Muscles of the Upper Limb

Muscle Tone

State of slight contraction with a certain degree of vigor and tension

Isotonic contraction

The tension in the muscle remains the same whereas its length decreases

Isometric contraction

The length of the muscle remains the same but tension is developed in the muscle

Muscle fatigue

failure of a muscle to maintain tension as a result of previous contractile activity

Motor unit

All of the muscle fibers controlled by a single motor neuron constitute a motor unit

Muscle named based on:

Size, shape, direction of fibers, location, number of origins and insertion, and action performed **biceps brachii (brachii is upper arm)

Vocabulary that describes muscle size

1. Vastus (huge) //Maximus (large) // Longus (long) // minimus (small) // brevis (short)

Vocabulary that describes muscle shape

1. Deltoid (triangular)2. Rhomboid 3. Latissimus (wide)4. Trees (round)5. TRapezius (like a trapezoid, 4 figure 2 parallel sides)

Vocabulary that describes direction of fibers

1. Rectus (straight)2. Transverse (across other fibers)3. Oblique (diagonally)4. Orbicularis (circular)

Vocabulary that describes location of muscles

1. Pectoral is (chest)2. Gluteus (buttock or rump))3. Brachii (arm)4. Supra (above)5. Infra (below ) (e.g supraspinatus6. Sub- (under or beneath)7. Lateralis (lateral)

Vocabulary that describes number of muscle origins

1. Bicep (two head)2. TRicep (three heads)3. Quadriceps (four head)

Vocabulary that describes origin and insertion of muscles

1. Sternocleidomastoid (origin on sternum or clavicle, insertion on mastoid process)2. Brachioradialis (origin on rm, insertion on radius

Vocabulary that describes muscle actions

1. Abductor (to abduct structure)2. Adductors (to adduct a structure) 3.Flexor (to flex a structure)4. Extensor (to extend a structure)5. Levator (to lift or elevate a structure)6. Masseter (a chewer)

Body movement (name all movements)

Abduction, adduction, rotation, circumduction, flexion, extension, supination, pronation, plantar flexion, dorsiflexion, inversion, eversion

Group actions of muscles

1. Agonist (prime mover) - muscles which produce the desired action2. Antagonist (opponent) - muscles which produces the opposite movement of prime mover3. Fixators -muscles which stabilize the proximal joints of a limb, so that desired movement at the distal joints may occur4. Synergists - muscles which produce the same movements at a particular joint when contracting

Skeletal Muscle Attachments

1. Direct attachment - muscle fibers fuse directly with periosteum of the bone2. Indirect attachment - tendon/aponeurosis (extensions of CT) attach muscle to periosteum of the bones/CT of the other muscles

Diagram of Indirect Skeletal muscle attachments

A: Tendon - thick rope like connective tissueB: Aponeurosis - broad sheet-like connective tissue (multiple attachments)

Raphe muscle attachment

A seam that joins two muscles together.

Origin and Attachment (defenition) + image of gastrocnemius

1. Origin - fixed and stable attachment of the muscle2. Insertion - more movable attachment of the muscle3. Belly/Gaster - fleshy part of the muscle

4. Subgroups of the upper limb

1. Muscles moving pectoral girdle2. Muscles moving the arm3. Muscles moving the forearm4. Muscles moving hand and fingers

Muscles involved in pectoral girdle movement

*** of the scapula 1. Trapezius (move medially)2. Rhomboid Major (pulls scapula medially, holds to rib cage)3. Levator scapulae (elevate and shrug shoulders)4. Serratus Anterior ( pulls scapula anteriorly and inferiority, holds scapula to ribcage, pushing object)5. Pectoralis minor ( located beneath pec. Major, pulls scapula inferiorly

Muscles that move the arm

Flexors = pectoralis major and coracobrachialis Extensors = Teres Major & Latissimus dorsi Abductors = Supraspinatus and deltoid Adductors = pectoralis major (sternal), teres major, Latissimus dorsi Rotators = subscapularis, infraspinatus and teres minor

Role of pectoralis major in arm movement

-adduction, flexion and medial rotation of the arm at shoulder joint

Role of coracobrachialis in movement of the arm

adduction, flexion of the arm at the shoulder joint

Role of Latissimus dorsi in movement of the arm

adduction and medial rotation of the arm at the shoulder joint

Teres major

Adduction and medial rotation of the arm at shoulder joint


1. abduction of the arm at shoulder joint2. attaches humerus to scapula 3. common area for intra muscular injections

Rotator cuff muscles

**Assist in holding the head of the humerus in the Glennoid cavity of the scapula during movement of joint1. Subscapularis - medial rotation2. Supraspinatus - abduction3. Infraspinatus - lateral rotation4. teres minor - lateral rotation

Muscles that move the forearm

Flexors - biceps brachii, brachialis, brachiodialisExtensors - triceps brachiiRotators- supinator, prontor teres, prontor quadrus


Located at elbow joint, one of two primary flexors (biceps brachii) and responsible for flexion of the forearm

Muscles responsible for posterior compartment movement of forearm

- Triceps brachii is the primary extensor- brachioradialis (runs along the ulna), also responsible for flexion of forearm at elbow joint

Supinator and PRonator muscles

Responsible for the supination nd pronation of the arm. Origin at elbow joint and insertion slightly down the radius/ulna