714 - Exam 4 Review

What are the attachment sites of the articular disc at the sternoclavicular joint? 

superior → clavicle

inferior → manubrium, cartilage of 1st rib, joint capsule

Explain the arthrokinematics at the sternoclavicular joint during elevation-depression and protraction-retraction including the plane and axis of motion for each. 

frontal plane, A-P axis, convex medial clavicle on concave stationary disc

elevation

• superior roll

• inferior glide

depression

• inferior roll

• superior glide

transverse plane, S-I axis, concave clavicle on convex sternum & 1st rib

protraction

• anterior roll

• anterior slide

retraction

• posterior roll

• posterior slide

 

Explain the relationship between ACJ morphology and rotator cuff pathology. 

shape and position of acromion changes positioning of clavicle

• hooked (type III) acromion more shoulder dysfunction

What are the two coracoclavicular ligaments? Where is each located and what motions does each restrain? 

A-P or M-L = trapezoid 

S-I = conoid 

What is the role of the coracoclavicular ligaments in scapular mechanics?

clavicle rotation & scapular upward rotation during elevation

What are the component motions of protraction and retraction of the scapula? 

protraction → scap ABD + IR

retraction → scap ADD + ER

What is the normal resting position of the scapula?

superior angle at T1

inferior angle at T7

root of spine at T3

2-3 inches from SP

5-10 slight upward rotation

30-45 IR

10-15 anterior tilt

What muscles are short/stiff and long/weak for the following scapular dysfunction:  Scapular depression/insufficient elevation

short/stiff = pec minor, pec major, lats, lower trap, serratus

long/weak = upper trap, levator

What muscles are short/stiff and long/weak for the following scapular dysfunction: Scapular downward rotation/insufficient upward rotation

short/stiff = rhomboids, levator, pec minor, pec major, lats

long/weak = upper trap, lower trap, serratus

What muscles are short/stiff and long/weak for the following scapular dysfunction: Scapular internal rotation/insufficient external rotation

short/stiff = pec minor, pec major, lats, posterior cuff (deltoid, teres major, etc.)

long/weak = serratus, middle trap, subscap

What muscles are short/stiff and long/weak for the following scapular dysfunction: Scapular anterior tilt/insufficient posterior tilt

short/stiff = maybe biceps, pec minor, coracobrachialis

long/weak = serratus, lower trap

What is the clinical presentation of increased retroversion of the humerus?  

normal retroversion = 20-30°

• arm sits in ER to align humeral head in glenoid

  • antecubital fossa is oriented more laterally

• ↑ ER

• ↓ IR

What is the most common direction of instability for the glenohumeral joint? Why? 

anterior

• less articular congruence anteriorly than posteriorly

• anterior structures are most challenged with lots of daily motions (overhead, ER, etc.)

  • most likely to be injured

• no muscular attachment anteriorly

What is the role of the rotator cuff? Please elaborate as much as possible. 

dynamic stabilization

• compress humeral head in glenoid fossa

proprioception

coordinates scapulohumeral rhythm, rotates shoulder

What is the capsular pattern of the glenohumeral joint?  

loss of motion in multiple planes

• ER most limited

In what position is each of the following ligaments taut and able to serve as a primary restraint to motion at the glenohumeral joint?

• Superior GH ligament

• Middle GH ligament

• Inferior GH ligament

superior

• taut w/ arm in neutral

• resists anterior and inferior motion

middle

• taut w/ arm at 0-60°

• resists anterior motion

inferior

• taut w/ arm at 45-90°

  • anterior in ER (resists anterior motion)

  • posterior in IR (resists posterior motion

What structure is most vulnerable to stresses in the subacromial space?  

supraspinatus tendon

List the factors that can contribute to a decrease in the subacromial space.  

shape of acromion

bone spurs

osteophytes

↑ size of coracoacromial ligament

↑ size of humeral head

abnormal scapulohumeral rhythm

abnormal humeral positioning

Explain the arthrokinematic motions that occur during shoulder flexion, abduction, and external rotation. 

flexion

• anterior/superior spin

• posterior/inferior glide

ABD

• superior spin

• inferior glide

ER

• posterior spin

• anterior glide

What motions are required at the sternoclavicular joint and scapulothoracic joint for end-range shoulder elevation? 

SCJ → posterior rotation

STJ → upward rotation, posterior tilt, ER

Describe the force couple between the trapezius and serratus anterior during shoulder elevation. What motions does each portion of the trapezius and the serratus anterior produce and control? 

• serratus is a depressor, upper trap offsets with elevation 

• serratus protracts, middle trap offsets with adduction 

Describe the force couple between the rotator cuff and the deltoid during shoulder elevation. What motions does each of the rotator cuff muscles and the deltoid produce and control? 

• with arm at side, deltoid just drives humeral head straight up, not a good rotary moment arm

• all 4 SITS lock in humeral head in glenoid socket so deltoid can rotate more efficiently

What muscles are innervated by the suprascapular nerve? What is the clinical presentation for a patient with a suprascapular nerve injury? 

supra & infra

• atrophy

• RTC strength

• shoulder pain

What articulations are a part of the elbow and share a joint capsule? 

humeroulnar

humeroradial

PRUJ

What is the primary restraint to valgus force at the elbow? What osseous structures help provide additional restraint to valgus force? What muscle is most important for supporting against valgus force? 

1° → medial (UCL) collateral ligament (anterior bundle)

osseous → coronoid process

muscle → FCU

What is the role of the annular ligament? What is a unique aspect of the annular ligament to help with this role? 

keep radial head in radial notch

lined w/ articular cartilage

What is the normal carrying angle at the elbow? 

8-15°

Explain the arthrokinematics that occur at the proximal and distal radioulnar joints during forearm pronation and supination. 

PRUJ → convex on concave

supination

• posterior roll

• anterior glide

pronation

• anterior roll

• posterior glide

DRUJ → concave on convex

supination

• anterior roll

• anterior glide

pronation

• posterior roll

• posterior glide

Which structures of the distal radioulnar joint are taut at end-range forearm pronation? 

dorsal radioulnar ligament

↑ tension inf TFCC

What are the positions of active and passive insufficiency of the biceps brachii? 

passive

• pronation, elbow extension, shoulder extension

active

• pronation, elbow extension, shoulder extension

• supination, elbow flexion, shoulder flexion

Which muscles are innervated by the axillary nerve? 

deltoid

teres minor

List three entrapment sites of the median nerve.

ligament of struthers

bicipital aponeurosis

pronator teres

FDS & FDP

carpal tunnel

What is the clinical presentation of entrapment of the anterior interosseous nerve (AIN)? 

no sensory loss

pure motor symptoms

• FDP, FPL, pronator quadratus

List three entrapment sites of the ulnar nerve. 

arcade of struthers

cubital tunnel

FCU

Guyon’s canal

What is the triangular fibrocartilage complex or “TFCC”? Explain the innervation and vascularization of this structure. 

TFCC → structure at end of ulna

contains free nerve endings

central portion is avascular

What is positive and negative ulnar variance? How does the thickness of the TFCC vary between positive and negative ulnar variance? What structures at the radiocarpal joint are under increased stress with negative ulnar variance? Positive ulnar variance? 

positive → relatively longer ulna 

• thinner TFCC bc more compression & less space 

• more stress on TFCC/ulnar side 

negative →

• radial side has more axial load 

What are the bones of the proximal and distal carpal rows? 

proximal → scaphoid, lunate, triquetrum, pisiform

distal → hamate, capitate, trapezoid, trapezium

Which bones in the proximal carpal row undergo increased compressive forces during axial loading? What is the clinical relevance of this information? 

scaphoid & lunate

potential for DISI & VISI

Explain the difference between the extrinsic and intrinsic ligaments of the wrist. 

extrinsic

• carpals to radius, ulna, mets

• more likely to fail

• better healing potential (have blood flow)

intrinsic

• b/w carpals

• rely on synovial fluid for nutrition

Where is the carpal tunnel located? What structures pass through the carpal tunnel?

made by carpals & transverse carpal ligament

structures

• median nerve

• FPL tendon

• 4 FDS tendons

• 4 FDP tendons

List which tendons pass through each of the six extensor tunnels of the wrist. 

1 → APL & EPB

2 → ECRL & ECRB

3 → EPL

4 → ED & EI

5 → EDM

6 → ECU

Describe the arthrokinematics motions that occur during flexion-extension and radial-ulnar deviation at the radiocarpal joint. 

(all convex on concave)

flexion

• palmar roll

• dorsal slide

extension

• dorsal roll

• palmar glide

radial deviation

• radial roll

• ulnar glide

ulnar deviation

• ulnar roll

• radial glide

Describe dorsal intercalated segmental instability (DISI) and volar intercalated segmental instability (VISI) including which ligament is disrupted and the motion that is occurring at the scaphoid, lunate, and triquetrum for each. 

DISI

• scapholunate ligament

• scaphoid → flexes

• lunate → extends

• triquetrum → extends

VISI

• lunotriquetral ligament

• scaphoid → flexes

• lunate → flexes

• triquetrum → extends

Explain the relationship between the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) both anatomically and functionally. 

FDP → active w/ gentle motions

FDS → active w/ greater forces

What are the positions of active and passive insufficiency for the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS)? 

passive 

• elbow extended, wrist extended, fingers extended, supinated 

active 

• elbow extended, wrist extended, fingers extended, supinated 

• elbow flexion, wrist flexion, finger flexion, supination 

Describe the finger flexion mechanisms including all structures that facilitate gliding of the finger flexor tendons and stabilize the finger flexor tendons to prevent bowstringing. 

Annular pulleys (5)

Cruciate pulleys (3)

Synovial sheaths around tendons

Campers chias mallows FDP to extend more distally

Describe the relationship between the extensor digitorum communis and the lumbricals and interossei in relation to finger extension mechanisms. Please include a description of intrinsic plus and intrinsic minus and how it relates to each muscle. 

Extrinsic muscles can only extend MCP

PIP & DIP need intrinsic muscles to extend

• interossei & lumbricals

Intrinsic (+) → MCP flexion, IP extension

Intrinsic (-) → just MCP extension

Describe the “extensor expansion” or “extensor hood” and the extensor mechanism of the hand. 

What is the convex-concave relationship between the trapezium and the base of the 1^st metacarpal? Based on this relationship, what are the arthokinematic motions at the 1^st carpometacarpal joint during flexion-extension and abduction-adduction of the thumb? 

• flexion/extension - concave met, convex trapezium 

• abd/add - convex met, concave trapezium 

Explain the pathology of Ape Hand. What nerve is involved and why does it present in that pattern? 

What is the clinical presentation of median nerve entrapment at the carpal tunnel?