The arm Flashcards
Distal end of humerus
- medial epicondyles
- lateral epicondyles
- supracondylar ridges
- capitulum
- trochlea
- radial fossa
- coronoid fossa
- olecranon fossa
what is an epicondyle?
a rounded protuberance at the end of a bone serving as a place of attachment for ligaments/tendons/muscles
medial and lateral epicondyles
bony protrusion palpable at medial and lateral sides of elbow
capitulum
articulates with radius of forearm
trochlea
articulates with ulna of forearm
radial fossa
superior to capitulum on anterior surface
coronoid fossa
superior to trochlea, adjacent to radial fossa
Olecranon fossa
posterior surface, superior to trochlea
radius and ulna location
radius is lateral to ulna
Bony landmarks of anterior radius
- head of radius
- neck
- radial tuberosity
- lateral styloid process
- ulnar notch
bony landmark of posterior radius
- head of radius
- neck
- lateral styloid process
- ulnar notch
bony landmarks of anterior ulna
- trochlear notch of ulna
- coronoid process
- radial notch of ulna
- ulnar tuberosity
- medial styloid process
- head
bony landmarks of posterior ulna
- olecranon
- styloid process
Names of septum divisions in arm
- lateral intermuscular septum
- medial intermuscular septum
Anterior compartment of arm
Contains muscles that predominantly flex the elbow
Posterior compartment
contains muscles that predominantly extend the elbow
Muscles in the anterior compartment of the arm
- Biceps brachii
- brachialis
- coracobrachialis
Muscles in the posterior compartment of arm
triceps brachii
Biceps brachii origin
short head:
- apex of coracoid process of scapula
long head:
- supraglenoid tubercle of scapula
Biceps brachii insertion
radial tuberosity and bicipital aponeurosis
Biceps brachii innervation
musculocutaneous nerve
biceps brachii action
- flexor of forearm at elbow joint
- powerful supinator of the forearm when elbow joint is flexed
- also flex glenohumeral joint as the 2 heads of the muscle cross the joint
Popeye deformity
- characteristic deformity following rupture of the tendon of biceps brachii
- on elbow flexion, a prominent bulge of the muscle belly is seen as unrestrained fibres contract
Biceps reflex
a tap on the tendon of the biceps brachii at the elbow is used to test the integrity of musculocutaneous nerve C5/6
Brachialis origin
distal half of anterior surface of humerus
brachialis insertion
coronoid process and ulnar tuberosity
brachialis innervation
musculocutaneous nerve. a small component of the lateral part is innervated by radial nerve
brachialis action
flexes forearm at elbow joint
coracobrachialis origin
tip of coracoid process
coracobrachialis insertion
middle 1/3 medial surface of humerus
coracobrachialis innervation
musculocutaneous nerve
coracobrachialis action
flexion and adduction of arm
triceps brachii origin
long head:
- Infraglenoid tubercle
lateral head:
- posterior surface of humerus superior to radial groove
medial head:
- posterior surface of humerus inferior to radial groove
The 3 heads converge to form a large tendon
triceps brachii insertion
superior surface of olecranon of ulna, fascia of forearm
triceps brachii innervation
radial nerve
Triceps brachii action
extends forearm
Anconeus what is it?
small, triangular muscle on the posterolateral aspect of the elbow
Anconeus origin
lateral epicondyle of humerus
anconeus insertion
lateral side of olecranon and upper 1/4 of posterior surface ulna
anconeus innervation
radial nerve
anconeus action
assists triceps extend the forearm
tenses the capsule of elbow joint, preventing pinching during extension
