Human Anatomy Upper Limb 4 PDF

Lac:8 2024-2025 Human anatomy 1st stage Upper Limb 4 (Anterior & posterior compartments of arm) Dr.Sameeah algenabi College of medicine/University of anbar ...

Lac:8 2024-2025 Human anatomy 1st stage Upper Limb 4 (Anterior & posterior compartments of arm) Dr.Sameeah algenabi College of medicine/University of anbar  The arm(bracium) Fascial compartment of arm: The arm is enclosed in a sheath of deep fascia. Two facial intermuscular septa, one on the medial side and one on the lateral side, extend inward from this sheath and attached to the medial and lateral supracondylar ridges of humerus, this called medial and lateral intermuscular septums. In this way, the arm is divided into an anterior and posterior compartment. Contents of ant. fascial compartment of arm: -Muscles: biceps brachii, coracobrachialis, & brachialis muscles. -Blood vessels: brachial artery & its branches. -Nerves: musculocutaneous, median, and ulnar nerves. Muscles of the anterior compartment arm In the anterior compartment: Three flexors: biceps brachii Brachialis Coracobrachialis All These muscles supplied by : Musculocutaneous nerve 1-Biceps brachii muscle: arises by two heads. Origin:-Long head: from supraglenoid tubercle of scapula -short head: from the tip of coracoid process of scapula. Tendon crosses humeral head within capsule of shoulder joint & surrounded by a synovial sheath & lies in bicipital groove. Insertion: The two heads fuses at the middle of arm & inserted into bicipital tuberosity of radius & bicipital aponeurosis into deep fascia of med. aspect of forearm. -Action: as strong supinator of the forearm, flexor of elbow joint and weak flexor of shoulder joint. 2-Coracobrachialis muscle: Origin: The tip of coracoid process of scapula & runs downward Insertion: into middle of med. side of shaft of humerus. -Action: It flexes the arm at shoulder joint & weak adductor. 3-Brachialis muscle arises from lower half of ant. surface of humerus and passes downward & ant. to elbow joint where it is inserted into the ant. surface of coronoid process of ulna)ulnar tuberosity). Action: It is regarded as a strong flexor of the elbow joint. Nerve supply of all above muscles: Musculocutaneous -Brachial artery -It begins at lower border of teres major as continuation of axillary artery. It travels through anter.copmartment of arm & its branches supply the entire arm. -It terminates opposite neck of radius by dividing into radial & ulnar arteries. It is related to: 1. Ant.: It is superficial & is overlapped from lat. side by coracobrachialis & biceps muscles. The med. cutaneous n. of forearm lies in front of its upper part, while its middle and lower parts are crossed by median n. & bicipital aponeurosis respectively 2. Post.: It lies on triceps, & brachialis muscles. 3. Med.: Ulnar n. & basilic v. in the upper part of the arm while in lower part of arm it is related to median n. 4. Lat.: Above; median nerve and coracobrachialis and biceps muscles. Below; the tendon of biceps muscle. Branches of brachial artery: 1. Muscular branches to the anterior compartment of the arm. 2. Nutrient artery to humerus. 3. Profunda brachii artery arises near origin of brachial artery & follows radial n. into spiral groove of humerus. It supplies triceps muscle & takes part in the arterial anastomosis around the elbow joint. 4. Sup. ulnar collateral artery arises at middle of arm & follows ulnar n. to enter post. compartment of arm. 5. Inf. ulnar collateral artery arises near termination of brachial artery & takes part in arterial anastomosis around the elbow joint. Nerves of ant. compartment of arm: -Musculocutaneous n. Origin: Lateral cord of brachial plexus in axilla. Course: It descends downward and laterally, piercing coracobrachialis muscle, and then passes between biceps & brachialis. It appears at lateral margin of biceps tendon, piercing deep fascia above elbow, where it descends as lateral cutaneous nerve of forearm on the lateral aspect of forearm It gives off: -muscular branches to coracobrachialis, biceps, and brachialis muscles. -Cutaneous branch: lateral cutaneous nerve of the forearm to supply skin of front & lateral sides of forearm down to the root of the thumb. -articular branches to elbow joint -Median nerve Origin: medial and lateral cord of brachial plexus in axilla Course: -Above: lies, at upper arm, lat. to brachial artery. -At the mid-arm: it crosses the front of brachial artery. -Below: it becomes medial to the brachial artery. -At the level of elbow joint: it is crossed by bicipital aponeurosis. It gives off no branches in arm, except for a small vasomotor nerve for brachial artery. -Ulnar nerve. Origin: medial cord of brachial plexus. Course:runs downward on med. side of brachial artery as far as middle of arm where it pierces med.fascial septum & is accompanied by sup. ulnar collateral artery. Thus it enters post. compartment of arm & passes behind med. Humeral epicondyle. It gives off no branches in ant. compartment of arm. Contents of post. compartment of arm: It contains :Triceps muscle, radial and ulnar nerve, & the Profunda brachii & ulnar collateral vessels. -Triceps muscle: It is a large muscle that forms the greater part of the substance of the back of the arm. It is composed of three heads: Long head arises from the infraglenoid tubercle of scapula. Lat. head arises from the upper half of the post. surface of humerus above the spiral groove. Med. head which arises from the lower half of the post. surface of humerus below the spiral groove. The heads unite to be inserted into upper border of olecranon process of ulna. -Radial n.: Enters the post. compartment of the arm between long & medial heads of triceps muscle. Then it runs in the spiral groove of humerus between the lat. and med. heads of triceps muscle. It pierces the lateral fascial septum above the elbow joint and continues downward into the cubital fossa in front of the elbow joint between & supply brachialis(small branch) & brachioradialis. In the spiral groove the nerve is accompanied by Profunda brachii vessels and it is in direct contact with the shaft of the humerus. Branches in the axilla: 1. Muscular branches to med. & long heads of triceps. 2. Post. cutaneous nerve of arm for skin of the back of the arm. Branches in the spiral groove: 1. Muscular branches to med & lat. heads of triceps. 2. Muscular branch to anconeus. 3. Lower lat. cutaneous n. of arm for skin over the lateral & anterior aspect of the lower part of the arm. 4. Post. cutaneous n. of forearm; it runs down middle of the back of forearm as far as the wrist. Branches in ant. compartment of arm: 1. Muscular branches to brachialis, brachioradialis, and extensor carpi radialis longus muscles. 2. Articular branches to elbow joint. Ulnar n.: In upper half of arm, it is a content of ant. fascial compartment. At middle of arm it pierces the med. fascial septum & descends behind the septum & covered post. by med. head of triceps muscle. It is accompanied by sup. ulnar collateral artery. At elbow joint it lies behind med. humeral epicondyle on the med. lig. of elbow joint. Cubital fossa: It is a triangular depression of skin that lies in front of elbow joint. Its apex directed distally it is bounded: Laterally: by brachioradialis muscle. Medially: by pronator teres muscle. Base of the triangle is formed by an imaginary line drawn between the two humeral epicondyles. Floor of the fossa is formed by: -Supinator muscle laterally -Brachialis muscle medially. Its roof is formed by the skin and fascia and is reinforced by the bicipital aponeurosis. Contents of cubital fossa: from med. to the lat.: 1. Median nerve. 2. Bifurcation of brachial artery. 3. Tendon of biceps muscle. 4. Radial n. and its deep branch