Anatomy of Biceps Brachii Muscle

9 Questions

What is the action of the short head of the biceps brachii muscle?

Weak flexor of the shoulder joint

What is the termination of the brachial artery?

Opposite the neck of the radius

What is the nerve supply of the lateral part of the brachialis muscle?

Radial nerve

What is the largest branch of the brachial artery?

Profunda brachii

Which muscle is supplied by the muscular branches of the lateral cutaneous nerve?

Brachialis

What is the origin of the lateral root of the median nerve?

Lateral cord of the brachial plexus

Where does the ulnar nerve pierce the medial intermuscular septum?

Opposite the insertion of coracobrachialis

Which head of the triceps brachii originates from the infraglenoid tubercle of the scapula?

Long head

What is the course of the median nerve after it crosses the brachial artery from lateral to medial?

It runs downward on the medial side of the brachial artery

Study Notes

Anterior Compartment

Biceps Brachii:
- Origin: 2 heads (long head from supraglenoid tubercle of scapula, short head from tip of coracoid process)
- Insertion: biceps tendon into posterior rough part of radial tuberosity, bicepital aponeurosis into deep fascia of forearm
- Nerve supply: musculocutaneus nerve
- Action: flexor of elbow, supinator when elbow is flexed, stabilizes head of humerus in glenoid cavity
Coracobrachialis:
- Origin: tip of coracoid process
- Insertion: middle of medial border of humerus
- Nerve supply: musculocutaneus nerve
- Action: flexion and weak adduction of arm
Brachialis:
- Origin: lower half of front of humerus, lateral and medial intermuscular septa
- Insertion: ulnar tuberosity
- Nerve supply: medial part by musculocutaneus nerve, lateral part by radial nerve
- Action: flexion of elbow joint
Brachial Artery:
- Origin: continuation of axillary artery at lower border of teres major
- Course: descends downwards and laterally from medial side of humerus to front of arm
- Termination: divides into radial and ulnar arteries opposite neck of radius
- Branches: profunda brachii, nutrient artery of humerus, superior ulnar collateral, inferior ulnar collateral, muscular branches
Musculocutaneus Nerve:
- Origin: continuation of lateral cord of brachial plexus (C5, 6, 7)
- Course: descends downward and laterally, lateral to 3rd part of axillary artery
- Branches: muscular branches to biceps brachii, brachialis, coracobrachialis, articular to elbow joint, lateral cutaneous nerve of forearm
Median Nerve:
- Origin: by 2 roots (lateral root from lateral cord of brachial plexus, medial root from medial cord)
- Course: medial root crosses in front of 3rd part of axillary artery, unites with lateral root, runs downward on lateral side of brachial artery
- No branches in arm
Ulnar Nerve:
- Origin: medial cord of brachial plexus (C8, T1)
- Course: runs downward on medial side of brachial artery, pierces medial intermuscular septum, descends in front of medial head of triceps
- No branches above the elbow

Posterior Compartment

Triceps Brachii:
- Origin: 3 heads (long head from infraglenoid tubercle of scapula, lateral head from posterior surface of shaft of humerus, medial head from posterior surface of shaft of humerus)