The arm and the forearm Flashcards
Four main segments of the upper limb
shoulder
arm
forearm
hand
Where is the clavipectoral region
what is the cubital region
anterior to the elbow
What is the main difference between the upper and lower limb
Stability of the lower limbs versus mobility of the upper limbs
- The iliac bones are anatomically connected posteriorly (at the sacroiliac joint); as a result, movement of one lower limb affects movement of the other lower limb
*The scapulae are not connected posteriorly, such that the upper limbs can move relatively
independently
*In addition, although both are ball and socket joints, the hip has a much deeper bony
articulation than the glenohumeral joint
Function of the clavicle
- acts as a mobile strut keeps the upper limb away from the thorax to improve range of motion
- attaches the upper limb to the trunk
can you tell the difference between the ends and surfaces of the clavicle?
conoid tubercle and trapezoid line are on the under side toward the acromial end
allow for attachment of the respective named ligaments
the inferior surface is rough whereas the top can be described as smooth
Clavicular fracture types
what ligaments can be affected
what may be required?
displaced (unaligned fragment from main bone) and non displaced (broken bone but still aligned with main bone)
coracoclavicular ligament (trapezoid and conoid)
surgical stabilization and perhaps ligament fixing
Where does the humerus tend to break?
surgical neck
What fascia surround the structures of the upper arm and forearm?
brachial fascia: proximal to elbow
antebrachial fascia: distal to elbow
what divides the space inside the brachial fascia into anterior and posterior components
intermuscular septa and the humerus
what divides the space inside the antebrachial fascia into anterior and posterior components
interosseous membrane and radius and ulna
what does the antebrachial fascia divide into
palmar carpal ligament, flexor retinaculum, extensor retinaculum
both retinaculum are important for flexion and extension of hand and digits at the wrist and the interphalangeal and metacarpal joints
Describe the layers of the arm proximal to the elbow, distal to the elbow, and at the wrist
see slide
what is the importance of the transverse carpal ligament/ flexor retinaculum
forms the roof of the carpal tunnel
Describe the contents of the carpal tunnel
flexor retinaculum/transverse carpal ligament
- contains 9 tendons and the median nerve
- 4 flexor digitorum profundus
- 4 flexor digitorum superficialis
- 1 flexor pollicis longus
- median nerve
Mnemonic: my (median) fingers (FDP) funny (FDS) for (FPL) many (median) nights (9 tendons total)
What muscles flex the forearm
biceps brachii (short and long head)
brachialis
brachioradialis
pronator teres (not main action)
palmaris longus
Muscle: Biceps brachii
* origin
* insertion
* action
* innervation
origin:
Long head: Supraglenoid tubercle of the scapula
Short head: coracoid
process of scapula
insertion: Radial tuberosity + bicipital aponeurosis
action:
Both heads: Flexion of forearm, supination of forearm
Long head: Flexion of arm
(weakly)
innervation: musculocutaneous nerve
Muscle: brachialis
* origin
* insertion
* action
* innervation
origin: body of humerus
insertion: ulnar tuberosity
action: flexion of forearm
innervation: musculocutaneous nerve and radial nerve
most powerful forearm flexor; loses power in supination
Muscle: triceps brachii
* origin
* insertion
* action
* innervation
origin:
* Long head: infraglenoid tubercle of scapula
* Lateral head: Body of the humerus, superior to the radial groove
* Medial head: Body of the humerus, inferior to the radial groove
insertion: Posterior olecranon process of the ulna
action:
All heads: Extension of forearm
Long head: Extension of arm; adduction of arm
innervation: radial nerve
Muscle: Pronator teres
* origin
* insertion
* action
* innervation
origin: medial epicondyle of the humerus
insertion: lateral surface of the radius
action: pronation and flexion of forearm
innervation: median nerve