Muscles And Brachial Plexus - Lab Exam 1

The correct order for the "break-up" of the brachial plexus is Roots, Trunks, Divisions, Cords, Terminal Branches. This is the correct sequence in which the different structures of the brachial plexus branch out from each other. The roots are the initial structures that give rise to the trunks, which then divide into divisions. The divisions further split into cords, and finally, the cords give rise to the terminal branches.

The suprascapular nerve innervates the supraspinatus and infraspinatus muscles. This nerve originates from the upper trunk of the brachial plexus and passes through the suprascapular notch to reach the muscles. The supraspinatus muscle is responsible for initiating abduction of the arm at the shoulder joint, while the infraspinatus muscle is involved in the external rotation of the arm.

The Upper Subscapular nerve innervates the Subscapularis muscle.

The correct origin/insertion for the Subscapularis is the Subscapular fossa of scapula and the Lesser tubercle of humerus.

The statement is true because all three heads of the Triceps Brachii muscle, namely the long head, lateral head, and medial head, insert at the olecranon process of the ulna. The Triceps Brachii muscle is responsible for extending the forearm at the elbow joint, and its insertion at the olecranon process allows it to exert force and generate movement in this joint.

The Triceps Brachii, Brachioradialis, and Anconeus muscles are innervated by the Radial nerve. The Radial nerve is responsible for supplying motor innervation to the muscles of the posterior compartment of the arm, including the Triceps Brachii muscle which is responsible for extending the forearm. The Brachioradialis muscle, located in the forearm, is also innervated by the Radial nerve and assists in flexion of the forearm. The Anconeus muscle, which is involved in elbow extension, is also innervated by the Radial nerve.

The deltoid muscle is a large, triangular muscle located on the shoulder. It has three parts: anterior, middle, and posterior. The deltoid tuberosity is a bony prominence on the humerus where the muscle inserts. The correct answer states that all three parts of the deltoid muscle insert at the deltoid tuberosity of the humerus. This means that the muscle fibers from all three parts converge and attach to this specific point on the humerus bone.

The correct origin for Pectoralis Minor is the anterior surface of ribs 3, 4, 5, near the costal cartilages.

It is found on the ANTERIOR surface.

The supraspinatus muscle is responsible for the first 15 degrees of humeral abduction. This muscle is located in the upper part of the shoulder and plays a key role in initiating the movement of raising the arm away from the body. It is one of the four muscles that make up the rotator cuff and is specifically responsible for the initial phase of abduction before other muscles, such as the deltoid, take over.

The dorsal scapular nerve innervates the levator scapulae and rhomboid major and minor muscles, but it does not innervate the subscapularis muscle.

The correct origin/insertion for the Supraspinatus muscle is the Supraspinous fossa of the scapula and the Greater tubercle of the humerus (superior facet). This means that the muscle originates from the Supraspinous fossa of the scapula and inserts onto the Greater tubercle of the humerus at its superior facet.

The brachial plexus is a network of nerves that originates from the spinal cord in the neck and supplies the upper limb. The terminal branches of the brachial plexus include the musculocutaneous nerve, median nerve, ulnar nerve, axillary nerve, and radial nerve. These nerves innervate different muscles and provide sensory and motor functions to the arm and hand. The pectoral nerve is not a terminal branch of the brachial plexus but is a branch of the medial cord.

The correct insertion of the Latissimus Dorsi muscle is the Bicipital (intertubercular) groove of the humerus. This muscle originates from the lower spine and iliac crest and inserts into the front of the upper arm bone. It is responsible for various movements of the shoulder joint, such as extension, adduction, and medial rotation. The Bicipital groove is a depression on the front of the humerus where the tendon of the muscle passes through and attaches.

The Levator Scapula originates from the C1-4 transverse processes.

The abduction of the humerus to 90 degrees is performed by the Deltoid - Middle muscle. The deltoid muscle is responsible for the movement of the arm away from the body, known as abduction. The deltoid has three parts: anterior, middle, and posterior. In this case, the middle portion of the deltoid muscle is specifically involved in the abduction of the humerus to 90 degrees.

The correct answer is "Lateral/Acromion/Spine of the Scapula." The anterior deltoid originates at the lateral third of the clavicle, the middle deltoid originates on the lateral surface of the acromion, and the posterior deltoid originates on the spine of the scapula.

The long head of the Triceps Brachii muscle is located medially and originates at the Infraglenoid tubercle of the scapula.

The posterior division of the brachial plexus actually supplies the extensor parts of the upper limb, not the flexor parts. The flexor parts are supplied by the anterior division. Therefore, the statement is incorrect and the correct answer is False.

The correct insertion for Pectoralis Minor is the coracoid process of the scapula (medial border of superior surface). This means that the muscle attaches to the inner edge of the upper surface of the coracoid process.

The correct origin for the middle trapezius is the C7-T3 spinous processes. The middle trapezius is a muscle located in the upper back, and its origin refers to the point where the muscle attaches to the bone. In this case, it attaches to the spinous processes of the vertebrae C7-T3, which are located in the middle of the back. The other options mentioned, such as ligamentum nuchae, spine of the scapula, and C1-4 transverse processes, are not correct origins for the middle trapezius.

The clavicular head of the Pectoralis Major muscle is responsible for humeral flexion, which means it helps to bring the arm towards the body by bending the elbow joint. This specific action is in addition to the overall function of the Pectoralis Major muscle, which is to adduct and medially rotate the arm at the shoulder joint. Therefore, the statement that the clavicular head of Pectoralis Major has the additional specific action of humeral flexion is true.

The correct origin for Rhomboid Major is the T2-T5 spinous processes. The rhomboid major muscle is located in the upper back and connects the spinous processes of the thoracic vertebrae to the medial border of the scapula. The T2-T5 spinous processes specifically refer to the vertebrae in the thoracic region between the second and fifth ribs. This muscle plays a role in retracting and stabilizing the scapula, and its origin at the T2-T5 spinous processes allows it to perform these functions effectively.

The correct origin for the Coracobrachialis is the coracoid process of the scapula, and the correct insertion is the middle 1/3 of the medial surface of the humeral shaft.

The Subscapularis muscle is responsible for the medial rotation and adduction of the humerus. This means that it helps to rotate the arm inward towards the midline of the body and bring the arm closer to the body. It does not contribute to lateral rotation or abduction of the humerus. Additionally, the answer also mentions the lateral (upward) rotation of the scapula, which is not a specific action of the Subscapularis muscle.

The correct actions of Teres Major are extension, medial rotation, and adduction of the humerus. Teres Major helps to extend the arm backward, rotate it inward towards the midline of the body, and bring it closer to the body's centerline. These actions are important for various movements such as pulling, throwing, and reaching across the body.

The Biceps Brachii has two heads, the long and short. The long head is located medially and the short head is located laterally. The long head originates at the supraglenoid tubercle of the scapula, while the short head originates at the coracoid process of the scapula. Both heads insert at the Tuberosity of the Radius and the Bicipital Aponeurosis.

The Brachialis muscle originates at the lower half of the anterior shaft of the humerus. It terminates at the tuberosity and coronoid process of the ulna. It performs flexion of the elbow.

The medial head of the Triceps Brachii muscle originates below the spiral groove of the posterior humerus. This means that it originates on the posterior side of the humerus bone, specifically below the area where the spiral groove is located.

The correct answer is Dorsal Scapular Nerve. The dorsal scapular nerve does not branch off the trunks. The suprascapular nerve and the nerve to the subclavius both branch off the upper trunk of the brachial plexus. The dorsal scapular nerve, on the other hand, arises from the C5 root directly and does not pass through the trunks.

The Medial Pectoral nerve innervates the Pectoralis Major - Sternal Head and Pectoralis Minor muscles. However, it does not innervate the Pectoralis Major - Clavicular Head muscle.

The lower subscapular nerve innervates the teres major and subscapularis muscles, but not the teres minor muscle.

The Axial nerve innervates the Teres Minor and Deltoids muscles. The Teres Minor is a small muscle located in the shoulder joint that helps with external rotation of the arm. The Deltoids are the main muscles responsible for shoulder abduction and flexion. Both of these muscles receive their nerve supply from the Axial nerve, which allows for their proper function and movement.

The Musculocutaneous nerve innervates the Coracobrachialis, Biceps Brachii, and Brachialis muscles. These muscles are located in the anterior compartment of the arm. The Musculocutaneous nerve arises from the lateral cord of the brachial plexus and supplies motor innervation to these muscles, allowing for flexion of the elbow joint. The Triceps Brachii muscle, on the other hand, is innervated by the Radial nerve, while the Brachioradialis muscle is innervated by the Radial nerve and the Skin of the Forearm is innervated by the Median and Ulnar nerves.

The lateral cord gives rise to the Lateral Pectoral Nerve.

The Lateral Pectoral nerve innervates the Pectoralis Major - Clavicular Head. This nerve originates from the lateral cord of the brachial plexus and supplies motor fibers to the clavicular head of the Pectoralis Major muscle. The Pectoralis Major - Clavicular Head is responsible for flexion, adduction, and medial rotation of the arm at the shoulder joint.

The correct answer is "Posterior humerus above spiral groove." The lateral head of the Triceps Brachii muscle originates from the posterior aspect of the humerus bone, specifically above the spiral groove. This is an important attachment point for the muscle and helps in its function of extending the elbow joint.

The correct origin for the Brachioradialis is the lateral supracondylar ridge of the humerus, while the correct insertion is the styloid process of the radius.

The correct insertion for the Levator Scapula is the vertebral border of the scapula from the superior angle to the root of the spine. This means that the muscle attaches to the inner edge of the scapula, starting from the top corner and extending down to where the spine of the scapula begins. This insertion allows the Levator Scapula muscle to elevate and retract the scapula, helping to rotate and stabilize the shoulder blade.

The correct answer states that the Rhomboid Major and Minor have the same actions, which are Adduction (retraction) of the scapula and Medial (downward) rotation. This means that both muscles work together to pull the scapula closer to the spine (adduction) and rotate it downward towards the midline of the body (medial rotation).

The correct origin for Rhomboid Minor is the C7-T1 spinous processes. The rhomboid minor is a muscle located in the upper back, and it originates from the spinous processes of the cervical vertebrae C7 and T1. These spinous processes are the bony projections that extend from the back of each vertebra. Therefore, the correct answer is C7-T1 spinous processes.

The Infraspinatus muscle originates from the infraspinous fossa of the scapula and inserts at the greater tubercle of the humerus on the middle facet.

The correct origin/insertion for the Subclavius is the 1st rib costocartilage junction and the inferior shaft of the clavicle - middle 1/3.

Extension, horizontal abduction, lateral rotation, and scaption of the humerus are actions of the Deltoid - Posterior muscle. This muscle is located at the back of the shoulder and is responsible for these movements. It helps in extending the arm backward, moving the arm away from the body in a horizontal motion, rotating the arm outward, and raising the arm in a diagonal plane.

The coracobrachialis muscle is responsible for flexion of the humerus, which is the movement of bringing the upper arm closer to the body. In addition to that, it also performs adduction of the humerus, which is the movement of bringing the upper arm towards the midline of the body. This muscle helps in stabilizing the shoulder joint and assisting in various arm movements.

The correct origin for the Serratus Anterior is the lateral surface of the upper 8 ribs (by finger like slips). The correct insertion for the muscle is the vertebral border of the scapula - anterior surface.

The sternocostal head of the Pectoralis Major muscle is responsible for additional actions such as humeral extension and assisting in the anterior tilt of the scapula. This means that when the muscle contracts, it helps to extend the arm backward at the shoulder joint and also assists in tilting the shoulder blade forward. Therefore, the statement is true.

The Latissimus Dorsi muscle originates from the thoracolumbar aponeurosis, lower 6 thoracic spinous processes, sacrum, iliac crest of ilium, lower 3 to 4 ribs, and the inferior angle of the scapula. However, it does not originate from the spine of the scapula.

The correct answer is that the Rhomboid Major inserts at the vertebral border of the scapula from the root of the spine to the inferior angle, while the Rhomboid Minor inserts at the root of the spine of the scapula.

The correct answer is that both the clavicular and sternocostal heads of the Pectoralis Major insert at the lateral lip of the bicipital groove of the humerus. This means that both parts of the muscle attach to the same point on the humerus bone, specifically the outer edge of the groove where the long head of the biceps tendon runs. This insertion point allows the Pectoralis Major to contribute to movements of the shoulder joint, such as flexion, adduction, and medial rotation.