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BLOCK 1: L1 - 3 Upper Limb Bones + Back/Shoulder Muscles

Terms in this set (89)

Name the bones of the pectoral girdle
clavicle and scapula
Which joint aids in medial and lateral rotation of the humerus?
glenohumeral
Which joint aids in extension and flexion of the humerus?
glenohumeral
Which joint aids in the adduction and abduction of the humerus?
glenohumeral
(Radial/ulnar) deviation = wrist aBduction
(Radial/ulnar) deviation = wrist aDduction
Radial
Ulnar
Which joint allows 45º extension of the digits?
MCP
Flexion of digit I in coronal plane moves it (medially/laterally)

Extension of digit I in coronal plane moves it (medially/laterally)
medially

laterally
ADduction of digit I in sagittal plane moves it (anteriorly/posteriorly)

ABduction of digit I in sagittal plane moves it (anteriorly/posteriorly)
posteriorly

anteriorly
Out of the two joints on the clavicle, which is positioned medially?

Which is positioned laterally?
sterno-clavicular joint

acromio-clavicular joint
What is the most commonly fractured bone?
Which part of the bones is the most vulnerable to breaks?
clavicle
middle 1/3 (80%)
What is the function of the clavicle?
• acts as strut
• keeps upper limb lateral
How can the medial/lateral and superior/inferior ends of a clavicle be distinguished?
medial: round cross-section (sternal)
lateral: flat cross-section (acromial)

superior: smooth
inferior: ridge, groove
Which bones are often abnormal in individuals with craniofacial growth abnormalities (dysostosis)?
Why?
clavicles
• only post-cranial bone to form via intramembranous ossification (like cranial bones)
The humerus articulates with which part of the scapula?
glenoid fossa
The coracoid process of the scapula projects (anteriorly/posteriorly).

The acromion process of the scapula projects (anteriorly/posteriorly).
anteriorly

posteriorly
Describe the function of the sternoclavicular joint
• Between manubrium & clavicle
• Saddle joint
• Movement of clavicle in all 3 planes (elevation/depression, re/protraction, posterior rotation)
Name the scapulo-clavicular ligaments

What is their function?
• Coracoclavicular Ligaments (2)
• Coracoacromial Ligament
• Acromioclavicular Ligament

Stabilize AC joint
During a game, a football player gets sacked, flips over, and lands directly on the point of their shoulder. Which ligament of the arm is likely affected?

How is this often presented in patients with this injury?
scapulo-clavicular

"step deformity"
Which part of the humerus articulates with the radius?
Which part articulates with the ulna?
capitulum
trochlea
Glenohumeral joint can be described as a multi-axial ____________ joint

What is the function of the glenoid labrum?
ball & socket

Fibrocartilage rim that functionally deepens glenoid fossa
A softball player comes into the ER complaining of shoulder pain when they go up to pitch. You suspect they have a SLAP tear. The tendon of which muscle is likely affected?
biceps brachii
• twisting tendon puts tension on glenoid labrum
"Dislocated shoulder" results from displacement of humeral head from ________________

In 95% of shoulder dislocations the humeral head is dislocated (anteriorly/posteriorly).
glenoid fossa

anteriorly
What complications are associated with a dislocated shoulder?

Describe how a patient would present with this injury.
• Nerve damage (mostly axillary)
• Hill-Sachs Lesion - bony surface of posterior humerus digs into glenoid rim; divot gets caught and stuck

square" shoulder presentation with inferiorly displaced arm and minimal deltoid contour
Shoulder bursitis is usually from the _______________ bursa.
How does this develop?
subacromial

• Direct pressure of humerus on acromion process (leaning elbow on table drives humerus superiorly)
• Overhead movement of humerus impinges bursa in subacromial space
The interosseus membrane can be found between which two bones of the upper limb?
radius and ulna; holds them together
Which joints are involved in pronation of the forearm?
Humeroradial joint,
Radioulnar joints (Proximal & Distal)

*radius moves over ulna; ulna is stationary
Describe the action of the humeroulnar joint

Describe the action of the humeroradial joint

Proximal Radioulnar Joint
flexion/extension (hinge)

flexion/extension and pronation/supination (hinge)

pronation/supination (pivot)
What is the function of the annular ligament in the elbow?
Maintains articulation of radius and ulna
Which elbow ligament limits aDduction?
Which elbow ligament limits aBduction?
radial collateral
ulnar collateral
How does Nursemaid's elbow occur?
How is it presented?
• rapid pull on pronated arm
• radial head slips out of annular ligament

• limited limb motion, forearm usually held in flexed-prone position (pain upon supination)
Name the three bursae supporting the triceps brachii muscle and tendon at the elbow

Elbow bursitis is typically due to direct pressure on which bursa from resting elbow on hard surface?
• Subtendinous bursa
• Intratendinous bursa
• Olecranon bursa

olecranon
Describe a Colle's fracture
• Fracture during wrist extension
• Fall On Out-Stretched Hand "FOOSH"
• Dorsal displacement of distal radius
"Dinner fork" deformity
Describe a Smith's fracture
• Fracture during wrist flexion
• "Reverse Colle's" Fracture
• Palmar displacement of distal radius
"Garden spade" deformity
What complications are associated with someone who has suffered a Colle's fracture?
Compartment syndrome, nerve damage (carpal tunnel)
Name the carpals in the distal row (medial to lateral)

Name the carpals in the proximal row (medial to lateral)
trapezium, trapezoid, capitate, hamate

scaphoid, lunate, triquetrum, pisiform
Movement of the radiocarpal joint involves which 3 proximal carpals?

Movement of the ulnocarpal joint involves which 3 proximal carpals?
scaphoid, lunate, triquetrum

scaphoid, lunate, triquetrum
What makes the CMC joint of digit 1 the most moveable?
• Saddle joint (2 axis)
• Flexion/Extension
• ADduction/ABduction
A man walked into the ER complaining of pain in his hand. He recently got into a fight at a bar and admitted to throwing a few punches. Which bone of this hand is most likely broken?
5th metacarpal (pinky)
• Boxer's fracture
The metacarpophalangeal (MCP) joint is a ________ joint that allows in which types of movement?
condyloid
• Flexion/Extension
• ADduction/Abduction
• Rotation (minimal)
What allows increased biomechanical efficiency of the pollex musculature?
sesamoid
The ulnar sesamoid allows forceful flexion of which muscle in the hand?
The radial sesamoid allows forceful flexion of which muscle in the hand?
Adductor Pollicis

Abductor pollicis brevis
Flexor pollicis brevis
What is the function of the extrinsic (superficial) muscles of the back?

What is the function of the intermediate layer of back muscles?

What is the function of the intrinsic muscles of the back?
move upper extremity

respiratory

move trunk and back
Name the extrinsic (superficial) muscles of the back acting on the pectoral girdle
• Trapezius
• Levator Scapulae
• Rhomboid Major
• Rhomboid Minor
Name the extrinsic (superficial) muscle(s) of the back acting on the arm
Latissimus dorsi
Trapezius - Attachments
Midline from occipital to spinous process of T12 vertebrae
• Lateral 1/3 clavicle, spine of scapula
Trapezius - Actions:
• Upper portion
• Middle portion
• Lower portion
• Upper portion: elevate & upward rotate scapula
• Middle portion: retract scapula
• Lower portion: depress & downward rotate scapula
Trapezius - Innervation
accessory nerve (CN XI)
Trapezius - Blood supply
branches of thyrocervical trunk
Levator Scapulae - Attachments
• Transerverse processes of C1-C4 vertebrae
• Superior angle of scapula
Rhomboid Minor - Attachments
• Spinous processes of C7-T1 vertebrae*
• Medial border of scapula
* variable
Rhomboid Major - Attachments
• spinous processes T2-T5*
• medial scapular border from level of spine to inferior angle
*variable
Levator scapulae, Rhomboid minor, and Rhomboid major - Actions
elevate & retract scapula
Levator scapulae, Rhomboid minor, and Rhomboid major - Innervation
Dorsal scapular nerve
Levator scapulae, Rhomboid minor, and Rhomboid major - Blood supply
Dorsal scapular artery (from Thyrocervical Trunk)
Latissimus dorsi - Attachments
• Spinous processes of T7-12 vertebrae, Thoracolumbar fascia, and iliac crest
• ANTERIOR shaft of humerus
Latissimus dorsi - Actions
ADducts, extends, and medially rotates arm
Latissimus dorsi - Innervation
Thoracodorsal nerve
Latissimus dorsi - Blood supply
Thoracodorsal artery
Which three muscles make up the boundaries that form the Triangle of Auscultation?
• Inferior - Latissimus Dorsi
• Superior - Trapezius
• Lateral - Rhomboid major
The Triangle of Auscultation overlies the __________ __________ space making it a good place for assessing respiratory sounds with stethoscope.
6th intercostal
Which joint do the intrinsic muscles of the shoulder act on?
glenohumeral
Name the intrinsic muscles of the shoulder
• Supraspinatus
• Infraspinatus
• Teres minor
• Subscapularis
• Teres major
• Deltoid
Name the rotator cuff muscles
• Supraspinatus
• Infraspinatus
• Teres minor
• Subscapularis
(SITS)
Supraspinatus:
- Attachments
- Action
- Innervation
- Blood supply
• Scapula: Supraspinous fossa
• Humerus: Greater turbercle
- Abduction of arm (1st 15°)
- Suprascapular n.
- Suprascapular a.
Infraspinatus:
- Attachments
- Action
- Innervation
- Blood supply
• Scapula: Infraspinous fossa
• Humerus: Greater turbercle
- Lateral rotation of arm
- Suprascapular n.
- Suprascapular & Circumflex scapular a.
Teres Minor:
- Attachments
- Action
- Innervation
- Blood supply
• Scapula: Lateral border
• Humerus: Greater turbercle
- Lateral rotation of arm
- Axillary n.
- Circumflex scapular & Posterior Circumflex humeral a.
Subscapularis:
- Attachments
- Action
- Innervation
- Blood supply
• Scapula: Subscapular fossa
• Humerus: LESSER turbercle
- Medial rotation of arm
- Upper and Lower Subscapular n.
- Subscapular a.
Rotator cuff tears usually affect which tendon of the arm?
supraspinatus
Teres major:
- Attachments
- Action
- Innervation
- Blood supply
• Scapula: Inferior angle
• Humerus: anterior humeral shaft
- Medial rotation of arm
- Lower subscapular n.
- Circumflex scapular & subscapular aa.
Teres Major is a synergist of which muscle, which both act to medially rotate arm?
latissimus dorsi
Teres Minor is a synergist of which muscle, which both act to laterally rotate arm?
Infraspinatus
The deltoid attaches to which 3 bones?
• Scapula: spine and acromion
• Clavicle: lateral 1/3
• Humerus: deltoid tuberosity
Deltoid - Action:
• Anterior part
• Middle part
• Posterior part
• Clavicular part: flexes + medially rotates arm
• Acromial part: abducts arm (15-90°)
• Spinal part: extends & laterally rotates arm
Deltoid -
• Innervation
• Blood supply
• Axillary n
• Thoracoacromial a.; Ant. & posterior humeral circumflex aa.
Which muscle is responsible for the first 15% of humeral abduction?
Which muscle is responsible for the next 90º of abduction?
Which muscle is responsible for 60º rotation of the scapula?
• supraspinatus
• deltoid
• trapezius and serratus anterior
Arm abduction follows a scapulohumeral rhythm in which muscle actions are coordinated. What is the ratio associated with this movement?
1:2 scapular/humeral ratio
The Drop Arm Test is used to test function of which muscle?
supraspinatus
Name the anterior axio-appendicular muscles
• Pectoralis Major
• Pectoralis Minor
• Subclavius
• Serratus Anterior
Pectoralis Major - Attachments
• Medial clavicle, sternum, & costal cartilages
• Crest of greater tubercle (anterior humerus)
Pectoralis Major - Actions:
• Clavicular portion
• Sternocostal portion
Adduct and medially rotate arm
• Clavicular: flex arm (from extended position)
• Sternocostal: extend arm (from flexed position)
Pectoralis Major -
• Innervation
• Blood supply
Lateral pectoral n. AND Medial pectoral n.

Thoracoacromial Trunk (Pectoral branch)
Clavicular fractures often result in a "kick-stand" deformity.
Which muscle pulls the medial fragment superiorly?
What pulls the lateral fragment inferiorly?
What pulls the arm and lateral fragment medially?
• sternocleidomastoid m.
• weight of arm
• pectoralis major
Pectoralis major - Attachments
• Ribs 3-5
• Coracoid process of scapula
Pectoralis major - Actions
• Protracts scapula
• Downward rotation of scapula - rotates glenoid fossa inferiorly
Pectoralis major -
• Innervation
• Blood supply
Medial pectoral n.
Thoracoacromial Trunk (Pectoral branch)
Subclavius -
• Attachments
• Action
• Innervation
• Blood supply
• Rib 1 and Clavicle
• Stabilize clavicle
• N. to subclavius
• Thoracoacromial Trunk (clavicular branch)
Serratus Anterior -
• Attachment
• Actions
• Ribs 1-9
• Medial border of scapula

• protract & stabilize scapula on trunk
• depression of scapula
• upward rotation of scapula - rotates glenoid fossa superiorly
Serratus Anterior -
• Innervation
• Blood supply
• Long thoracic nerve
• Lateral thoracic a. & Thoracodorsal a.
Winged scapula is the inability to protract ______________ using the __________ muscle.
It results from damage to the muscle or the ______________ nerve.
medial scapula, Serratus anterior
long thoracic
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