The arm
The armFascia Anterior compartment Biceps brachii Brachialis Coracobrachialis Posterior compartment Triceps Brachial artery Anastomosis around the elbow
Blood pressure
Fascia
The arm is enclosed in a sheath of deep fascia from which two fascial intermuscular septa extend to the medial and lateral supracondylar ridges of the humerusCompartments
The medial and lateral intermuscular septa divide the arm into anterior and posterior fascial compartments.Anterior compartment
contains three muscles Biceps brachiiAnterior compartment
contains three muscles Biceps brachii CoracobrachialisAnterior compartment
contains three muscles Biceps brachii Coracobrachialis Brachialisbiceps
brachialis
Anterior compartment
The nerve of the compartment is the musculocutaneous nerve the artery is the brachial arteryBiceps brachii
This muscle has 2 heads of origin (as its name implies), long head (which is lateral, L. for L.) and short head which is medialLong head
short head
Long head of biceps brachii
arises from the supraglenoid tubercle of the scapula within the capsule of the shoulder jointLong head of biceps brachii
emerges at the top of the intertubercular sulcus surrounded by a tube-like extension of synovial membranelies in the sulcus then joins the short head
Long head of biceps brachii
Long head
short head
Medial head of biceps brachii
arises from the tip of the coracoid process of the scapula in common with coracobrachialis muscleshort head
coracobrachialis
Coracoid process
Biceps brachii
The muscle lies in front of brachialis with the musculocutaneous nerve sandwiched between thembiceps
biceps
brachialis
brachialis
Insertion of biceps brachii
The tendon is inserted into the radial tuberosity
Insertion of biceps brachii
A bursa is present between the tendon and radial tuberosityBicipital aponeurosis
An extension from the tendon of biceps brachii A thin sheet of connective tissue that passes medially to blend with the deep fascia of the forearmAction of biceps brachii
The muscle is a powerful flexor and supinator of the forearmAlimentary muscle
its long head helps in flexion at the shoulder
Action of biceps brachiiThe supinator action of biceps is due to its insertion onto the posterior aspect of the radial tuberosity
Action of biceps brachii
when the biceps contracts, not only is the forearm flexed but the radius unwinds as its tuberosity is rotated anteriorly i.e. the forearm supinates
Action of biceps brachii
Brachialis origin
Arises from the front of the distal part of the humerus and the intermuscular septabrachialis
brachialis
Medial & lateral intermuscular septa
Brachialis insertion
Is inserted into the coronoid process and tuberosity of the ulna.brachialis
Brachialis action
Passing in front of the elbow joint the muscle is a powerful flexor of the elbowCoracobrachialis origin
Is a small muscle arises from the tip of the coracoid process in common with the short head of biceps brachiiCoracobrachialis insertion
into the middle third of the medial surface of the humerus.short head of biceps
Coracobrachialis action
It is a weak flexor and adductor of the shoulderCoracobrachialis
The musculocutaneous nerve passes through the muscle giving its branch of supply before doing soPosterior compartment of the arm
Contains one muscle with three heads (triceps)Posterior compartment of the arm
the nerve of the compartment is the radial nervePosterior compartment of the arm
The artery of the compartment is the profunda brachii and ulnar collateral arteries branches of the brachial artery
Profunda brachii
Ul;nar collaterals
Triceps
As its name indicates this muscle has three heads of origin Long Lateral Mediallong
lateral
medial
Long head of triceps
arises from the infraglenoid tubercle of the scapulaLateral head of triceps
arises from the posterior surface of the humerus superior to the radial grooveMedial head of triceps
Arises from the posterior surface of the humerus inferior to the radial grooveRadial nerve in the radial groove
Triceps heads
It might help to understand the relations of the heads to consider a superficial part of the muscle formed of the long and lateral heads lie side by side and are comparable to bicepslong
lateral
lateral
long
biceps
the medial head is actually in a deeper plane and is comparable to brachialis in that it is deep and takes origin from the lower part of the shaft and the intermuscular septum
Triceps heads
medial
brachialis
Triceps insertion
The tendon of the muscle is inserted into the olecranon of the ulnaTriceps action
The muscle is an extensor of the elbowits long head arising from the infraglenoid tubercle aids in extending the shoulder joint and is an important factor in the stability of the abducted shoulder
Triceps action
Bursae related to triceps tendon
Subcutaneous bursa located in the subcutaneous tissue Subtendinous olecranon bursa located between the tendon and olecranonStudent’s elbow The subcutaneous bursa is liable to be inflamed by repeated friction this is called "student's elbow "
Brachial artery
is the continuation of the axillary arteryIt runs on the medial border of brachialis muscle
brachialisBrachial artery
At the cubital fossa in front of the elbow joint, it ends opposite the neck of the radius by dividing into radial and ulnar arteriesMedian nerve
The median nerve is formed by the union of the medial and lateral roots lateral to the axillary arteryMedian n.
Median nerve
The median nerve crosses anterior to the brachial artery in the middle of the armMedian nerve
at the elbow, the median nerve lies medial to the brachial arteryMedian n.
Brachial a.
Brachial artery variation
Sometimes the artery divides into its terminal branches in the armBrachial artery
The artery is accompanied by venae comitantes (brachial veins) and is superficial throughout its course lying just deep to the deep fasciaProfunda brachii
is the first and largest branch of the brachial artery Passes along the radial groove of the humerus divides into anterior and posterior descending branches which participate in anastomoses around the elbow joint
Superior ulnar collateral
arises about the middle of the arm accompanies the ulnar nerve posterior to the medial epicondyle of the humerus.Inferior ulnar collateral
arises proximal to the elbow passes downwards anterior to the medial epicondyle of the humerus both the superior and inferior ulnar collateral arteries participate in the arterial anastomoses around the elbow joint.Arterial blood pressure
The brachial artery is commonly used for measuring arterial blood pressureThe stethoscope is placed over the artery in the cubital fossa just medial to the biceps tendon (the same site where you can feel its pulsations)
Arterial blood pressure
Compression of the brachial artery
Compression against the humerus of the brachial artery may be required to control hemorrhage in cases of injury or operationCompression of the brachial artery
If the pressure is made in the upper part of the arm it should be directed laterally
Compression of the brachial artery
if in the lower part it should be directed backwards because the artery lies medial to the humerus above and in front of it belowCompression of the brachial artery
The best place is to compress the brachial artery near the middle of the arm where the artery lies on the tendon of coracobrachialis muscle medial to the humerusAnastomosis around the elbow
the radial artery supplies the radial recurrent artery, which ascends and anastomoses with the anterior descending branch of the profunda brachii arteryAnastomosis around the elbow
The ulnar artery supplies the anterior ulnar recurrent artery, which anastomoses with the inferior ulnar collateral arteryAnastomosis around the elbow
The ulnar artery also supplies the posterior ulnar collateral artery, which arises distal to the anterior and passes posterior to the medial epicondyle of the humerus to anastomose whit the superior ulnar collateral artery.Anastomosis around the elbow
The common interosseous artery arises from the ulnar artery It divides into anterior and posterior interosseous arteries. The posterior interosseous passing posteriorly between the radius and ulna