Arm muscles (Quiz 1) Flashcards
What are the 3 flexor muscles in the anterior compartment?
1) biceps brachii
2) brachialis
3) coracobrachialis
What nerve supplies the anterior flexor compartment of the arm?
musculocutaneous n.
What is the extensor muscle in the posterior compartment?
triceps brachii
What nerve supplies the posterior extensor compartment of the arm?
radial n.
A distally placed assistant to the triceps, the ___________, also lies in the posterior compartment
anconeus
The flexor muscles of the anterior compartment are almost twice as strong as the extensors in all positions; consequently, we are better _________ than __________
pullers, pushers
The extensors of the elbow are particularly important for what?
raising oneself out of a chair and for wheelchair activity
Conditioning of the triceps is particularly important in who?
elderly or disabled patients (to help them sit up from chair or be able to move around wheelchair)
The biceps is a ___ joint muscle- at the glenohumeral, elbow, and radioulnar joints, although it primarily acts at the latter two.
3
When the forearm is pronated, the biceps brachii is the primary (most powerful)…..
supinator of the forearm
The long head of the biceps brachii arises from the ______________________ and descends in the ___________________________
supraglenoid tubercle, intertubercular groove of the humerus
What ligament holds the tendon of the long head of the biceps in the intertubercular groove/bicipital groove?
transverse humeral ligament
What is biceps tendonitis?
-inflammation of the biceps tendon
-usually the result of repetitive microtraumas
-common in sports involving throwing, like baseball, or using a racquet, like in tennis
A tight, narrow and/or rough intertubercular groove may irritate and inflame the biceps tendon, producing tenderness and….
crepitus (crackling sound)
Which muscle’s distal attachment covers the anterior part of the elbow joint?
brachialis
What muscle is the primary flexor of the forearm in all positions?
potential test q
brachialis
What muscle is regarded as the workhorse of the elbow flexors?
brachialis
The ____________________ helps flex and adduct the arm and stabilizes the glenohumeral joint. It serves as a shunt muscle, resisting downward dislocation of the head of the humerus, as when carrying a heavy suitcase
coracobrachialis
What muscle is the main extensor of the forearm?
triceps brachii
What muscle helps stabilize the adducted glenohumeral joint by serving as a shunt muscle, resisting inferior displacement of the head of the humerus?
triceps brachii
What muscle’s medial head is the workforce of forearm extension?
potential test q
triceps brachii
The ______________ helps the triceps extend the forearm and tendons of the capsule of the elbow joint, preventing it being pinched during extension
aconeus
What are the 5 muscles of the arm?
1) biceps brachii
2) coracobrachialis
3) brachialis
4) triceps brachii
5) anconeus
What is the origin/proximal attachment of the short head of the biceps brachii?
tip of coracoid process of scapula (same as coracobrachialis origin)
What is the origin/proximal attachment of the long head of the biceps brachii?
supraglenoid tubercle of scapula
What is the insertion/distal attachment of the biceps brachii?
radial tuberosity and fascia of forearm via bicipital aponeurosis
What innervates the biceps brachii?
musculocutaneous n.
What are the actions of the biceps brachii?
-supinates forearm when it is prone
-flexes forearm
-short head resists dislocation of shoulder
What is the origin/proximal attachment of the coracobrachialis?
tip of coracoid process of scapula (same as biceps brachii short head origin)
What is the insertion/distal attachment for the coracobrachialis?
middle third of the medial surface of the humerus
What innervates the coracobrachialis?
musculocutaneous n.
What are the actions of the coracobrachialis?
-helps flex and adduct arm
-resist dislocation of shoulder
What is the origin/proximal attachment of the brachialis?
distal half of the anterior surface of the humerus
What is the insertion/distal attachment of the brachialis?
coronoid process of the ulna and ulna tuberosity
What innervates the brachialis?
musculocutaneous n. and radial n.
What are the actions of the brachialis?
flexes forearm in all positions
What is the origin/proximal attachment for the long head of the triceps brachii?
infraglenoid tubercle of scapula
What is the origin/proximal attachment of the lateral head of the triceps brachii?
posterior surface of the humerus (superior to the radial groove)
What is the origin/proximal attachment of the medial head of the triceps brachii?
posterior surface of the humerus (inferior to radial groove)
What is the insertion/distal attachment of the triceps brachii?
proximal end of the olecranon of the ulna and fascia of the forearm
What innervates the triceps brachii?
radial n.
What are the actions of the triceps brachii?
-chief extensor of forearm
-long head resists dislocation of humerus
-important for adduction
-long head is the least active head
-medial is the workhorse of forearm extension
-lateral head is the strongest but usually for going against resistance
Which head of the triceps is the least active head?
long head
Which head of the triceps is known as the workhorse of forearm extension?
medial head
Which head of the triceps is the strongest against resistance?
lateral head
What is the origin/proximal attachment for the anconeus?
lateral epicondyle of the humerus
What is the insertion/distal attachment of the anconeus?
lateral surface of the olecranon and superior part of the posterior surface of the ulna
What innervates the anconeus?
radial n.
What are the actions of the anconeus?
-assist triceps in extending forearm
-stabilizes elbow joint
-may abduct ulna during pronation
