antebrachium/forearm (not to be confused with the lateral aspect, which gets cutaneous innervation from lateral cutaneous nerve of the forearm). Just look at the name of the nerve!

. Your 38 year old patient, Harvey Spector was rushed into the emergency room for a penetrating injury to his arm. After he was treated for his injuries and give proper pain medication, you are asked by your attending to test for any motor or sensory defects. You find that the biceps brachii is affected. What nerve is most likely injured? A. Axillary (C5,C6) B. Radial (C5-C8,T1) C. Musculocutaneous (C5-C7) D. Ulnar (C7-T1)

Musculocutaneous (C5-C7) A. Incorrect, this nerve innervates the deltoid and teres minor. B. Incorrect, this nerve innervates all the extensor muscles of the arm and forearm. C. CORRECT, the biceps brachii together with the coracobrachialis and brachialis are innervated by this nerve. D. Incorrect, this nerve innervates muscles in the forearm and hand, but no muscles in the arm.

While boiling water to make a spaghetti dinner, Addison bumped his lateral forearm against a scolding pot. He suffered an excruciatingly painful 2nd degree burn. Which of the main terminal branches of the brachial plexus gave rise to the nerve that is responsible for the sensation Addison is feeling?

Musculocutaneous nerve The terminal branch of the brachial plexus should be the Musculocutaneous nerve. This nerve will further give rise to the Lateral Cutaneous Nerve of the Forearm (LAC, Lateral antebrachial cutaneous n.), which will relay sensation and pain felt on the lateral forearm.

A 33-year-old, overweight male becomes ill and is diagnosed with hyperkalemia (high extracellular K+). What effect would this have on neuronal resting membrane potentials? A) Hyperpolarize B) Repolarize C) No effect D) Depolarize

No effect

Which of the following scenarios would most likely depolarize a neuron the most? A) Increased K+ permeability B) Open voltage gated potassium channels C) GABA binding to post-synaptic receptors increasing Cl permeability D) Efflux of K+ E) Open voltage gated sodium channels

Open voltage gated sodium channels

The nerve running through the triangular interval is a branch of what cord of the brachial plexus? A. Posterior B. Anterior C. Medial D. Lateral E. Superior

Posterior Two structures run through triangular interval: radial nerve and profundi brachii artery. Radial nerve is the posterior cord of the brachial plexus

A landscaper presents to his primary care physician describing extreme difficulty when starting his pull start lawnmower and turning his arm towards his body. He says it began as just weakness that has now progressed to an inability to start his lawn mower, and he decided to come in when his wife noticed his right forearm muscles beginning to "shrink." When the physician measures the left forearm he finds that its circumference is significantly larger, and that the patient has loss of sensation to the back of his arm extending over his elbow to his thumb, and first two fingers but NOT the tips. His physician sends him to a medical imaging center for a chest x-ray and notes a mass compressing his axillary sheath and makes a diagnosis of a progressive Pancoast Tumor. What Portion of the Brachial plexus is most likely affected? A. Anterior Cord B. Medial Cord C. Posterior Cord D. Radial Nerve of the Posterior Cord E. Ulnar Nerve of the Medial Cord F. Supraspinous nerve of the Anterior Cord

Posterior Cord The patient presented with an inability to start a lawnmower. If you sit and act that out in you seat you can see it involves pulling the trunk towards the arm, or adduction (latissimus dorsi), he also describes difficulty turning his arm towards his body or MEDIAL rotation (internal rotation). These are all actions of the Latissimus dorsi, subscapularis, teres major and deltoid. The shrinking of the forearm is another nerve of the Posterior cord the radial nerve, which supplies all the forearm muscles of the posterior compartment. Lastly the dermatomes involved are the C5-C7 or the radial nerve. The Radial nerve cannot be the correct answer because the radial nerve is a terminal branch of the posterior cord and damage to a nerve would have very specific consequences, only causing deficit in muscles of the posterior compartment for the arm and the forearm. The patient presented with other symptoms as well, not just the radial nerve. There is no Anterior cord, only lateral posterior and medial. There is no supraspinous nerve.

A weight lifter was working out in the gym when he suddenly felt a severe pain in his right shoulder. After the incident, he could not lift his right arm past 15 degrees and also could not laterally rotate the same arm. The injury to the nerve most likely occurred in which of the following locations of the brachial plexus? A. Anterior Division, Lateral Cord B. Anterior Division, Posterior Cord C. Anterior Division, Medial Cord D. Posterior Division, Lateral Cord E. Posterior Division, Posterior Cord F. Posterior Division, Medial Cord

Posterior Division, Posterior Cord The damaged nerve is Axillary Nerve (C5,6). From the presentation, the patient could not lift arm past 15 degrees (Deltoid) and also could not laterally rotate the arm (Teres minor). The combination of the two deficits should give you the clue that the Axillary nerve is injured. Axillary nerve is from the posterior division and posterior cord of the brachial plexus.

Someone comes into your clinic and they report that they've been stabbed in the quadrangular space. After thanking them for knowing their anatomy, you worry that a branch of which cord in the brachial plexus has been damaged? A. Inferior cord B. Posterior cord C. Medial cord D. Middle cord E. Superior cord F. Lateral cord

Posterior cord The contents of the quadrangular space are the axillary nerve and the posterior circumflex humeral artery. The axillary nerve is a terminal branch of the Posterior cord

A 30-year-old man has diminished sensation on the lateral aspect of his upper left arm following a bad fall down the stairs. Which action is also most likely impaired in this patient on the same side? A. Initiation of abduction of the arm B. Raising arm above head C. Medial rotation of the arm D. Adduction of the arm

Raising arm above head Cutaneous sensation to the lateral aspect of the upper arm is provided by the axillary nerve. Damage to this nerve would also impair abduction of the arm past 15 degrees, thus disabling the patient from raising his arm above his head

What is the landmark where the subclavian artery changes name to the axillary artery? A. Rib 2 B. Teres major C. Rib 1 D. Teres minor

Rib 1 The lateral border of rib 1 is the appropriate landmark for when the subclavian artery changes its name to axillary artery.

During a bout with a bear, former Soviet wrestler Zangief sustains several debilitating injuries to the right shoulder and humerus. While attempting his 360 degree pile-driver, he incorrectly assessed his and the bear's center of gravity. As a result, he lands flat on his right arm and shoulder dorsally and the bear comes down on top of his right axilla ventrally. He sustains fractures of the clavicle, 1st rib, and mid humerus. Zangief has paralysis of the anterior compartment of his arm with severe swelling. After your physical examination, you isolate the nerve damage as restricted to the lateral cord of the brachial plexus. What other clinical manifestation would likely be present? A. Motor paralysis to the posterior compartment of the arm B. Motor paralysis to abductor muscles of the arm C. Sensory loss to medial cutaneous regions of the arm and forearm with partial motor paralysis of pectoralis major D. Motor paralysis to pectoralis major and pectoralis minor E. Sensory paralysis to the lateral region of the forearm with partial motor paralysis to pectoralis major

Sensory paralysis to the lateral region of the forearm with partial motor paralysis to pectoralis major Sensory innervation to the lateral forearm is carried by afferent nerve fibers that bundle with musculocutaneous in the upper arm. Musculocutaneous travels in the lateral cord of the brachial plexus. Radial and axillary branches of the brachial plexus travel through the posterior cord of the brachial plexus. Lateral pectoral nerve is derived from the lateral cord of the brachial plexus.

The long thoracic nerve innervates which muscle: A. suprascapulis B. Middle scalene C. Anterior scalene D. Serratus anterior E. Teres major

Serratus anterior Injury to this nerve presents with a protruding scapula, also known as "winged scapula".

Which of the following branches of the Axillary artery contribute to anastomoses around the Scapula? A. Suprascapular artery B. Subscapular artery C. Dorsal scapular artery D. Posterior circumflex humeral artery E. Lateral thoracic artery

Subscapular artery Suprascapular artery and dorsal scapular artery are branches of Subclavian artery. Circumflex scapular artery is a branch of Subscapular artery which itself is a branch of the Axillary artery. Axillary --> Subscapular --> Circumflex scapular artery

. You are out with your special someone, celebrating the 5th year anniversary. You decide to go to a fine french restaurant and are very excited because you've heard great reviews about this especially overpriced restaurant. As you were paying your bill, you noticed a waiter walk by with his arm medially rotated, adducted and extended. You are outraged by this blatant gesture for a tip, and complain to the manager. The manager explains to you apologetically, that the waiter actually has a birth defect, something to do with being pulled out of the womb by the arm. You recollect that he probably has a severed ___________ portion of his brachial plexus roots, resulting in ____________. As you leave the restaurant you hate yourself for being so judgmental. A. Middle (C5-C6); Erb's palsy B. Superior (C4-C5); Klumpke's paralysis C. Inferior(C8-T1); Shoulder Dystocia D. Superior (C5-C6); Erb's Palsy E. Superior(C6-C7); Shoulder Dystocia

Superior (C5-C6); Erb's Palsy The waiter has Erb's Palsy (shoulder dystocia) and it is a result of severing the superior roots of the brachial plexus, C5-C6.

The supra scapular nerve is a direct branch of what part of the brachial plexus? A. Lateral Cord B. C7 Nerve Root C. Inferior Trunk D. Superior Trunk

Superior Trunk Suprascapular nerve branches off before the nerves are divided into cords, so it cannot be (A). C7 is not part of the superior trunk and therefore does not provide innervation for the supra scapular nerve

A family physician was seeing a patient for an annual check up. She noticed that her patient's shoulder was slightly elevated, so she sent her patient to get a CT scan. The scan showed that the muscle originating from the junction of the first rib and its cartilage and inserting into the groove of the posterior surface of the clavicle was atrophied, with no other signs of damage. The physician knows a possible diagnosis is that the nerve innervating this muscle could be damaged. From which portion of the Brachial Plexus does this nerve originate from? A. Superior Root B. Anterior Division C. Lateral Cord D. Superior Trunk

Superior Trunk The question is asking about the Nerve to Subclavius, which innervates the Subclavius muscle. This nerve comes off the Superior Trunk of the Brachial Plexus. The Superior trunk also gives rise to the Suprascapular nerve. The other answers are INCORRECT because: The Roots/Anterior Rami of the Brachial Plexus give rise to the Dorsal Scapular nerve and the Long Thoracic nerve only. The Divisions of the Brachial Plexus do not give rise to ANY nerves. The Lateral Cord of the Brachial Plexus gives rise to the Lateral Pectoral nerve only.

With an injury that causes the 'waiter's tip deformity (Erb's Palsy), which nerve deficit causes the humerus to medially rotate? A. Musculocutaneous Nerve B. Suprascapular Nerve C. Dorsal Scapular Nerve D. Ulnar Nerve E. Lateral Pectoral Nerve

Suprascapular Nerve Erb's Palsy is an injury to the C5-C6 roots of the Brachial Plexus. The Suprascapular nerve is damaged with an Erb's Palsy injury because it branches off the superior trunk of the brachial plexus. It supplies the Infraspinatus musce which laterally rotates the humerus. Also, the axillary nerve would be affected because its roots are C5-C6. With the axillary nerve affected, the Teres Minor can no longer laterally rotate the arm either. When there is damage to the Suprascapular nerve and Axillary nerve, the arm has unopposed medial rotation.

A lesion of the lateral cord will lead to severe weakness in: A. Pectoralis minor B. The upper arm flexors C. The upper arm extensors D. The deltoid and teres minor E. Supraspinatus and infraspinatus

The upper arm flexors The musculocutaneous nerve is a branch from the lateral cord.

A patient is rushed to the emergency room after getting in a street fight. The patient was stabbed with a knife, which inflicted a deep penetrating wound. If the wound extended deep through the distal end of pectoralis minor, which of the following arteries is most as risk of being severed? A. Thoracoacromial artery B. Superior thoracic artery C. Thoracodorsal artery D. Posterior circumflex humeral artery

Thoracoacromial artery Recognize that the pectoralis minor demarcates the axillary artery in to the three segments, and that the muscle itself overlays the second segment. Then realize that the thoracoacromial artery is a branch of the second segment, making it the best answer available.

A patient presents to the clinic with a stab wound to the right upper arm. Upon examination it is noted that there is pulsatile bleeding coming from the wound. The wound itself is found to be between the teres minor, teres major, and medial to the long head of the triceps. What is this space called and what blood vessel was hit? A. Triangular space - dorsal scapular artery B. Triangular space - circumflex scapular artery C. Triangular interval - profunda brachii D. Triangular space - profunda brachii E. Triangular interval - circumflex scapular

Triangular space - circumflex scapular artery Knowing the boundaries and contents of the triangular space and interval and the quadrangular space can be helpful in the diagnosis of traumatic injury

A young man complains of sensory loss over the anterior and posterior surfaces of the medial third of his hand, as well as on the medial one and one-half fingers. You inform him he injured his "funny bone". Which of the following nerves is injured? A. Musculocutaneous n. B. Axillary n. C. Radial n. D. Ulnar n. E. Median n.

Ulnar n. The Ulnar nerve supplies sensory innervation to the skin overlying the palmar and dorsal surfaces of the medial third of the hand, as well as the medial one and one-half fingers.

Jealous of your neighbor's Christmas lights, you decide to go up on the roof and put as many lights as you can. Not paying attention, you slid on a piece of ice and fall off the roof and land on the ground injuring your shoulder. The ER physician described your clinical presentation as "Waiter's Tip" Deformity. Describe which brachial plexus trunk and injured and its clinical presentation? A. Upper Trunk (C5-C6); upper limb is adducted, medially rotated arm and extended elbow B. Upper Trunk (C5-C6); upper limb is abducted, medially rotated arm and extended elbow C. Upper Trunk (C5-C7); upper limb is adducted, medially rotated arm and extended elbow D. Upper Trunk (C5-C7); upper limb is abducted, medially rotated arm and extended elbow

Upper Trunk (C5-C6); upper limb is adducted, medially rotated arm and extended elbow Upper trunk brachial plexus injury, C5-C6 injured, upper limb is adducted due to the deltoid muscle being affected (axillary nerve), medially rotated arm due to the infraspinatus and teres minor being affected (suprascapular and axillary nerves) and extended elbow (no flexion due to the musculocutaneuos nerve being affected).

In a neuron, what will be the result of doubling extracellular [K+]? A) The amplitude of Vm will double B) Vm will depolarize C) K+ will not contribute to Vm D) Vm will hyperpolarize towards EK

Vm will depolarize

A construction worker slipped off a ladder, fell, and fractured the midshaft of the humerus. What is the most likely presentation of the patient? A. Erb's palsy B. Benedict Hand C. Ape Hand D. Claw Hand E. Wrist Drop

Wrist Drop Fracturing the shaft of the humerus will most likely damage the radial nerve. Damaging the radial nerve will result with a wrist drop. Median nerve damage will present with either Benedict (if damaged at the elbow) or ape hand (if damaged at the wrist). Claw hand is when ulnar nerve is damaged.

At a bar fight, a patron was cut by a glass bottle. This resulted in a mid-shaft fracture of the humerus. In addition to the deep artery of the arm being severed (resulting in massive bleeding), the corresponding nerve was also severed. How will the patient's hand present? A. Ape Hand B. Claw Hand C. Hand of Benediction D. Wrist Drop E. Volkmann's Contracture

Wrist Drop The nerve severed is the radial nerve. A patient with a severed radial nerve presents with wrist drop. Ape Hand is when the median nerve is severed (at the level of the wrist). Claw hand is when the ulnar nerve is severed.

A 25 year old woman has just given birth to her first son, her labour was very difficult and she seems to have concern about the position of her newborn son's right arm. As the years progressed, she noticed that her son is unable to lift his right arm. He was diagnosed with Erb's palsy and she is considering suing the physician for the excessive shoulder pulling of her infant during labor. What position did she find her son's arm in and what nerve roots were damaged? A. adducted and medially rotated, C5-C6 B. abducted and laterally rotated, C5-C6 C. adducted and medially rotated, C5,C6,C7,C8 D. abducted and laterally rotated, C5-C6 E. adducted and laterally rotated, C5, C6, C7

adducted and medially rotated, C5-C6 Erb's palsy is a form of upper brachial plexus palsy where it affects the nerves C5 and C6. It often occurs during trauma of childbirth. The damage to the C5-C6 nerve (Axillary nerve) will result in weakness to the Deltoids, and loss of abduction, thus the arm will be ADDUCTED. The medial rotation is due to the contraction of the muscles NOT affected by the axillary nerve damage such as the Subscapularis are intact and thus medially rotate the arm.

An elderly gentleman presents to the ER with a wrist drop after sustaining a fall at home. He tells you that he slipped and hit his right arm on the edge of the table. You order an X-ray of the arm and notice a midshaft humeral fracture. You suspect damage to the radial nerve. (a) What vascular structure would you be most concerned may also be damaged and (b) what head of the triceps would most likely have lost innervation?

profunda brachii (deep artery of the arm), medial (a) The profunda brachii travels in close proximation to the radial nerve, also making it susceptible to humeral fractures in this region. (b) The medial head of the triceps is the last to receive innervation from the radial nerve, the long and lateral heads receive innervation prior to the radial nerve positioning in the radial groove