The arm - Short description - from the front there is bicecps brachia and brachialis under the biceps , specially on the lower half of the arm - on the lateral side above the elbow joint , there is brachioradialis - notice that : these muscles name refer to the origin of them … like : *coracobracilis which is origin is ( corocoid process ) and it’s insetions is ( brachial ) *and oppiste to it is brachioradialis which origin is lateral supracondyler ridge of humerus and inserted into styloiad process of radius … - anconeus muscle , is located behind the elbow joint .. and it’s function is ( extension ) - for the arm , it’s enclosed in sheath of deep fascia ( we first locate the skin then superficial fascia and then deep fascia enclosed in the muscle , and with the muscle we locate nerves and blood vessels ) - in the arm we have to facial septa , one in the medial side and the other on the lateral side and the facial septa is attached to the medial and lateral sypracondyler ridge .. so they are located in the lower half of the arm… and these two septa are the one which separate the anterior compartment from the posterior compartment … - the anterior compartment contains the flexor muscles , and the postioer compartments contain the extensor muscle to the elbow joint… - so we have two septa divide the upper arm into anterior and posterior facial compartement .. each having it’s own muscles and nerves and blood vessels… - Anterior compartment of the upper Arm : Muscles : - we have the biceps brachii ( it’s named to distinguish it from other muscles that also have two heads such as: biceps femoris in the back of the thigh ) - coracobrachialis , it’s located in the anterior compartment and medialy -brachialis , under the bicesps
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- Short description...Blood supply: all these muscles take blood supply from “ rachial artery “ Nerve supply: musculocutaneous nerve , a branch from the lateral cord of brachial
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The arm
- Short description
- from the front there is bicecps brachia and brachialis under the biceps , specially on the lower half of the arm
- on the lateral side above the elbow joint , there is brachioradialis
- notice that : these muscles name refer to the origin of them … like :
*coracobracilis which is origin is ( corocoid process ) and it’s insetions is ( brachial )
*and oppiste to it is brachioradialis which origin is lateral supracondyler ridge of humerus and inserted into
styloiad process of radius …
- anconeus muscle , is located behind the elbow joint .. and it’s function is ( extension )
- for the arm , it’s enclosed in sheath of deep fascia ( we first locate the skin then superficial fascia and then deep
fascia enclosed in the muscle , and with the muscle we locate nerves and blood vessels )
- in the arm we have to facial septa , one in the medial side and the other on the lateral side and the facial septa
is attached to the medial and lateral sypracondyler ridge .. so they are located in the lower half of the arm… and
these two septa are the one which separate the anterior compartment from the posterior compartment …
- the anterior compartment contains the flexor muscles , and the postioer compartments contain the extensor
muscle to the elbow joint…
- so we have two septa divide the upper arm into anterior and posterior facial compartement .. each having it’s
own muscles and nerves and blood vessels…
- Anterior compartment of the upper Arm :
Muscles :
- we have the biceps brachii ( it’s named to distinguish it from other muscles that also have two heads such as:
biceps femoris in the back of the thigh )
- coracobrachialis , it’s located in the anterior compartment and medialy
-brachialis , under the bicesps
Blood supply : all these muscles take blood supply from “ Brachial artery “
Nerve supply : musculocutaneous nerve , a branch from the lateral cord of brachial plexus…
* in the anterior compartement , we will study the musculocutaneous nerve , the median nerve , the ulnar nerve
, radial nerve , the brachial artery , basilica vein , and the muscles …
First : the muscles ( we have 3 muscles in the anterior compartment )
1 - The biceps :
Origin : it has two heads , long and short
* short head : from the corocoid process
*long head : it cross in the bicipital grove , and under a ligament called “ transverse humeral ligament “ which
keep and save the tendon of the bicips , then cross through the upper part of the shoulder joint towards it’s origin
in the supragelnoid tubercle above gelnoid cavity
Insertion : radial tuberosity , and bicipital aponeurosis ( which is a fascia covering the cubital fossa )
nerve supply : musclocutenous nerve ( after piercing the coracobrachilis , it cross between the bicepis and
brachialis .. then goes to the lateral side , and above the elbow it comes superficial and ends as lateral cutanous
nerve of the forearm .. which supply the skin on the lateral side of the forearm
Action : flexion in the elbow joint , and supination during flexion and this action is called “ screwing “
( it works in the elbow joint because the tendons of it cross through the elbow joint )
* there is another muscle is called “ supinator “ and it also make supination , but in the extension of the elbow
joint….
2 - Coracobrachilis :
Origin : Coracoid process
Insertion : medial aspect of the shaft of the humerus in the middle …. And this inseriotn because it’s in the
middle side of the humerus , it’s considered as a land mark in the anatomical changes in this level … for example :
* opposite to the insertion of coracobrachilis , we have the insertion of the deltoid which is on the lateral side
* medin nerve crossing the brachil artery at the level of the insertion of coracobrahiclis ( it’s coming from lateral
and crossing to become medial )
And these changes is so important …
Nerve supply : musclocutenous
Action : flexion of the arm , and weak adductor of the arm…
3 -Brachilis : it lies under the bicips
Origin : from the lower half of the anterior surface of the humerus
Insertion : coronoid process of ulna ( or ulnar tuborosity )
Nerve supply : it has two innervations ,
* medial half from musclocuteneous
* lateral half from radial
And this is sooo important to know for questions !
Eg : Q : all of the following have dual innervations ( or double innervations ) except :
And till now , we have take the following muscles as a double innervation muscles :
- brachialis ( musclocutenous & radial )
- pectoralis major ( lateral and medial pectoral nerve )