BIOL 4260 Human Evolutionary Anatomy Lecture 14: Shoulder, Arm, Hand Lecture 2: Fossil Record
Appendicular Musculature Functions: Stabilizing the pectoral and pelvic girdles Moving the upper and lower limbs Muscular connections between pectoral girdle and axial skeleton and shock absorption Account for roughly 40 percent of the skeletal muscles in the body Two major groups of appendicular muscles: The muscles of the pectoral girdle and upper limbs The muscles of the pelvic girdle and lower limbs
Muscles of the Pectoral Girdle and Upper Limbs Muscle groups: Muscles that stabilize the pectoral girdle (scapula/clavicle) Muscles that move the humerus (arm) Muscles that move the forearm and hand Muscles that move the hand and fingers
Anterior Muscles that stabilize the pectoral girdle Pectoralis Minor Serratus anterior Pectoralis minor Subclavis
Posterior Muscles that stabilize the pectoral girdle 5
Posterior Muscles stabilize the pectoral girdle Posterior group Trapezius Posterior group Rhomboid major Rhomboid minor 6
Muscles that stabilize the pectoral girdle Posterior group Levator Scapulae 7
8 Summary :
Muscles That Move the Humerus Anterior view (usually insert on humerus): Coracobrachialis Deltoid Pectoralis major Biceps brachii (short head and long head). DOES NOT insert on humerus Subscapularis
SUPERFICIAL DEEP Clavicle Sternum Deltoid Pectoralis major Ribs (cut) Subscapularis Coracobrachialis Teres major Biceps brachii, short head Biceps brachii, long head T 12 Anterior view
Pectoralis major 11
Muscles That Move the Humerus Posterior view (usually insert on humerus) Supraspinatus Deltoid Infraspinatus Teres Major Teres Minor Triceps brachii (long head). Does NOT insert on humerus Lattisimus Dorsi
SUPERFICIAL DEEP Supraspinatus Vertebra T 1 Supraspinatus Infraspinatus Deltoid Teres minor Latissimus dorsi Teres major Triceps brachii, long head Triceps brachii, lateral head Thoracolumbar fascia Posterior view
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Summary of Attachments to the Scapula
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Muscles That Move the Forearm and Hand Most of these muscles originate on the humerus and insert upon the forearm and wrist Exceptions include: Long head of triceps brachii -originates on the infraglenoid tubercle of scapula and inserts on the olecranon Long head of biceps brachii - originates on the supraglenoid tubercle of scapula and inserts of the radial tuberosity of the radius
Muscles That Move the Forearm and Hand Flexors of the Elbow Biceps brachii: flexes at the elbow and shoulder Brachialis: flexes at the elbow Brachioradialis: flexes at the elbow
Biceps brachii Brachialis 19
Muscles That Move the Forearm and Hand Extensors at the Elbow Anconeus: extension at the elbow Triceps brachii Lateral head: extension at the elbow Long head: extension at the elbow and adduction at the shoulder Medial head: extension at the elbow
Muscles That Move the Forearm and Hand Pronators and Supinators Pronator quadratus: pronates the forearm Pronator teres (B): pronates the forearm Supinator (A): supinates the forearm
Muscles That Move the Wrist, Hand and fingers Flexors of the wrist Flexor carpi radialis: flex and abduct the wrist Flexor carpi ulnaris: flex and adduct the wrist Palmaris longus: flexion at the wrist
Coracoid process of scapula Humerus Coracobrachialis Biceps brachii, short head Biceps brachii, long head Triceps brachii, long head Triceps brachii, medial head Brachialis Medial epicondyle of humerus Pronator teres Palmar carpal ligament Brachioradialis Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis Pronator quadratus Flexor retinaculum Superficial muscles of the right upper limb, anterior view
Extensor carpi radialis longus Anterior view Posterior view 25
Muscles That Move the Wrist, Hand and fingers Extensors of the wrist Extensor carpi radialis longus: extend and abduct at the wrist Extensor carpi radialis brevis: extend and abduct at the wrist Extensor carpi ulnaris: extension and adduction at the wrist
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28 Extensor carpi ulnaris
Muscles That Move the Hand and Fingers Extrinsic Muscles of the Hand Relatively large muscles that perform flexion and extension at the joints of the fingers Provide strength and crude control of the hand and fingers These muscles are found mostly on the anterior and posterior surfaces of the forearm Their tendons carpus enclosed in sheaths associated with connective tissue thickenings called retinacula
Muscles That Move the Hand and Fingers Intrinsic Muscles of the Hand Smaller muscles that provide fine control of hand Responsible for flexion and extension, and abduction and adduction of the fingers at the metacarpophalangeal joints Responsible for opposition and reposition of the thumb These muscles are found mostly in the palm or the back of the hand
Extrinsic Muscles of the Hand Flexor muscles Flexor digitorum superficialis: flexion at the wrist and some digits Flexor digitorum profundus: flexion at the wrist and some digits Flexor pollicis longus: flexion of the thumb
Tendon of biceps brachii Median nerve Pronator teres (cut) Brachial artery Radius Ulna Brachioradialis (retracted) Flexor carpi ulnaris (retracted) Flexor digitorum superficialis Flexor pollicis longus Flexor digitorum profundus LATERAL MEDIAL Anterior view of the middle layer of muscles. The flexor carpi radialis muscle and palmaris longus muscle have been removed.
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Supinator Brachialis Cut tendons of flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Pronator quadratus (see Figure 11.8f) LATERAL MEDIAL Anterior view of the deep layer of muscles
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Extrinsic Muscles of the Hand (continued) Extensor/Abductor Group Abductor pollicis longus: abduction of thumb Extensor digitorum: extension of fingers and wrist Extensor pollicis brevis: extension of thumb, abducts the wrist Extensor indicis: extension and adduction of index finger Extensor digiti minimi: extension of little finger, extension of wrist
37 Summary for extensors of digits
Anconeus Extensor digitorum Extensor digiti minimi Tendon of extensor pollicis longus Abductor pollicis longus Extensor pollicis brevis MEDIAL LATERAL Posterior view of the middle layer of muscles
Anconeus Supinator Ulna Abductor pollicis longus Extensor pollicis longus Extensor indicis Extensor pollicis brevis Radius Tendon of extensor digiti minimi (cut) Tendon of extensor digitorum (cut) MEDIAL LATERAL
Intrinsic Muscles of the Hand Thenar Muscles Adductor pollicis : adducts the thumb Abductor pollicis brevis: abducts the thumb Opponens pollicis: opposition movement of the thumb Flexor pollicis brevis: flex and adduct thumb Hypothenar Muscles Flexor digiti minimi brevis: flex little finger Opponens digiti minimi: brings digits into opposition with the small digit Abductor digiti minimi: abducts little finger Palmaris brevis: moves the skin on the medial side of the palm
Intrinsic Muscles of the Hand Midpalmar Muscles Lumbricals: flexion of the digits at metacarpophalangeal joints Dorsal interosseus: abduction of digits 2 4 Palmar interosseus: adduction of digits 2, 4, and 5
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Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis Synovial sheaths First dorsal interosseus Tendon of flexor pollicis longus Lumbricals Palmar interosseus Tendons of flexor digitorum (both profundus and superficialis) Opponens digiti minimi Flexor digiti minimi brevis Palmaris brevis (cut) Abductor digiti minimi Flexor retinaculum Adductor pollicis Flexor pollicis brevis Opponens pollicis Abductor pollicis brevis Tendon of palmaris longus Tendon of flexor carpi radialis Tendon of flexor carpi ulnaris Anterior (palmar) view
Figure 11.11a Intrinsic Muscles, Tendons, and Ligaments of the Hand Tendon of extensor indicis First dorsal interosseus muscle Tendon of extensor pollicis longus Tendon of extensor pollicis brevis Tendon of extensor carpi radialis longus Tendon of extensor carpi radialis brevis Tendon of extensor digiti minimi Abductor digiti minimi Tendon of extensor carpi ulnaris Extensor retinaculum Posterior (dorsal) view