LM 4.1: Upper Extremity Osteology Flashcards

1
Q

what is the shoulder girdle comprised of?

A
  1. clavicle
  2. scapula
  3. manubrium of the sternum
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2
Q

what is the function of the clavicle?

A

it serves as a strut to keep the limb away from the body wall and allows a free range of motion of the arm

it is the only bony connection between the upper limb and the axial skeleton and importantly transmits forces from the upper limb to the axial skeleton

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3
Q

what movements can the clavicle make?

A
  1. elevation
  2. depression
  3. anterior and posterior rotation
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4
Q

what is the weakest point of the clavicle?

A

the infection point

it’s the change in curvature between the medial 2/3rds and the lateral 1/3rd of the clavicle

the inflection point is the location where the clavicle cannot flex to absorb a load and resulting in a place where fractures are likely to occur

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5
Q

the clavicle is a landmark for the insertion of what?

A

most anterior portion of the clavicle is a major palpatory landmark for insertion of a catheter into the subclavian vein (venous access)

at this palpable point the subclavian vein (s.c.v.) sits posterior and superior to the bone and is running in a direction to hit the sternal notch, a feature of the manubrium

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6
Q

where is the scapula located?

A

the scapula rests at a position on the posterior thorax approximately 2 inches from the midline, between the second through seventh ribs

the scapula articulates with Acromioclavicular (AC) and Sternoclavicular (SC) joints and ALSO a scapulothoracic “joint” which is not a true anatomic joint

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7
Q

what is the anatomy of the ventral surface of the scapula?

A

a broad concavity called the subscapular fossa

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8
Q

what is the glenoid cavity?

A

a shallow articular surface of the scapula that articulates with the head of the humerus

it’s the hole in the scapula that the humerus fits into

the cavity forms the glenohumeral joint (shoulder joint)

the rim of the cavity is slightly raised to give attachment to a fibrocartilaginous structure called the glenoid labrum which deepens the cavity for added joint stability of the glenohumeral joint

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9
Q

what is the acromium process?

A

the continuation of the scapular spine where it articulates with the clavicle to form the acromiclavicular joint (AC joint)

the process forms the “point of the shoulder”

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10
Q

what is the supraglenoid tubercle?

A

a region of the scapula from which the long head of the biceps brachii muscle attaches

it is a small, rough projection superior to the glenoid cavity near the base of the coracoid process

inflammation of the tendon of the long head of the biceps brachii originates at the supraglenoid tubercle in about 30% of cases

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11
Q

what is tendinitis?

A

inflammation of a tendon, often developing after degeneration (tendinopathy)

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12
Q

what is tenosynovitis?

A

tendinitis with inflammation of the tendon sheath lining

symptoms usually include pain with motion and tenderness with palpation.

chronic deterioration or inflammation of the tendon or tendon sheath can cause scars that restrict motion

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13
Q

what is the infraglenoid tubercle?

A

the region of the scapula from which the long head of the triceps brachii attaches

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14
Q

what is the largest bone in the upper extremity?

A

humerus

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15
Q

what does the humerus articulate with?

A

at the proximal end, the head of the humerus articulates with the glenoid cavity of the scapula to form the glenohumeral joint

the humeral head 3X larger than the glenoid cavity so the major reinforcement to help stabilize this joint is the glenoid labrum, which deepens the socket for added stability

at the distal end, the humerus articulate with the radius and ulna to form the elbow joint

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16
Q

what’s the difference between the anatomical and surgical neck of the humerus?

A

the anatomical neck is between the head and greater/lesser tubercles and is a line of attachment for the glenohumeral (shoulder) joint capsule

the surgical neck is a common fracture site and is found distal to the greater and lesser tubercles

17
Q

which tuberosities are on the shaft of the humerus?

A
  1. deltoid tuberosity = attachment site for the deltoid muscle
  2. radial groove = on the posterior side of the humerus is an oblique radial groove that contains the radial nerve and deep brachial artery
18
Q

what are the names of the condyles of the humerus?

A

the capitulum articulates with the head of the radius

the trochlea articulates with the trochlear notch of the ulna

19
Q

what are the articulations points of the ulna?

A

3 bony articulations

two with the radius = a proximal and distal radioulnar joint

one with the trochlea of the humerus

the ulna DOES NOT articulate with the carpal bones

20
Q

does the ulna move?

A

the ulna is the STABLE bone of the forearm and DOES NOT move during supination and pronation motions

21
Q

which part of the ulna is palpable?

A

stylus process

22
Q

what are the functions of the radius?

A
  1. main function is to carry out pronation/supination and flexion/extention
  2. it receives and transmits stress from the hand through the wrist to the ulna via the interosseous membrane
23
Q

what does the radius articulate with?

A
  1. ulna
  2. the proximal row of carpal bones
  3. humerus
24
Q

which muscles are used for pronation?

A

the pronator teres and pronator quadratus

these two muscles work together to achieve pronation by pulling on the radius bone

the radius is designed to rotate at the proximal and distal radioulnar joint

25
Q

which bones are the the proximal row of carpal bones?

A

lateral to medial = scaphoid, lunate, triquetrum and the pisiform

the proximal row will articulate with the radius

26
Q

which bones are the the distal row of carpal bones?

A

lateral to medial = trapezium, trapezoid, capitate, hamate

the proximal row will articulate with the radius

27
Q

what is the carpal tunnel?

A

a volume of space that accommodates 9 flexor tendons and the median nerve on there path to enter the hand

28
Q

what is the target bone in the proximal row of carpal bones?

A

scaphoid

it sits on the radial side of the lunate

29
Q

what happens when the scaphoid is fractured?

A

scaphoid fractures may be radiologically occult in the acute setting and may result in avascular necrosis

avascular necrosis can happen because the scaphoid is made of a proximal, distal and neck region but the arterial supply is ONLY to the distal portion so nutrients can only reach the proximal portion via diffusion across the neck of the bone

a consequence of this anatomy is that the proximal fragment following a neck fracture (20% of the cases) receives no blood supply, and therefore has a high probability of undergoing the process of necrosis

30
Q

what is the orientation of the base vs. the head of a metacarpal?

A

the base is proximal and the head is distal

31
Q

what are the different regions of a phalange?

A

the phalanges with the exception of the thumb each have a proximal, middle and distal phalanx.