Block 9 - L11 Flashcards by Maggie Musso

What innervates the biceps muscles?

Musculocutaneous nerve, C5, C6

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What innervates the deltoid muscles?

Axillary nerve, C5, C6

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What innervates the infraspinatus muscles?

Suprascapular nerve, C4, C5, C6

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What innervates the supraspinatus muscles?

Suprascapular nerve, C4, C5, C6

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What innervates the triceps muscles?

Radial nerve, C6, C7, C8

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What is the most common birth injury neuropraxia?

Erb’s palsy

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Where is the lesion in Erb’s palsy?

Upper nerve root/trunk lesion (C5, C6); lower roots are preserved

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What happens in Erb’s palsy?

Loss of abduction (deltoid, supraspinatus), external rotation (infraspinatus), and supination (supinator)

“Waiter’s tip”

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What is the most commonly injured ligament in ankle sprains?

Anterior talofibular ligament (ATFL)

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What tendon is most commonly injured in a rotator cuff tear?

Supraspinatus tendon

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By what process do the long bones ossify?

Osteoblasts deposit minerals over a hyaline cartilage mold

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Which embryonic layer is bone derived from?

Mesoderm

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Which type of fracture is most likely to suggest an etiology of child abuse?

Spiral fracture

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List the types of complete fractures.

Transverse
Oblique
Spiral
Comminuted (crushed, several different fragments)
Avulsion (muscle/tendon pulls off a chunk of bone)

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List the types of incomplete fractures.

Buckle

2. Greenstick

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14 y/o football player is tackled from the side during a high school football game. When he tries to stand up, his right leg buckles. He is taken to the ED where physical exam reveals that the patient’s tibia is easily moved anteriorly in relation to the femur. An MRI of the patient’s knee is shown in the image. Which injured structure is responsible for the findings in the patient’s physical exam?

Anterior Cruciate Ligament (ACL)

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What happens in a knee valgus injury?

ACL-MCL-lateral meniscus

Lateral compression injury (valgus injury, tears ACL)
Medial distraction injury

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List the motion, nerve root, and peripheral nerve - supraspinatus.

Abduction
C5-6
Suprascapular

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List the motion, nerve root, and peripheral nerve - infraspinatus

External rotation
C5-6
Suprascapular

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List the motion, nerve root, and peripheral nerve - subscapularis

Internal rotation
C5-6
Subscapular

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List the motion, nerve root, and peripheral nerve - deltoid

Abduction
C5-6
Axillary

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List the motion, nerve root, and peripheral nerve - biceps brachii

Elbow flexion
C5-6
Musculocutaneous

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List the motion, nerve root, and peripheral nerve - wrist extensors

Wrist extension
C6
Radial

List the motion, nerve root, and peripheral nerve - wrist flexors

Wrist flexion
C7
Median

List the motion, nerve root, and peripheral nerve - finger tendons

Finger flexion C8 Median

List the motion, nerve root, and peripheral nerve - dorsal interossei

Finger abduction T1 Ulnar

Which muscles are controlled by both C5-6 nerve roots?

1. Supraspinatus 2. Infraspinatus 3. Subscapularis 4. Deltoid 5. Biceps brachii

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the axillary (C5, C6) nerve.

Cause: fractured surgical neck of humerus, dislocation of humeral head Motor deficit: arm abduction at shoulder Sensory deficit: over deltoid muscle Sign: flattened deltoid

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the radial (C5-C8) nerve.

Cause: fracture at midshaft of humerus, "Saturday night palsy" (extended compression of axilla by back of chair or crutches) Motor deficit: wrist extension, finger extension and MCP joints, supination, thumb extension and abduction Sensory deficit: posterior arm and dorsal hand and dorsal thumb Sign: wrist drop

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the median (C6-C8, T1) nerve (proximal injury).

Cause of injury: fracture of supracondylar humerus Motor deficit - proximal: opposition of thumb Sensory deficit - dorsal and palmar aspects of lateral 3 1/2 fingers, thenar eminence Sign: "ape hand"

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the median (C6-C8, T1) nerve (distal injury).

Cause of injury: carpal tunnel syndrome; dislocated lunate Motor deficit - lateral finger flexion, wrist flexion Sensory deficit - dorsal and palmar aspects of lateral 3 1/2 fingers Sign: ulnar deviation of wrist upon wrist flexion

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the ulnar (C8, T1) nerve (proximal injury).

Cause of injury: fracture of medial epicondyle of humerus Motor deficit - medial finger flexion, wrist flexion Sensory deficit - medial 1/2 fingers, hypothenar eminence Sign: radial deviation of wrist upon wrist flexion

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the ulnar (C8, T1) nerve (distal injury).

Cause of injury: fracture of hook of hamate (falling onto outstretched hand) Motor deficit - abduction and adduction of fingers (interossei), adduction fo thumb, extension of 4th and 5th fingers (lumbricals) Sensory deficit - ? Sign: ulnar claw hand and Pope's blessing when asked to straighten fingers

List the cause of injury, motor deficit, sensory deficit, and sign of injury to the musculocutaneous (C5-C7) nerve.

Cause of injury: upper trunk compression Motor deficit - flexion of arm at elbow Sensory deficit - lateral forearm

A 21 y/o man presents to the ED following an injury to his shoulder that he sustained while playing football. His shoulder appears flattened and he is not able to abduct his arm. He is found to have a fracture at the surgical neck of his humerus. The muscle that is most likely injured in this patient receives innervation from which nerve roots?

C5-6

A 60 y/o man presents to the physician with a limp that he has had since childhood. When he walks, the patient takes a step with his right leg, then leans all the way over to his right, so that he can swing his left leg to take a step. He reports one major illness as a child after which he developed this limp. Which nerves or roots is most likely injured in this patient?

Superior gluteal nerve (gluteus medius)

What causes post-polio syndrome and how does it present?

Superior gluteal nerve; Trendelenberg gait

List the cause of injury, motor deficit, and sensory deficit for the obturator nerve.

Cause: anterior hip dislocation Motor deficit: thigh adduction Sensory deficit: medial thigh

List the cause of injury, motor deficit, and sensory deficit for the femoral nerve.

Cause: pelvic fracture Motor: thigh flexion and leg extension Sensory: anterior thigh and medial leg

List the cause of injury, motor deficit, and sensory deficit for the common peroneal nerve.

Cause: trauma to lateral aspect of leg or fibula neck fracture Motor: foot eversion and dorsiflexion; toe extension Sensory: anterolateral leg and dorsal aspect of foot

List the cause of injury, motor deficit, and sensory deficit for the tibial nerve.

Cause: knee trauma Motor: foot inversion and plantarflexion, toe flexion Sensory: sole of foot

List the cause of injury, motor deficit, and sensory deficit for the superior glutial nerve.

Cause: posterior hip dislocation or polio Motor: thigh abduction (+ Trendelenberg sign)

List the cause of injury, motor deficit, and sensory deficit for the inferior gluteal nerve nerve.

Cause: posterior hip dislocation | Motor deficit: cannot jump, climb stairs, or rise from a seated position

A 32 y/o old woman who is a tennis player presents to the physician with pain on the lateral aspect of the elbow radiating down her forearm. Repetitive use of which muscles most likely lead to this patient’s condition?

Extensor carpi radialis

Where do wrist extensors insert? Where do wrist flexors insert?

Extensors insert on the lateral epicondyle Flexors insert on the medial epicondyle

What is tennis elbow?

Lateral epicondylitis

What is golfer's elbow?

Medial epicondylitis

A 15 y/o boy is brought to the ED because he has pain in his hand following a fist fight. The physician tells the patient that he has a broken hand. What is the most likely site of this patient’s fracture?

Metacarpals (usually the 4th or 5th)

How many bones are in the hand and wrist?

24 (carpals, metacarpals, phalanges)

What portion of the hand is innervated by the median nerve?

Lateral 3 1/2

What portion of the hand is innervated by the ulnar nerve?

Medial 1 1/2

What portion of the hand is innervated by the radial nerve?

Dorsolateral 3 1/2

Proximal scaphoid fracture leads to a risk of ___.

Avascular necrosis

The metacarpals tolerate up to ___ degrees of angulation.

A 20-year-old male soccer player gets kicked on the lateral side of the leg. He has some swelling, and a limp. Where will he have weakness and sensory loss? What nerve is injured?

Weakness with dorsiflexion and sensory loss on the anterolateral leg; peroneal nerve

Discuss skeletal muscle contraction.

AP depolarization opens Ca2+ channels in SR.

Discuss skeletal muscle contraction.

1. The active site on actin is exposed a Ca2+ binds troponin. 2. The myosin head forms a cross-bridge with actin. 3. During the power stroke the myosin head bends and ADP and phosphate are released. 4. A new molecule of ATP attaches to the myosin head, causing the cross-bridge to detach. 5. ATP hydrolyzes to ADP and phosphate, which returns the myosin to the cocked position.