Lecture 6: The Arm and the cubital fossa Flashcards
what nerve innervates the deltoid?
axillary n
what is the origin and the insertion of the deltoid?
O- anatomical horseshoe
I-Deltoid tuberosity
what is the main action of the middle deltoid fibers?
abducts arm
What are the main actions of the anterior deltoid fibers?
flex shoulder/humerus
internally rotate arm
abduct/adduct arm with posterior fibers( depending on shoulder position)
what is the function of the posterior deltoid fibers?
-extend shoulder
-externally rotate the arm
-abduct/adduct arm( depending on shoulder position)
where does teres major muscle originate and insert?
O-inferior angle and lateral border of scapula(posteriorly)
I- medial lip of intertubercular groove
what nerve innervates teres major?
lower subscapular nerve
(Teres major is located below scapula= lower subscapular)
what are the actions of teres major?
internal rotation of the arm
adducts shoulder
what are the 3 heads of triceps brachii?
long, lateral, and medial
what are the origins and insertions of the triceps brachii heads?
long head:
“O”-infra glenoid tubercle
Lateral and medial heads:
“O”-Back of humerus
“I” for all 3: olecranon of ulna
what nerve innervates the triceps brachii?
radial nerve
what is the common group of muscles that radial nerve supplies?
extensor compartment of the arm
what is the blood vessel that supplies tricep brachii?
branches of profunda brachii artery
what nerve and artery pass through the quadrangular space?
axillary n
the posterior humeral circumflex artery
what nerve and artery pass through the triangular space?
a branch of circumflex scapular artery
where do the radial nerve and the profunda brachii emerge ?
from behind the triangular interval
what is the origin and insertion of brachialis?
O- anterior humerus and intermuscular septa
I-ulnar tuberosity
what nerve innervates the flexor compartment of the ARM?
musculocutaneous(anterior)
what nerve innervates the extensor compartment of the ARM?
radial( posterior)
on what epicondyle does the common flexor tendon of the forearm attach?
medial epicondyle. Muscles go to the anterior flexor compartent
on what epicondyle does the common extensor tendon of the forearm attach?
lateral. Muscles travel to the posterior extensor comp. of the forearm
which muscle does not share the common tendon but belongs to the anterior/ flexor compartment of the forearm?
pronator teres
‘O’ and ‘I’ of long and short heads of biceps brachii
‘O’ long head: supraglenoid tubercle
‘O’ short head: coracoid
‘I’: radial tuberosity and bicipital aponeuroses(blends with deep fascia of the forearm)
‘O’ and ‘I’ of brachialis
‘O’- anterior surface of distal humerus( including the intermuscular septa)
‘I’-tuberosity of ulna
‘O’ and ‘I’ of coracorachialis
‘O’- coracoid
‘I’-medial side of humerus(opposite deltoid tuberosity)
what muscle works the most when carrying heavy loads?
coracobrachialis
what is the function of the long head of biceps brachii
holds the humerus in place. prevents dislocation
pushes the head of the humerus up against the glenoid fossa-> stabilisation
what is this and what causes it?
“Popped muscle” due to rupture of long bicep head tendon
with age-develop bony spores on the sides of the tubercle->friction can cause the tendon to rupture
what are the actions of the coracobrachialis?
adduction of the shoulder
flexion of shoulder
what are the actions of brachialis?
main elbow flexor
what are the actions of biceps brachii?
-supinator
-elbow flexor
-flexion of shoulder
*EOM
1-cephalic vein
2-pectoralis major
3-musculocutaneous nerve
4-median nerve
5-brachial artery
6-basilic vein
7-ulnar nerve
8-arteria profunda brachii
9-radial nerve
10-biceps brachii
11/12-Corachobrachialis
13-humerus
14-medial head of triceps brachii
15-lateral head
16-triceps brachii
17-long head
18-deltoid
*EOM
1-cephalic vein
2-musculocutaneous nerve
3-radial nerve
4-arteria profunda brachii
5-nerve to anconeus
6-middle collateral branch of arteria profunda brachii
7-ulnar nerve
8-superior ulnar collateral artery
9-medial cutaneous nerve of the forearm
10-basillic vein
11-median nerve
12-brachial artery
13-vena comitans
14-biceps brachii
15-brachialis
16-triceps brachii
17-humerus
what are the actions of triceps brachii?
1- elbow extensor
2-shoulder adductor, shoulder extensor
what are the most and least active parts of the triceps?
most- medial
least-long
‘O’ and ‘I’ of triceps brachii
‘O’ long head: infra glenoid tubercle
‘O’ of lateral and medial heads: back of the humerus
‘I’ of all three: olecranon of ulna
1-axillary nerve
2-posterior circumflex humeral artery
3-profunda brachii artery
4-radial nerve( in radial or spiral groove)
5-inferior lateral cutaneous nerve of the arm
6-lateral intermuscular septa
7-posterior cutaneous nerve of forearm
8-ulnar nerve(posterior to medial intermuscular septa)
9-medial epicondyle
10-
11-circumflex scapular artery
what nerve can get damaged if the intramuscular injection into the shoulder is too low?
axillary nerve
what nerve and artery are at risk of getting damaged if there is a midshaft fracture in a humerus?
radial n and profunda brachii artery( lie close to the bone)
most damaged to the forearm muscle
what is the name of the muscle that is part of the forearm BUT contributes to elbow extension together with triceps?
anconeus
what are the “Shunt muscles of arm”
at what anatomical landmark does axillary artery become brachial artery?
inferior border of teres major
what is the function of anastomosis?
what are the boundaries of the cubital fossa?
superior: imaginary line between medial and lateral epicondyles
medial: lateral edge of pronator teres
lateral: medial boundary of brachioradialis
floor: brachialis tendon
roof: biceps tendon
what nerve innervates the tricep brachii?
radial n
why is the distal end of the humerus split into compartments?
some of the forearm muscles start originating at the humerus
forearm muscles need to be long to generate enough strength. Forearm muscles provide strength for the hands as the hands themselves cannot accommodate powerful muscles.
what nerve/s innervates the anterior compartment of the forearm?
ulnar & median n
what nerve/s innervates the posterior compartment of the forearm?
radial n
what nerve innervates teres major?
lower subscapular n
