11.6 Muscles of the Pectoral Girdle and Upper Limbs

Lindsay M. Biga; Staci Bronson; Sierra Dawson; Amy Harwell; Robin Hopkins; Joel Kaufmann; Mike LeMaster; Philip Matern; Katie Morrison-Graham; Kristen Oja; Devon Quick; Jon Runyeon; OpenStax

11.6 Muscles of the Pectoral Girdle and Upper Limbs

Learning Objectives

By the end of this section, you will be able to:

List the muscles of the pectoral girdle and upper limbs as well as give their origins, insertions, actions and innervations

Muscles of the Pectoral Girdle and Upper Limbs

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.

Muscles That Position the Pectoral Girdle

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 are located either on the anterior thorax or on the posterior thorax (Figure 11.6.1 and Table 11.11). 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.

The left panel shows the anterior lateral view of the pectoral girdle muscle, and the right panel shows the posterior view of the pectoral girdle muscle. — ***Figure 11.6.1 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.

Table 11.11: Muscles That Position the Pectoral Girdle
Prime mover	Position in the thorax	Movement	Target	Target motion direction	Origin	Insertion
Subclavius	Anterior thorax	Stabilizes clavicle during movement by depressing it	Clavicle	Depression	First rib	Inferior surface of clavicle
Pectoralis minor	Anterior thorax	Rotates shoulder anteriorly (throwing motion); assists with inhalation	Scapula; ribs	Scapula: depresses; ribs: elevates	Anterior surfaces of certain ribs (2–4 or 3–5)	Coracoid process of scapula
Serratus anterior	Anterior thorax	Moves arm from side of body to front of body; assists with inhalation	Scapula; ribs	Scapula: protracts; ribs: elevates	Muscle slips from certain ribs (1–8 or 1–9)	Anterior surface of vertebral border of scapula
Trapezius	Posterior thorax	Elevates shoulders (shrugging); pulls shoulder blades together; tilts head backwards	Scapula; cervical spine	Scapula: rotests inferiorly, retracts, elevates, and depresses; spine: extends	Skull; vertebral column	Acromion and spine of scapula; clavicle
Rhomboid major	Posterior thorax	Stabilizes scapula during pectoral girdle movement	Scapula	Retracts; rotates inferiorly	Thoracic vertebrae (T2–T5)	Medial border of scapula
Rhomboid minor	Posterior thorax	Stabilizes scapula during pectoral girdle movement	Scapula	Retracts; rotates inferiorly	Cervical 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 11.6.2 and Table 11.12a). 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 and has multiple points of origin including the lumbosacral fascia attached to the inferior 6 thoracic vertebrae, the inferior 3 ribs, the iliac crest and inferior angle of the scapula.

The top left panel shows the lateral view of the pectoral and back muscles. The top right panel shows the posterior view of the right deltoid and the left back muscle. The bottom left panel shows the anterior view of the deep muscles of the left shoulder, and the bottom right panel shows the deep muscles of the left shoulder. — ***Figure 11.6.2 – Muscles That Move the Humerus:*** (a, c) 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). (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).

Table 11.12a: Muscles That Move the Humerus
Prime mover	Movement	Target	Target direction movement	Origin	Insertion
Pectoralis major	Brings elbows together; moves elbow up (as during an uppercut punch)	Humerus	Flexion; adduction; medial rotation	Clavicle sternum; cartilage of certain ribs (1-6 or 1-7) aponeurosis of external oblique muscle	Greater tubercle of humerus
Latissimus dorsi	Moves elbow back (as in elbowing someone standing behind you); spreads elbows apart	Humerus; scapula	Humerus: extension, adduction, and medial rotation; scapula: depression	Thoracic vertebrae (T7-T12); lumbar vertebrae; lower ribs (9-12); iliac crest	Intertubercular sulcus of humerus

Table 11.12b: Muscles That Move the Humerus
Prime mover	Movement	Target	Target direction movement	Origin	Insertion
Deltoid	Lifts arms at shoulder	Humerus	Abduction; flexion; extension; medial lateral rotation	Trapezius; clavicle; acromion; spine of scapula	Deltoid tuberosity of humerus
Subscapularis	Assists pectoralis major in bringing elbows together and stabilizes shoulder joint during movement of the pectoral girdle	Humerus	Medial rotation	Subscapular fossa of scapula	Lesser tubercle of humerus
Supraspinatus	Rotates elbow outwards, as during a tennis swing	Humerus	Abduction	Supraspinous fossa of scapula	Greater tubercle of humerus
Infraspinatus	Rotates elbow outwards, as during a tennis swing	Humerus	Extension; adduction	Infraspinous fossa of scapula	Greater tubercle of humerus
Teres major	Assists with medial rotation at the shoulder	Humerus	Extension; adduction	Posterior surface of scapula	Intertubercular sulcus of humerus
Teres minor	Assists infraspinatus in rotating elbow outwards	Humerus	Extension; adduction	Lateral border of dorsal scapular surface	Greater tubercle of humerus
Coracobrachialis	Moves elbow up and across body, as when putting hand on chest	Humerus	Flexion; adduction	Coracoid process of scapula	Medial surface of humerus shaft

The rest of the shoulder muscles originate on the scapula and help to move the arm. The deltoid is the major abductor of the arm but also facilitates flexing and medial rotation, as well as extension and lateral rotation. The subscapularis originates on subscapular fossa and medially rotates the arm. Named for their locations, the supraspinatus (originating from the supraspinous fossa) and the infraspinatus (originating from the infraspinous fossa) 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 its adduction and medial rotation. The long teres minor laterally rotates the arm. Finally, the coracobrachialis flexes and adducts the arm.

The tendons of the 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. Although the shoulder joint allows a great deal of freedom of movement due to the shallow glenoid cavity it is extremely vulnerable to downward dislocation. The muscles and tendons of the rotator cuff provide stability to the 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 bringing 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. When the forearm faces anteriorly, it is supinated. When the forearm faces posteriorly, it is pronated. 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 turns the forearm anteriorly.

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 brachial is a synergist in forearm flexion. 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 11.6.3 and Table 11.13).

This multipart figure shows the different muscles that move the forearm. The major muscle groups are labeled. — ***Figure 11.6.3 – 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 11.13: Muscles That Move the Forearm
Muscle Type	Prime mover	Movement	Target	Target motion direction	Origin	Insertion
Anterior muscles (flexion)	Biceps brachii	Performs a bicep curl; also allows palm of hand to point toward body while flexing	Forearm	Flexion; supination	Coracoid process; tubercle above glenoid cavity	Radial tuberosity
Anterior muscles (flexion)	Brachialis	Performs an elbow-bending motion	Forearm	Flexion	Front of distal humerus	Coronoid process of ulna
Anterior muscles (flexion)	Brachioradialis	Assists and stabilizes elbow during bicep-curl motion	Forearm	Flexion	Lateral supracondylar ridge at distal end of humerus	Base of styloid process of radius
Posterior muscles (extension)	Triceps brachii	Extends forearm, as during a punch	Forearm	Extension	Infraglenoid tubercle of scapula; posterior shaft of humerus; posterior humeral shaft distal to radial groove	Olecranon process of ulna
Posterior muscles (extension)	Anconeus	Assists in extending forearm; also allows forearm to extend away from body	Forearm	Extension; abduction	Lateral epicondyle of humerus	Lateral aspect of olecranon process of ulna
Anterior muscles (pronation)	Pronator teres	Turns hand palm-down	Forearm	Pronation	Medial epicondyle of humerus; coronoid process of ulna	Lateral radius
Anterior muscles (pronation)	Pronator quadratus	Assists in turning hand palm-down	Forearm	Pronation	Distal portion of anterior ulnar shaft	Distal surface of anterior radius
Posterior muscles (supination)	Supinator	Turns hand palm-up	Forearm	Supination	Lateral epicondyle of humerus; proximal ulna	Proximal 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.

Extrinsic Muscles of the Hand

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 11.14a and Table 11.15). However, repetitive movement with 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 originate on the radius and ulna. These include the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis (see Table 11.14a).

Table 11.14a: Muscles of the Superficial Anterior Compartment of the Forearm
Prime mover	Movement	Target	Target motion direction	Origin	Insertion
Flexor carpi radialis	Bends wrist toward body; tilts hand to side away from body	Wrist; hand	Flexion; abduction	Medial epicondyle of humerus	Base of second and third metacarpals
Palmaris longus	Assists in bending hand up toward shoulder	Wrist	Flexion	Medial epicondyle of humerus	Palmar aponeurosis; skin and fascia of palm
Flexor carpi ulnaris	Assists in bending hand up toward shoulder; tilts hand to side away from body; stabilizes wrist	Wrist; hand	Flexion; abduction	Medial epicondyle of humerus; olecranon process; posterior surface of ulna	Pisiform, hamate bones, and base of fifth metacarpal
Flexor digitorum superficialis	Bends fingers to make a fist	Wrist; fingers 2-5	Flexion	Medial epicondyle of humerus; coronoid process of ulna; shaft of radius	Middle phalanges of fingers 2-5

Table 11.14b: Muscles of the Deep Anterior Compartment of the Forearm
Prime mover	Movement	Target	Target motion direction	Origin	Insertion
Flexor pollicis longus	Bends tip of thumb	Thumb	Flexion	Anterior surface of radius; interosseous membrane	Distal phalanx of thumb
Flexor digitorum profundus	Bends fingers to make a fist; also bends wrist toward body	Wrist; fingers	Flexion	Coronoid process; anteromedial surface of ulna; interosseous membrane	Distal phalanges of fingers 2-5

Table 11.14c: Muscles of the Superficial Posterior Compartment of the Forearm
Prime mover	Movement	Target	Target motion direction	Origin	Insertion
Extensor radialis longus	Straightens wrist away from body; tilts hand to side away from body	Wrist	Extension; abduction	Lateral supracondylar ridge of humerus	Base of second metacarpal
Extensor carpi radialis brevis	Assists extensor radialis longus in extending and abducting wrist; also stabilizes hand during finger flexion	Wrist	Extension; abduction	Lateral epicondyle of humerus	Base of third metacarpal
Extensor digitorum	Opens fingers and moves them sideways away from the body	Wrist; fingers	Extension; abduction	Lateral epicondyle of humerus	Extensor expansions; distal phalanges of fingers
Extensor digit minimi	Extends little finger	Little finger	Extension	Lateral epicondyle of humerus	Extensor expansion; distal phalanx of finger 5
Extensor carpi ulnaris	Straightens wrist away from body; tilts hand to side toward body	Wrist	Extension; abduction	Lateral epicondyle of humerus; posterior border of ulna	Base of fifth metacarpal

Table 11.14d: Muscles of the Deep Posterior Compartment of the Forearm
Prime mover	Movement	Target	Target motion direction	Origin	Insertion
Abductor pollicis longus	Moves thumb sideways toward body; extends thumb moves hand sideways toward body	Wrist; thumb	Thumb: abduction, extension; wrist: abduction	Posterior surface of radius and ulna; interosseous membrane	Base of metacarpal; trapezium
Extensor pollicis brevis	Extends thumb	Thumb	Extension	Dorsal shaft of radius and ulna; interosseous membrane	Base of proximal phalanx of thumb
Extensor pollicis longus	Extends thumb	Thumb	Extension	Dorsal shaft of radius and ulna; interosseous membrane	Base of distal phalanx of thumb
Extensor indicis	Extends index finger; straightens wrist away from body	Wrist; index finger	Extension	Posterior surface of distal ulna; interosseous membrane	Tendon of extensor digitorum of index 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 11.6.4). These muscles allow your fingers to 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 ulnar aspect of the palm, and the intermediate muscles are midpalmar.

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.

This multipart figure shows the intrinsic muscles of the hand with the major muscle groups labeled. — ***Figure 11.6.4 – 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.

Table 11.15: Intrinsic Muscles of the Hand
Prime mover	Muscle	Movement	Target	Target motion direction	Origin	Insertion
Abductor pollicis brevis	Thenar muscles	Moves thumb toward body	Thumb	Abduction	Flexor retinaculum; and nearby carpals	Lateral base of proximal phalanx of thumb
Opponens pollicis	Thenar muscles	Moves thumb across palm to touch other fingers	Thumb	Opposition	Flexor retinaculum; trapezium	Anterior of first metacarpal
Flexor pollicis brevis	Thenar muscles	Flexes thumb	Thumb	Flexion	Flexor retinaculum; trapezium	Lateral base of proximal phalanx of thumb
Adductor pollicis	Thenar muscles	Moves thumb away from body	Thumb	Adduction	Capitate bone; bases of metacarpals 2–4; front of metacarpal 3	Medial base of proximal phalanx of thumb
Abductor digiti minimi	Hypothenar muscles	Moves little finger toward body	Little finger	Abduction	Pisiform bone	Medial side of proximal phalanx of little finger
Flexor digiti minimi brevis	Hypothenar muscles	Flexes little finger	Little finger	Flexion	Hamate bone; flexor retinaculum	Medial side of proximal phalanx of little finger
Opponens digiti minimi	Hypothenar muscles	Moves little finger across palm to touch thumb	Little finger	Opposition	Hamate bone; flexor retinaculum	Medial side of fifth metacarpal
Lumbricals	Intermediate muscles	Flexes each finger at metacarpo-phalangeal joints; extends each finger at interphalangeal joints	Fingers	Flexion	Palm (lateral sides of tendons in flexor digitorum profundus)	Fingers 2–5 (lateral edges of extensional expansions on first phalanges)
Palmar interossei	Intermediate muscles	Adducts and flexes each finger at metacarpo-phalangeal joints; extends each finger at interphalangeal joints	Fingers	Adduction; flexion; extension	Side 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 3
Dorsal interossei	Intermediate muscles	Abducts and flexes the three middle fingers at metacarpo-phalangeal joints; extends the three middle fingers at interphalangeal joints	Fingers	Abduction; flexion; extension	Sides of metacarpals	Both sides of finger 3; for each other finger, extensor expansion over first phalanx on side opposite finger 3

Chapter Review

The clavicle and scapula make up the pectoral girdle, which provides a stable origin for the muscles that move the humerus. The muscles that position and stabilize the pectoral girdle are located on the thorax. The anterior thoracic muscles are the subclavius, pectoralis minor, and the serratus anterior. The posterior thoracic muscles are the trapezius, levator scapulae, rhomboid major, and rhomboid minor. Nine muscles cross the shoulder joint to move the humerus. The ones that originate on the axial skeleton are the pectoralis major and the latissimus dorsi. The deltoid, subscapularis, supraspinatus, infraspinatus, teres major, teres minor, and coracobrachialis originate on the scapula.

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. The supinator is the only one that turns the forearm anteriorly.

The extrinsic muscles of the hands originate along the forearm and insert into the hand in order to facilitate crude movements of the wrists, hands, and fingers. The superficial anterior compartment of the forearm produces flexion. These muscles are the flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and the flexor digitorum superficialis. The deep anterior compartment produces flexion as well. These are the flexor pollicis longus and the flexor digitorum profundus. The rest of the compartments produce extension. The extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris are the muscles found in the superficial posterior compartment. The deep posterior compartment includes the abductor longus, extensor pollicis brevis, extensor pollicis longus, and the extensor indicis.

Finally, the intrinsic muscles of the hands allow our fingers to make precise movements, such as typing and writing. They both originate and insert within the hand. The thenar muscles, which are located on the lateral part of the palm, are the abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, and adductor pollicis. The hypothenar muscles, which are located on the medial part of the palm, are the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. The intermediate muscles, located in the middle of the palm, are the lumbricals, palmar interossei, and dorsal interossei.

Review Questions

Critical Thinking Questions

The tendons of which muscles form the rotator cuff? Why is the rotator cuff important?

Reveal

The biceps femoris, semimembranosus, and semitendinosus form the hamstrings. The hamstrings flex the leg at the knee joint.

List the general muscle groups of the shoulders and upper limbs as well as their subgroups.

Reveal

The rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius form the quadriceps. The quadriceps muscles extend the leg at the knee joint.

Glossary

abduct: move away from midline in the sagittal plane
abductor digiti minimi: muscle that abducts the little finger
abductor pollicis brevis: muscle that abducts the thumb
abductor pollicis longus: muscle that inserts into the first metacarpal
adductor pollicis: muscle that adducts the thumb
anconeus: small muscle on the lateral posterior elbow that extends the forearm
anterior compartment of the arm: (anterior flexor compartment of the arm) the biceps brachii, brachialis, brachioradialis, and their associated blood vessels and nerves
anterior compartment of the forearm: (anterior flexor compartment of the forearm) deep and superficial muscles that originate on the humerus and insert into the hand
biceps brachii: two-headed muscle that crosses the shoulder and elbow joints to flex the forearm while assisting in supinating it and flexing the arm at the shoulder
brachialis: muscle deep to the biceps brachii that provides power in flexing the forearm.
brachioradialis: muscle that can flex the forearm quickly or help lift a load slowly
coracobrachialis: muscle that flexes and adducts the arm
deep anterior compartment: flexor pollicis longus, flexor digitorum profundus, and their associated blood vessels and nerves
deep posterior compartment of the forearm: (deep posterior extensor compartment of the forearm) the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, and their associated blood vessels and nerves
deltoid: shoulder muscle that abducts the arm as well as flexes and medially rotates it, and extends and laterally rotates it
dorsal interossei: muscles that abduct and flex the three middle fingers at the metacarpophalangeal joints and extend them at the interphalangeal joints
extensor carpi radialis brevis: muscle that extends and abducts the hand at the wrist
extensor carpi ulnaris: muscle that extends and adducts the hand
extensor digiti minimi: muscle that extends the little finger
extensor digitorum: muscle that extends the hand at the wrist and the phalanges
extensor indicis: muscle that inserts onto the tendon of the extensor digitorum of the index finger
extensor pollicis brevis: muscle that inserts onto the base of the proximal phalanx of the thumb
extensor pollicis longus: muscle that inserts onto the base of the distal phalanx of the thumb
extensor radialis longus: muscle that extends and abducts the hand at the wrist
extensor retinaculum: band of connective tissue that extends over the dorsal surface of the hand
extrinsic muscles of the hand: muscles that move the wrists, hands, and fingers and originate on the arm
flexor carpi radialis: muscle that flexes and abducts the hand at the wrist
flexor carpi ulnaris: muscle that flexes and adducts the hand at the wrist
flexor digiti minimi brevis: muscle that flexes the little finger
flexor digitorum profundus: muscle that flexes the phalanges of the fingers and the hand at the wrist
flexor digitorum superficialis: muscle that flexes the hand and the digits
flexor pollicis brevis: muscle that flexes the thumb
flexor pollicis longus: muscle that flexes the distal phalanx of the thumb
flexor retinaculum: strong band of connective tissue at the anterior wrist that spans the top of the U-shaped grouping of the carpal bones to form the roof of the carpal tunnel
hypothenar: group of muscles on the medial aspect of the palm
hypothenar eminence: rounded contour of muscle at the base of the little finger
infraspinatus: muscle that laterally rotates the arm
intermediate: group of midpalmar muscles
intrinsic muscles of the hand: muscles that move the wrists, hands, and fingers and originate in the palm
latissimus dorsi: broad, triangular axial muscle located on the inferior part of the back
lumbrical: muscle that flexes each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints
opponens digiti minimi: muscle that brings the little finger across the palm to meet the thumb
opponens pollicis: muscle that moves the thumb across the palm to meet another finger
palmar interossei: muscles that abduct and flex each finger at the metacarpophalangeal joints and extend each finger at the interphalangeal joints
palmaris longus: muscle that provides weak flexion of the hand at the wrist
pectoral girdle: (also, shoulder girdle) the set of bones, consisting of the scapula and clavicle, which attaches an upper limb to the axial skeleton at the sternum
pectoralis major: thick, fan-shaped axial muscle that covers much of the superior thorax
pectoralis minor: muscle that moves the scapula and assists in inhalation
pronator quadratus: pronator that originates on the ulna and inserts on the radius
pronator teres: pronator that originates on the humerus and inserts on the radius
retinacula: fibrous bands that sheath the tendons at the wrist
rhomboid major: muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae
rhomboid minor: muscle that attaches the vertebral border of the scapula to the spinous process of the thoracic vertebrae
rotator cuff: strong connective tissue structure formed by the fusion of four rotator cuff muscle tendons to the articular capsule of the shoulder joint; surrounds and supports superior, anterior, lateral, and posterior sides of the humeral head
serratus anterior: large and flat muscle that originates on the ribs and inserts onto the scapula
subclavius: muscle that stabilizes the clavicle during movement
subscapularis: muscle that originates on the anterior scapula and medially rotates the arm
superficial anterior compartment of the forearm: flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum superficialis, and their associated blood vessels and nerves
superficial posterior compartment of the forearm: extensor radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and their associated blood vessels and nerves
supinator: muscle that moves the palm and forearm anteriorly
supraspinatus: muscle that abducts the arm
teres major: muscle that extends the arm and assists in adduction and medial rotation of it
teres minor: muscle that laterally rotates and extends the arm
thenar: group of muscles on the lateral aspect of the palm
thenar eminence: rounded contour of muscle at the base of the thumb
trapezius: muscle that stabilizes the upper part of the back
triceps brachii: three-headed muscle that extends the forearm

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Anatomy & Physiology 2e Copyright © 2025 by Lindsay M. Biga, Staci Bronson, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Kristen Oja, Devon Quick, Jon Runyeon, and OpenStax is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.