What muscle is found on the lateral aspect of the shoulder and elevates the arm?

Muscles of the shoulder and upper limb can be divided into four groups: muscles that stabilize and position the pectoral girdle, muscles that move the arm, muscles that move the forearm, and muscles that move the wrists, hands, and fingers. The pectoral girdle, or shoulder girdle, consists of the lateral ends of the clavicle and scapula, along with the proximal end of the humerus, and the muscles covering these three bones to stabilize the shoulder joint. The girdle creates a base from which the head of the humerus, in its ball-and-socket joint with the glenoid fossa of the scapula, can move the arm in multiple directions.

Muscles That Position the Pectoral Girdle

Muscles that position the pectoral girdle are located either on the anterior thorax or on the posterior thorax (Figure 1 and Table 1).

Figure 1. Muscles That Position the Pectoral Girdle. The muscles that stabilize the pectoral girdle make it a steady base on which other muscles can move the arm. Note that the pectoralis major and deltoid, which move the humerus, are cut here to show the deeper positioning muscles.

The anterior muscles include the subclavius, pectoralis minor, and serratus anterior. The posterior muscles include the trapezius, rhomboid major, and rhomboid minor. When the rhomboids are contracted, your scapula moves medially, which can pull the shoulder and upper limb posteriorly.

Table 1. Muscles that Position the Pectoral GirdlePosition in the ThoraxMovementTargetTarget motion directionPrime moverOriginInsertionAnterior thoraxStabilizes clavicle during movement by depressing itClavicleDepressionSubclaviusFirst ribInferior surface of clavicleAnterior thoraxRotates shoulder anteriorly (throwing motion); assists with inhalationScapula; ribsScapula: depresses; ribs: elevatesPectoralis minorAnterior surfaces of certain ribs (2–4 or 3–5)Coracoid process of scapulaAnterior thoraxMoves arm from side of body to front of body; assists with inhalationScapula; ribsScapula: protracts; ribs: elevatesSerratus anteriorMuscle slips from certain ribs (1–8 or 1–9)Anterior surface of vertebral border of scapulaPosterior thoraxElevates shoulders (shrugging); pulls shoulder blades together; tilts head backwardsScapula; cervical spineScapula: rotates inferiorly, retracts, elevates, and depresses; spine: extendsTrapeziusSkull; vertebral columnAcromion and spine of scapula; claviclePosterior thoraxStabilizes scapula during pectoral girdle movementScapulaRetracts; rotates inferiorlyRhomboid majorThoracic vertebrae (T2–T5)Medial border of scapulaPosterior thoraxStabilizes scapula during pectoral girdle movementScapulaRetracts; rotates inferiorlyRhomboid minorCervical and thoracic vertebrae (C7 and T1)Medial border of scapula

Muscles That Move the Humerus

Similar to the muscles that position the pectoral girdle, muscles that cross the shoulder joint and move the humerus bone of the arm include both axial and scapular muscles (Figure 2, Figure 3, and Table 2).

Figure 2. Muscles That Move the Humerus. The muscles that move the humerus anteriorly are generally located on the anterior side of the body and originate from the sternum (e.g., pectoralis major) or the anterior side of the scapula (e.g., subscapularis).

Figure 3. Muscles That Move the Humerus. (b) The muscles that move the humerus superiorly generally originate from the superior surfaces of the scapula and/or the clavicle (e.g., deltoids). The muscles that move the humerus inferiorly generally originate from middle or lower back (e.g., latissiumus dorsi). (d) The muscles that move the humerus posteriorly are generally located on the posterior side of the body and insert into the scapula (e.g., infraspinatus).

The two axial muscles are the pectoralis major and the latissimus dorsi. The pectoralis major is thick and fan-shaped, covering much of the superior portion of the anterior thorax. The broad, triangular latissimus dorsi is located on the inferior part of the back, where it inserts into a thick connective tissue shealth called an aponeurosis.

Table 2. Muscles That Move the HumerusMovementTargetTarget motion directionPrime moverOriginInsertionAxial musclesBrings elbows together; moves elbow up (as during an uppercut punch)HumerusFlexion; adduction; medial rotationPectoralis majorClavicle; sternum; cartilage of ribs (1–6 or 1–7); aponeurosis of external oblique muscleGreater tubercle of humerusMoves elbow back (as in elbowing someone standing behind you); spreads elbows apartHumerus; scapulaHumerus: extension, adduction, and medial rotation; scapula: depressionLatissimus dorsiThoracic vertebrae (T7–T12); lumbar vertebrae; lower ribs (9–12); iliac crestIntertubercular sulcus of humerusScapular musclesLifts arms at the shoulderHumerusAbduction; flexion; extension; medial and lateral rotationDeltoidTrapezius; clavicle; acromion; spine of scapulaNasal boneAssists the pectoralis major in bringing the elbows together and stabilizes the shoulder joint during movement of the pectoral girdleHumerusMedial rotationSubscapularisSubscapular fossa of the scapulaLesser tubercle of humerusRotates the elbow outwards, as during a tennis swingHumerusAbductionSupraspinatusSupraspinous fossa of the scapulaGreater tubercle of humerusRotates the elbow outwards, as during a tennis swingHumerusExtension; adductionInfraspinatusInfraspinous fossa of the scapulaGreater tubercle of humerusAssists the infraspinatus in rotating the elbow outwardsHumerusExtension; adductionTeres majorPosterior surface of the scapulaIntertubercular sulcus of humerusAssists the infraspinatus in rotating the elbow outwardsHumerusExtension; adductionTeres minorLateral border of the dorsal scapular surfaceGreater tubercle of humerusMoves the elbow up and across the body, as when putting a hand on the chestHumerusFlexion; adductionCoracobra chialisCoracoid process of the scapulaMedial surface of humerus shaft

The rest of the shoulder muscles originate on the scapula. The anatomical and ligamental structure of the shoulder joint and the arrangements of the muscles covering it, allows the arm to carry out different types of movements. The deltoid, the thick muscle that creates the rounded lines of the shoulder is the major abductor of the arm, but it also facilitates flexing and medial rotation, as well as extension and lateral rotation. The subscapularis originates on the anterior scapula and medially rotates the arm. Named for their locations, the supraspinatus (superior to the spine of the scapula) and the infraspinatus (inferior to the spine of the scapula) abduct the arm, and laterally rotate the arm, respectively. The thick and flat teres major is inferior to the teres minor and extends the arm, and assists in adduction and medial rotation of it. The long teres minor laterally rotates and extends the arm. Finally, the coracobrachialis flexes and adducts the arm.

The tendons of the deep subscapularis, supraspinatus, infraspinatus, and teres minor connect the scapula to the humerus, forming the rotator cuff (musculotendinous cuff), the circle of tendons around the shoulder joint. When baseball pitchers undergo shoulder surgery it is usually on the rotator cuff, which becomes pinched and inflamed, and may tear away from the bone due to the repetitive motion of bring the arm overhead to throw a fast pitch.

Muscles That Move the Forearm

The forearm, made of the radius and ulna bones, has four main types of action at the hinge of the elbow joint: flexion, extension, pronation, and supination. The forearm flexors include the biceps brachii, brachialis, and brachioradialis. The extensors are the triceps brachii and anconeus. The pronators are the pronator teres and the pronator quadratus, and the supinator is the only one that turns the forearm anteriorly. When the forearm faces anteriorly, it is supinated. When the forearm faces posteriorly, it is pronated.

The biceps brachii, brachialis, and brachioradialis flex the forearm. The two-headed biceps brachii crosses the shoulder and elbow joints to flex the forearm, also taking part in supinating the forearm at the radioulnar joints and flexing the arm at the shoulder joint. Deep to the biceps brachii, the brachialis provides additional power in flexing the forearm. Finally, the brachioradialis can flex the forearm quickly or help lift a load slowly. These muscles and their associated blood vessels and nerves form the anterior compartment of the arm (anterior flexor compartment of the arm) (Figure 4 and Table 3).

Figure 4. Muscles That Move the Forearm. The muscles originating in the upper arm flex, extend, pronate, and supinate the forearm. The muscles originating in the forearm move the wrists, hands, and fingers.

Table 3. Muscles That Move the ForearmMovementTargetTarget motion directionPrime moverOriginInsertionAnterior muscles (flexion)Performs a bicep curl; also allows palm of hand to point toward body while flexingForearm Flexion; supinationBiceps brachiiCoracoid process; tubercle above glenoid cavityRadial tuberosityForearm FlexionBrachialisFront of distal humerusCoronoid process of ulnaAssists and stabilizes elbow during bicep-curl motionForearm FlexionBrachioradialisLateral supracondylar ridge at distal end of humerusBase of styloid process of radiusPosterior muscles (extension)Extends forearm, as during a punchForearmExtensionTriceps brachiiInfraglenoid tubercle of scapula; posterior shaft of humerus; posterior humeral shaft distal to radial grooveOlecranon process of ulnaAssists in extending forearm; also allows forearm to extend away from bodyForearmExtension; abductionAnconeusLateral epicondyle of humerusLateral aspect of olecranon process of ulnaAnterior muscles (pronation)Turns hand palm-downForearmPronationPronator teresMedial epicondyle of humerus; coronoid process of ulnaLateral radiusAssists in turning hand palm-downForearmPronationPronator quadratusDistal portion of anterior ulnar shaftDistal surface of anterior radiusPosterior muscles (supination)Tuns hand palm-upForearmSupinationSupinatorLateral epicondyle of humerus; proximal ulnaProximal end of radius

Muscles That Move the Wrist, Hand, and Fingers

Wrist, hand, and finger movements are facilitated by two groups of muscles. The forearm is the origin of the extrinsic muscles of the hand. The palm is the origin of the intrinsic muscles of the hand.

Muscles of the Arm That Move the Wrists, Hands, and Fingers

The muscles in the anterior compartment of the forearm (anterior flexor compartment of the forearm) originate on the humerus and insert onto different parts of the hand. These make up the bulk of the forearm. From lateral to medial, the superficial anterior compartment of the forearm includes the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis. The flexor digitorum superficialis flexes the hand as well as the digits at the knuckles, which allows for rapid finger movements, as in typing or playing a musical instrument (see Table 4). However, poor ergonomics can irritate the tendons of these muscles as they slide back and forth with the carpal tunnel of the anterior wrist and pinch the median nerve, which also travels through the tunnel, causing Carpal Tunnel Syndrome. The deep anterior compartment produces flexion and bends fingers to make a fist. These are the flexor pollicis longus and the flexor digitorum profundus.

The muscles in the superficial posterior compartment of the forearm (superficial posterior extensor compartment of the forearm) originate on the humerus. These are the extensor radialis longus, extensor carpi radialis brevis,extensor digitorum, extensor digiti minimi, and the extensor carpi ulnaris.

The muscles of the deep posterior compartment of the forearm (deep posterior extensor compartment of the forearm) originate on the radius and ulna. These include the abductor pollicis longus, extensor pollicis brevis,extensor pollicis longus, and extensor indicis (see Table 4).

Table 4. Muscles That Move the Wrist, Hands, and ForearmMovementTargetTarget motion directionPrime moverOriginInsertionSuperficial anterior compartment of forearmBends the wrist toward the body; it also tilts the hand to the side away from the bodyWrist; handFlexion; abductionFlexor carpi radialisMedial epicondyle of the humerusBase of second and third metacarpalsAssists in bending the hand up toward the shoulderWristFlexionPalmaris longusMedial epicondyle of the humerusPalmar aponeurosis; skin and fascia of palmAssists in bending the hand up toward the shoulder; it also tilts the hand to the side away from the body and stabilizes the wristWrist; handFlexion; abductionFlexor carpi ulnarisMedial epicondyle of the humerus, the olecranon process, and the posterior surface of the ulnaPisiform, hamate bones, and base of fifth metacarpalBends the fingers to make a fistWrist; fingers 2–5FlexionFlexor digitorum superficialisMedial epicondyle of the humerus, the coronoid process of the ulna, and the shaft of the radiusMiddle phalanges of fingers 2–5Deep anterior compartment of forearmBends the tip of the thumbThumbFlexionFlexor pollicis longusAnterior surface of the radius and the interosseous membraneDistal phalanx of thumbBends the fingers to make a fist; it also bends the wrist toward the bodyWrist; fingersFlexionFlexor digitorum profundusCoronoid process, the anteromedial surface of the ulna, and the interosseous membraneDistal phalanges of fingers 2–5Superficial posterior compartment of forearmStraightens the wrist away from the body; it also tilts the hand to the side away from the bodyWristExtension; abductionExtensor radialis longusLateral supracondylar ridge of the humerusBase of second metacarpalAssists the extensor radialis longus in extending and abducting the wrist; it also stabilizes the hand during finger flexionWristExtension; abductionExtensor carpi radialis brevisLateral epicondyle of the humerusBase of third metacarpalOpens the fingers and moves them sideways away from the bodyWrist; fingersExtension; abductionExtensor digitorumLateral epicondyle of the humerusExtensor expansions; distal phalanges of fingersExtends the little fingerLittle fingerExtensionExtensor digiti minimiLateral epicondyle of the humerusExtensor expansion; distal phalanx of finger 5Straightens the wrist away from the body; it also tilts the hand to the side toward the bodyWristExtension; abductionExtensor carpi ulnarisLateral epicondyle of the humerus and the posterior of the ulnaBase of fifth metacarpalDeep posterior compartment of forearmMoves the thumb sideways toward the body; it also extends the thumb and moves the hand sideways toward the bodyWrist; thumbThumb: abduction, extension; wrist: abductionAbductor pollicis longusPosterior surface of the radius and ulna and in the interosseous membraneBase of first metacarpal; trapeziumExtends the thumbThumbExtensionExtensor pollicis brevisDorsal shaft of the radius and ulna and in the interosseous membraneBase of proximal phalanx of thumbExtends the thumbThumbExtensionExtensor pollicis longusDorsal shaft of the radius and ulna and in the interosseous membraneBase of distal phalanx of thumbExtends the index finger; it also straightens the wrist away from the bodyWrist; index fingerExtensionExtensor indicisPosterior surface of the distal ulna and in the interosseous membraneTendon of extensor digitorum of finger

The tendons of the forearm muscles attach to the wrist and extend into the hand. Fibrous bands called retinacula sheath the tendons at the wrist. The flexor retinaculum extends over the palmar surface of the hand while the extensor retinaculum extends over the dorsal surface of the hand.

Intrinsic Muscles of the Hand

The intrinsic muscles of the hand both originate and insert within it (Figure 5). These muscles allow your fingers to also make precise movements for actions, such as typing or writing. These muscles are divided into three groups. The thenar muscles are on the radial aspect of the palm. The hypothenar muscles are on the medial aspect of the palm, and the intermediate muscles are midpalmar.

Figure 5. Intrinsic Muscles of the Hand. The intrinsic muscles of the hand both originate and insert within the hand. These muscles provide the fine motor control of the fingers by flexing, extending, abducting, and adducting the more distal finger and thumb segments.

The thenar muscles include the abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, and the adductor pollicis. These muscles form the thenar eminence, the rounded contour of the base of the thumb, and all act on the thumb. The movements of the thumb play an integral role in most precise movements of the hand.

The hypothenar muscles include the abductor digiti minimi, flexor digiti minimi brevis, and the opponens digiti minimi. These muscles form the hypothenar eminence, the rounded contour of the little finger, and as such, they all act on the little finger. Finally, the intermediate muscles act on all the fingers and include the lumbrical, the palmar interossei, and the dorsal interossei.

Table 5. Muscles That Move the Wrist, Hands, and ForearmMuscleMovementTargetTarget motion directionPrime moverOriginInsertionThenar muscles Moves thumb toward bodyThumbAbductionAbductor pollicis brevisFlexor retinaculum; nearby carpalsLateral base of proximal phalanx of thumbThenar musclesMoves thumb across palm toward bodyThumbOppositionOpponens pollicisFlexor retinaculum; trapeziumAnterior of first metacarpalThenar musclesFlexes thumbThumbFlexionFlexor pollicis brevisFelxor retinaculum; trapeziumLateral base of proximal phalanx of thumbThenar musclesMoves thumb away from bodyThumbAdductionAdductor pollicisCapitate bone; bases of metacarpals 2–4; front of metacarpalMedial base of proximal phalanx of thumbHypothenar musclesMoves little finger toward bodyLittle fingerAbductionAbductor digiti minimiPisiform boneMedial side of proximal phalanx of little fingerHypothenar musclesFlexes little fingerLittle fingerFlexionFlexor digiti minimi brevisHamate bone; flexor retinaculumMedial side of proximal phalanx of little fingerHypothenar musclesMoves little finger across palm to touch thumbLittle fingerOppositionOpponens digiti minimiHamate bone; flexor retinaculumMedial side of proximal phalanx of little fingerIntermediate musclesFlexes each finger at metacarpo-phalangeal joints; extends each finger at interphalangeal jointsFingersFlexionLumbricalsPalm (lateral sides of tendons in flexor digitorum profundus)Fingers 2–5 (lateral edges of extensional expansions on first phalanges)Intermediate musclesAdducts and flexes each finger at meacarpo-phalangeal joints; extends each finger at interphalangeal jointsFingersAdduction; flexion; extensionPalmar interosseiSide of each metacarpal that faces metacarpal 3 (absent from  metacarpal 3)Extensor expansion on first phalanx of each finger (except finger 3) on side facing finger 3Intermediate musclesAbducts and flexes the three middle fingers at metacarpo-phalangeal joints; extends the three middle fingers at interphalangeal jointsFingersAbduction; flexion; extensionDorsal interosseiSides of metacarpalsBoth sides of finger 3; for each other finger, extensor expansion over first phalanx on side opposite finger 3

Self-Check Questions

Take the quiz below to check your understanding of the Muscles of the Pectoral Girdle and Upper Limbs:

What muscle is found on the lateral aspect of the shoulder and?

Which muscle is involved in the elevation of arm?

What muscle elevates the shoulders?

What muscle is found on the lateral aspect?