BIOL 3310 Lab - Muscles of Shoulder & Upper Limbs

Deltoid Muscle Function

Flex and medially & laterally rotate and abduct arm

Abduction, flexion, extension of arm at shoulder joint

Involved in arm swinging during such actions as walking or bowling

Deltoid Muscle

Deltoid Muscle

Deltoid Muscle

Deltoid Muscle

Biceps Brachii Muscle Function

Rapid or forceful supination of forearm

Slight shoulder flexion

*Long & short head

Biceps Brachii Muscle

Biceps Brachii Muscle

Biceps Brachii Muscle

Brachialis Function

Prime mover of elbow flection (bending of joint)

Flexion of arm at elbow joint

Brachialis Muscle

Brachialis Muscle

Three Muscles

Biceps Brachii Muscle, Brachialis Muscle, Brachioradialis Muscle

Triceps Brachii Muscle Function

Extends elbow/arm

Extension of forearm at elbow joint

Triceps Brachii Long Head, Lateral Head, & Medial Head

Triceps Brachii Muscle

Coracobrachialis Muscle

Coracobrachialis Muscle

Coracobrachialis Muscle Location

Originates from the coracoid process of the scapula and inserts onto the medial aspect of the humerus

Subscapularis Muscle Function

Medial rotation of arm at shoulder joint

Rotates humerus medially

Prevents humeral head from sliding upward

Subscapularis Muscle

Subscapularis Muscle

Supraspinatus Muscle Function

Aids deltoid in abduction of arm

• Abduction of arm at shoulder joint

Resists downward slippage of humeral head when arm is relaxed or when carrying weight

Supraspinatus Muscle

Supraspinatus Muscle

Infraspinatus Muscle Function

Rotates humerus laterally

• Lateral rotation of arm at shoulder joint

Adduction of arm at shoulder joint

Prevents humeral head from sliding upward

Infraspinatus Muscle

Infraspinatus Muscle

Teres Minor Muscle Function

Rotates humerus laterally

• Lateral rotation of arm at shoulder joint

Adduction of arm at shoulder joint

Controls action of deltoid, preventing humeral head from sliding upward

Teres Minor Muscle

Teres Minor Muscle

Teres Major Muscle Function

Extends & medially rotates humerus

• Extension, adduction, medial rotation of arm at shoulder joint

Contributes to arm swinging

Teres Major Muscle

Teres Major Muscle

Teres Major Muscle

What muscles is the Rotator Cuff made up of? (4)

Infraspinatus Muscle, Supraspinatus Muscle, Subscapularis Muscle, & Teres Minor Muscle

Rotator Cuff

Brachioradialis Muscle

Brachioradialis Muscle