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Home , Greater tubercle, Hypothenar eminence, Lesser tubercle, Muscles of the hand, Rotator cuff, Supraglenoid tubercle

Lab 7

FUNCTIONAL HUMAN ANATOMY LAB #7 UPPER EXTREMITY MUSCULATURE

The following tips will help you in naming the muscles of the and :

The is located on the pinky side of the , the is located on the side of the wrist. This will be maintained regardless of hand position (pronated vs. supinated). The anterior side of the forearm and the palmar side of the hand contain muscles that perform flexion and may have flexor in the name. The posterior side of the forearm and the dorsal side of the hand contain muscles that perform extension and may have extensor in the name. Most muscles in the anterior forearm originate or appear to originate from the medial epicondyle of the . Most muscles in the posterior forearm originate or appear to originate from the lateral epicondyle of the Humerus.

Any muscle that attaches to the 1st digit (thumb) has Pollicus in the name

Any muscle that attaches to the 2nd digit (index ) has Indicis in the name

Any muscle that attaches to the 5th digit (pinky finger) has Digiti Minimi in the name

Any muscle that attaches to all of the digits (2-5) has Digitorum in the name

Radialis muscles perform radial deviation

Ulnaris muscles perform ulnar deviation

MUSCULATURE:

BACK/UPPER EXTREMITY:

Latissimus Dorsi Medial attachment: may occasionally have some attachment thoracolumbar (spinous processes of inferior 6 thoracic vertebre along the inferior angle of the and all lumbar vertebre, iliac crest) and inferior 3 or 4 ribs Lateral attachment: floor of interturbicular (bicipital) groove

Function: Adduction or extension of the at the . Internal rotation of the arm at the shoulder

Teres major Medial attachment: synergistic with latissimus dorsi posterior surface on inferior angle of scapula

Lateral attachment: medial ridge of interturbicular groove

Function: same as Latissimus Dorsi

1 Lab 7

Supraspinatus Medial attachment: one of 4 muscles; primarily supraspinous fossa of scapula concerned with maintaining the position of the humeral head in the ; Lateral attachment: counterbalances forces placed on the joint superior facet on greater of humerus externally and by other muscles acting on the joint. Function: Abduction of the arm at the shoulder. Only effective during the first 80 degrees (approx.) of adduction

Infraspinatus Medial attachment: one of 4 rotator cuff muscles; primarily infraspinous fossa of scapula concerned with maintaining the position of the humeral head in the glenoid fossa; Lateral attachment: counterbalances forces placed on the joint middle facet on of humerus externally and by other muscles acting on the joint. Function: External rotation of the arm at the shoulder

Teres minor Medial attachment: one of 4 rotator cuff muscles; primarily lateral border of scapula concerned with maintaining the position of the humeral head in the glenoid fossa; Lateral attachment: counterbalances forces placed on the joint inferior facet on greater tubercle of humerus externally and by other muscles acting on the joint. Function: External rotation of the arm at the shoulder

Subscapularis Medial attachment: one of 4 rotator cuff muscles; primarily subscapular fossa of scalpula concerned with maintaining the position of the humeral head in the glenoid fossa; Lateral attachment: counterbalances forces placed on the joint of humerus externally and by other muscles acting on the joint. Function: Internal rotation of the arm at the shoulder

2 Lab 7

Deltoid Proximal attachment: consists of anterior, middle and posterior distal end of the clavical, process of scapula, spine of heads (functional) scapula Distal attachment: of humerus

Function: Flexion and internal rotation (anterior head), abduction (middle head), extension and hyperextension and external rotation (posterior head) of the arm at the shoulder

Pectoralis major Medial attachment: consists of clavicular, sternal and abdominal proximal half of clavical, lateral side of manubrium and sternum, heads (functional) medial aspect of inferior border of ribcage Lateral attachment: lateral ridge of interturbicular groove of humerus

Function: Flexion and internal rotation (clavicular head), horizontal adduction and internal rotation (sternal head), flexion from a hyperextended position and internal rotation (abdominal head) of the arm at the shoulder

Subclavius Medial attachment: exact function unknown, may help to draw the costochondrial joint of 1st rib clavical anteriorly Lateral attachment: inferior surface of distal end of clavical

Function: unknown

ARM:

Biceps brachii Proximal attachment: consists of long and short heads (anatomical); long head: of scapula long head is lateral, short head is medial; long short head: corocoid process of scapula head sits in interturbicular groove Distal attachment: both heads joins distally and attach to ; non-functional attachment to Function: Flexion of the arm at the shoulder, flexion of the forearm at the only when the wrist is supinated

Coracobrachialis Proximal attachment: shares proximal attachment with short head of corocoid process of the scapula brachii Distal attachment: medial side, approx. 1/3 of the way down humerus

Function: Flexion and horizontal adduction of the arm at the shoulder

3 Lab 7

Brachialis Proximal attachment: workhorse of the arm anterior side, body of humerus

Distal attachment: ulnar tuberosity

Function: Flexion of the forearm at the elbow in all wrist positions

Triceps brachii Proximal attachment: consists of long, lateral and medial heads long head: of scapula (anatomical); medial head is deep to long and lateral head: posterior side, body of humerus lateral heads medial head: posterior side, body of humerus Distal attachment: all heads join and attach to process of ulna

Function: Extension and hyperextension of the arm at the shoulder (long head only), extension of the forearm at the elbow (long, lateral and medial heads)

Anconeus Proximal attachment: lateral epicondyle of humerus

Distal attachment: lateral side, proximal end of ulna

Function: Extension of the forearm at the elbow

FOREARM:

Brachioradialis Proximal attachment: only anterior forearm muscle that attaches on proximal to lateral epicondyle of humerus the lateral side of the humerus; radial , vein and emerge under this muscle Distal attachment: lateral side, distal end of radius

Function: Flexion of the forearm at the elbow in all wrist positions, although this muscle favors a semiprone or neutral wrist position (palms facing each other)

4 Lab 7

Pronator teres Proximal attachment: medial epicondyle of humerus

Distal attachment: lateral side, approx. 1/3 of the way down radius

Function: Pronation and flexion of the forearm at the elbow

Flexor carpi radialis Proximal attachment: medial epicondyle of humerus

Distal attachment: base of 2nd metacarpal

Function: Flexion of the forearm at the elbow, flexion of the hand at the wrist, radial deviation of the hand at the wrist

Palmaris longus Proximal attachment: does not have a bony, rigid distal attachment medial epicondyle of humerus

Distal attachment: flexor retinaculum

Function: tightens the flexor retinaculum and subsequently the

Flexor digitorum superficialis Proximal attachment: the is located under this muscle; medial epicondyle of humerus note tendon arrangement at Distal attachment: middle phalanges of digits 2-5

Function: Flexion of the forearm at the elbow, flexion of the hand at the wrist, flexion of the digits (from the middle phalanges)

Flexor carpi ulnaris Proximal attachment: , vein and nerve emerge under this medial epicondyle of humerus muscle Distal attachment: base of 5th metacarpal

Function: Flexion of the forearm at the elbow, flexion of the hand at the wrist, ulnar deviation of the hand at the wrist

5 Lab 7

Flexor digitorum profundus Proximal attachment: located deep to flexor digitorum superficialis; anterior side, body of radius and ulna note tendon arrangement at fingers Distal attachment: distal phalanges of digits 2-5

Function: Flexion of the hand at the wrist and flexion of the digits (from the distal phalanges)

Flexor pollicus longus Proximal attachment: lateral side, body of ulna

Distal attachment: distal phalange of pollux

Function: Flexion of the hand at the wrist, flexion of the thumb

Pronator Quadratus Medial attachment: primary pronator of forearm distal end of ulna

Lateral attachment: distal end of radius

Function: Pronation

Extensor carpi radialis brevis and longus Proximal attachment: longus is more superficial, brevis is deep; also lateral epicondyle of humerus longus muscles have longer Distal attachment: longus: base of 2nd metacarpal (dorsal side) brevis: base of 3rd metacarpal (dorsal side) Function: Extension of the forearm at the elbow, extension of the hand at the wrist, radial deviation of the hand at the wrist

6 Lab 7

Extensor digitorum Proximal attachment: lateral epicondyle of humerus

Distal attachment: distal phalange of 2nd - 5th digits

Function: Extension of the forearm at the elbow, extension of the hand at the wrist, extension of the digits

Extensor digiti minimi Proximal attachment: located along side extensor digitorum lateral epicondyle of humerus

Distal attachment: distal phalange of 5th digit

Function: Extension of the 5th digit (pinky finger)

Extensor carpi ulnaris Proximal attachment: lateral epicondyle of humerus

Distal attachment: base of 5th metacarpal (dorsal side)

Function: Extension of the forearm at the elbow, extension of the hand at the wrist, ulnar deviation of the hand at the wrist

Extensor indicis Proximal attachment: located deep to extensor digitorum body of ulna

Distal attachment: distal phalange of 2nd digit

Function: Extension of the hand at the wrist, extension of the 2nd digit

Abductor pollicus longus Proximal attachment: tendon comprises part of snuff box; shortest of dorsal side, body of radius the three pollicus muscles in this area Distal attachment: base of 1st metacarpal

Function: Radial deviation of the hand at the wrist, abduction of the thumb

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Extensor pollicus brevis Proximal attachment: tendon comprises part of snuff box dorsal side, body of radius

Distal attachment: base of proximal phalange of pollux

Function: Radial deviation of the hand at the wrist, extension of the thumb

Extensor pollicus longus Proximal attachment: tendon comprises part of snuff box; longest of medial side, body of radius the three pollicus muscles in this area Distal attachment: base of distal phalange of pollux

Function: Radial deviation of the hand at the wrist, extension of the thumb

Supinator Proximal attachment: located deep to most of the muscles attached lateral epicondyle of humerus to the lateral epicondyle of the humerus Distal attachment: medial side, approx. 1/3 of the way down radius

Function: Supinates

The muscles above that operate the digits are extrinsic (the contractile part of the muscle is located outside of the hand and the tendons extend down into the hand); the muscles below are intrinsic muscles of the hand (the entire muscle is located within the hand)

HAND:

Palmaris brevis Function: very thin muscle located over the hypothenar Tightens the flexor retinaculum and subsequently the palmar eminence and attached to the flexor aponeurosis retinaculum

Abductor pollicus brevis Function: most lateral palm muscle; in the thenar Abduction of the thumb eminence

8 Lab 7

Flexor pollicus brevis Function: just medial to adductor pollicus brevis; in the Flexion of the thumb

Abductor digiti minimi Function: most medial palm muscle; in the hypothenar Abduction of the 5th digit eminence

Flexor digiti minimi Function: just lateral to abductor digiti minimi; in the Flexion of the 5th digit

Opponens Function: deep to the thenar and hypothenar eminence Opposition muscles

Adductor pollicus Function: located in between the pollux and 2nd digit Adduction of the thumb

Lumbricals Function: located along side the tendons for flexor Flexion of the metacarpals and simultaneous extension/hyperextension digitorum superficialis of the digits

Dorsal/palmar interosseous Function: Located inbetween the metacarpals in the Adduction of all of the digits (palmar interosseous) and abduction of all hand of the digits (dorsal interosseous)

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